HomeMy WebLinkAbout2000-04-18 AdjournedRIVANNA WATER 8: SEWER AUTHORITY
P. O, BOX 18 · CHARLOTTESVILLE. VIRGINIA 22902-00'1B · (804) 977-2970
PUBLIC INFORMATION MEETING
Water Supply Project: Alternatives Analysis
Sponsored by: Rivanna Water & Sewer Authority
Tuesday, April 18, 2000
LOCATION: CITY OF CHARLOTTESVILLE CITY COUNCIL CHAMBERS
TIME: 6:30 PM TO 10:00 PM
AGENDA
OPEN FORUM
0 Review Materials/Boards
<) Informally Talk with RWSA Staff and Consultant Team
6:30 - 7:30
H. WELCOME - Arthur Petrini (RWSA Executive Director)
7:30
IH.
OPENING REMARKS - Jack Marshall (RWSA Board Chairman)
0 Decision Making Process at the Local Level
7:35 ,- 7:45
IV.
INTRODUCTION - Nancy Barker (VItB) and William Ellis (MB&C)
0 Purpose of the Meeting
0 Regulatory Process
7:45 - 8:10
ALTERNATIVES OVERVIEW - George Rest (O'Brien & Gere)
0 Highlights of Alternatives
8:10 - 8:50
VI. PUBLIC INPUT/QUESTIONS AND ANSWERS
8:50 - 9:55
VII. NEXT STEPS - William Ellis
9:55
Vawill\projects\30502\wp\mist\pi041800agenda
SERVING CHARLOTTESVILLE & ALBEMARLE COUNTY
RIVANNA WATER & SEWER AUTHORITY
P. O, BOX 18 ' CHARLOTTESVILLE. VIRGINIA 22902-OO18 · (804) 977-2~70
MEMORANDUM
TO:
FROM:
DATE:
SUBJECT:
CHARLES MARTIN, CHAIR, BOARD OF SUPERVISORS
DR. JACK MARSHALL, CHAIRMAN, BOARD OF DIRECTORSp]~,~
APRIL 5, 2000
PUBLIC MEETING ON THE COMMUNITY'S FUTURE WATER
SUPPLY
I would like to personally invite you to attend the public meeting this month on our
Future Water Supply. The meeting, sponsored by the Rivarma Water and Sewer
Authority, will be held on Tuesday evening, April 18, in the Council Chambers of the
Charlottesville City Hall.
,Beginning at 6:30 p.m. we'll have an hour to view displays about the water supply
alternatives, and to talk informally with RWSA staff and our consultants from Vanasse
H~ih~n Bru~st~flTn-(VHB).--At 7~0-~wfllpreserrt-wsunmmi~y-of their-most up-to--date
analysis of the alternatives. From about 8:30 the meeting will be open to questions and
comments from the public.
I believe it is important that local elected officials stay informed as we obtain and
examine new data about the 30-some water supply alternatives; it is also valuable to be
aware of the questions and concerns raised by local citizens.
Shortly after this meeting we must begin to pare down the alternatives; your informed
opinions will help us.
I hope you will be able to participate in the April 18, meeting. If you have any questions
before or after it, please do not hesitate to contact me (phone: 974-6390; e-mail:
criiack~cville.net).
Jm/csw
S:\LeEers & Memos\Carol'u~nvitation to BOS FWSM apirl t8, 2000 Jack M..doc
~ERVING CHARLOTTESVILLE & ALBEMARL~E COUNTY
Public Information
Meeting
April 18, 2000
Sponsored by: Rivanna Water &
Sewer Authority
/
/
/
//
McSweeney Burtch &
Crump, P.C.
O'Brien & Gere
Engineers, Inc.
WATER SUPPLY STUDY
The Rivanna Water and Sewer Authority (RWSA) is responsible for providing potable water to the Albemarle
County Service Authority and the City of Charlottesville Public Works Department who then distribute the
water to their respective customers. The following information is a synopsis of the ongoing water supply
study being conducted on behalf of the RWSA by the firms of Vanasse Hangen Brustlin, Inc., O'Brien &Gere
Engineers, Inc., and McSweeney Burtch and Crump, P.C.
PLANNING HORIZON: Year 2050 STUDY AREA:
SUMMARY OF WATER SUPPLY AND WATER DEMAND ANALYSIS
"Urban Service Area"
City of Charlottesville and portions of Albemarle County
There are currently three sources of raw water for customers in the Urban Service Area: 1) South Fork Rivanna River Reservoir. 2) the Sugar
Hollow Resewoir and Ragged Mountain Reservoir system, and 3) an intake at the North Fork of the Rivanna River. As of the 1997 analysis,
the "safe yield" of this system (the amount of water that can be safely withdrawn during a severe drought) was between 12 and 13 million
gallons per day (mgd).
In the fall of 1997, the study team published the results of their water supply and water demand analyses which included projections of
available water supply and anticipated water demand within the Urban Service Area in the year 2050. Based on the results of the supply
analysis, the safe yield of the existing water supply system is expected to decrease to approximately 4.5 mgd in 2050 primarily as a result of
sedimentation in the South Fork Rivanna River Reservoir. Using four different approaches, the study team also projected the amount of water
to be used in the future by customers within the Urban Service Area. Based on the results of this analysis, water demand in the year 2050 is
expected to be between 18 to 21 mgd. Combining the results of the water supply and the water demand analysis, a future water deficit of
approximately 15 mgd is being used for the ongoing planning efforts.
To meet future water needs, the study team developed the following range of alternatives which may be implemented either alone or in
combination with each other. These alternatives are described in greater detail in the report entitled 'l/rater Supply Project - Analysis of
Alternatives", dated February 2000.
ALTERNATIVES UNDER CONSIDERATION
I. Improvements to ExiSting Water Resources
Alternatives that Increase Water Supply
A. South Fork Rivanna Reservoir
Dredge South Fork Rivanna Reservoir- Dredging of accumulated sediments from the reservoir either as a single event prior
to 2050 (returning it to its original storage capacity) or as part of an annual dredging program (gradually increasing the storage
volume).
2. Reduce Sediment Load into South Fork Rivanna Reservoir - Implementation of watershed protection measures aimed at
reducing the amount'of sediment transported to the reservoir. Considered two specific options: 1) construction of additional
regional stormwater management ponds {BMP's) to capture and treat 50% of volume entering the reservoir and 2) modifying
the existing Water Protection Ordinance to expand buffer requirements in agricultural areas from 25 feet to 50 feet.
3. Alternate Release Scenario at South Fork Rivanna Reservoir- Revision of current release regime at S. Fork Rivanna dam
such that natural stream flow would not be augmented during severe drought conditions.
4. Add Crest Controls on South Fork Rivanna Dam - Considered two options - the addition of four-foot and eight-foot crest
controls on existing dam to increase the normal pool elevation of the reservoir by four feet and eight feet respectively.
5. Use South Fork Rivanna Reservoir as Pumped Storage Reservoir- Removal of water from the Rivanna River during high
flow conditions and pumping it to the existing S. Fork Reservoir for storage.
B. Chris Greene Lake
Use Lake to Supply N. Fork Rivanna Water Treatment Plant- During severe drought conditions, convey water from Chris
Greene Lake to the North Fork Rivanna WTP (through either pipeline or direct discharge into N. Fork Rivanna River) in order
to supplement the existing N. Fork Rivanna River water system. Considered two levels of lake drawdown: 1) a 5-foot
drawdown and 2) a drawdown of up to 20-feet.
Use Chris Greene Lake as Pumped Storage Facility - Removal of water from the North Fork Rivanna River during high flow
conditions and pumping it to Chris Greene Lake for storage.
C. Beaver Creek Reservoir
8. Use Beaver Creek Reservoir to Supplement Flows in Mechums River- Conveying water from Beaver Creek Reservoir to
the Mechums River during severe drought conditions to supplement flows to the S, Fork Rivanna Reservoir.
D. Sugar Hollow/Raqqed Mountain Reservoir System
9. Dredge Sugar Hollow Reservoir - A one-time dredging of Sugar Hollow Reservoir to remove debris deposited in the 1995
landslide and any accumulated sediment.
10. Conversion of Ragged Mountain to Pumped Storage Reservoir - Withdrawal of water from the Mechums River at the site
of the abandoned pump station during conditions of high flow. Water would be pumped to an expanded Ragged Mountain
Reservoir System. Would include raising dam at Lower Ragged Mountain Reservoir by 50' to increase storage vo(ume. Would
also require rehabilitation of the pump station and intake.
E. Indirect Reuse
11. Pumpback to Mechums River - Pumpback of treated effluent from the Moore's Creek wastewater treatment plant to the
headwaters of the Mechums River via a new pipeline (12.5 miles). The discharge would flow 13 miles to then augment flow
into the South Fork Rivanna River Reservoir.
12. Pumpback to Moorman's River - Pumpback of treated effluent from the Moore's Creek wastewater treatment plant to the
Uoormans River via a new pipeline (22 miles). The discharge wouJd flow 16 miles to then augment flow into the South Fork
Rivanna River Reservoir,
Alternatives that Manage Water Demand
F. Demand Manaqement
13. Water Conservation - Development and implementation of a long-term water conservation program including plumbing
fixture changeout, a revised pricing structure and public education/awareness programs.
14. Growth Management - Attempt to slow population growth in the Albemarle County portion of the Urban Service Area to
reduce future water demand.
G. Drought Manaclement Plan
15. Mandatory Water Use Resb'ictions - Development and implementation of a drought management plan including mandatory
water use restrictions during severe drought conditions, i.e. bans on car washing, landscape irrigation, filling of pools, etc.
16. Water Supply System Management/Operations - The synergistic operation of the existing reservoirs - storage volume ~n
the Ragged Mountain would be preserved by increasing operating levels of the S. Fork Rivanna treatment plant.
H. Leak Detection and Control
17. Leak Detection and Meter Change Out/Calibration- Evaluation of leak detection/meter calibration programs implemented
by the Albemarle County Service Authority and the City of Charlottesville who distribute finished water to the end users.
I1.
Physical Additions to the Existing Water Supply System
I. Groundwater
18. Aquifer Storage and Recovery - Storage of treated water in a suitable aquifer when water supply exceeds demana, and
subsequent recovery of water during drought conditions.
] ~). Conventional Withdrawal -Conventional withdrawal of groundwater via installation of approximately 15 wells and then piping
water to existing water treatment plants.
J. Reservoirs
20. Buck Mountain Creek - Construct a dam and 670-acre reservoir on Buck Mountain Creek 1.5 miles upstream of confluence
of Buck Mountain Creek and the S. Fork Rivanna River Reservoir.
21. Preddy Creek - Construct a dam and 932-acre reservoir on Preddy Creek 2.5 miles northeast of the North Fork Rivanna
water treatment plant.
22. Moormans River Reservoir - Construct a dam and 817-acre reservoir on the Moormans River just downstream of its
confluence with the Doyles River.
23. North Fork Rivanna River - Construct a dam and 1,057-acre reservoir on the North Fork of the Rivanna River 2 miles west of
the North Fork Filtration Plant.
24. Mechums River Near Lake Albemarle - Construct a dam and 973-acre reservoir on the Mechums River 0.5 miles northeast
of Batesville.
25. Mechums River Near Midway- Construct a dam and 477-acre resewoir on the Mechums River 1 mile upstream of the 1-64
crossing near Midway.
26. Buck Island Creek- Construct a dam and 1,707-acre reservoir on Buck Island Creek 0.5 miles upstream of Route 53.
Surface Water Withdrawals
27. James River at Scoffsville - Withdrawal of water from the James River at Scottsville and pumping it through a new pipeline
(29 mitesl to the South Fork water treatment plant.
28. RJvanna River - Withdrawal of water from the Rivanna River near the Glenmore Country Club via a 2-mile pipeline and
treating it in a new water treatment plant.
Mechums River- Withdrawal of water from the Mechums River at the site of the abandoned pump station during conditions of
high flow. Water would be pumped to the Ragged Mountain Reservoirs. Would require rehabilitation of the pump station and
intake.
L. Re.qional Cooperation
30. Rapidan Service Authority - Based on coordination with neighboring water providers, the best prospect for regional
cooperation is with the Rapidan Service Authority (RSA}. Rather than identifying a surplus of water for possible use by RWSA,
the Rapidan Service Authority identified a long-term need for additional water. This alternative consists of the intemonnection
between RWSA's system and the RSA's system wa p,peline whereby the RWSA would supply water to the neighboring
Authority. This would increase the future water supply deficit for the RWSA.
III. No Action
31. No Action - No measures taken to either increase safe yield or reduce water demand.
ALTERNATIVES EVALUATION
The alternatives described above have been studied in terms of their ~safe yield"; their cost and practicability, as well as their potential for
impacts to sensitive natural and cultural resources. A matrix summarizing the information developed and collected to date for each alternative
is attached.
From the analyses conducted to date, it appears that a diverse range of options are available to the community including both stand-alone
projects or combinations of altematives. Some alternatives do not appear to hold much promise for contributing to an overall solution to
meeting future water needs in the Urban Service Area: using S. Fork Rivanna Reservoir or Chris Greene Lake as pumped storage facilities,
using Beaver Creek Reservoir, dredging Sugar Hollow Reservoir, groundwater, withdrawing surface water from the Mechums River, regional
cooperation, and "no-action~, These alternatives are either impracticable or do not adequately contribute to meeting the projected 2050 water
deficit.
The Rivanna Water and Sewer Authority is interested in receiving comments from the public on the water supply study. Written comments
should be sent to: Mr. Arthur Petrini, Rivanna Water and Sewer Authority, 200 Franklin St., Charlottesville, VA 22901
For more information on the Water Supply Study or to obtain copies of the reports referred to in this synopsis, please
contact the RWSA at (804) 977-2970 ext. 101
RIVANNA WATER SEWER AUTHORITY
WATER SUPPLY ALTERNATIVES MATRIX
INCREASE IN ESTIMATED ANNUAL UNIT COS~ POTENTIAL # OF POTENTIAL IMPACTS TO PREVIOUSLY PREVIOUSLY APPROXIMATE
ALTERNATIVE 2050 SAFE YIELD COST ($) O&M COST ($) (S/g)* RESIDENTIAL IDENTIFIED CULTURAL RESOURCES, IDENTIFIED T & E WETLAND IMPACTS
. . (mgd) DISPLACEMENTS ,STRUCTURES ARCHAEOLOGICAL SPECIES in vicinity (Acre~)
Dredge South Fork
Rivanna Reservoir
--Single Event 7.2 $ 71,000,000 n/a $9,86 0 i) 0 0 5
--Annual Dredging 7.2 $ 7,200,000 $ 800,000 $1.00 0 0 0 0 " 5
Reduce Sediment Load
into South Fork
Rivanna Reservoir
--B MPs 2 $ 8,800,000 n/a ~.40 0 0 0 0
--Land Use Controls ,2, $ 16,0(g),o~) n/a ,$8.00 . 0 0 0 0 0
Alternate Release -
Scenarios at South
Fork Rivanna Reservoir 1.6 $ 386,000 n/a $0.24 ....
0 0 0 0 minimal
Add 4 ft. Crest Controls on
~;outh Fork Rivanna Dam 7 $ 2,260,¢g}0 n/a $0.32 2 I ! James spinymussel 18
Add 8 ft. Crest Controls on
South Fork Rivanna Dam 11 $ 18,300,000 I n/a $1.66 2 I I James spinymussel 39
Use South Fork
Rivanna Reservoir as a
Pumped Storage Reservoir 0 n/a n/a Ida 0 (} 0 0 minimal
Up tO 5 ft. Drawdown of Chris
Greene Lake 2.9 $ 7,400.000 not si~gnificant $2.55 0 0 0 0 minimal
20 ft. Draw Down of Chris
Greene Lake . 5.5 $ t4,700,000 not significant $2.67 0 0 0 0 minim~l/temporar~
Use of Chris Greene Lake
as a Pumped Storage
Reservoir o n/a n/a n/a 0 0 0 o minimal
Use Beaver Creek
Reservoir to Supplement
Flows in Mechums River 0 $ 50[),000 tlot significant n/a 0 0 0 0 minimal
Dredge Sugar Hollow
Reservoir 0.1 $, 4,9(X),000 nul ~i~nlflcant $49 0 0 0 0 2
Conversion of Ragged Mtn.
to Pumped Storage Reservoir
10 $ 47,000,000 not significant $4.70 I 0 0 0 5
Pumpback to Mechums
giver tS $ 56,000 000 $ 150,000 $3.73 0 unknown unknawn James spiaymusael 2
Pumpback to Moormans
River 1~ $ 69,0{R),000 $ 280,000 $4.60 0 unknown unknown James spinymussel 5
*[Inlt nn~f h~ad nnht nn o~nH'~! ono~- ~ .... II~ "
y per gallon.
Does not include effects of annual operations and maintenance costs,
\\WILLVA\PROJECTS\30502\SHEETS\SAlternmatrix\Sheetl
RIVANNA WATER SEWER AUTHORITY
WATER SUPPLY ALTERNATIVES MATRIX
REDUCTION ESTIMATED ANNUAL UNIT COST POTENTIAL # OF POTENTIAL IMPACTS TO PREVIOUSLY PREVIOUSLY APPROXIMATE
ALTERNATIVE IN COST ($) O&M COST (S/g)* RESIDENTIAL IDENTIFIED CULTURAL RESOURCES IDENTIFIED T & E WETLAND IMPACTS
DEMAND.,(,m§d) DISPLACEMENTS STRUCTURES ARCHAEOLOGICAL SPECIES in vicinity (Acres)
Water Conservation
--Plumbing Changeout 1.13 o n/a 0 0 o 0 0 o
--Pricing Structure 0.13 unknown fda n/a 0 0 0 0 0
--CommdIndustrial 0.28 0 fda 0 0 0 0 0 0
--LandseapingfXeriseaping 0 fda n/a fda 0 0 0 0 0
--Education o. 13 $ 2,500,000 n/a $19.23 0 0 0 0 0
--System Pressure Reduction 0 n/a n/a n~a 0 0 0 0 0
Growth
Management 1.7 unknown n/a n/a 0 0 0 0 0
Drought Management
Demand Side 1A $ 250,000 n/a $0. i8 0 0 0 0 0
Drought Management
Supply Side I unknown n/a n/a 0 0 0 0 0
Leak Detection and
Meter Calibration o r~a n/a n/a 0 0 0 0 o
capital per gallon.
Does not include effects of annual operations and maintenance costs.
\\WILLVA\PROJECTS\30502\SH EETS\3AItemmat rix\Sheet i (2)
RIVANNA WATER SEWER AUTHORITY
WATER SUPPLY ALTERNATIVES MATRIX
INCREASEIN ESTIMATED ANNUAL UNITCOST , POTENTIAL#OF POTENTIAL IMPACTS TO PREViOUSL-'~y PREVIOUSLy APPROXIMATE
ALTERNATIVE ao$o SAFE YIELD COST ($) O&M COST ($) ($]gallon)* RESIDENTIA£
~ IDENTIFIED CU.] .TURAL RESOURCES _ IDENTIFIED T & E WETLAND IMPACTS
--__ _ _ DISPLACEMENTS ~ STRUCTURES ARCHAEOLOGICAL SPECIES in vicinit. _ (Acres)
Aquifer Storage -- -- _ __
& Recovery...__._~ 0 n/a n/a ./a ./a n/a
Conventional Withdrawal of -- ,~/a
Groundwater 0.1 $ 1,200,000. fda $12 0 0
Construct Dam on ~ __ o o o
Buck Mountain Creek 14.4 $ 57,000,000 not sign/ficant 33.96 1 6
Construct Dam on 0 James splnynlussel 59
~k 6.4 $ 91,000,000 ~ $14.22 6 7 0
Construct Dam on ~ 0 77
Moormans River li.a $ 106,000,000_ ~ $9.14 22 14 1
Construct Dam on - - ~ 0 68
North Fork Rivanna River 1~.4 $ 79,0~0,000 ~ $~.13 2 3 4
Construct Dam on -- James s ,tn- mussol _ 72
Mechums River
[~ear Lake fllbemarle 13.3 $ 68,000,000 not significant $5.11 21 15
Construct Dam on 2 James spinymussel 144
Mechums River
Near Midwa- _ 5._ 6 _ $ 26,000,000_ ~ $4.64 _ 6 6
Construct Dam on ---- o James spirit mussel - 52
Buck Is!and Creek 15 $- 118,000,0(n} not significant $7.87 14 fi
James River Withdrawal 0 0 103
at Seottsville 15 $ 72,000,(I00 $ 170,001~ $4.80 0 unknown
Rivanna River I unkn°wn 5
Withdrawal 4.7 $ 18,000,000 not significant 33.83 0 unknown
Mechums River unknown 0 2
Withdrawal
0.2 - $ ~ ~ $4.25 - 0 ~ unknown _ unknown . Jame~ spinymussel . minimal
ESTIMATED
ALTERNATIVE IN COST (3) O&M COST ($) (S/g)* RESIDENTIAL APPROXIMATE
IDENTIFIED CULTURAL RESOURCES ] IDENTIFIED T & E WETLAND IMPACTS
[Regiona--~ DEMANO (~qd) ~
DISPLACEMENTS STRI2'C'I', ~t I~g ARCHAEOLOGI _~ SPECIES in vicinity (Aer~)_..
IC°°Perati°n 3 $ 3,100,000 n/a ~ n/a 0 uaknown ~ unknown ~ 0 minimal
ALTERNATIVE
No-Action
REDUCTION I ESTIMATED [ ANNUAL
IN I COST ($) O&M COST (3)
SAFE ylt~!.n (mgd)
7.7 ! nra n/a
(S/g)* RESIDENTIAL IDENTIFIED CULTURAL RESOURCES IDENTIFIED T & E ] WETLAND IMPACTS
DISPLACEMENTS STRUCTURES ARCHAEOLOGICAL SPECIES in vic nlty
,,da 0 0 0 0 /(Acres) d
*Unit cost based only on capital cost per gallon, o
Does not include effects of annual operations and maintenance costs.
\\WILLVA\P ROJECTS\30502\SHEETS\3Aiternmat rix\Sheet I (3)
Rivanna Water and
Sewer Authority
Prelimina~'v Alte~nat~ cs {} 7111 Public [~lt:orrnation Meeti~g
April 20, 1999
Project
/
Meormans River
Re~er~o~r
Dredge Sugar
Holbw Reservoir
AUGUSTA
Mechums River
P~servoiv {Dowr~lream)
Mechums River
Res~r,~oir (Upstream)
Reh~b of Existing Pump Station
NELSON
Mechums River Wi'~orawa aha
Conversion el Ragged Moun~aies
Lo~um_ped Storage
GREENE
ORANGE
Uflizalioe of of Chris Greene Lake:
5' and 2~' Drawd~wn,
Pumged Storage
Soulh Fed( Rivama Reservoir:
4' an~ 8' Crest Gates, Revised Release
Predgi~ and Pumped Storage
LOUISA
'~' R~aP, m3 R/vet
WilhdzawaJ
Pumobac~ Io
~ums R~er
-
~ I~ Cmek
James River
~w~
/
/
Charlol;esville City L/mits
Urban Service Area
Existing Rese~voir/Water Supply
Reservoiff Water Sapply Allernalivcs
James River Withdrawal
Rivanna }-liver Withdrawal
New Intake
New Treatrnen[ Plant
New Pml~lp Statioll
New Pilxdine
/
/
/
RIVANNA WATER SEWER AUTHORITY
PRELIMINARY WATER SUPPLY ALTERNATIVES
Increase in Estimated Unit Cost
Alternative Safe Yield (mgd) Cost ($) (S/gallon) Comments
Aquifer Storage
& Recovery 0 ~ N/A N/A
Conventional Withdrawal
of Groundwater 0. l 1,200,000 12/gallon
James River Withdrawal
at Scottsville 15 72,000,000 4.80/gallon .
Rivanna River
Withdrawal 4.7 17,800,000 3.79/gallon
Mechums River
Withdrawal 0.2 850,000 4.25/gallon
Mechums River Withdraw. +
Conversion of Ragged Mtm
to Pumped Storage Reservoir 10 47,000,000 4.70/gallon
Construct Dam on
Buck Mountain Creek 14.4 57,000,000 3.96/gallon
Construct Dam on
~lorth Fork Rivanna River 15.4 79,000,000 5.13/gallon
Construct Dam on
Preddy Creek 6.4 91,000,000 14.22/gallon
Construct Dam on
Mechums River
Near Lake Albemarle ~ 13.3 68,000,000 5.11/gallon
Construct Dam on
Mechums River
Near Midway 5.6 26,000,000 4.64/gallon
Construct Dam on
Buck Island Creek 15 118,000,000 7.87/gallon
Construct Dam on
Moormans River 11.6 106,000,000 9.14/gallon
No Action 0
\\WillvakProjects\30502\Sheets\Alternative Comments 3\Sheet 3
4/12/99 @ 9:15 AM
RIVANNA WATER SEWER AUTHORITY
PRELIMINARY WATER SUPPLY ALTERNATIVES MATRIX
INCREASE IN ESTIMATED UNIT COST POTENTIAL ,9 OF POTENTIAL IMPACTS TO PREVIOUSLY PREVIOUSLY Al'PROXIMATE
ALTERNATIVE z0s0 SAFE YIELD COST ($) (S/g) RESIDENTIAL IDENTIFIED CULTURAL RESOURCES IDENTIFIED T & E WETLAND IMPACTS
(rngd) DISPLACEMENTS STRUCTURES ARCHAEOLOGICAL SPECIES in vicinity (Acres)
Dredge South Fork I
Rivanna River Reservoir l0 112,000,000 $11,20/gallon 0 0 0 5
Decrease Sediment Load
into South Fork To be
Rivanna River Reservoir Determined
Revise Downstream
Release Regime at South
Fork Rivanna River Reservoir 3.8 386,000 $0.12/gallon 0 0 0 0
Add 4 ft. Crest Controls on
South Fork Rivanna Dam 6 4,300,000 $0.72/gallon 2 I I James Spiuy Mussel 18
Add 8 ft. Crest Controls on
South Fork Ri vanna Dam I I 14,700,000 $1.34/gallon 2 I I James Spiny Mussel 39
Utilize South Fork
Rivanna River Reservoir as a
Pumped 'Storage Reservoir 0 0 0 0 miuimal
5 ft. Drawdown of Chris
Greene Lake 3 7,400,000 $2.47/gallon 0 0 0 minimal
20 it. Draw Down of Chris
Greene Lake 5.5 14,000,000 $2.54/gallon 0 0 0 minimal
Utilize Chris Greene Lake
as a Pumped Storage
Reservoir 0 0 0 0 minimal
Dredge Sugar Hollow
Reservoir o. I 7,400,000 $74/gallon 0 0 0 2
Pumpback to South Fork
Rivanna River Reservoir 15 56,000.000 $3.73/gallon 0 0 0 James Spiny Mussel 2
\\WlLLVA\PROJECTS\30502\SHEETS\3AIternmatrix\Sheetl 4/12/99 @ 9:15 AM
RIVANNA WATER SEWER AUTHORITY
PRELIMINARY WATER SUPPLY ALTERNATIVES MATRIX
REDUCTION ESTIMATED UNIT COST POTENTIAL # OF POTENTIAL IMPACTS TO PREVIOUSLY PREVIOUSLY APPROXIMATE
ALTERNATIVE IN COST ($) (S/g) RESIDENTIAL IDENTIFIED CULTURAL RESOURCES IDENTIFIED T & E WETLAND IMPACTS
DEMAND (mgd) DISPLACEMENTS STRUCTURES ARCHAEOLOGICAL SPECIES in vicinity (Acres)
Water Conservation
--Plumbing Fixture I..~ o o o o o
--Comm./Industrial 0.08
--Education 0.17 2,500,000
Drought Management
Demand Side 2.4 0 0 0 0
Drought Management
Supply Side ~ 0 0 0 0
Leak Detection and
Meter Calibration Not applicable 0 0 0 0
Growth
Mana[~ement 1.7
INCREASE ESTIMATED UNIT COST POTENTIAL # OF POTENTIAl. IMPACTS TO PREVIOUSLY PREVIOUSLY APPROXIMATE
ALTERNATIVE IN COST ($) (S/g) RESIDENTIAL IDENTIFIED CULTURAL RESOURCES IDENTIFIED T & E WETLAND IMPACTS
DEMAND (mgd) DISPLACEMENTS STRUCTURES ARCHAEOLOGICAL SPECIES in vicinity (Acres)
Regional
Cooperation 3
\\WILLVA\PROJECTS\30502~SHEETS\3AIternmatrix\Sheetl (2) 4/12/99 @ 9:15 AM
RIVANNA WATER SEWER AUTHORITY
PRELIMINARY WATER SUPPLY ALTERNATIVES MATRIX
INCREASE IN ESTIMATED UNIT COST POTENTIAL # OF POTENTIAL IMPACTS TO PREVIOUSLY PREVIOUSLY Al'PROXIMATE
ALTERNATIVE 2o5o SAFE YIELD COST ($) (S/gallon) RESIDENTIAL IDENTIFIED CULTURAL RESOURCES IDENTIFIED T & E WETLAND IMPACTS
(mgd) DISPLACEMENTS STRUCTURES ARCHAEOLOGICAL SPECIES in vicinity (Acres)
Aquifer Storage
& Recover), 0 Not applicable Not applicable
Conventional Withdrawal of
Groundwater o. I 1,200,000 $12/gallon 0 0 0 minimal
James River Withdrawal
at Scottsville 15 72,000,000 $4.80/gallon 0 I I 5
Rivanna River
Withdrawal 4.7 17,800,000 $3.79/gallon 0 0 0 2
Mechums River
Withdrawal 0.2 850,000 $4.25/gallon 0 0 0 minimal
Mechums River Withdraw. +
Conversion of Ragged Mtn.
to Pumped Storage Reservoir 10 47.000,000 $4.70/gallon I 0 0 5
Construct Dam on
Buck Mountain Creek 14.4 57,000,000 $3.96/gallon I 6 0 James Spiny Mussel 59
Construct Dam on
North Fork Rivanna River 15.4 79,000,000 $5.13/~allon 2 3 4 72
Construct Dam on
Predd), Creek 6.4 91,000,000 $14.22/gallon 6 7 0 77
Construct Dam on
Mechums River
Near Lake Al bernarle 13.3 68,000,000 $5.1 I/gallon 21 18 I James Spiny Mussel 107
Construct Dam on ,
Mechums River
Near Midway 5.6 26.000,000 $4.64/gallon 6 7 0 Jmnes Spiny Mussel 52
Construct Dam on
Buck Island Creek 15 118,000,000 $7.87/gallon 14 6 0 103
Construct Dam on
Moormans River 11.6 106,000.000 $9.14/gallon 22 14 I 68
No Action 0 0 0 0 0
\\WlLLVA\PROJECTS\30502\SHEETS\3AIternmatrix\Sheetl (3) 4/12/99 @ 9:15 AM
AssumPtions
All pricing is in current dollars 0anuary 1999)
Costs are based on an "order of magnitude" estimate
Cost for property acquisition based on $11,000/ acre ($8,000/acre for wetland mitigation)
Cost estimates include:
15% engineering/legal/administrative fees
20% contingency
Costs for water distribution system improvements are not included
Transportation costs are not included except where noted otherwise
Wetland mitigation costs are included in the cost estimate and are based on approximate
wetland impacts
Cost estimates do not include costs associated with mitigation for threatened/endangered
species and cultural resources
7QlO or 30% mean annual flow is adequate to meet agency requirements
Pipeline alignments are conceptual and for cost estimating purposes only
Peaking factor of 1.5 used to size the waterworks facilities where appropriate
Operation and maintenance costs not included
8
w~ttva\ 30502ho.p65
Dredging South.
Reservoir
River
Dredging of bottom sediments in the middle and upper reaches of the reservoir
approximately three times through 2'050, .each time returning the reservoir to
it's original storage disposal of dredged spoil.
Includes 3 mgd expansion of South Fork Rivanna water treatment plant, raw
and finished water pump stations.
· Increase in 2050 safe yield-10 million gallons per day
· Estimated cost- $112 million through 2050
· Locating suitable sites for dredge spoil disPosal poses challenge
· Approximately 100 acres 'of land needed per dredging event
· Temporary water quality impacts
Direct impact to 5 acres of wetlands; additional impacts to shallow water habitat
No anticipated impacts to cultural resources and threatened/endangered species
· No residential displacements
9
wilDa\ 30502ho.p65
Decreas
South FOrk Rivanna River
Implementation of watershed protection measures within the South Fork
Rivanna River Reservoir watershed which encompasses over 260 square miles.
May include construction of regional stormwater managementponds on target
watersheds, the effects of a new Water Protection Ordinance adopted in 1998,
and possible expansion of stream buffer requirments.
· Increase in 2050 safe yield for regional stormwater management ponds alone- million
gallons per day
· Increase in 2050 safe yield for ordinance alone- __ million gallons per day
· Increase in 2050 safe yield for both regional ponds and expansion of stream buffer
requirements- million gallons per day
· Estimated cost- $ million for regional ponds
· Estimated cost for implementation and expansion of stream buffer requirements- $
· Target sites suitable for regional stormwater management ponds
· Environmental benefits to water quality
· Approximately acres of wetland impacts for regional ponds
· May require surveys for threatened/endangered species and cultural resources
· Assumed approximately 50% sediment removal efficiency for regional ponds based on
preliminary results of Lickinghole Creek basin monitoring
1 0 willva\ 30502ho.p65
Decrease Sedi
(continued...)
ad into
ervoir
Assumed % removal of sediment load for watershed protection measures implemented as
a result of the watershed protection, ordinance
No anticipated residential diSplacements.
Impacts to private property, in the form of reduced agricultural land
11
willva\ 30502ho.p65
Revise 'DoWnstream Release at
South Fork Rivanna River Reservoir
Presently, the release regime at South Fork Rivanna River Reservoir would
consist of augmenting natura{ streamflows during severe drought conditions.
The revised release scenario would be operated such that the natural stream-
flow would not be augmented during severe drought conditions. Includes
installation of stream gages on major reservoir tributaries as well as controls/
valves on the existing dam.
· Increase in 2050 safe yield- 3.8 million gallons per day
· Estimated cost- $ 386,000
· Minimal environmental impacts over long term
· Downstream habitat assessment may be required
· No anticipated impacts to cultural resources and threatened/endangered species
· No residential displacements
12 wi,va~ 30502ho.p65
4' Crest
Rivanna Dam
Addition of four-foot crest con,trois to increase the normal poot elevation from
382feet to 386feet. Requires'rePlacement of Route 676 bridge over Ivy Creek
and acquisition of land around the reservoir. Assumed no discharge, of fill mate-
rial into jurisdictional areas and therefore no requirements for wetland mitiga-
tion.
· Increase in 2050 safe yield- 6 million gallons per day
· Estimated cost- $4.3 million
· Increases useable storage volume by 600 million gallons
· Increase in storage volume reduces rate of system storage loss over time
· Purchase of approximately 70 acres of land surrounding reservoir
· Requires alteration to existing FERC license exemption
· Approximately ~/acres of wetlands inundated by new pool
· James spiny Mussel previously identified in vicinity; would need to examine potential
impacts
· Possible impact to one previously identified archaeological site (eligibility not determined);
additional archaeological surveys may be required
· Potential indirect impact to one previously identified historic structure (eligibility not deter-
mined); additional architectural surveys may be required
· Possible displacement of 2 residences
· Possible impacts to private property around reservoir such as docks, boat houses, etc.
13
wiltva\ 30502ho.o65
on South FOrk
Rivanna Dam
Addition of eight-foot crest controls to increase the normal pool elevation from
382feet to 390feet. Requires replacement of Route 676 bridge over Ivy Creek
and acquisition of land around the reservoir. Includes 4.5 mgd expansion of
South Fork Rivanna Reservoir intake, plant and pump stations. Assumed no
discharge of fill material into jurisdictional areas and therefore no require°
ments for wetland mitigation.
· Increase in 2050 safe yield- 11 million gallons per day
· Estimated cost- $14.7 million
· Increases useable storage volume by 1,300 million gallons
· Increase in storage volume reduces rate of system storage loss over time
· Purchase of approximately 170 acres of land surrounding reservoir
· Requires alteration to existing FERC license exemption
· Approximately 39 acres of wetlands inundated by new pool
· James spiny Mussel previously identified in vicinity; potential effects undetermined
· Possible impact to one previously identified archaeological site (eligibility not determined);
additional archaeological surveys may be required
· Potential indirect impact to one previously identified historic structure (eligibility not
determined); additional architectural surveys may be required
· Possible displacement of 2 residences
· Possible impacts to private property around reservoir such as docks, boat houses, etc.
14
wttiva\ 30502ho.
South F
Pumped Storage Reservoir
tzS
High flow skimming from the Rivanna River into the South Fork Rivanna River
Reservoir. Includes a new pump station and new intake on the Rivanna River
just downstream of the confluence of the North and South Forks of the Rivanna
River. The drainage,area of the Rivanna River at the intake is approximately
450 square miles. No withdrawal to occur when flow in the Rivanna River drops
below 30% of mean annual flow.
· Increase in 2050 safe yield- 0 million gallons per day
· Insufficient flow exists in Rivanna River when South Fork Rivanna River Reservoir has
available volume to re£fll
· No storage available in reservoir during non-drought conditions
· Sedimentation into reservoir results in continued reduction in available storage
· Minimal wetland impacts
· No anticipated impacts to cultural resources and threatened/endangered species
· No residential displacements
15
willva\ 30502ho.965
of Chris Greene Lake to'
Convey water from Chris Greene Lake to the North FOrk Rivanna water treat-
ment plant during severe drought conditions to supplement the North Fork
Rivanna River water system. Would be limited to a 5-foot drop of Pool elevation.
Includes a 3.2~mgd expansion of the North~Fork Rivanna finished water pump
station and water treatment plant. Chris Greene Lake 'is a 52-acre impoundment
with storage volume of 334 million gallons.
· Increase in 2050 safe yield- 3 million gallons per day
· Estimated cost- $7.4 million
· Would require coordination to address prior use of Land and Water Conservation Funds
· Currently designated a water supply protection area
· Currently used for swimming, fishing and boating
· Frequency of occurrence: approximately once every decade
· Possible impacts to existing recreational activities during drawdown
· Anticipate minimal environmental impacts
· No anticipated impacts to cultural resources and threatened/endangered species
· No residential displacements
16 wiliva', 30502ho. D65
Suppleme
to
Rivanna River
Convey water from Chris Greene Lake to the North Fork Rivanna water treat-
ment plant duri~ng severe drought conditions to supplement the North Fork
Rivanna River water systemi Would allow for a maximum drawdown of 2O feet.
Includes a 7.2 mgd expansiOn of the North Fork Rivanna finished water pump
station and water treatment plant.
· Increase in 2050 safe yield- 5.5 million gallons per day
· Estimated cost- $14 million
· Would require coordination to address prior use of Land and Water Conservation Funds
· Greater drawdown could have significant recreational impacts
· Potential impacts to fish populations
· No anticipated impacts to cultural resources and threatened/endangered species
· No residential displacements
17
wdlva\ ~502ho. P65
Use Lake as
Storage Reservoir
High flow skimming from the North Fork Rivanna River into Chris Greene Lake
via a river intake and pump station. During drought conditions, raw water
would be conveyed from Chris Greene Lake to the North Fork Rivanna water
treatment plant. No skimming to occur when flow in the Rivanna RiVer drops
below 30% of mean annual flow.
Increase in 2050 safe yield- 0 million gallons per day
Insufficient flow in North Fork Rivanna River when Chris Greene Lake has available volume
to refill
No available storage in reservoir during non-drought conditions
Minimal wetland impacts
No anticipated impacts to cultural resources and threatened/endangered species
· No residential displacements
1 ~ willva\ 30502ho.p65
Dredging of landslide debris and bottom sediments in the reservoir once
through 2050. Requires disposal of dredge spoil but minimal dewatering. During
drought conditions, the additional volume would be released to the South Fork
Reservoir or diverted to tbe~Ragged Mountain Reservoirs.
· Increase in 2050 safe, yield- 0.1 million gallons per day
· Estimated cost- $7.4 million
· Locating suitable sites for dredge spoil disposal poses challenge due to topography
· Approximately 25 acres of land needed for disposal
· Temporary water quality impacts
· Direct impact to 2 acres of wetlands; minimal impacts to shallow water habitat
· No anticipated impacts to cultural resources and threatened/endangered species
· No residential displacements
,19
wdlva\ 30502ho.p65
Pumpback to South
Reservoir (Indirect Re-Use)
Pumpback of treated effluent from the Moore's Creek waste water treatment
plant to the MechUms River to augment flow into the South Fork Rivanna River
Reservoir. Includes a 10.5 mgd expansion of the S. Fork Rivanna River Reservoir
pump stations and water treatmentplant, a new 22.5 mgd pump station at
Moore's Creek, new filters at the Moore's Creek treatment plant, a new 22.5 mgd
booster pu mp station, and a new 3 6-inch pipeline along 1-64 for a distance of
approximately 12.5 miles.
· Increase in 2050 safe yield - 15 million gallons per day
· Estimated cost- $56 million
· XY, rdl require the acquisition of land along the pipeline corridor
· Anticipate close scrutiny by Virginia Dept. of Health
· Approximately 2 acres of wetland impact
James Spiny Mussel previously identified in the vicinity; would need to examine potential
impacts
· Impacts to cultural resources not known; additional surveys may be required
· No anticipated residential displacements
20 willva\ 30502ho. D65
Water Conservation
Development and implementation of a long term water conservation program
consisting of plumbing fixture changeout (without retrofit program), pu&lic
education / awareness programs. Short term savings resulting from outdoor
watering restrictions and mandatory conServation are addressea under drought
management.
· Reduction 'in Demand - 1.5 mgd (Residential) due to plumbing fixture changes through the
year 2050'
· Reduction in Demand - 0.08 mgd (Commercial and Industrial)
· Reduction in Demand - 0.17 mgd (Residential) due to water conservation public awareness
and education
· Cost of plumbing fixture changeout, $0
· Cost of Public Education/Awareness program -$50K per year ($2.5 million through 2050)
· No major permanent restrictions on outdoor water use' assumed
· Savings estimates based on the following assumptions:
Fixture Type Current Type Assumed Use
Toilet 3.5 gallons 1.6 gallons
per flush per flush
Showerhead 5.0 gallons 2.5 gallons
per minute per minute
21
wtllva\ 30502ho.065
Drought Management
Development and implementation ora drought management plan. Plan in-
clUdes mandatory water conservation and a ban on outdoor water use. Plan
also includes a drought management operating scenario for the RWSA existing
water supply facilities. Supply side techniques include synergistic operation of
existing facilities, reduction or elimination of downstream releases, and diver-
sion from other uses.
1.8 mgd reduction in demand due to mandatory water conservation and limitations on
outdoor water use during summer drought
· Indoor water consumption reduced by 5%
· Outdoor water consumption reduced by 25%
0.6 mgd reduction in demand for similar restrictions during winter drought
· I mgd increase in safe yield due to system wide drought management
22
willva\ 30502ho Jo65
Leak Detection a
Leak Detection and Meter Calibration programs are implemented by the
Albemarle County Service Authority (ACSA) and the City of Charlottesville as
the distributors of finished water to the end user. Both currently have active leak
detection and meter calibration efforts underway
· No specific reduction in demand can be directly attributed to this alternative
· Financial incentive exists for leak detection
· Meter calibration and changeout is revenue neutral
Overall documented system losses indicate that entire system is operating within generally
accepted limits
Leaks are detected and responded to early using billing monitoring and written notification
system
· Meter change out is being done systematically by both the ACSA and City
· Meter calibration results from1998 indicate acceptable meter performance
23
willva\ 30502ho.~::C:x5
Growth Management
Attempt to slow population growth in the Albemarle County portion of the
Urban Service Area to reduce future demand for public water supply. Potential
means include further restricting the size of Urban Service Area, increasing
minimum lot sizes, and actively discouraging industrial, commercial, or
business development within the Urban Service Area.
· Could decrease 2050 demand by as much as 1.5 million gallons per day
· Costs would be significant but cannot reasonably be quantified
Reducing population growth within the Urban Service Area would likely result in
increased growth in surrounding rural areas on well and septic systems
May be politically infeasible as it reverses Comprehensive Plan and policy of two decades
attempting to guide growth into Urban Service Area and away from rural areas
Secondary impacts would include dispersed development outside the Urban Service Area,
requiring construction and maintenance of infrastructure improvements to roads and
utilities
· Transportation and safety impacts could be expected
24 willva\ 30502ho. D65
Regional Cooperation
Interconnection between the Rivanna Water and Sewer Authority water supply
system and the Rapidan Service Authority system in order to provide additional
water supply to the Rapidan Service Authority. The Rapidan Service Authority
projects additional demand for approximately2.0 to 3.0 mgd of water through
the year 2050. Connection would be via pipeline approximately 3.5 miles long
at the closest approach of the two service areas, along U.S. Route 29 south of
Ruckersville.
Increase in 2050 demand- 3 million gallons per day
Estimated cost- $
The Rapidan Service Authority is considering a variety of short term and long term solutions
to their future water needs
Potential environmental impacts not yet determined
25
willva\ 30502ho.p65
,Aquifer Storage and Recovery
Storage ~of treated water in a suitable aquifer during tl'mes when available wa-
ter supply exceeds demand and subsequent recovery of water during drought
conditions.
Increase in 2050 safe yield - 0 million gallons per day
Unsuitable geologic conditions: presence of subsurface rock with low transmissivity
· Not feasible
26
willva", 30502ho.~65
Conventional :Withdrawal of Groundwater
Installation of 15 shallow groundwater wells and piping water to the existing
South Fork and North Fork water treatmentplants (WTP): 6 wells in the vicinity
of North Fork WTP and 9 wells in the vicinity of South Fork WTP. Includes instal-
lation of wells, pump, piping and land acquisition. Groundwater is typically of
good quality but has the potential for high iron.
Increase in 2050 safe yield - 0.1 million gallons per day
Estimated cost- $1.2 million
Minimal environmental impacts
· No residential displacements are anticipated
27
willv a',. 30502ho.p65
James River :Withdrawal at: Scottsville
Withdrawal of water from the James River at Scottsville with a new 22.5 mgd
river intake, raw water pump station, a new 36-inch pipeline to the South Fork
water treatment plant, and a 10.5 mgd expansion of the South Fork Rivanna
water treatment plant and finished waterpump station. Alternatively, an option
was considered which included a new 22. 5 mgd river intake, raw and finished
water pump stations, and a new water treatment plant at Scottsville with 36-
inch pipeline along Route 20 to Charlottesville. The costs were essentially equiva-
lent. The option presented provides water treatment at the South Fork Plant.
· Increase in 2050 safe yield - 15 million gallons per day
· Estimated cost - $72 million
· Requires acquisition of a 25' wide easement along entire pipeline length
· Approximately 5 acres of wetland impacts
· Impacts to threatened/endangered species not known; additional surveys may be required
Potential impact to archaeological resources along James River; additional archaeological
surveys may be required
Potential impact to previously identified Scottsville Historic District; additional surveys
related to historic structures may be required
· No anticipated residential displacements
28 wiI~va\ 30502ho.p65
Rivanna ,River' With
Withdrawal of water from the Rivanna River near Glenmore Country Club.
Includes a new 7 mgd river intake, raw and finished water pump station, water
treatment plant, booster pump station, and a new 24-inch/16-inch pipeline from
the finished waterpump to the existing 16-inch main along Route 250 which
currently serves the Village of Rivanna.
· Increase in 2050 safe yield - 4.7 million gallons per day
· Estimated cost - $17.8 million
· Potential water quality concerns
· Moore's Creek waste water treatment plant discharge is located more than 5 miles upstream
· Requires acquisition of a 25' wide easement along entire pipeline length
· Approximately 2 acres of wetland impacts
· Impacts to threatened/endangered species not known; additional surveys may be required
· Impacts to cultural resources not known; additional survey for cultural resources may be
required
· No anticipated residential displacements
29
willva\ 30502ho.o65
Mechums River Withdrawal:
Skimming of high flows from the Mechums River at the site of the abandoned
intake and pump station near Lake Albemarle and pump to the Ragged
Mountain Reservoirs. Includes rehabilitation of the river intake, pump station
and ancillary, features, as well as access road improvements.
· Increase in 2050 safe yield - 0.2 million gallons per day
· Estimated cost - $850,000
· Insufficient flows in Mechums River during severe drought conditions
· Useful only when there are droughts in two successive years
· Minimal impacts to wetlands
· Impacts to cultural resources or threatened/endangered species not known; additional
surveys may be required
· No anticipated residential displacements
30
wlllva\ 30502ho.p65
Mechums
of Ragged Mountain to Pumped Storage
Reservoir
Skimming of high flows from the Mechums River into Ragged Mountain Reser-
voirs by rehabilitating and expanding the abandoned intake and pump station
on the Mechums River to 10 mgd. This option is combined with raising the dam
for Lower Ragged Mountain Reservoir by 50' creating a normal pool elevation
of 700' with a surface area of 275 acres and storage capacity of 2,800 million
gallons. Results in inundation of existing dams. Option' also includes new 24-
inch pipeline, 15 mgd intake on Ragged Mountains, and 8 mgd expansion of
Observatory water treatment plant and pump station.
· Increase in 2050 safe yield - 10 million gallons per day
· Estimated cost - $47 million
· Requires purchase of approximately 125 acres of additional land
Approximately 5 acres of wetlands inundated by increased pool elevation at Ragged Moun-
tain Reservoirs
Impacts to cultural resources or threatened/endangered species not known; additional
surveys may be required
· One potential residential displacement
31 wittva\ 30502ho.o65
Mountain Creek
on Buck
Construction of a dam and reservoir on Buck Mountain Creek 1.5 miles, up-
stream of the confluence of Buck MoUntain Creek and the S. Fork Rivanna Reser-
VOir. InclUdes: new 21.6 mgd intake, 9. 6 mgd expansion of the existing S. Fork
Rivanna intake, raw water pump station, water treatmentplant and finished
water pump station. Normal pool elevation of the new reservoir 480feet with
surface area of 670 acres and storage capacity of 5;242 million gallons. Drain-
age area of reservoir 38 square miles.
· Increase in 2050 safe yield - 14.4 million gallons per day
· Estimated Cost - $57 million
· Assumes minimum flowby = 7Q 10 based on short affected .stream segment
· Does not require purchase of additional land
· Approximately 59 acres of wetland impacts
· Potential impacts to previously identified populations of James spiny Mussel
· Direct impact to 2 previously identified historic structures (eligibility not' determined)
· Potential indirect impacts to 4 previously identified historic properties (eligibility not
determined); additional cultural resource surveys necessary
· Potential displacement of 1 residence
32
wiliva\ 30502ho. D65
Constru
Fork Rivanna River
ir,, on, North
Construction of a dam and reservoir on North Fork Rivanna River 2 miles west
of the North Fork Filtration Plant. Includes: new 23 mgd intake and pump sta-
tion, 11 mgd expansion of the S. Fork Rivanna Reservoir intake, pump stations
and treatment plant, and a new 3 6-inch pipeline from .the North Fork Rivanna
pump station to the South Fork Rivanna River Reservoir. Normal pool elevation
of new reservoir 490feet with surface area of 1,057 acres and storage capacity
of 10, 059 million gallons. Drainage area of reservoir 63 square miles.
· Increase in safe yield - 15.4 million gallons per day
· Estimated cost o $79 million
· Will require land acquisition
· Assumes minimum flowby = 30% of mean annual flow
· Approximately 72 acres of wetland impacts
· Impacts to threatened/endangered species not known; additional surveys may be required
· Direct impacts to 4 previously identified archaeological sites (eligibility not determined);
additional archaeological surveys required
· Potential indirect impacts to 3 previously identified historic properties (eligibility not
determined); additional architectual surveys necessary
· Potential displacement of 2 residences
33
willva\ 30502ho,p65
of Dam and
Construction of a dam and reservoir on Preddy Creek 2.5 miles northeast of the
North Fork Rivanna water treatment plant. Includes a new 9. 6 mgd intake struc-
ture, raw water pump station, water treatment plant, finished water pump sta-
tion, and a new 24-inch pipeline. Normal poo! elevation of reservoir 460feet
with surface area of 932 acres and storage capacity of 9,134 million gallons.
Drainage area of reservoir 14 square miles.
Increase in 2050 safe yield - 6.4 million gallons per day
Estimated cost - $91 million
Will require land acquisition
Assumes minimum flowby = 30% of mean annual flow
Approximately 77 acres of wetland impacts
Impacts to threatened/endangered species undetermined; survey may be required
Direct impacts to 4 previously identified historic structures (eligibility not determined);
additional architectural surveys required
Potential indirect impacts to 3 previously identified historic properties (eligibility not
determined); additional surveys necessary
Potential displacement of 6 residences
34
wluva\ 30502ho.D65
Mechums River Near Lake:Albemarle
Construction of a dam. and reservoir on Mechums River 0.5 miles northeast of
Batesville. Includes a new 20 mgd intake structure, 8 mgd~expansion of the
South Fork Rivanna Reservoir intake, raw water pump station, water treatment
plant and finished water pump station. Normal pool elevation of reservoir 520
feet with surface area of 973 acres and storage capacity of 7,896 million gallons.
Drainage area of reservoir 94 square miles.
Increase in 2050 safe yield - 13-3 million gallons per day
Estimated cost - $68 million
Will require land acquisition
Assumes minimum flowby = 30% of mean annual flow
Approximately 107 acres of wetland impacts
James Spiny Mussel previously identified in vicinity; will need to examine potential impacts
Direct impacts to 1 archaeological site and 8 historic structures previously identified (eligibil-
ity not determined); additional cultural resource surveys reqUired
Potential indirect impacts to 10 previously identified historic properties (eligibility not
determined)
Potential displacement of 21 residences
35
w~llva\ 3050250.065
of
Mechums River Near Midway
Construction of dam and reservoir on Mechums River one mile upstream of the
1-64 crossing near Midway. Includes a new 8.4 mgd intake structure. Normal
pool elevation of reservoir 580feet with surface area .of 477 acres and storage
capacity of 3, 477 million gallons. Drainage area of reservoir 34 square miles.
Increase in 2050 safe yield - 5.6 million gallons per day
Estimated cost - $26 million
Will require land acquisition
Assumes minimum flowby = 30% of mean annual flow
Approximately 52 acres of wetland impacts
James Spiny Mussel previously identified in vicinity; will need to examine potential impacts
Possible direct impact to 1 National Register Property (Miller School); will require furture
investigation
Direct impact to 1 previously identified historic structure (eligibility not determined);
additional architectural survey required
Potential indirect impacts to 5 previously identified historic properties (eligibility not
determined); additional survey required
· Potential displacement of 6 residences
36 wi{Iva~ 30502ho. o65
Construction of Dam
Buck Island Creek
and ReS ervoir on
Construction of a dam and reservoir on Buck Island Creek 0.5 miles upstream
of Route 53. Includes anew 22.5 mgd intake structure, raw water pump station,
water treatment plant and finished water pump station. Normal pool elevation
of reservoir 340feet with surface area 1, 707 acres and storage capacity of
13,950 million gallons. Drainage area of reservoir 38 square miles.
· Increase in 2050 safe yield - 15 million gallons per day
· Estimated cost - $118 million
· Will require land acquisition
· Assumes minimum flowby = 30% of mean annual flow
· Approximately 103 acres of wetland impacts
· Impacts to threatened/endangered species not determined; additional surveys may be re-
quired
· Direct impacts to 4 previously identified historic structures (eligibility not determined);
additional cultural resource surveys required
· Potential indirect impacts to 2 previously identified historic properties (eligibility not deter-
mined)
· Potential displacement of 14 residences
37
w~ilva\ 30502bo.o65
Construction of Dam and Reservoir on
Moormans River
Construction of a dam and reservoir on Moormans River just downstream of
confluence with Doyles River. Includes a new 17.4 mgd intake structure and 5.4
mgd expansion of the South Fork Rivanna River intake, raw water pump
station, water treatment plant and finished water pump station. Normal pool
elevation of reservoir 680feet with surface area of817 acres and storage
capacity of 9,202 million gallons. Drainage area of reservoir 53 square miles.
· Increase in 2050 safe yield - 11.6 million gallons per day
· Estimated cost - $106 million
· Will require land acqUisition
· Assumes minimum flowby = 30% of mean annual flow
Approximately 68 acres of wetland impacts
Impacts to threatened/endangered species not determined; additional surveys may be
required
Direct impacts to 9 historic structures and 1 archaeological site previously identified
(eligibility not determined); additional cultural resource surveys required
· Potential indirect impacts to 5 previously identified historic properties (eligibility not deter-
mined)
· Potential displacement of 22 residences
38 willva\ 30502ho.p65
·
477 McLaws Circle, Suite 1
Williamsburg, Virginia 23185
757 220-0500
FAX 757 220-8544
Vanasse Hangen Brustlin, Inc.
Transportation
Land Development
Environmental Services
Meeting
Notes
Attendees:
See Attached List
Study Team:
Arthur Petrini - RWSA
Jack Marshall - RWSA
Gene Potter - RWSA
Nancy Barker - VHB
Karin Ertl - VHB
Chris DeWitt - VHB
Larry Welford - VHB
William Ellis - MB&C
George Rest - O&G
Thomas Dumm - O& G
Date/Time: April 18, 2000
Project No.: 30502
6:30 p.m. - 9:30 p.m.
Place: City of Charlottesville Re:
City Hall
Water Supply Project
Notes taken by: kee
The Rivanna and Water Sewer Authority sponsored a public information meeting to present
information and solicit input from the public on the water supply study currently underway. A
summary of this meeting is provided below.
Open Forum 6:30 - 7:30 p.m.
The study team talked with the public and answered questions in an informal setting that
included poster boards with information on many of the water supply alternatives under
consideration.
II.
III.
Presentation
Members of the study team made a formal presentation regarding water supply
alternatives. A copy of the slide presentation is attached.
Questions and Answers/Comments
After the presentation, members of the audience provided the following comments.
Copies of written comments provided at the meeting are also attached.
\\\30502\WP\ NOTES\ 041800Public.doc
Date: April 18, 2000
· 6:30 p.m.
Project No.: 3050Z
Speaker: Ed Imhoff
Re-examine the use of "pricing structures" under water conservation; the 1%
reduction in demand noted in report may be too low.
)~ A letter received from Mr. Albani stated that the reduction "could be significantly
greater under the right circumstances".
Do not get discouraged by the 1%; we may not be able to quantify the effectiveness
but it is still a very Iow cost way to get additional water.
Speaker:
Treva Cromwell
Not willing to give up on the S. Fork Rivanna River Reservoir.
Important to reduce sediment load into reservoir- many efforts have been made to
accomplish this goal as listed on pages 16 and 17 of Alternatives Analysis report.
The community may not have done a good job ofimplementing and enforcing
existing ordinances, policies, etc. For example, the 1977 Runoff Control Ordinance
only applied during construction - after construction, the County assumed the owner
responsible for maintenance of BMP's. Hopefully this is no longer a problem.
RWSA is responsible for the effectiveness of the Lickinghole Creek regional
stormwater management pond; additional ponds could improve the situation.
Land use controls, stormwater ordinances, and additional BMP's are all important.
Question: Why is there no regulatory requirement for the 8 mgd release atthe reservoir;
is it needed to dilute effluent downstream at Moore's Creek waste water treatment plant?
Answer: The flow in the S. Fork Rivanna River is sufficient to provide assimilative
capacity for the effluent. The study team continues to evaluate the regulatory status of
the release from the reservoir.
Speaker: F. li×abeth Murray (written comments also provided)
} Control sediment into the S. Fork Rivanna River Reservoir - enforce existing
ordinances.
In future discussions of reservoir options, reflect the fact that 568 acres in the vicinity
of the Preddy Creek Reservoir site may be designated in the future as a Natural Area.
Speaker: Elizabeth Petofi
> Subdivisions are taking more groundwater.
~ Wells in Greene and Orange County are lowering the flow in Preddy Creek; the
calculations for that proposed reservoir may therefore be inaccurate.
Speaker: Nick Evans (written comments also provided)
~ Water conservation and improving the S. Fork Rivanna Reservoir should be part of
the solution.
Strongly in favor of doing something on the S. Fork Rivanna River Reservoir -
mitigation of sediment into the reservoir and sediment removal.
\ 30502\ W P\ NOTES~ 041800Public.doc
Date: April 18, 2000
6:30 p.m.
Project No.: 30502:
Recent evidence suggests that erosion and sediment control practices and other
BMP's may not be as effective as hoped. For example, sediment loads in the James
River watershed have only been reduced by 2% since the Chesapeake Bay Act.
In addition to overland transport of sediment into streams, there is erosion within the
stream channels themselves - need to tailor sediment reduction strategies
accordingly. There are things that can be done that go beyond Best Management
Practices.
The Thomas Jefferson Soft and Water Conservation District will be doing a study on
the Mechums River and Ivy Creek.
Speaker: Tim Sansule
"Easy come, easy go" - concerned if stream flow in S. Fork Rivanna River ~-ill be cut
off during drought if alternate release scenario is implemented.
)~ "Waste not, want not" - quality of life can be maintained with less water.
"Two wrongs don't make a right" - building another reservoir not an intelligent
response if reservoirs silt in.
Speaker: Jason Halbert
Report seems weak on water conservation; it should consider composting toilets and
catching rainwater.
~ Cows should be kept out of streams.
Why are BMP's not required for logging activities? Dickenson Count' was given the
authority to regulate logging at the local level.
Speaker: Russell Perry (refer to press release for candidates M. Richards, M. Cox, and K.
L_vnch)
~ Applaud RWSA for sound planning.
City Council Democratic Candidates endorse the following principles: live within
our water means, support re-use when feasible, avoid damming streams if possible,
meet water needs in the least environmentally invasive way possible and without
compromising the vitality of waterways.
Speaker: Francis Martin
Question: Can the sediment in the S. Fork Rivanna Reservoir be flushed out 1~, means
releases through the bottom of the dam?
Answer: The majority of sediment is trapped in the upper reaches of the rese~'oir, not
the dam. Releases at the dam are not able to flush this sediment out.
Speaker: Kevin Lynch
Applaud RWSA for seeking community input
Dams appear too expensive.
Water conservation and crest gates on the S. Fork Rivanna River Reservoir look more
attractive.
\ 30502\WP\ NOTES'~ 041800Pubiic.d oc
Date: April 18, 2000
6:30 p.m.
Project No.: 30502:
Challenge RWSA to look closer at commercial/industrial conservation; encourage
businesses to use less water.
Speaker: Lindsey Dorrier
Question: Does the study team have a recommendation for a local process?
Answer: No, the study team does not have a recommendation for procedures to be used
in Albemarle County.
Speaker: Bob Gilges
If growth continues uncontrolled, there will be insufficient water to meet the
demand.
Question: Why was "Growth Management" dealt with differently than "Demand
Management"?
Answer: The concept of growth management lacks specific techniques that are also legal
If anyone can. suggest an effective growth control measure that is also legal, the study
team would evaluate it.
Speaker: lohn Hermsmeier
An example of a specific growth management technique would be to implement
through zoning an occupancy limit for housing.
> The growth management alternative is under considered - it should not be
dismissed.
Should address number of users in the Urban Service Area and in the surrounding
rural area.
Speaker: William Findley
With regard to Buck Mountain reservoir, it is not appropriate to take land from the
Rural Area to provide water in the Urban Service Area.
> Using the James River is the best alternative - it is an abundant resource and
federal/state authorities ensure water quality is acceptable.
~ Would not fish in the Moorman's River if effluent discharged into that stream.
Question: For the reuse options, is the technology advanced enough to ensure no
serious adverse effects?
Answer: The technology today does make the reuse option technically feasibIe. As
proposed, the effluent pumpback would not occur continuously - maybe only once every
ten years.
Speaker: Lois Rochester
~ The indirect reuse sounds very interesting; it should not be ruled out.
The James River withdrawal appears problematic, including the cost, the
vulnerability of a pipeline, and City of RiChmond water rights (granted in1794) that
could delay the process for years.
\30502\ WP\ NOTES\ 0418§0Pu blic.doc
Date: April 18, 2000
6:30 p.m.
Project No.: 30502:
The community should live within its means.
\ 30502\ WP\ NOTES\ 041800Public.doc
WA TER SUPPL. Y STUD Y
Public Information Meeting - Attendance L.ist
April 18, 2000
City of Charlottesville
Name
Ed Imhoff
Treva Cromwell
Bess Murray
Virginia Daugherty
Dan Gabriel
Robert Gilges
Carroll Gilges
Gene Smith
David Hirschman
Nancy Damon
Jim Murray
Elizabeth Neff
Joy Matthews
Robert Johnson
Kevin Lynch
Patrick Punch
Wayne Harbeiyh
Jim Moore
Name
Bob Watson
Elizabeth Petofi
Greg Johnson
Rochelle Garwood
Wanda and Tim Sansule
Darren Pace
Liz Palmer
Randy Parker
Peter Craddock
Sharry Buttrick
Harold Via, Jr.
Ann Via
Russell Perry
John Hermsmeier
Nick Evans
Jason Halbert
Marsha Parkinson
~R~R.18.:;'OO0 c'1;:':307..~or'~,E~T,,.~.;c,.,V?~ 804 828 2836;
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Friends oJ'the Moormans River
Apr' - 18 - O0
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April 16, 2000
Karcn E. Ertl
Em, ironmenta! Scientist
Vanasse IIangen Brusflin, Ix,..c.
477 McLaws Circle, Suite 1
Willimxasburg, VA 23185
Dear Ms. Ertl;
We are residents of and riparian landowners along :he Moorrmans River in
Albemarle Count3,, and we write re respond to the VI-lB report Water Supply Project-
.4nat. vsi. t of Alternatives, which will be discussed publicly on Apr/l 18% We are
disapPoh~red that in the alternatives presented there is no proposed inclusion of a minimal
flow release hate the headwaters of the Moormans River, We feel this serious deficiency
arises Rom a combination of several ovet~igllts that in mm cause concern about fhe
premises underlying this report.
First.. there is a false premise about the historical commitment of this community
to embrace modern drought management/water conservation practices. The realistic
economic and environmental impacts of iow-cost solutions such as water conservation
are minimized, The concept that modest water conservation alone could restore
summertime flows in the Moormans is historically entrenched in this community's public
record and curimmly is not discussed.
Second, zhere is minimal attempt to address water supply demand in the larger
context of environmental needs of the entire watershed system. As a result, the
alternadvcs are presented in a piecemeal, isolated manner without integration into a
comprehensive picture of how components of the system interact locally and regionally.
l Jnregulated societal water requirements are emplmsized without discussion of
environmental preservation Mthin important watershed components, such as the
Moorn~m~ River,
Third, alternatives such as dred~ng the South Fork Rivanna Reservoir (SFRR)
are presented that are not truly choices. The silting-in of the SFRR is euphemistically
referred to as "loss of-qafe yield", when in fact what is not discussed is the po~enti.~l
environmental disaster (and excessive costs) of dealing with the resulting alteration of
upstream floodplains and sedimentation flows into the Rivanna river. Thus, althou~a
recovery. ,and maintenance dredging of the South Fork Rivan.na Reservier (SFRR) is
presented as an "alternative", a closer analysis reveals that the community has no realistic
choice but to preserve this reservoir
The combined result of these omissions is lhat no meaningful view emcees of
decremented community commitment to environmental preservation or wglingness to
conserve water for the health of the watershed system. While isolated environment~
impacts of individua~ 'alternatives are discussed, overall protection of watershed ecology',
a goal stated on multiple occasions by Albemarle County, is absent. The result is a °ne-
di mensionai water supply alternative report built on the primary assumption that
unregulated water demand must be accommodated. [f commtmity water policy and
environmental priorities had been considered, demand figures would be si~,mificantly
1
6430 S~g, ar Hollow Road
Moormans R~m sr~ com
Cro~, VA 22922
~ HO. 054 P. 2
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2
al[er-ed, summertime water flow's in the Moormans co,fid have been easily'
accommodated, and a more realistic set of alternatives could have been produced.
Planning for release into the Moormans River should have been considered from the
outset of the VI-lB study.
For years, we have been asking Albemarle County government and the RWSA to
help solve tke problem of no flow in tlxe Moormans. Over the years many more people
and groups have johxed us. This issue was already well known to RWSA before the
permitting process began in the fall of 1997.
March 4, 1997: On this date we appeared before the Planning Commission
during a Work Session on the need to include "Water Conservation" as part oft~e
Comprehensive Plan. Ttms, Arthur Pexrin~ (RWSA) and Bill Brenr (ACSA) were
present. Among topics of discussion 'were water supply issues and "the charge ofrhe
ACSA and the City of Charlottesville Public I~brks Department to develop a Water
Conservation Program (with the RWSA offi'ring suppor0 "'. We asked the Plarming
Commission that "the Moormar~' River be given minimum in-x~ream fto~' protection
within the framework of the Comprehensive Plan ". We also requested that RWSA
modify the dam during upcoming repairs to incorporate release of water. David Tice
(Planning Commissioner) recommended that in redrafting this section of the
Comprelxensive Plan, the following point should be emphasized:
"the Waler EJficiency section should not Only be county policy./br meeting future
demands but should also say that we have existing goat. r which might ~nclude restoralion
of an insrream flow on the Moormans River, that demand.fide management of water
should be a priorityJbr the eammuniry." This section was rewritten as suggested by the
Plmming Commission and approved by the Board of Supervisors. It includes a reference
xo the need for water conservation and sets forth the goal of restoration of instream flow
in the Moormmas.
Several months after the Planning Commission meeting, we went b~ff'orc the
R.WSA Board and asked them again to incorporate a release mechanism into ~eir
proposed dam alteration ptmxs for the Sugar Hollow Reservoir. Our request was denied.
The simple modifications that would have been necessary were nor incorporated.
In addition, duhng a telephone call that summer, Arthur Petrini advised us to
present our requesr to VHB at the outset of'their study. He saic[ we would have an
opportunity to ~sk fox mlnimmn i~ stream flow a~ a public meeting planned for the tall.
He explained th. at ~e potential loss et'water ~rom the Sugar Hollow Reserv6ir would
have to be factored in by VHB as they evaluated overall supply m~d demand. However,
as it turned om, this meeting never took place.
Our community has a l'dstory exter~ding back several years of requesting that
minimum flows during summertime periods be established by KWSA in the headwaters
of she Moormans River. There has been ample opportunity to include this calculation of
Donna and Jim 13etmetl
2
6430 ,gugar Holla~v Road
Moorman$R(.a~,msn. corn
Crozet, Vd 22932
~en~
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Friends of the Moormans River
release from Sugar Hollow Dam in tlae water supply planning process, and we are unclear
as to why this has not taken place.
In addition, two Commonwealth of Virgmla Agencies involved in the permitting
process have recently expressed concern about lack of flow in the headwaters of the
Moormans River.
"We recommend that the RWS'A release.flows into the Moormans River at the base of
St~gar ttollow reservoir or in the White HaH vicinity. C~rrently, the flow in the
Moorrnar~.~ River i.v sig~nificantly reduced becausa of the Sugar Hollow diversion and lack
of any release requirement. Flow releases into the Moormar~, River instead of the
Mechums River wilt solve a tow-flow problem that has been a concern for our agency
and area residents. ' (Raymond T. Fernald: Manager, Environmental Services Section,
Department of' Game m~d Inland Fisheries)
"Lastly, sacrific#~g instream flows on the Moormans River and on ~he South Fork
R ivanna River may make good water supply po licy but b e bad e~vironmental policy.
That type of over appropriation could result in the unintended consequence of spawning
the ever Surface V/arer Management Area" (Joseph P. Hassell, Environmental Program
Manager, Department of Environmental Quali~)
There is an extensive chronology of public concern about lack of flow in the
Moormans River:
Timeline of Events to Provide Mini .rrtum Flow to the Moormans River
· .[.993..We observe first period of prolonged, drying of riverbed, prompting t~n~
page story in Richmond T~mes. We inform State Scenic River Advisory Board.
March 4, 1997. We go before Planning Commission, with RWSA
representatives present. (See discussion above) Make requests: (1) Problem of
MIF during summer months be addressed in context of Comprehensive Plaa.
Planning Commission acts on our request (final draft of Water Resources portion
of Comprehensive Plan .mbsequenty contains reference to Moormans River). (2)
Also, request tlaat MIF be provided for during dam repairs being planned by
RWSA. Planning Commission asks RWSA to consider our request.
July 24. 1997~We write follow up letter to Arthur Petrini, Executive Director of
RWSA, with full text of presentation to Planning Commission, asking what
RWSA pitons m do.
Au_~ust. 1997~W¢ appem' before RWSA Board of Directors Meeting. State
problem, cite peer-rexdewed literature documenting negative effects of dry, river
bed on macroinvertebrate populations, state belief that water usage policy viola[es
spirit of law, note RWSA has no formal water conservation program. We are told
RWSA will not release any water into Moormans.
Donna and Jim Eennerr
3
~430 Sug~tt' Ho~]ow Road
Crozet, VA 22932
~ent ER ................ ,,,a ......... , 804 823 2836; Apr-18-00 12.'0;3PM; Page
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4
December, 1997--We request Arthur Petrini, RWSA, to hold a public meeting re:
dam repairs of the Sugar l-Iollow Dam. We are told meeting would only be held
aRer RWSA makes its final decision on a repair plan..Not to be a meeting to
solicit opinion about design options. However, Alterations Permit would allow
"Local Advisory. Committee".
Mav~7. 1998--We send letter (via email) to Kay Slaughter (Mayor of
Charlottesville) re:. planned Sugm.r Hollow Dam repairs and opportunity to cl~.nge
dam to accommodate MIT.
June 9,.199~8--Public Information Meeting is held by RWSA re: £mal design
plans for Sugar Hollow Dam repairs. Our requested changes to dam for MIT,
m'Me at March, I997 Planning Commission Meeting, are disregarded. Many
others, attending meeting, request minor modifications of the Sugar Hollow Dm
to alloxv release. These include adding valve to outflow pipe or siphon tube. We
question fact that final repairs decided upon by RWSA, although more costly than
other repair almrnatives, would not trigger 401 Certification that would change
MIF status of Sugar Hollow Dam. We question whether repair alternative
selected by RWSA is chosen primarily because it would avoid need for Federal
401 certificate, which would require Mil: study at~d environmental impact stu,~y.
August, 1998--We meet with Robert Tucker (Albemarle Coun¢' Executive
Director zed member of Board of Directors of RWSA) to go over full-se~e of
Moormans River problean.
· Seutember 20, 1998 We send follow up errm/1 to Mr. 'rucker.
· October 5. 1998~We write ih'st letter to Emily Couric, with. information given to
Mr. Tucker.
October 29. 1998~Ten local groups, representhag hundreds of people, meet
informally with Arthur Petrini to discuss Moormans River problem. We propose
concept: 0fproporfional release of water from Sugar Hollow dam into Moo~.
Arthur Petrini states RWSA's position as follows: MIF in the Moormans is not
possihle because it will cause premature depletion of Sugar HoLlow reservoir
supply under drought conditions. This will lead to institution of water
eonscrvation procedures t~vo weeks earlier than planned. Also, RWSA h~s no
control over demand and cannot request water conservation me'utes from their
"customers"= the Albemarle County. Service Authority mid the Charlottesville
Water Works. R. equests for water conservation must originate from govemhzg
boards of these customers or in the Board of Supervisors and City Council Mr.
Pert/nj states that the sole mission of the RWSA is to provide w~ter to theSr
customers.'
' Last spring, just before the 1999 drought, itwas discovered that there ~,~as no
county ~rdinance or state law that detailed a drought management plan. it w~s
decided that Bill Brant, Executive Director of the Albemarle Ccunty Service
4-
d430 Sugar Hollow Ro~d Crozet. I/.4 25952
Moorrna~xR~m,n. eom
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Friends of the Moormans River
5
Authority should write such an ordinance.) Therefore, RWSA could have
changed procedures to accemmoda[e voluntary release into the Moormans by
choosing to ask for voluntary wmer coaservation much earlier in the evolving
drought.
Janua~. 199~9. County Board of Supervisors passes Nature] Resources Section of
Comprehensive Plan containi~g reference to need for water conservation planning
and need for MIF tn Moorraans River.
February: 1'999--We present Moormans River problem and proposal for
voluntary proportional release by RWSA to members of Citizens for Albemarle.
Arthur Petrini present tbr RWSA position and debate on subject.
March 3. _19_=9_9---PresenLationjointly by residents of Sugar Hollow and Moormans
Scenic River Advisory Board to AJbemm'le County Board of Supervisors. We
give summon, of problem, propose voluntary proportional release, subm/t
answers to Sally Thomas's quemions in advance. Then, we take part in Work
Session with Board. Final decision: Albemarle County Board cf Supervisors
asks RWSA to stop telling them they can't fred a solution to the problem and to
come up with potential solutions to provide minimum flow. No known follow up
from RWSA to Board to t_h~s date.
_April 15, 1999~LWV publishes booklet on "Water in the New Millennium:
Balancin8 ~he Needs of People and the Environment", v4th reference to
Moormans River problem as part of overall water supply issues.
April 20. 1999 Vi-lB presents information regarding AJtemarivcs for water
supply. Public asks about fate of Moorrrmm River in planning for new water
supply.
June 5, 1999~group of interested citizens form ad hoc Water Conservation
Committee to discuss need for water conservation plan in the community and
need for comprehensive watershed policy coordinated among RWSA, Albemarle
County and Charlottesville C~ty. Moormans River problem eked as primary
example of lack of coherent policy.
June 1.5. 199.9--We meet with Mr. J.W. Brent, Executive Director of the
Albemarle County Service Authority, and request assistance in developing a
water conservation 'pledge' plan. Our 'public relations' idea would promote
water conservation as a means for people to Play a role in putting water back in
the Moon, ans, Water consumers ~vouJd directly participate in benefith~g natural
resources ~rough their water savings. Several protection areas could be targeted
along with the Moormans River, such as Chris Greene Lake and zhe Rivanna
River. He receives ~he idea favorably, but fl~e details are yet to be worked oat
(and no promises).
· Juae 15, 1999--We present ~e same idea to County Board of Supervisors.
5
l)orma and Jim i~ennerr 6450 Sugar Hollctw Road Crozet, VA 22932
MrJorman,rR ~(~'nxn. com
, HO.D54
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Friends of the Moormara' River
June 21.1999--We send letter to RWSA critiquing VHB Alternatives with
special emphasis on our concerns re: no water in Moormans. (cc: to federal and
state regulators. Charlottesville City Council, and Albemarle County Board of
Supervisors).
July, 1999--League of Women Voters and Pdvmma Roundtabte request two Joint
Work Sessions ofA Ibemarle County Board of Supervisors and Charlottesville
Civ Counci I. Purpose of request: to give the ad hoc Water Conservation
Committee members or representatives an opportunity to address concerns about
water cor~serva~on, water ~upply planning and coordinated, comprehensive
watershed planning.
· Au~mst 6, 1999. Second letter to Senator Emily Couric, describing the problem
and derailing our efforts to solve the problem locally.
November 18. t 999 ad hoc Water Conservation Committee presents concerns
about water supply planning proce~ and decision-making issues. Moormans
River cited as prime example of lack of coherent policy.
February 14. 2000, J.W. Brent responds in a letter to our request of June 15, 1999.
Citing software costs as the nmin reason he writes that ACSA cannot develop
community, chest" type water conservation campaign.
Conclusion:
Omitting restoration of summertime flow in the Moormans from the report is not
acceptable. Thc Moormans River must be given autonomous status in the current
plamfing process as a higlaly valued and environmentally sensitive component of the
,,varersl~ed system. This conclusion is suppormd by both the community's historical
devotion and commiu:aent to the Moormans and the opinions of the two major Virghtia
environmental regulatory agencies.
6
6430 ,?ugar Hollow Road
Moormans RQb)~rr~t~. corn
Crozet, ~'~f 22932
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There is a long-standing history of support in this community for water
c o nservation.
We wish to point out ~at certain premises underlying the demand and supply
analyses ofthis report are questionable. Specifically, this report does not reflect thc
historical interest and public involvement of this community wi& respect to its water
resources.
t, The rep. orr ihils to acknowledge this.oommuniW's track record in reduoin~
water eon~tml~:tion when asked to. In addition to the Planning Commission
comments of March, 1997 (see above), a water conservation plan had been
studied and approved by R. WSA in 1979. In 1979, RWSA Board approved the
report from "The Four Party Conservation Comrnitree". After a drought in the
summer m~d fall of 1977 m~d another dry period in 1978, the committ~
determined that there was a need '~to provide a continuing program 'aimed at
permmxent water conservation." The report noted that a 20% reduction in
consumption was achieved in 1977; and thus, aimed at a setting a goat of'~ten
percent reduction in water consumption". In spite of the fact that the proposed
water oo,tservation plan was approved by RWSA, it was never put into practice.
Although we do not know why that occurred, what is imponm~t is the fact that a
goal ora pemqanent reduction of 10% of water consumption was part of RWSA's
fl'finkh-~g at ~at time.
2. One of the most compe[king~xamr~les o~f commun, iW involvement in water
resource issues is the attemet over many year. s by the League of Women Voters to
bring water conservation policy ..changes to fruition. Mo~ recently: (a). The
League's suggestion to create Citizens Advisory Cornmlttee for RWSA was
motivated by a desire to address the need for a water conservation plan through
citizen input. (b) The ad hoc Water Conservation Committee, composed of city
and county residents, ,.vas initiated by the League. This interest of the League
arose from an interest in water conservation as part of strategy to protect and
sustain natural resources.
Conclusion:
Thus, there is every reason to believe that our cormnunity Would respond
fkvorably and in a quantitatively significaat manner to requests to conserve water. As
discussed above; them is an extensive historical commi~nent in this community,, in both
desire and action, to utilize water conservation as a means to protect the eavironment and
exrend the usefulness of our water supplies. The major consequence for this report of our
comrmmity's commitnxent to water conservation is the manner in which demand figures
were, c~culated. For that reason, several demand scenarios could have been proposed at
the outset of the perm/t'ting process, instead ora sin~e, worst case. In particular, an easily
achieved 10% reduction in summertime usage would have provided both adequate water
for release into thc headwaters of the Moormans River and a significant reduction in
ov ,roll demand figures.
Doztno and d£m Bennett
7
6430 Sugar Hollow Road
Moormans RrF~,~ m sn. eom
Croz~t, VA 22952
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Loss of "safe yield"at SFRR is not an option.
The continued silting in and marked reduction of storage capacity in the SFR.R
would represent: loss of both recreational and water supply resources for this community.
Both o£these losses would need to be decided ahead of time by the affected public, and
public discussion of the consequences of SFRR loss has not yet taken place.
What ]s not discussed in this report are the practical consequences of allowing the
SFRR to silt-in. As discussed :he ~eservoir Sedimentation Handbook (RSH, G.L. Morris
and j. Fan, McGraw Hill, 1998), there are multiple potential negative upstream and
downstream consequences or' reservoir ~ilting-in that must be considered before the
option is exercised of decommissioning a reservoir/dam system due to siltation. Among
these consequences are effects on upstream and downstream floodplains and
environmental impacts o£ downstream delivery of sediment loads during the
decommissioning process.
Given the episodic high flows in the RR corridor, alteration of upstream
fleodplain morpholog3, axed consequences to landowners along the new floodplains need
to be modeled. A decision by local government to allow siltation infill ol"the SFRR may'
- result in "takings" of private properties due to upstream floodplain encroachment, with
associated costs of'restitution.
Abandonment of the SFRR will require planning as to whether partial breaching
of the SI-'RR dam will be done to allow a sedimentation channel to form, what the
consequences of delivery of such sedimentation to the downstream Rivarma river might
be, and whether sihmificant sediment delivery downstream would even be allowed by
current environmental regulations. It is not ir~conceivable that environmemal regulations
would require that abandonmen~ of the SFRR necessitate sediment removal and disposal
from the reservoir on a much larger scale than that proposed in this report for partial
reservoir recovery and maintenance.
It is very. unlikely that the SYRR dam would be allowed to remain in place
crocheted.,, due to the potential of floodwaters breaching the dam abutments and causing
dam instability. Thus, pardal dam breael'fing to allow floodwater passage, and ~e
,'esuking increase in sediment delivery downstream must be factored in be~bre my
decision can be made to consider loss of the SFRR.
Conclusion:
Loss 0fthe SFRR due to silting-in carmot be considered an option at this time.
Viewing the resetw'oir as simply filling up and becoming a wetlands is not consi.~mnt with
known consequences of reservoir siltation, Upstream and downstream floodplain mad
sedimentation consequences have not been considered and are likely to be economically
and environmentally prohibitive. Abandonment of the SFRR dam would likely requite at
least partial dam breaching, which in tm'n would require sedhnent nm~mgement to prevent
do~a-nstream environmental impacts. This could turn ou~ to be more costly than measures
proposed to reduce sediment inflow into SFRR and maintain reservoir volume bi5'
maintenance dredging.
Don2~a and Jim Bennett
8
6430 Sugar Hollow Road
Moormar~R(~mxrt. corn
CrozeL I/~ 22932
H0.054 P.~
~n~ ~P~.l$.£~OOof12:33PMorm~H~-B-~.¥HB 804 823 2~6~ Apro18-O0 12:06P~j Pa~ 9/16
_Friends of the Moormans River
9
Comments on Specific Alternatives
#1. Dredge South Fork RJvanna Reservoir.
Az discussed earlien we do not feel dredging should be considered as an
alternative. Because costs are discussed in this section, however, we will address the
subjcc~ of dredging costs in this section. According to the Reservoir Sedimentation
Handbook, typical reservoir dredging costs run between $2 to $3 per cubic yard, with $5
per cubic yard being the highest cost I'or the mos~ complex case. Please explain the high
costs o£'both permanent and maintenance dredging..Dredging Cost Estimates are too
hi_~h. The projected estimated armual cost of Mudcat dredging ($§00,000/65,000 cu Yd -
$I3/cu yd) is 4-5 times higher than acv.~al experience. Ifa dewatering site can be located
within 3 miles of the SFRR, such that pumping stations are not needed, then annual
operating costs in actual dredging projects are closer to $3/cu yd of material removed,
including labor and material costs and depreciation on the dredge. This calculation
assumes dmt ~ere are no other disposal costs associated with the dewatered silt.,, which
has a variety of potential uses.
#3. Alternate Release Scenarios At South Fork Rivanna River R~ervoir
It is of special interest to us that you have elected Io base m~ alternate release
scenario on the measurement of"natural flows" of the Mechums and Moorm~n_~ Rivers.
We proposed a similar measurement plan for the North and SoUth Forks of the Moormans
River. Our "proportional release plm~'~ (attached), was suggested as a means or
measuring real thee flow into the Sugar Hollow Reservoir in Qrder to determine an
amount to be voluntarily released into the Moonnans l-{iVer during the months when
diversions create dry conditions in the river bed below the Sugar Hollow Dam.
At present, because of excessive sununertim¢ usage and thc fact that ~e Sugar
Hollow Reservoir and Ragged Mountain Reservoir are used az a system, with a combined
volume of approximately 900 million gallons, and wkh a relatively small drainage area of
approximately 20 square mi[es, water is diverted that would flow naturally into the
Mom'mans, In your repo~ you recormuead the installation of stream gages on the
Moormans m~d Mechums, just above their juncmre with the South Fork Rivarma
Reservoir in order to measure their "natural flow"_ We question whether present
operating procedures would peru-fit an accurate 'natural' flow measurement of the
Moormans River'at this location.
Ed Imhoff, a certified professional geologist, points out that "the natural flow
which the Moormans contributes to the Rivarma l~ver at South Fork Dam would be the
amount of water that would flow down the Moormans, ifdrough~ inflows to Sugar
Hollow were not stored and d/vetted for municipal and industrial water supply.
'Reconstructing' the natural flow of thc Moormans...is a necessary prelude to estimating
the natural flow ~o be released from South Fork Reservoir to the Rivanna River, since the
Moormans is a nmjor trJbutazs'." (see attachment) Mr. Imhoffre¢ommends the
in~ta[lation of two additional stream, gages on the North and South Forks of the
Moormans to measure natural flow into the Sugar Hollow Reservoir, Once this natural
flow is determined, he explains, the combined mounts would be released to the
Moormans, to be measured downstream at the proposed gaging poskion near the South
Fork Rivanna Reservoir. He observes that "natural flow", including floe North and South
Donna and.Jim
9
6430 Sugar Hollo* Road
~o arman~'nsn, com
Crozer r/A22932
HO. 954 P. 18
S~llt E~IsR. 1S.2008o112:33P~ormS. E-HT-.-.B-Y-.V,H5 804 823 2636; Apr-18-00 12:06PMj Page 10/16
Frfends of l~e ,~v~oor?n~ns River
10
Forks of the Moon'nans, would likely be higher than the flow scenario proposed in
Alternate #3.
Combined discussion of#10, Conversion of Ragged Mountain ~o Pumped Storage
Reservoir and #11. Pumpback to Mechums River
We would like re present a slightly different 'alternative", combining the conversion of
Ragged Mounta/n to a pumped storage reservoir and pumpback to tko Mechurns River.
However, our idea does not require the raising of the height of the Ragged Mountain
Keservoff. Use pumpback into Mechums Pdver as described in #11. Once treated effluent
is pumped into upstream portion of Mechums, it becomes part of Meehums River flew.
Upgrade the existing pump station dorm river of doe inlet point oa the Mechurns. Pump
'run of the river' (combined river and effluent) to present Ragged Mountain Keservok
(which has a total store capaci .ty o£610 MG), With availability of pumped effluent, no
raising of the dam would be necessaw. With a new souxce of water for Ragged Mountain
Keservoir, the Sugar Hollow Reservoir could act independently of the RMR (to which it
is presently linked as a somx:e of water). The Sate Yield of the RMR would become
much larger than it ~s at presem; thus, the present "safe yield" ~vould no longer need to be
supplied by Sugar Hollow Reservoir. This additional supply could be used for release
into thc Moormans. ~t would be partially captured for Use at the SFRR and the Ragged
Mountain Reservoir could supplement supply to the Observatory. Hill Treatment Plan*._
There would be no need to raise the Ragged Mountain Dam 50 feet,, because mn of the
river flows could be made available when necessary~rrmintaining high volume ~'torage
at Raggec[ Mountain.
Note on ~11, Pm,apback: You explain the b~ne/its of pumpback to tke Mechums River in
the tbllox~qng way.'
"gradual acriYafion of the pumpback would result in maintenance of normaI stream jTow.¥
during the most a'eYere droughts that wouM otherwise completely dry the stream. This
wouM be a substantia! benefil to many species that cannot migrate to other habitats
during such .~trexxful e~entx. "
We agree wholeheartedly with tiffs s -tatement, but ar~ disappointed that similar logic ,.as
not applied to the situation in ~e Moormans River.
Water Conservation and Drought Management: General Principle~
The projected water supply deficit derives from a combination &three things:
projected increase in population sep,'ed in the County Urban Ring, continued per capita
water consumption based on historical usages, and [ess of SFP,.R sat~ yield .due to
s~lmdor~ The issue of population ~rowth control is beyond the scope of the presen~
analysis, andwe have previously d/scussed the problem of restoring and maintaining ~e
SFRR. We now wish to comment on the lack of value placed on water conservation
practices as contributing to a drought mmaagement plan.
10
~'30 Sugar Hollow Road
:91oorrn ar~ R.f~msn. corn
Crozec ~A22952
HO. 0~4 P. 11
S~n~ ~R~R.1S.200~]of12:34P~orm~.S..E-MT.-8.Y~,"~H~ 804 823 26381 l~r-18-O0 12:07PM; Pag~ 11/16
Friend~ of'the Moormans River
1'1
Recent historical t~sage patterns indicate a lack of reasonable controls on water
consumption during dry spells. The cool wemher consumption rates of this commun/ty
are typically in the range of 10-11 MGD. Most recently, summertime cormumptions have
reached [4.5 M@D, ar the safe yield of the present system, wi~out any attempts by
RWSA to intervene. This paradoxical 40% increase in consumption at a time when
reservoir recharge rotes are at their minimum s~rongly suggests that this community has
not been properly i~fformed of the problem. Tb.e response of this community in ] 977 (a
20% reduction in consumption rates) testifies to the rational belmvior of r. he water
consumers when they are told that a problem exists. We do not understand the motives
behind the lack of encouragement ro conserve water provided to the community during
dry weather, and we do not accept use of uncontrolled historical consumption rates as
predictors of future water needs,
The report suggests that an additional 5% reduction in indoor use and 25%
reduction in outdoor usc is possible. This translates m aborn 1,5 MOD reduction in
summertime consumption (0.5 MGD of indoor and 1,0 MGD of outdoor usages). This
represents overall about'a 10% reduction in peak summertime usage and a sliglxtly larger
reduction in average summertime usage. This is unrealistically low and does not reflect
flxe historical capacity of this community to reduce water consumption when asked.
Further, even this proposed level oft'educed summertime consumption (1.5
MGD) Js adequate to provide flows in the otherwise totally ch'y beginning of the
Moormans River below Sugar Hollow Dam. Such a modest saving would easily allow
1.0 MGD to be released, with the expectation ti:at the majority of released water would
be captured downstream at SFILIL
This community needs a more modem drought management policy than what is
proposed An immediate l0 % reduction in overall usage should be sought,, and more
aggressive reductions in outdoor summertime usages achieved. This eon be
accomplished by a combination of increased education and public awareness associated
with tiered usage pricing during dry seasons. Such policies could add an additional 2.5-
3:0 MOD to the summertime supply without any capital costs.
#13. Water Conservation.
.as we discussed earlier, water conservation strategies should be part of the
thinking about both water supply/demand and protection of natural resources.
Conserving water ~o preserve aquatic habitat should be given equivalent value in
plam~ing for any water diversions. For this.reason, conservation methods should be more
aggressive, especially in anticipation of drought. You state that ~'Con.servation strategies
hold the potential to reduce the need for capital investments throagh the planing period,
and could also convey significant env/ronmental benefits." Throug}x conservation, water
'sources' could be developed which are adequate to provide flow into the Moot-mans,
provide flow into the P,2vanna, and avoid drawing down Ch.ds 'Greene Lake. These arc
three desirable environmental benefits that could be achieved in the immediate future ff
aggressive conservation measures ,,,,'ere adopted right now.
In your earlier report (December 12, 1998), you described a more compreb_en~ix, e
conservation stramgy. Your present ana/ysis is limited to few suggestions for actual
water savings and conservative estimates of actual savings from these methods. Greater
reductions in .peak summer usage are more likely with modest rate changes, based on
1l
fi-q30 Stagar ttotlow Road
MoormansR(~msn. eom
Crozet, kg~ 22932
H0.054
804 823 2636j Apr-18-O0 12:07P~;
P.12
12/16
.Vriend~ of the Moormar~ River
12
recent surveys of US municipal water consumption. These are discussed in more detail
in the analysis by Nfl:. Imhoff (attached) and the letter to him from Mr. Albani, one of thc
authors of the study on which Mr. Imhoffbased his comments.
glS, Drought Management Plan.
Drought management, like water conservation, ne6ds to become part afc more
comprehensive strategy aimed at sustaining natural (water) resources. The value of
preservation of alt beneficial uses of streams, i.e., river protection, should be considered
equivalent to water supply concerns. A modern drought plan should utilize the most
sophi stieated and technologically advanced methods of assessing such variables as
t~ffall dam and soil moisture retention data. A mare modem plan would be 'predictive'
rather than reactive. Drought management strategies should represent coordinated efforts
between the two water customers (CWW and ACSA) and the Water Resources division
of the Albemarle County Engineering Department. The times when voluntary and
mandatory water restrictions are called for should be determined in the most up to dare
and scientific wa), with both resource and water supply needs 'in mind. The idea stated in
# 13 that conservation can "convey significant environmental benefits" should be applied
to Drought Management as v-ell.
We hope you find these cormnents useful in your further analyses of the water
supply problems in oux community.
Sincerely,
Donna Bennett
Attachments:
Imhoffreview and letter
Proportional release plan
CC:
Mr. Joseph Hazselll DEQ
Mr. Thomas Wilcox, D@IF
Ms. Janet Norman, USFWS
Mr. James Brogdon, ACOE
Ms. Regina Poeskc, EPA
Mr. Arthur Petrini, RWSA
Albemarle County Board of Supervisors
Albemarle County Plmming Commission
Clm.rlottesville City Council
Jim Bennett
12
6430 Sugar Hollow Road
Moarman,,RCc~rnsn. corn
Crozet, k'~ 22932
I",tO. 054
Apr"-I 8. O0 12.' 08PM;
P.13
Page 15/18
imhoff Review Comments on
"Water Supply Project: Analysis of Alternatives," Feb. 2000
In the following discussion, I comment critically on the
analysis and description of two of the alternatives included in
this VHB report to the Rivanna Water & Sewer Authority (RWSA).
Th~ alternatives I address are: "Alternative Release Scenarios at
South Fork Rivanna River Reservoir" (pp. 25-27), an~ "Water
conservation/Pricing structures," (pp. 52-54),
With respect to these alternatives, I consider the
consultant's analyses incomplete, some conclusions questionable,
and some statements contradictory.
A.- Releases downstream from South Pork Res. durinq drouqhts%
The consultant proposes a new water release scenario in
which "natural streamflow" in the estimated amount of 6.24 mgd
would be released to the Rivanna River, instead of the present
release of 8 mgd, an amount which the consultant states is not a
"regulatory requirement." The report estimates this change would
increase the year 2050 safe yield of South Fork by 1.6 mgd.
Although one could commend the consultant and RWSA for
raising the issue of "natural streamflow," this report is
incomplete without clarification--by a water rights expert (which
I am not)--of the range of possible interpretations of "natural
flow" under the riparian rights doctrine. The public officials
and citizens who read this report are owed a discussion of the
significance and likely outcome of introducing "natural flow"
considerations into the water supply planning process now
underway. It is my understanding that, under the reasonableness
test of the riparian doctrine, a wide range of interpretations of
natural flow are possible, including one I present below--that
has a different outcome than the scenario in the report.
To measure (not estimate) the natural flow of the Rivanna
River at South Fork Reservoir, VHB recommends installinq single
stream gages, on the Moormans and Mechums Rivers, Just above
their respective junctures with South Fork Reservoir. in
recommending this action, %q~B is implying that the "natural flow"
of the Moormans River during drought conditions will continue to
be that resulting from the present operating procedures of RWSA:
i.e., diversions from Sugar Hollow, which effectively dry up the
Moormans for months at a time below Sugar Hollow Dam.
Under a reasonableness test which is sometimes applied
during drought conditions--but a me~hod not used by VArB in this
report--the natural flow which the Moormans contributes %o the
Rivanna River at South Fork Dam would be the amount of water that
would flow down the Moormans, if drought inflows to Sugar Hollow
were not stored and diverted for municipal and industrial water
supply. "Reconstructing" the natural flow of the Moormans, of
course, is a necessary prelude to estimating the natural flow to
be released from South Fork Reservoir to the Rivanna River, since
the Mcormans is a major tributary.
18.Z000 ^,1£:35PM, .... SEMT BY VHB
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Page 14/16
Imhoff - 2
Under the scenario I am sketching, two additional stream
gages would be installed, one each on South and North Branches of
the Moormans River, to measure %he natural inflow to Sugar
Hollo~. (Yes, there is flow in these streams, even during severe
droughts.) These combined amounts would be released to run the
M~ormans down to the gage VHB would install just above South
Fork. The "natural flow" resulting at the VHB gage--even with
transit losses to evapotranspiration and recharge--would likely
be higher under my version of natural flow than under VHB's
version. This higher value of natural flow would, in %urn, appear
in the calculations of natural flow to be released from South
Fork Reservoir, so that the natural flow to be released to the
Rivanna River might even exceed 8 mgd.
Finally, on this subject, it is important to note the
contradiction between the following two s~atements appearing in
the VHB report:
On page 26, we find, "Under this alternative, the minimum
release would be 8 mgd cr the rate cf natural inflow to the
reservoir, whichever is less,"; while, on page 27, the reader is
advised, "Under this atternativer stream flows downstream of ~=he
dam would be the same as natural streamflows into the reservoir
during severe drought events."
The reader is left asking just what is the point and
advmnta~e of this alternative?
B.- Water Conservation/Pricing Structures:
The consultant's treatment of this important subject has
several shortcomings which need to be corrected.
First, it is disingenuous to declare that the Albemarle
County Service Authority emplcysa uniforrawater rate structure
because "...only one system user e~ceeds the 4mg threshold .... "
(The report indicates this user gets a 13% price discount on the
overage.) This line of reasoning will cause reviewers of the
report to ask: What if this user's demands grow large, or, what
if several other users join this class? Do they still get
"rewarded" for using more water?
Having made the leap of logic to declare that -uniform rates
really are in effect in RWSA service areas, the report terms the
present rate m~ructures "transitional conservation." Logically,
reviewers will ask transitional to what? Is "real" or "final
stage" water conservation what they do in Los Angeles when, the
more you use the higher rate you pay per unit? Is it the reward
(rebates) and punishment (surcharges) water users in Santa Fe
experienc~ when water supplies run low? Yes, there are
conservation programs in effect in many places in the United
States in which incentive and disincentive programs lower water
demand by a large percent during peak use periods--which are
usually dry, h~t summer months.
The repor~ preparers seem not to have found any data which
would support assertions such as the ones I've made above. To the
contrary, in evaluating increasing block rates (a form of
18. 2080 o112: 3SPH, or--S£HT BY VH~
H0.054
Apr-la-O0 12:08P~;
P. 15
Pa?_ 15/16
Imhoff - 3
surcharge), the VHB report concludes: "Because they are permanent
and can be somewhat complex, evidence suggests that increasing
block ~ates may be less effective in reducing peak demand than
more simple methods described below." Then, th~ report moves on
to consider these simple methods, Seasonal Rates and Excess-use
Rates, ~nd to conclude that "...it is estimated that savings of
1% could be realized by implementing a revised rate structure..."
In puzzling over this minuscule savings, I decided to review
a reference the VHB consultants used as authoritative for this
subject (Jordan and Albani, 1999). And, after studying the
referenced article and corresponding with one of ~he authors, I
am convinced V~IB is presenting an overly pessimistic view of this
alternative.
Jordan and Albani report on a survey of the use of
conservation rate structures by twelve water utilities, There are
some very encouraging statements in the their report, e.g.: "The
average bill for peak months increased 31 percent for residential
customers...but average use in ~he peak period declined by 33
percent" (p. 71).
In studying the Jordan article, however, and reflecting om
my ow~ professional experiences, I found myself agreeing with V-HB
that, yes, structuring of water rates is a complex business and
that "Detailed calculations of d~mand and revenue impacts should
be performed prior to any rate change." (VSB, po54).
That good suggestion should be expanded, however to-include
a trial period, perhaps during the next drought, when surcharges
will be imposed and their effectiveness measured. To relegate the
water pricing alternative to the round file, without a trial
period is unwise. ~uilding a dam or a pumpback system--or just
about any measure ~o increase water supply--is complex and full
of uncertainties. This subject of water pricing warrants a more
through and unbiased study than it has received.
Sincerely yours,
Edgar A. Imhoff
(certified professional geologist)
=~ni. ER~3R. 3. S.2000 0112:~6Pr~orm;SEHT BY 'vl-iB 804 a23 2036; Apr-18.00 12;08PMj Page 16/16
Hagler Bailly
Healer Igatlly Services, [nc.
1530 Wilson Boulevard
March 2~. ~-000
Tel: (70.~) 351.o3o0
I~axt (7o~) ~51.0342
Mr. Edgar A,. Imhoff
1,,4.$0 ~remerton lane
Kc,wick. Virginia 22947
Dear Mr. lmhoft':
I am in receipt of your letter of March 5, 2000 requesting clarification ufa point that was made in
my article that ~ppeared in the August I999 AWWA Jo~trnal. I apologize in the deity in
responding to your letter. Your letter was forwarded to me. as I am currently on a long-term
assignment to design conservation-based rotes for the Alexander General Water Authorky, here
in Alexandria, Egypt.
~or the purpose of Table 5, on Page 69 of the dourn, al, peak period does mean higlxest-use month.
Howe,~er, peak period is most commonly used in technical ardcles to mean highest-use quarter.
Many of the respondent~ to ~he survey irt the cited study expressed their dam in terrm o1: highest-
use qumxer. In my analysis, I converted everything to highest u~e month so that my comparison
between utilities wm~ valid.
With respect to the VHB consultant's conclusion that a "savlng~ of I% could be realized by
iraplemendng a revised rate structure in conjunction with other conservation measures," is too
genera] a statement and is not true universally among all water ,ystems. in fact. our study shows
that the savings could be significantly greater under the right circmnstances, The "savings" is
affected by such ~ariablcs as air temperature, scarcity of supply, size of customer ba~e. and
composition of customers (i.e., percent of residential versus other classes ~t' customers). For
example, here La t~gypt where fresh water is very scarce and air temperatures are very hot
(causing high evaporation), a 2% increase in rates during thc high use season (April - October)
causes more than a 10% reduction in residential demand, because outside water use is curtailed so
that mom ,~vater is available for agricultural irrigation,
It' you do attempt a "trial run" with a revised ram s~ructure, thc trial I~riod should be at least two
years, so that you get the beneFtt of normalization of w~ather effects, becat~se Virginia has such
variability in weather from year to year. I do a~m'ee with the ~ consultant tlmr it is be. st to
implement other conservation me, utes, along with re~tructured rates, in order to maxirnLy~ uhe
reduction in demand.
Jeff Jordan and I are pleased that you found our conservation rates study to be useful_ It-you have
any additional qu~.~tions reg'arding rares or our- study, please e-ma~l rae a~:
rfatbani~d~xm.'s.¢om, e~ or send mc ano~her'letter, i u.'ill be happy to respond to your concerns. If
you wish to talk to someone ar Healer Bailly, you can call David Earley in my absence. I-to can be
reached at 703-312-0376, -,
Best wishes in serving your citizen, group in Virginia.
Rick Albani
Profe'~ional Servk:~s Worldwide
JAMES P. WAITE
2305 Rocky ama
Chartoiie..sdll~, VA 22901
April 9, 2000
Mr. William B. Ellis, Esq.
C/o McSweeney, Burtch & Crump
P.O. Box 1463
Richmond, VA
Dear Mr. Ellis:
Enclosed is a copy of comments that I am sending to Arthur
Petrini in advance of the April 18 public meeting on RWSA's draft
analysis of water alternatives. If you have any questions on my
comlnents, please feel free to call.
Sincerely,
Jim Waite
JAMES P. WAITE
Charlottesville, VA 2290
(804) 295-93~1
April 9, 2000
Mr. Arthur Petrini
Executive Director, Rivanna Water and Sewer
~.0. Box l@
Charlottesville, VA 22902
Authority
Dear Mr. Pet.rini:
The purpose of this letter %s to give you my thoughts on the
February 2000 water supply analysis (February report) in advance
of the April 18 public meeting. I hope that you or your ~eam can
address some of the points that I raise in that meeting. It is
clear that a lot of work has gone into this report, and it
presents a good mix of potential water supply alternatives, i
think th'e report has two serious flaws, however: it does no5
analyze ute feasibility of leaving more water in the Moormans
River in Sugar Hollow, and it does not discuss the loss of
recreational opportunities and the potentially serious
environmental consequences that would rezult if we allow the
South Fork givanna Reservoir to fill with sediment. I think, that
these two issues can be addressed in your study without
significant delay or expense. At least one mix of alternatives
from your list would (1) boost safe yield by 15 MGD in 2050 for
less money than Buck Mountain Creek would cost, (2) rewater Sugar
Hollow and preserve the South Fork Rivanna Reservoir as a
reservoir, and (3) produce minimal environmental consequences-
This mix is discussed below.
I am not a water expert, and i know that i have probabl~
made some mistakes (small ones, I hope) in my calculations and
assumptions- ! apologize in advance for any such errors.
The Final Mix of klter3~atives Should Tnclude Both Watem e~va '
I am glad that you have included these alternatives in your
mix. They are among the most economics! alternatives, mhd they
benefit the environment. Your assumptions are conservative bmsed
on results from other localities. For example, you have assumed
savings of !ess than ten percent ~rom drought-period demand
management. Norfolk reduced its water demand by eighteen percent
during the 1980-81 drought through the curtailment of less
essential uses such as car washing and lmwn watering. Norfolk
ultimately cut its water demand by forty-two percent through the
use of tougher restrictions, but i agree that we should plan to
avoid severe restrictions during a drought.
I hope that you will consider a more aggressive pricing
structure than you have proposed so far ~o reduce summertime
demand. T_he Daily Progress editorial of March 30 reported that one
home in Farmington used 254,700 gallons of wauer during our
extraordinary drought last summer. We should not draw cur
streams down to pitiful levels in order to feed this kind of
extraordinarily wasteful use. (I have enclosed a cartoon that
describes the situation 'far better than Ican:) Your proposed
pricing structure may not have much effect, it would have
increased the Farmington home's water bill by only $115 for the
summer. (~2.70 - $2.25) x 254.7 thousand gallons. That will not
have much effect on this household. And a household that is
wasting .10~000 gallons of water on excessive lawn watering would
see their bill increase by only S4.50. Whether you use seasonal
rates, excess-use rates, or some other structure, you need to
give significant rewards to people who use water sparingly, and
significant penalties to people who use water extravagantly.
W~ Shgu!d Examine tkm_F_easibi!ity qf Leav%ng.More Water.in %he
~ormans in Sucar Kollo~--?ermmnentlv Combininc Alternative ~16
W~th ~ ! MGD M~nimum Release
As you know, heavy wacer withdrawals from the Sugar Hollow
Reservoir have resulted in zero release to the Moormans River ~or
extended periods of the year (often six months at a stretch) for
most of the past decade. This sisuation is not iimitsd to summer
months. I took my children to Sugar Hollow in late April 199~ to
play in the river, and the river was reduced to isolated pools
below the dam despite a good flow in the North Fork of the
Moormans above the reservoir.
The drying up of the Moormans in Sugar Hollow is a very
serious recreational and aesthetic loss to this community. The
Moormans is perhaps our most beautiful stream, as its Scenic
River status attests. Moreover, the section of the Moormans in
Sugar Hollow is the most visible and accessible section of the
river. Most of the Moormans is bordered by private property and
is away from roads. The Moormans in 'Sugar Hollow flows c~oss
beside a road, howevers~ and it is accessible to the publ±c since
the RWSA 6wns pro~erty there. This road gets substantial traffic
on weekends from people traveling to the scout camp, to fish in
the reservoir or to hike above the reservoir. These motorists
enjoy e r~re (in this county) visual trea~ when they get to drive
alongside this beautiful stream for a few miles and there is
water flowing in i5. The road is also popular with bicyclists,
especially families with children, because of the river views,
and because the road is safer than most of our county roads, it
gets almost no truck traffic, i take my children biking there
about a dozen times a year. Cyclists get an even better look at
the river than motorists do. You frequently see children playing
in the river in the mile below the dam. Finally, the river is a
stocked catch-and-release fly-fishing stream (when there is water
in it). The first mile of the Moormans below the Sugar Hollow
Dam offers more aesthetic and recreational benefits to the
General public than any other small stream in this county. These
benefits disappear during the summer months (and longer), when
they are'most needed, because the mile of river below the dam is
reduced to isolated pools and long stretches of dry rocks'.
in the past, this situation has existed not so much because
we needed the water, but because it is cheaper to use the clean,
Gravity-fed Ragged Mountain/Sugar Hollow water than South Fork
water. The KWSA has taken water out of Ragged Mountain/Sugar
Hollow first. February report at 58 and telephone conversation
with you. You have told me, and the repor~ at 58 confirms, that
the RWS~ is presently reducing the uss of Ragged Mounta±n/gugar
Hollow water in response to public concern, and to develop cost
data for Alternative 16. (You told me over the phone, however,
that you were not sure whether this change in policy would result
in substantially more w~ser cresting the dam in Sugar Hollow, or
whether it would mainly serve to keep Kagged Mountain full.) I
applaud this move, but we should take advantage of' this very
rare, comprehensive planning process to'decide whether we will
make this 'change permanent (and we should make sure that it would
benefit the Moormans in Sugar Hollow).
The existence of Alternative 16 in your mix of a!tmrnatives
presents an opportunity to evaluate rewaterinG Sugar Hollow
without significantly delaying or increasing the cost of your
study. As I understand it after talking to you, Alternative 16
says that we would gain 1 MGD of system safe yield by reducing
the use of Ragged Mountain/Sugar Hollow water during droughts to
keep those reservoirs full as long as possibie.~ It should be
relatively easy to evaluate a modified Alternative 16---
implementing Alternative 16 all of the time, not just during
droughts, and establishing a minimum release of ! MOD at Sugar
Hc!!ow. At worst, the safe yield impact of this change would be
~ou are using this operating mode now on a temporary basis,
but the base safe yield figures in the February report reflect
your traditional operating mode, which is to maximize the use of
Ragged 'Mountain/Sugar Hollow water. As i undersuand Alternative
!6, you would reduce the use of Ragged Mountain/Sugar Hollow
water to the point where those reservoirs are kept fu!!~ buu
without causing water to go over the dams.
zero--the i MGD gain from Alternative 16 minus the 1 MGD release
from Sugar Hollow- This worst case ~ssumes than none of the
released wmtar would be recovered mt the South Fork Rivanna
Reservoir. In my proposed mix of alternatives below, I have
assumed that 0.5 MGD of the released water would be recovered mt
the South Fork, but ! think that it would be fine for you to
assume zero recovery if that would simplify your analysis of this
alternative. This modified Alternative 16 would incur additional
operating costs for treating and pumping water, and probably
capital costs for expanding waterworks facilities at the South
Fork. Your present use of this operating mode should mi!ow you
to quantify the cost impact. The benefit of this alternanive is
that it would provide a minimum flow in Sugar Hollow without
costing any system safe yield that would have to be made uo from
other sources.
The RWsk position is thmt it will examine sugar ~ollow ~
this planning process is complete. This flies in the face of all
logic. The most efficient time to look at Sugar Hollow is now,
when you already have consultants at work and you have the
flexibili{y to modify plans. When you have finished your study,
lined up fin~ncinu for capital improvements~ and told people wh~5
water will cost, then it really will be difficult to come up with
some money for Sugar Hollow.
Your legal counsel has given you five reasons not 5o study a
Sugar Hollow minimum flow in this planning process: (l) the
natural flow into the Sugar Eoliow Reservoir goss to zero durin~
moderate droughts, so that a minimum release would actually
augment natural flows; (2) m minimum rs!ease is not legally
required; (3) while some released waker could probably be
captured downstream at the South Fork Reservoir (some would De
lost in route to evaporation and groundwater recharge),.using
this water might require expansion of the South Fork waterworks
mt a cost that might run into the tens of mi'llions of dollars;
(4) minimizing use of Ragged Mountain/Sugar Hollow water would
result in increased 5reatment and pumping costs, and it would
entail the effective abandonment of a portion of the Observanory
Hill waterworks; (5) the net environmental benefit of providing ~
minimum flow in Sugmr Hollow and replacing the lost water (the
portion than is lost to evaporation or groundwater recharge) with
wmter ~rom another source is unclear. It ms not clear whether
regulatory agencies would allow the RWS~ to replace the released
Sugar Hollow water with water from a new source--this would
depend on a thorough environmental assessment of the net
environmental ~effecns. Performing such an ~ssessment would delay
completion of the curr.~nt water study b~ at least one year, and
add at least $78,000 to the cost of the study. If preliminary
studies suggested a significant environmental b~nefit from a
minimum flow in Sugar Hollow, then further studies would tak~
another year or more and cost several hundred thousand dcl!ars.
February 1, !999 letter from William B. Ellis to Arthur psnrini.
This letter grossly exaggerates the difficulties of studying
Sugar Hollow as part of this planning process, and it ignores or
trivializes the ~ronq argumenns for studying Sugar Ho!~iow now.
For example, the letter totally ignores the aesthetic and
recreational benef%ts that I have discussed above. When Mr.
Ellis wrote his letter he may not have known that a change in
operating mode would allow you to release water from Sugar Hollow
without any net loss of safe yield.: I would like to address
each of the above arguments:
(1) Flow into the Sugar Hollow Reservoir does not go to zero
during normal droughts. There were visible flows into the
reservoir from both the South and the North Forks of the Moormans
even during the worst part of last year's extraordinary drought.
While the North Fork disappeared in stretches u~der the rocks
left behind by the big flood of a few years ago, it was still
flowing. If the streams kept flowing during last year's drought,
it seems unlikely that they would go close to zero in a 'normal'
drought I would like to see the evidence for the statement that
the flows into the reservoir go to zero. There is an inooe~-tive
stream gage on the North Fork, but nons on the South Fork. it is
my understanding that the gage on the North Fork was never able
to accurately measure iow flows. Is this true?
(2) A minimum release may not be legally recuired (although
Virginia Department of Game and Inland Fisheries has expressed
serioUS concern about the situation in sugar Hollow), but the
question here is whether this community ~ to keep more water
in the Moormans in Sugar Hollow and to pay the associated costs.
(3) Recapturing minimum releases for use at the South Fork
waterworks would not involve costs to expand treatment capacity
running into the tens of millions of dollars, it might not cost
anything- Keep in mind that nobody is proposing a minimum
release greater than ! MGD. Some of this water would be !os~ to
evaporation and groundwater recharge before reaching the South
Fork Reservoir, so less than ! MGD could be recovered there. As
you know, treatment capacity at the South Fork will be
underutilized in 2050 unless we adopt a!ternmtives that will make
use of it. I am assuming that we will adopt such alternatives,
however, so a ! MGD minimum release at Sugar Hollow durin~
droughts might require an expansion of, say, 0.75 MGD in
treatment capacity (0.5 MGD of water recovered x 1.5 maxlmrum day
factor). The February report indicates that a 4.5 MGD incremse
in treatment capacity would cost S$.8 million. See 8' crest
:The April 20. !9~9 water study that came out shortly after
Mr. Ellis's letter talked abou~ drought-period supply-side
measures, but it did no~ elaborate on what those measures wculd
be. It did not mention the reduction in use of Ragged Mountain/
Sugar Hollow water. See April 20, 1999 report at 22.
5
control discussion. This works out to about $1.5 million for a
0.75 MGD expansion. The logical capacity increases appear to
occur in steps, however. For example, the 8 MGD expansion in
capacity required for alternative 2.4 and the 9.6 MGD expansion
required for Alternative 20 would both cost about $20 million.
See Fsbruary report at pages 64 and 73. So the 0.75 MGD cf
treatment cmpacity might kick us up to the next step in capacity.
costing a few million dollars, or it might fall within the step
increase required by another ainernative, in which case it would
cost us nothing for treatment capacity. If we look at Sugar
Hollow relemses in this plan, then we can quickly determine the
answer to this.
(4) You should let the community decide whether rewatering Sugar
Hollow would be worth the financial expense. It is true that it
will cost more to decrease the use of Ragged Mountain/Sugar
Hollow Water and to use more South Fork water. ~he whole
of this planning process is to allow the community to make
informed decisions. Tell the community what the cost difference
would be, and let their elected officials decide. Note that the
Observatory Hill treatment capacity is a sunk cost. The oust of
abandoning some of this capacity and replacing it with Sou~h Fork
treatment capacity is discussed under point three above.
(5) Studying Sugar Hollow does not have to delay or significantly
increase the cost of this water study. First let me say that
members of this community have been asking 'the KWSA to address
Sugar ~ollow for years. I have clippings from T;ne Daily
dating back to October, 1993 demanding action on Sugar Hollow.
The County Planning Commission asked the RWSA to evaluate citizen
requests for a minimum release in Sugar Hollow back in 1997. The
county supervisors noted the need for this minimum re!esso in the
comprehensive plan that they adopted in March, 1999r anal the
supervisors voted no demand that the RWSA look a.-- a minimu-n
release. Walter Perkins, the supervisor for the dis~rict nha5
includes Sugar Kollow, asked you in February, 1999 why you must
'pull every drop out of Sugar Hollow.' You said that the RWSA was
"looking into applying for grant money to investigate dlver~ing
water from the [Sugar Hollow] reservoir." r~he Sa/fy Progress, Feb.
4, 1999 at B1, B3. (Has this gone anywhere in the past fourte-=n
months? Whey not_j_us~._study .Sugar Hollow as p_art of .this plan?
e_m ....
Your Alterna~'ive 16 shows that you have already dot ~ ~=' that
we could provide a I MGD minimum release in Sugar Ho!low. w'i~h no
net loss of system safe yield. Ail you need to develop is cost
information.) After the ~WSA presented its first drafz !'2s5 of
alternatives on April 20, 1999, you received more com~ments fr~m
the public asking you .to look at Sugar Hollow. For example, _-he
Daily Prcc_ress printed my letter in May, 1999 asking you zo roll
sugar Hollow into your study. On April 20, 1999 your study
at a very early stage of development. It weuld have been-easy
start looking at Sugar Hollow then. The public -~anted another
meeting soon where they could make their views known ~c you. The
editorial in The Uai~y Progress of May 28, 1999 was titled
~isregard for public shown by authority.' One member of your
board was quoted as saying that there was no point in having
another meeting until the RWSA had 'new information.' Th~ Progress
took this to mean ~rofessional information. The implication is
that citizen information isn't nearly as important. That the
authority doesn't need or want any more input from the people who
will actually have to drink the water, pay for the improvements
and/or use conservation measures.' me Progress noted that other
members of your board did want a public meeting, but no such
meeting took place until November, 1999, seven months later.
So the public has not been dilatory in urging you to look at
Sugar Hollow. The RWSA has had plenty of time to roll Sugar
Hollow into the current study, and the failure to do so is the
RWSA's responsibility.
But you could still roll Sugar Hollow into your study
without much cost or delay. Since the flow in the Moormans does
not naturally go to zero, it is clear that some environmental
benefit would accrue to the Moormans from a minimum release. A
low flow is healthier for aquatic life than bone-dry, dusty
rocks. It is also clear that there would be aesthetic and
recreational benefits in the mile of the stream immediately below
the dam if we. leave more water in the Sugar Hollow Reservoir and
the Moormans.~ Several regulatory agencies, including Game and
Inland Fisheries and the Corps of Engineers, attach significant
weight to aesthetic and/or recreational resources. No regulatory
agency will require us to precisely quantify the environmental
benefits of providing a small minimum release, which would be
recuired by taw..for a new d~m, if we c~n show that the release
would not cause any significant adverse environmental impacts.
We can show this now, without much additional work. It appears
that Alternative 16, modified to allow a i MGD minimum release,
~A 1 MGD release during ~ severe drought may not make much
of a difference to recreation in the Moormans (although it may
keep trout alive) but there is a significant aesthetic difference
between the-Moormans with a low flow and a bone-dry Moormans.
Moreover, if Sugar Hollow is kept full most of the time, then
there will be water coming over the dam more o~ten during periods
of normal rainfall. Over the past decade, the water level in the
Sugar Hollow Reservoir has been well below the spillway, with no
water being released, for much of the year, even during periods
of relatively normal rainfall. At those times, rains merely
served to replenish the_reservoir somewhst, if we keep the Sugar
Hollow Reservoir full most of the ~ime, then rains during non-
drought periods will cause water to flow over the dam, and we
will get substantial recreauiona! and aesthetic benefits. Having
water flow over the sugar Hollow Dam during periods of normal
rainfall is not a safe yield issue, it is ~n economic cost issue.
7
would produce a modest cain in system safe yield, or, at worst,
zero impact on safe yield. So you can tell regulators that
rewatering Sugar Hollow will have almost no adverse environmanta!
impacts. No new source of supply would b~ needed to offset a
safe yield decrease. The only possible adverse environmental
impact would be a decrease in flow of 1 MGD or lass {almost
certainly leee) at the South Fork Rivanna Dam.~ This is less
than the 1.6 MGD reduction in release proposed under Alternative
number three. Virginia's Department of Game and Inland Fieheriee
is concerned enough about Sugar Hollow that they have proposed
pumping treated effluent all the way up to ths base of the Suqar
Hollow Dam for release there.. Nov. 4, !999 letter from Raymond
T. Ferna!d to Karin Ertl at 2. This is unnecessary, but the fact
that an agency w~u!d suggest ouch an expensive solution to the
problem shows that increased flows in the Moormans would be
received favorably.
If you are worried about the regulators, you could ask them
this question now: "If we demonstrate that the'only adverse
environmental impact would be reducing the minimum 8 MGD release
an the South Fork Dam by 1 MGD or lass, and that there would be
zero loss of system safe yield (possibly a modest gain), would
you require us to prove the environmental benefits of releasing
MGD into the Moormans River,-a state-designated Scenic River, at
the Suqar Hollow Dam, which typically has a release cf zero for
about half of each year?'
In order to roll Sugar Hol!ow into your study you mainly
just need to identify the financial costs, associated with
decreasing the use of Ragged Mountain/Sugar Hollow water. This
should not involve toc much time or expense since you have been
using this mode for some time now on a tria!'basis. Moreover,
your study is still at a fairly early stage. You have-not yet
dropped some clear losers from your list of alternatives, much
less proposed a preferred alternative. The cost infcrmaaion is
at an early stage of development, it is not like you would have
tc modify a semi-finished document. Foiling to roll Sugar Hollow
into your study now may actually delay your study's completion,
because one of the regulatory agencies may insist that you
a~dress Sugar Hollow before they will approve your final plans.
And if you r~fu~e to modify your study now based on public
commen~ then you will be making a mockery of the Public comment
~If all of the ! MGD release at Sugar Hollow is lost to
evaporation or no groundwater recharge befdre reaching the South
Fork Kivann~ Reservoir, then releases at the Sou~h Fork ~ivanna
Dam would be reduced by ! MGD, because we will be taking an extra
i MGD of .treated water from the South Fork instead of Observatory
Hill.
process. You will in effect be telling the public, "yes, you can
comment, but we will not change our study based cn your comments,
because that would ds!ay us.
The Sough'Fork Rivan~a Reservoir Should Not B~ A!!ow~d to Silt-in
Like the Moormans River in Sugar Hollow, the South Fork
Rivanna Reservoir is a very important recreational resource for
this community. Many citizens already use the reservoir for
fishingr canoeing, and kayaking, despite the lack of good boat
put-ins. The put-in on Rte 676 (Woodlands) is dangerous,
requiring vehicles towing boat trailers to back up on a fairly
busy road. The canoe put-in on Reas Ford Road (Rte 660) involves
carrying the canoe down a steep, badly-rutted hill. if there
were good put-ins on the reservoir, it would be heavily used by
boaters.~ The reservoir is home to the UVA men's and women's
crews, and it is the site for a summer nature day camp that
involves canoeing- The reservoir is close to town, so people can
use it after work on summer evenings without making a long drive.
if we allow the reservoir to fill with sediment, these uses will
eventually be lost or severely curtailed. It is already becoming
difficult mo canoe into some of the more interesting coves on the
reservoir due to the sediment.
We do not know what environmental consequences would result
from abandoning the reservoir as a water storage facility end
allowing it to fill in. it might turn into a nice swamp over
zime, but we cannot assume this. -Will it become a source of foul
odors or mosquitoes? Before abandoning the reservoir to
siltation you will need to describe the consequences to the
public, and you will need to s=~dy these consequences if you do
not yet understand them.
I think that we should have a strong presumption in favor of
maintaining the reservoir as a reservoir unless costs are shown
to be prohibitive. As shown below, we can preserve the reservoir
as part of a mix of alternatives .that are more economical than
Buck Mountain Creek or the p~pback of treated effluent.
~! am not sugges~i~ng that the RWSA should pay for better
put-ins. This would be a good project for the county. The
Virg±nia DeparEment of Game and inland Fisheries has commented on
the poor angler acces to the South Fork Kivanna Reservoir, and
has offered assistance. See Nov 4, !999 letter from Raymond T.
Fernaid no Karin Ertl aE 3, 4.
?ro~osed Solution for ?roj~cted Water Su~!y Deficit of ~5
I propose the following combination of alternatives from
February 2000 report as possibly the optimum solution for
projected 2050 water deficit~ taking into account financial cost,
environmental and recreational impacts, and flexibility to meet
changed circumstances. This mix would rewater Sugar Hollow and
preserve the Soutk Fork ~iv~nna Keservoir.
increase Combined
in 2050 Capital/
t~ 0&M Cost.
(MOD) (S 000]
Water Conservation (Alt 413, page 52)
Drought Demand Mgmt (Att ~!5, page 57)
Supply Mgmt (modified Alt .#16, page 58)
Get 11.4 MGD from South Fork Rivanna
- 4' Crest Controls (Alt %4, page
- Replace Rte 676 bridge
- Scaled-back dredging (Alt %1, page !!)
- Expand treatment capacity to 17.85 MGD
L.7 $ 2,500
1.4 250
0.5 ~
7.0 2,260
- 2,000
4.4 35,0007
- ~
Total
15.0 S53,4!0
unit Cost (S/gallon)
.56
The rough cost estimate of $53.4 million needs to be
~ncreased for O&M costs associated with the modified klternacive
!6, but there is a Good chance that the dredging costs are
overstated by many millions of dollars. This mix of alternatives
w~uld be cost,competitive with other alternat±ves. For example,
pumping treated effluent back to tko Mechums River would cost $57
m:[llion for 15 ~GD; and the Buck Mountain Creek Reservoir would
cost $57 million for 14.4 MGD. The costs for water conservation,
drought demand management, and 4' crest controls are taken
straight from the February r~port, except that i am includin~ S2
million to replace the Rte 676 bridge. The report indicates the5
this would not be necessary with 4' crest controls, but this
appears to be an error.{ Moreover, raising the brid~e would
~The report states that the installation of 4' crest
controls would not necessitate the replacamen~ of the Rte 676
bridge over the reservoir. See report at page 28. But the
report states that the 4' controls would raise the normal pcoi
elevation from 382' 5o 386' (page 28) ~ and that the bottcm cf the
bridge deck is approximately a~ elevation 384' (page 3i) . if
these figures are correct, then the bridge would have 5o be
replaced.
10
certainly be necessary in order for boats 5o pass from ivy Creek
to the main reservoir.
The report indicates that O&M ccst information is being
developed for Alternative 16. Page 58. The added costs would
not be significant if Alternative !6 was implemented only during
extreme droughts, bu~ I am proposing that the Sugar Hollow
Keservoir be kept full most of the time to provide a minimum
instream flow in the Moormans in Sugar Hollow. So the added O&M
costs may be significant. We would also need to include the cosu
of a valve and gage for minimum releases at the Sugar Hollow Dam.
The 4' crest controls and scaled-back dredging would provide
a safe yield of 11.4 MGD from the South Fork, and i have assumed
that 0.5 MGD of the Sugar Hollow minimum release would be
recaptured at the South Fork for treatment there. Using the !.5
maximum day factor, the waterworks facilities would have to be
expanded from 12 MGD to 17.85 MGD. The February report ~ndicates
that a 4.5 MGD increase in waterworks capacity would cos% $8.8
million- Page 32 (8.' crest discussion). Based7 on this, i have
allowed $11.4 million for a 5.85 MGD increase.
My dredging cos{ estimate is based on figures in the report
for an annual dredging program. (Due to the length of this
calculation it appears at the end of this document.) The report
assumes that an ongoing dredging program would cost S13 per cubic
yard of dredged material, plus S5 million in infrastructure
costs. This may be slgnifi~antly overstated. The attached
information from El!icott International reports that &46,000
cubic yards of silt and sediment Were removed ~rom a i400-acre
lake in Iowa in 1990-92 at a cost of !ess than one dollar per
cubic ~ard, This sounds low, i admit. Another report from
Ellicott, also attached, indicates that a Mud Cat dredge can
remove 90 cubic yards of sediment per hour. No cost information
is given, but if this rate of removal is correct, then a
Si3/cubic yard cost. for dredging would indicate ~n hourly
operating cosz of $1,170, which seems high. Also casting dcubt
on the general accuracy of the dredging cost information in the
February report is the fact that the report shows a much higher
unit cost for a one-time dredging alternative than for annual
dredging. I hope that your consultants will give further ssudy
to dredging costs. It would be a shame to abandon the Soutk Fork
~ivanna Reservoir because ~e do not understand dredging cosss.
A cheaper mix'of alternatives Could be assembled, but 5hey
would have more unfavorable environmental and recreational
~I realize that treatment capacity increases may take ~Lace
in steps, and that it is probably not accurate ~o prorate
capacity increases in %his manner, but I am just trying ~e c~me
up with rough figures 5o spur discussion.
1!
impacts. The above mix would impact only 23 ~cres of wetlands,
and wcu!d have iong-term impacts on only 5 acres of wetlands, in
comparison, the 8' crest controls would flood 39 acres of
wetlands, destroying 26 acres permanently. Page 32. .The 4'
crest controls would flood sqme spinymussei habitat, but it is
possible that this impact could be mitigated through improvemenus
to Ivy Creek water quality. Page 30. (No money is included for
such improvements-) The 8' crest controls would flood more
spinymussel habitat, as would a Buck Mountain Creek Reservoir.
The above mix would preserve the South Fork Rivanna Reservoir ss
a recreational asset to the community. It would still be
available for fishing, boating, and competition by the UVA crew
teams. A new reservoir such as Buck Mountain Creek would be
located farther from town. It would be harder-for people to use,
especially on a summer evening after work. The pumpback of
treated effluent to the Mechums River would not preserve the
reservoir.
Another advantage of this mix is its flexibility. It
requires no large up-front capital expenditures, except possibly
for expanding treatmenn capacity. The ~' crest controls are
inexpensive, and the dredging costs would be spread out o~er
time. Dredging is flexible in that dredging rates can be
increased or decreased to reflect changed circumstances. Some of
the other supply options~ such as a Buck Mountain Creek
Reservoir, would require larger up-front capital expenditures,
and would create large amounts of temporary excess water
capacity. This might induce growth in the region and create
pressure to market water to cover costs.
I apologize for writing such a !on~ letter, but the issues
are comp!icatedr as you well know. On the attached page I have
listed a ~ew specific questions and comments regarding the
report, along with my-calculation of dredging costs.
Sincerely,
Jim Waits
cc: Col. Allan Carroll-
Raymond T. Fernald
Jack Marshall
Regina Poeske
Albemarle Board of Supervisors
William B. Ellis, Esq.
Joseph P. Hesse!!
Janet Norman
Charlottesville City Council
12
Questions ~d Co~ents ~c~rd4nc the February 2000 Re~or~
up to ~ive-foot drawdown o~ Chris Greene Lake: The report states
that under this alternative the lake would be drawn down below
normal less than 1% of the time. Page 36. This is hard to
believe, especially since we do not yet know which other
alternatives it would be combined with. Are you assuming that
Chris Greene would always be the last water resource thee would
be tapped? Since this is an important recreational resource, you
should defend the 1% number.
C~n you tell us where step cost increases occur for expaDding the
c~pacity of the South Fork Rivanna watarworks?
Can you give us the evidence that supports the belief that flows
into the Sugar Hollow Reservoir go ~o zero during normal
droughts, or during any droughts? Was s:ream flow ever measured
on the South Fork during a severe drought? Was the gage on the
North Fork able to accurately measure low flows?
Bmsed on the banks of sediment that line the Mschums River in the
vicinity of Lake Albemarle, and the dark red coicr that the
Mechums takes on after a rain, ! would expect a Mechums River
reservoir to fill with sedimenn in the blink of an eye.
I do no~ favor Alternative 3, the revised release scenario at the
South Fork Rivanna Reservoir, but i do think that you should
install the stream gages and relying described in the
alternative. These would provide basic information and control
capabilities that you need regardless of which alternative we
select, unless we abandon the reservoir, it was inappropriate
for you to reduce the releases in 1999 without public notice when
you had not put any drought period'use restricsions into effect.
This shows your extreme reluctance to ask the public 5o make
small sacrifices during severe droughts in order to keep our
'streams reasonably healthy, we were setting all-time records'for
water use (recall the Farmington house) when our stre{ms were
~nder severe stress.
13
Dredcin~ Cost C~lcu!stion (See pages 10-1!)
I assume that we will do enough dredging to increase safe yield
bY 4.4 MGD in 2050, the amount of increase that we would need tc
reach 15 MGD a~er all of the other alternatives are considered.
The October %997 Supply knalysis indicates that sedimentation
rates of approximately 65,000 cubic yards per year will reduce
the ~ross safe yield of the South Fork Reservoir from !5.2 MGD in
1997 to 6.6 MGD in 2050. Oct !997 analysis ah 12-!3- Thus,
there is a 2.50 ~al!on reduction in safe yield for each cubic
yard of accumulated sediment- (15.2 MGD - 6.6 MGD)/(65,000 cubic
yards per year x 53 years) = 2.50 gallons per cubic yard. The
safe yield must be reduced by the 8 MGD minimum release. Thus,
the projected safe yield in 2050 before dredging is minus !.~
MGD. To obtain a safe yield of 4.4 MGD in 2050, we would need to
boost safe yield by 5.8 MGD. 4.4 MGD + 1.4 MGD = 5.8 MGD. At
2.50 gallons of safe yield increase per cubic yard of sedimen~
dredged this would require dredging 2,320,000 cubic yards of
sediment between now and 2050. 5,800,000/2.50 = 2,320,000. The
February 2000 report includes two kinds of costs for annual
dredging: a fixed cost of' $5 million for infrastructure and costs
that vary with the amount of material that Will be dredged. The
variable cost for dredging 65,000 cubic yards is estimated kc be
$800~000 plus $44,000 for land. See report at %4. This totals
S844~000 or $!2.98 per cubic yard. Using this figure~ dredgin~
2,320,000 cubic yards of sediment would cost about S30 mii!icn in
variable costs, or $35 million including infrastructure.
JOHN ~I'EII/AKT BRYAN HI
P~ltsher
MARVIN E, GARRE'I'TE
Martallino Editor
Executive Edimn'
Th~-.stay, Allllat 11, 1988
Mr. Arthur Petrini
JAMES P. WAITE
2305 Rocky Run
Charlottesville, VA 22901
(804) 295-9321
Executive Director, Rivanna Water and Sewer Authority
P.O. Box 18
Charlottesville, VA 22901
Dear Mr. Petrini:
On April 9, I sent you some comments on the February 2000
water supply analysis (February report). This letter expands on
my support in those comments for partial dredging of the South
Fork Rivanna Reservoir (SFRR). In the past few days I have read
the relevant chapters from the Reservoir Sedimentation Handbook
by Gregory L. Morris and Jiahua Fan (McGraw-Hill 1998). This
book deals authoritatively with many aspects of reservoir
sedimentation, including dredging economics and the issues
involved in abandoning a reservoir to sedimentation. The book
supports the idea that the dredging costs in the February report
are far too high. I will summarize the information from the book
and then present revised cost estimates for the mix of water
supply alternatives that I proposed in my April 9 comments.
Abandoning the SFRR to Sedimentation Would Reauire a Lenathv
Analysis, It Could Produce Serious Environmental Conseauences,
and It Would Not Be Inex~ensiv~
Chapter 17 of the Sedimentation Handbook, dealing with the
decommissioning of dams, was written by George W. Annandale and
Gregory L. Morris.
Abandoning the SFRR to sedimentation would have some obvious
costs. The reservoir would no longer be available for fishing,
boating, and competition by the UVA crew teams. The
Sedimentation Handbook makes it clear that abandoning the SFRR
might produce many other hard-to-predict economic and
environmental costs. This is especially true with a reservoir
where a lot of sediment has accumulated. You face one set of
problems if you remove the dam:
Decision making to determine the feasibility of voluntary
decommissioning and dam removal is a complex process,
especially when fluvial conditions are to be reestablished
along the previously impounded reach, potentially mobil£zing
sediment that has accumulated for many decades.
Page 17.1. In other words, if you remove the dam the free-
flowing South Fork Rivanna may rapidly dislodge years of
accumulated sediment with potentially dire consequences
downstream. If ~you don't dredge the reservoir, you may have to
leave the dam in place: To leave sediments in place it is
necessary that they not be scoured and remobilized by the river
system, implying that the dam remains in place.' Page
17.6. If you breach or remove the dam and rely on natural
erosion to remove the accumulated sediments, then ~the savings
achieved at the reservoir need to be balanced against the
costs that may be experienced downstream because of the increased
sediment loading." Page 17.7. Determining whether these
downstream impacts would be acceptable would require a lengthy
and expensive analysis:
Prediction of the impact of turbidity changes on
aquatic life and habitat is a complicated issue: positive
impacts on certain species may have negative impacts on
others. Biological assessment, modeling, and monitoring of
the affected reach may be required, and biological impacts
may be an important parameter in selecting the optimal mix
of potential decommissioning actions.
Page 17.12. It may take decades for the "wave" of added sediment
to be flushed out of the downstream channel. Downstream impacts
can be severe--they dan include the blocking of tributaries and
increased flooding. Page 17.13. Dam removal can result in
various kinds of downstream monitoring costs. Page 17.14. In
summary, the Handbook says that "generally, dams are more costly
to remove than to construct .... ' Pages 17.14-17.15.
You face a different set of problems if you leave the dam in
place. This ~ay result in immediate savings, but may imply an
indefinite commitment to maintain, supervise, and operate certain
elements of the facility." Page 17.3. If you leave the dam in
place, then "future deposition of sediment may also affect
the structure of. the dam itself' and "future dam removal will
become increasingly difficult if sediments continue to
accumulate.' Page 17.3. Leaving the abandoned dam in place can
have upstream impacts:
If the dam is not removed and sediments remain in place, the
pattern of long-term sediment accumulation will continue
Not only will continued sediment deposition eventually
fill the reservoir pool, but it can also cause significant
deposition abov~ the pool level, thereby creating problems
such as increased upstream flood levels, and waterlogging of
riparian soils .... The extent of deposition above the
maximum normal rDool] level can be s±~nificant.
Page 17.12 (emphasis added).
It sounds like the analysis that would be required before we
could abandon the SFRR to siltation might be about as involved as
the entire current water study. If we decide to abandon the SFRR
there is a good chance that we will have to dredge it someday
anyway. So why not just include dredging as part of the solution
to the projected water supply deficit?
Summary of Miscellaneous Dredain~ Information in the HandboQk
The handbook speaks in terms of meters and hectares, but I
have converted these figures to feet, cubic yards and acres.
Most dredging in reservoirs is performed using a hydraulic
dredge with a rotating cutterhead. Page 16.5. This is the
technique that was proposed in the February report. The sediment
is mixed with water and removed in a slurry which can be pumped
long distances. The slurry contains much more water than
sediment, and this can impact the reservoir's safe yield unless
the slurry dewatering site is located upstream of the reservoir.
Page 16.13.
Slurry pumping efficiency can be greatly reduced by
atmospheric pressure limitations at dredging depths greater than
thirty feet. Pages 16.6-16.8. We could almost certainly avoid
this problem by dredging shallow areas of the SFRR.
Substantial amounts of debris or aquatic vegetation in
shallows can slow down dredging operations, but it is possible to
avoid the worst areas if you are only dredging a portion of the
reservoir. Pages 16.12, 16.14.
The Dredain~ of the SDrinafield. Illinois Reservoir Provide~ ~
Good Model for the SFRR.
The dredging of the Springfield, Illinois reservoir from
1987 to 1990 appears to provide a good model for partial dredging
of the SFRR. Large .reservoir dredging projects have been rare.
Lake Springfield is the largest to date in the United States at
three million cubic yards of sediment removed. Page 16.1. In
comparison, 2.2 million cubic yards of sediment have accumulated
in the SFRR to date, and another 3.2 million cubic yards will
accumulate over the next fifty years. It appears that dredging
has historically been a relatively expensive water supply option,
but other types of water sources are becoming more expensive, and
the discussion below will show that dredging is now cheaper than
many of our other alternatives.
Lake .Springfield is a shallow (original average depth 15
feet) 4,000-acre impoundment. (The SFRR has a surface area of
more than 400 acres. February report at 19.) It is heavily used
for recreation, and is ringed by 700 residences. Sedimentation
had reduced its original capacity of 97 million cubic yards by
134 or 12.4 million cubic yards. (2.2 million cubic yards~ of
accumulated sediment have reduced the useable capacity of the
SFRR by about one-third.) The accumulated sediment was 664 clay,
334 ~silt, and 14 sand. (The sediment in the SFRR is a silt-clay
mixture. February report at 11.) Dredging equipment included a
conventional cutterhead-type hydraulic dredge and a flexible
high-density polyethylene slurry pipeline. The largest pump used
was 1000-horsepower (hp),2 and an additional 1000-hp booster pump
was used for about half of the project. "Hospital-class' mufflers
were installed on the pumps.3 Seventeen tractor-trailers trans-
ported the dredge and equipment to the site. The pumping
distance to the 492-acre4 sediment disposal site ranged between
0.5 and 2.2 miles. Dikes at the disposal site ranged between
four feet and 23 feet in height. There was a very small
turbidity plume in the reservoir while the dredge was operating.
The dredge removed 2.98 million cubic yards of sediment from
the two upper arms of the lake over three years, starting in
1987. They did not dredge the main body of the lake. (The
February report assumes that we would dredge the middle and upper
regions of the SFRR, not the area near the dam. February report
at 1i.) The dredge operated twenty-four hours per day, five or
six days per week from April into December (to avoid ice). The
~64,370 cubic yards per year x 34 years from 1966 to 2000.
See February report at 11-12.
2The largest dredges that can be transported by truck have a
5000-hp pump and a solids-handling capacity of 2300 cubic meters
per hour. Hydraulic dredges typically operate twenty-four hours
per day, but actual dredging time will normally not exceed
eighteen hours per day due to the need to move the dredge and
perform maintenance. Pages 16.8 amd 16.13. Thus, a large dredge
operating five days a week, eight months per year (to avoid ice
during the winter) would have a maximum solids-handling capacity
of 5.5 million cubic yards of sediment per year. 52 weeks/year x
.67 years x 5 days/week x 18 hours/day x 2300 cubic meters/hour x
.7645 cubic yards/cubic meter. The Springfield project was
typical, however, in using a much less powerful dredge to reduce
capital costs and simplify operations. See Page 16.13.
~There were no complaints about noise despite the proximity
of residences and the 24-hour operation. Page 16.22.
4This works out to 0.165 acres per thousand cubic yards of
sediment removed. The February report assumes that we will need
4 acres for each 65,000 cubic yards of sediment, or 0.06 acres
per thousand cubic yards. See February report at 14.
4
dredging cost was $4.5 million, or $1.51 per cubic yard, end the
cost of acquiring and diking the disposal site added another $2.4
million, or $0.80 per cubic yard, for a total cost of $2.31 per
cubic yard. The disposal site was suitable for agricultural use
after two years of dewatering and consolidation. The above
information on Lake SPringfield came from pages 16.21-16.23.
Revised Cost Estimates for Proposed Mix of Water SuDDlv Options
Based on the Lake Springfield experience, it appears that
the dredging costs in the February report, which work out to $13
per cubic yard5 including land for a disposal site, are probably
far too high. I used the $13 figure in the cost summary at page
10 of my April 9 comments, so I would now like to revise those
comments to reflect a lower dredging cost. I will assume a unit
cost of $5 per cubic yard of solids removed. This is more than
double the unit cost of the Lake Springfield project, which took
place a little more than ten years ago. This should provide
ample margin for inflation and any factors that might make
dredging the SFRR more expensive. I am probably still
exaggerating the cost of dredging.
The revised cost summary for my proposed mix of alternatives
is shown below. The calculation of dredging cost appears in an
attachment to this l~tter. Please see my April 9 comments at
pages 10-12 for a detailed discussion of this mix.
Increase Combined
in 2050 Capital/
~ O&M Cost
(MGD) ($ 000)
Water Conservation (Alt #13, page 52)
Drought Demand Mgmt (Alt #15, page 57)
Supply Mgmt (modified Alt #16, page 58)
Get 11.4 MGD from South Fork Rivanna
- 4' Crest Controls (Alt #4, page 28)
- Replace Rte 676 bridge
- Scaled-back dredging (see attachment)
- Expand treatment capacity to 17.85 MGD
1.7 $ 2,500
1.4 250
0.5 TBD
7.0 2,260
- 2,000
4.4 11,600
- ~
Total (Must add TBD cost of Supply Mgmt) 15.0
$30,010+
Unit Cost (S/gallon)
$2.00+
~his is the apparent unit cost for the ongoing dredgin~
option. The unit cost for the one-time dredging alternative in
the February report is even higher.
5
The more realistic dredging cost assumption reduces the cost
of this mix by more than $23 million. The mix would cost roughly
half as much as pumping back treated effluent, and it would cost
much less than half as much as withdrawing water from the James
River. We would get aesthetic, recreational, and environmental
benefits in the bargain--rewatering Sugar Hollow and preserving
the SFRR for boating and fishing. The above mix of alternatives
avoids large, up-front capital expenditures, and it avoids large
amounts of excess water capacity that might lead to wasteful use.
Dredging makes the mix very flexible; we could increase or
decrease dredging rates to reflect changed circumstances. If
conservation measures produced more savings that expected, then
you could cut back on dredging and save money. If population
growth accelerates, then you could increase dredging rates.
The Sedimentation Handbook emphasizes that the Corps of
Engineers is the best source of expertise on dredging. I hope
that you will take advantage of that expertise in this study.
Please give me a call if you have any questions on my comments.
Sincerely,
Jim Waite
Attachment: Calculation of dredging costs
cc: Mr. James Brogden
Mr. Raymond T. Fernald
Mr. Joseph Hassell
Mr. Jack Marshall
Ms. Janet Norman
Ms. Regina Poeske
Albemarle Board of Supervisors
Charlottesville City Council
6
Dredoina Cost Calculation (Revision to page 13 of April 9
comments)
I assume that we will do enough dredging to increase safe yield
by 4.4 MGD in 2050, the amount of increase that we would need to
reach 15 MGD after all of the other alternatives are considered.
The October 1997 Supply Analysis indicates that sedimentation
rates of approximately 65,000 cubic yards per year will reduce
the gross safe yield of the South Fork Reservoir from 15.2 MGD in
1997 to 6.6 MGD in 2050. Oct 1997 analysis at 12-13. Thus,
there is a 2.50 gallon reduction in safe yield for each cubic
yard of accumulated sediment. (15.2 MGD - 6.6 MGD)/(65,000 cubic
yards per year x 53 years) = 2.50 gallons per cubic yard. The
safe yield must be reduced by the 8 MGD minimum release. Thus,
the projected safe yield in 2050 before dredging is minus 1.4
MGD. To obtain a safe yield of 4.4 MGD in 2050, we would need to
boost safe yield by 5.8 MGD. 4.4 MGD + 1.4 MGD = 5.8 MGD. At
2.50 gallons of safe yield increase per cubic yard of sediment
dredged this would require dredging 2,320,000 cubic yards of
sediment between now and 2050. 5,800,000/2.50 = 2,320,000.
Instead of the $13 per cubic yard unit cost of dredging in the
February 2000 report, I am now using a unit cost (including land
and infrastructure costs) of $5 per cubic yard based on more than
doubling the Lake Springfield unit costs. See page 5 of this
letter. Using this figure, dredging 2,320,000 cubic yards of
sediment would cost $11,600,000.
7
Sent By: Friends of the Moormans River; 804 823 2636; Aor-18-O0 2:49PMj Page 1
Friends of the Moormar~ River
April 16, 2000
Karen E. Ertl
Envirornnental Scientist
Vemasse Hangen Brustlin, Inc.
477 McLaws Circle, Suite 1
Williamsburg, VA 23185
Dear Ms. Ertl;
We are residents of and riparian landowners along the Moormans River in
Albemarle Coumy, and we write to respond to the VHB report Water Supply Project-
Analysis oj'Alternalives, which will be discussed publicly on Aprik, 18th.' We are
disappointed that in the alternatives presented there is no proposed inclusion of a minimal
flow release into the headwaters of the Moormans River. We feel this serious deficiency
arises from a combination of several oversights that in turn cause concern about the
premises underlying this report.
First, there is a false premise about the historical commitment of this community
to embrace modem drought managementtwater conservation practices. The realistic
economic and enviromncntal impacts of low-cost solutions such as water consev,'ation
m'e minimized. The concept that modest water conservation alone could restore
summertime flows in the Moormans is historically entrenched in this community's public
record and curiously is not discussed.
Second, there is minimal attempt m address water supply demand in the larger
context of environmental needs of the enti.re watershed system. As a result, thc
alternatives are presented in a piecemeal, isolated manner without integration into a
comprehensive picture of how components of the system 'interact locally and regionally.
Unregulated sodetal water requirements are emphasized without discussion of
environmental preser,~'ation within important watershed components, such as the
Moormans River.
Third, alternatives such as dredging the South Fork Rivanna Reservoir (SFRR)
are presented that are not truly choices. The silting-in of the SFRR is euphemistically
referred to as "loss of safe yield", when in fact what is not discussed ts the potential
environmental disaster (mid excessive costs) of dealing with thc resulting alteration of
upstream floodplains and sedimentation flows into the Rivanna river. Tlaus, although
recovery and maintenance dredging of the South Fork Rivanna Reservior (SFRR) is
presented as an "alternative', a closer analysis reveals that the community hlkq no realistic
choice bm to preserve this reservoir
The combined result of these omissions is that no meaningful view emerges of
documented community commitment to environmental preservation or willingness to
conserve watvr lbr the health of the watershed system. While isolated environmental
impacts of individual alternatives are discussed, overall protection of watershed ecology,
a goal stated on multiple occasions by Albemarle County, is absent. The remit is a one-
dimensional water supply alternative report built on the primary assumption that
unregulated water demand must be accommodated. If community water policy and
environmental priorities had been considered, den'ia, nd figures would be significantly
Donna and dim Bennett
1
6430 ~ugar Hollow Road
MoormansR~a.~msn. corn
Crozet. V.4 22932
Sent By: Friends of the Moormans River; 804 823 2636; Apr-18-O0 2:49PM; Page 2
Friends of the Moormans River
· altered, summertime water flows in thc Moormans could have been easily
accommodated,: and a more realistic set of alternatives could have been produced.
Planning for release into the Moormans River should have been considered from the
outset of the VIIB stud.v.
For years, we have been asking Albemarle County government and the RWSA to
help solve the problem of no flow in the Moonnans. Over the years many more people
and groups have joined tls. This issue was already well known to RWSA before thc
permitting process began in the fall of 1997.
March 4, 1997: On this date we appeared before the Planning Commission
during a Work Session on the need to include "Water Conservation" as part of the
Comprehensive Plan. Thus, Arthur Petrini (RWSA) and Bill Brent (ACSA) were
present. Among topics of discussion were water supply issues and "the charge of the
ACS.~ and the City of Charlottesville Public Works Department to develop a Water
Conservation Program (with the RWSA offbring supporO ", We asked the Planning
Commission that "the Moormans River be given minimum in-stream flow protectian
within the frameworl~ of the Comprehensive Plan ", We also requested that RWSA
modil'y the dam during upcoming repairs to incorporate release of water, David Tiee
(Planning Commissioner) recommended that in redraffing this sect{~n of the
Comprehensive Plan, the follow~ng point should be emphasized:
"the Water Efficiency section should not only be county poticy for meeting future
demand' but should also say that we have existing goals which might include restoration
of an instream./tow on the Moormans River, that demand-side management of water
should be a priority for the community." This section was rewritten as suggested by the
Planning Commission and approved by the Board of Supervisors, It includes a reference
to the need for water conservation and sets lbrth the goal of restoration ofinstream flow
in the Moormans.
Several months after the Planning Commission meeting, we went before the
RWSA Board and asked them again to incorporate a release mechanism into their
proposed dam alteration plans for thc Sugar Hollow Reservoir. Our request was denied.
The sin'tple modifications that would have been necessary were not incorporated.
In addition, during a telephone call that summer, Arthur Petrini advised us to
present our reques~ to VHB ar the outset of their study. He said we would have an
opportunity to ask for minimum in stream flow at a public meeting planned for the fall.
He explained that the potential loss of water from the Sugar Hollow Reservoir would
have to be fiactored in by VHB as they evaluated overall supply and demand. However,
as it turned om, this meeting never took place.
Our community has a history extending back several years of requesting tlmt
minimum flows during summertime periods be e~tablished by RWSA in thc headwaters
of the Moormans River. There has been ample opportunity to include this calculation of
Donna and Jim Bennett
2
6430 Sugar Hollow Road
MoormansR(d_)/rn,~n. corn
Crozet, FA 22932
Sent By: Friends of the Moormans River; 804 823 2636; Apr-18-O0 2:50PM; Page 3
Friend; o./'rhe Moormans River
release fi:om Sugar Hollow Dam in the water supply planning process, and we are ~.mclear
as to why this has not taken place.
In addition, [we Commonwealth of Virginia Agencies involved in the permitting
process have recently expressed concern about lack of flow in the headwaters of the
Moormans River.
"We recommend that the RWSA release flows into the Moormans River at the base of
Sugar ttollow reservoir or in the White Hall vicinity. Currently, the flow in the
Moormans River is significantly reduced because of the Sugar Hollow diversion and lack
of any release requirement: FJow releases into the Moormans River instead of the
Mechums R~ver will solve a low-flow problem that hm' been a concern for our agency
and area residents. "(Raymond T. Femald, Manager,Environmental Services Section,
Department of Game and Inland Fisheries)
"Lastly; sacrificing instream flows on the Moormans River and on the South Fork
Rivanna River may make good water supply policy but be bad enviromnental policy.
'That type of over appropriation could re,sult in the unintended consequence of spawning
the ever Surface Water Management Area" (Joseph P. Hassell, Environmental Program
Manager, Department of Environmental Quality)
There is an extensive chronology of public concern about lack of flow in the
Moormans River:
Timeline of Events to Provide Minimum Flow to the Moormans River
* j993. We observe first period of prolonged drying of riverbed, prompting front
page story in Richmond Time,'. We inform State Scenic River Advisory Board.
Match 4, t 997_. We go before Planning Cormnission, with RWSA
representatives present. (See discussion above) Make requests: (1) Problem of
MIF during summer months be addressed in context of Comprehensive Plan.
Planning Commission acts on our request (final draft of Water Resources portion
of Comprehensive Plan subsequent>, contains reference to Moormans RiVer). (2)
Also, mque~t that MIF be provided for during dam repairs being planned by
RWSA. Planning COmmission asks RWSA to consider our request.
July 24, 1997~We write follow up letter to Arthur Petrini, Executive Director of
RWSA, with tull text of presentation to Planning Commission, asking what
RWSA plans to do.
~~We appear before RWSA Board of Directors Meeting. State
problem, cite peer-reviewed literature documenting negative effects of dry river
bed on macroinvertebrate populations, state belief that water usage policy violates
spirit of lav~; note RWSA has no formal water conservation program. We are told
RWSA will not release any water into Moormans.
Donna and.lira Bennett
3
6430 Sugar Hollow Road
MoormansR(~>msr~ eom
Crozet, VA 22932
Sent By: Friends of the Moormans Rlver; 804 823 2636; Apr-18-00 2:51PM; Page 4
Friends of the Moormans River
4
December, 1997--We request Arthur Petrini, RWSA, to hold a public meeting re:
dam repairs of the Sugar Hollow Dmu. Wc arc told meeting would only be. held
after RWSA makes its final decision on a repair plan. Not to be a meeting to
solicit opinion about design options. However, Alterations Permit would allow
"Local Advisory Committee".
May 27_, 1998- -We send letter (via email) to Kay Slaughter (Mayor of
Charlottesville) re: planned Sugar Hollow Dam. repairs and opportunity to change
dam to accommodate MIF.
June 9. ! 99g--Public Information Meeting is held by RWSA re: final design
plans for Sugar Hollow Dam repairs. Our requested changes to dam for MIF,
made at March, 1997 Planning Commission Meeting, are disrewarded. Many
others, attending meeting, request minor moditications of the Sugar Hollow Dam
to 'allow release. These include adding valve to outflow pipe or siphon tube. We
question tier that final repairs decided upon by RWSA, although, more costly than
other repair alternatives, would not trigger 401 Certification that would change
MIF status of Sugar Hollow Dam. We question whether repair alternative
selected by RWSA is chosen primarily because it would avoid need for Federal
401 certificate, wtfich would require MIF study and environmental impact study.
August, 1998--We meet with Robert Tucker (Albemarle County Executive
Director and member of Board of Directors of RWSA) to go over full-scale of
Moormans River problem.
September 20, 1995--We send follow up email to Mr. Tucker.
October 5, 1998~We write first letter to Emily Courie, with information given to
Mr. Tucker.
· October 29, 199g--Ten local groups, representing hundreds of people, meet
informally with Arthur Petrini to discuss Moormans River problem. We propose
concept of proportional release of water from Sugar Hollow dam into Moormans.
Arthur Petrini states RWSA's position as follows: MI!= in the Moormans is not
possible because it will cause premature depletion of Sugar Hollow reservoir
supply under drought conditions. This will lead to institution of wa~er
conservation procedures two weeks earlier than planned. Also, RWSA has no
control over demand mad cannot request water conservation measures from their
"customers", the Albemarle County Service Authority and the Charlottesville
Water Works. Requests for water conservation must originate from governing
boards of these customers or in the Board of Supervisors and City Council. Mr.
Petdrd states that the sole mission of the RWSA is to provide water to their
customers.*
* La-~t spring, just before the 1999 drought, it was discovered that there v/as no
county ordinance or state law that detailed a drought management plan. It was
decided that Bill Brent. Executive Director of the Albemarle County Service
4
Donna and Jim Bermetf 6450 Sugar ttollow Road Crozet, FA 22932
Moorraa~R(q~rnsn. eom
Sent By: Friends of the Moormans River; 804 823 2636; Apr-18-00 2:51PM;
Page 5/17
Friends of the Moorrnans River
5
Authority should write such an ordinance.) Therefore, RWSA could have
changed procedures to accommodate voluntary release into the Moormans by
choosing to ask for voluntary water conservation much earlier in the evolving
drought.
..January., 1.999. County Board of Supervisors passes Natural Resources Section of'
Comprehensive Plan containing reference to need for water conservation planning
and need for MIF in Moonrtans River.
February. 1999--We present Moormans River problem and proposal fbr
voluntary proportional release by RWSA to members of Citizens for Albemarle.
Arthur Petrini present fbr RWSA position and debate on subject.
March 3, 1999--Presentation jointly by residents of Sugar Hollow and Moormans
Seenic River Advisory Board to Albemarle County Board of Supervisors. We
give summary of problem, propose voluntary proportional release, submit
answers to Sally Thomas's questions in advance. Then, we take part in Work
Session with Board. Final decision: Albemarle Count3, Board of Supervisors
asks P~WSA to stop telling them they can't find a solution to the problem and to
come up with potential solutions to provide minimum flow. No known follow up
from RWSA to Board to this date.
April 15, 1999---LWV publishes booklet on "Water in the New Millennium:
Balancing the Needs of People and the Environment", with reference to
Moormans River problem as part of overall water supply issues.
&l~.ril 20, 1999---VIIB presents information regarding Alternatives for water
supply. Public asks about fate of Moormans River in plaiming for new water
supply.
June 5, 1999_~group of interested citizens form ad hoc Water Conservation
Committee tn discuss need for water conservation plan in the community and
need for comprehensive watershed policy coordinated among RWSA, Albemarle
County and Charlottesville City. Moormans River problem cited as primary
example of lack of coherent policy.
J_me 15. 1999~We meet with Mr. J.W. Brent, Executive Director of the
Albemarle County Service Authority, and request assistance in developing a
water conservation 'pledge' plan. Our 'public relations' idea would promote
water conservation as a means for people to play a role in putting water back in
the Moormans. Water consumers would directly participate in benefiting natural
resources through thek water savings. Several protection areas could be targeted
along with the Moormans River, such as Chris Greene Lake and the Rivanna
River. He receives the idea favorably, but the details are yet to be worked out
(and no promises).
* June 15, 1999~We present the same idea to County Board of Supervisors.
5
Donna and dim Bennett 6430 Sugar Hollow Road Crozet, VA 22932
Moorman~R{~msn. corn
Sent By: Friends of the Moormans River; 804 823 2636; Apr-18-O0 2:52PM; Page 6/17
Friends of the Moormans River
June 2 t, 1999--We send letter to RWSA critiquing VHB Alternatives with
sp~cifl emphasis on our concerns re: no water in Moormans. (ce: to federal and
state regulators, Charlottesville City Council, and Albemarle Cmmty Board of
Supervisors).
July, 1999---League of Women Voters and Rivarma Roundtable request two Joint
Work Sessions of Albemarle County Board of Supervisors and Charlottesville
City Council. Purpose of request: to give the adhoc Water Conservation
Committee members or representatives an opportunity to address concerns about
water conservation, water supply planning and coordinated, comprehensive
watershed planning.
August 6, 1999. Second letter to Senator Emily Couric, describing the problem
and detailing our ettbrts to solve the problem locally.
November 18, I999 ad hoc Water Conservation Committee presents concerns
about water supply planning process and decision-making issues. Moormans
River cited as prime example of lack of coherent policy.
February. 14, 2000. J.W. Brent responds in a letter to our request of June 15, 1999.
Citing software costs as the main mason he writes that ACSA cannot develc~p "a
community chest" type water conservation campaign.
Conclusion:
Omitting restoration of surm~nertime flow in the Moormans from the report is not
acceptable. The Moormans River must be given autonomous status in the current
platming process as a highly v~ued and environmentally sensitive component of the
watershed system. This conclusion is supported by both the community's historical
devotion and commitment to the Moormans and the opinions of the two major Virginia
environmental regulatory agencies.
Donna and Jim Bennett
6
6430 Sugar Hollow Road
.~loormansR(~msn. com
Crozet, VA 22932
Sent By: Friends of the Moormans River; 804 823 2636; Apr-18-O0 2:52PM;
Page 7/1 7
I~'riends of the Moormans River
7
There is a long-standing history of support in this community for water
conservation.
We wish to point out that certain premises underling the demand and supply
analyses of this report are questionable. Specifically, this report does net reflect the
historical interest and public involvement of this community with respect to its water
rc3oflrC~$,
1. I.'h¢ report fails to acknowledge this community's track record in reducing
water consumption when asked to. tn addition to the Planning Commission
comments of March, 1997 (see above), a water conservation plan had been
studied and approved by RWSA in 1979. In 1979, RWSA Board approved the
report from "The Four Party Conservation Committee". After a drought in the
summer and fall of 1977 and another dry period in 1978, the committee
determined that there was a need "to provide a continuing program aimed at
permanent water cm~servation." "[he report noted that a 20% reduction in
consumption was achieved in 19 77; and thus, ',timed at a setting a goal of"ton
percent reduction in watex consumption". In spite of the tact that the proposed
water conservation plan was approved by RWSA, it was never put into practice.
Although we do not know why that occurred, what is important is the fact that a
goal of a permanent reduction of 10% of Water consumption w~q part of RWSA's
thinking at that time.
2. One of the most compellin~ examples of community inv.olvement in water
resource issues is the attempt over many years by the League of Women Voters to
bring water conservation policy changes to fruition. Most recently: (a). The
League's suggestion to create Citizens Advisory Committee for RWSA was
moti.vated by a desire to address the need for a water conservation plan through
citizen input. (b) The adhoc Water Conservation Committee, composed of city
and county residents, was initiated by the League. This interest of the League
arose from an interest in water conservation as part of strategy to protect and
sustain natural resources.
Conclusion:
Thus, there is every, reason to believe that our cormnunity would respond
favorably and in a quantitatively significant manner to requems to conserve water. As
discussed above, there is an extensive historical commitment in this community, in both
desire and action, to utilize water conservation as a means to protect the environment and
extend the usefulness of our water supplies. The major consequence for this report of our
community's commi'tment to waer conservation is the manner in which demand figures
were calculated. For that reason, several demand scenarios could have been proposed at
the outset of the permitting process, instead of a single, worst case. In particular, an easily.
achieved 10% reduction in summertime usage would have provided both adequate water
for release into the he',utwaters of the Moormans River and a significant reduction in
overall demand figures.
Donna and Jim Bennett
7
6430 ,g~tgar Hollow l~oad
Moor m ansR ®msn. c~m
Crozet, VA 22932
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Friends of the Moormans River
Loss of"safe yield"at SFRR is not an option.
The continued silting in and marked reduction of storage capacity ia the SFRR
wu uld re prescm loss of both recreational and water supply resources for this community.
Both of these losses would need to be decided ahead of time by the affected public, and
public discussion of the consequences of SFRR loss has not yet taken place.
What is not discussed in this report are the practical consequences of allowing the
SFRR to silt-in. As discussed the Reservoir Sedimentation Handbook (RSH, G.L. Morris
~d J. Fan, McGraw Hill, 1998), there are multiple potential negative upstream and
downstream consequences of reservoir silthlg-in that must be considered before the
option is exercised of decommissioning a reservoir/dam system due to siltation. Among
these consequences are effects on upstream and downstream floodplains and
environmental impacts of downstream delivery of sediment loads during the
decommissioning process.
Given the episodic high flows in the RR corridor, alteratiOn of upstream
floodplain morphology and consequences ro landowners along the new floodplains need
to be modeled. A decision by local government to allow siltation infill of the SFRR may
resultin "Jinxings'" ' "orpnvate" ' properties' due to upstream floodplain encroachment, with
associated costs of restitution.
Abandonment of the SFRR will 'require planning as to whether partial breaching
of'the SFRR dam will be done to allow a sedimentation channel to form, what the
consequences of delivery of such sedimentation to the downstream Rivanna river might
be, and whether significant sediment delivery downstream would even be allowed by
current environmental regulations. It is not inconceivable that environmental regulations
would require that abandonment of the SFRR necessitate sediment removal and disposal
l]rom the reservoir on a much larger scale than that proposed in this report for partial
reservoir recovery and maintenance.
It is very unlikely that the SFRR dam would be allowed to remain in place
unaltered, due to the potential of floodwaters breaching the dam abutments and causing
dana instability. Thus, partial dam breaching to allow floodwater passage, and the
resulting increase in sediment delivery' downstream must be factored in before any
decision can be made to consider loss of the SFRK
Conclusion:
Loss of'the SFRR due to silting-in carmot be considered an option at this time.
Viewing zhe reservoir as simpty filling up and becoming a wetlands is not consistent with
known consequences ofre~qervoir siltation. Upstream and downstream floodplain and
sedimentation consequences have not been considered and are likely to be economically
and environmentally prohibitive. Abandonment of the SFRR dam would likely require at
least partial dam breaching, which in turn would require sediment management to prevent
downstream environmental impacts. This could turn out to be more costly than measures
proposed to reduce sediment inflow into SFRR and maintain reservoir volume by
maintenance dredging.
Donna and Jim Bennett
8
6430 Sugar Hollow Road
MoormartsR(~msn. corn
Crozet, VA 22 932
Sent By: Friends of the Moormans River; 804 823 2636; Apr-18-O0 2:54PM;
Page 9/17
Friends of the Moormans River
9
Comments on Specific Alternatives
#1, Dredge South Fork Rivanna Reservoir.
As discussed curlier, we do not feel dredging should be considered as an
alternative. Because costs are discussed in this section, however, we will address the
subject of dredging costs in this section. According to the Reservoir Sedimentation
Handbook, t~q~ical reservoir dredging costs run between $2 to $3 per cubic yard, with $5
per cubic yard being the highest cost for the most complex case. Please explain the high
costs of both permanent and maintenance dredging. Dredging Cost Estimates are too
.high. The projected estimated annual cost of Mudcat dredging ($800,000/65,000 cu yd -
$13/cu yd) is 4-5 times higher than actual experience. If a dewatering site can be located
within 3 miles of the SFRR, such that pumping stations are not needed, then annual
operating costs in actual dredging projects are closer to $3/cu yd of material removed,
including labor and material costs and depreciation on the dredge. This calculation
assumes that there are no othm-disposal costs associated with the dewatered silt, which
has a variety of potential uses.
#3. Alternate Release Scenarios At South Fork Rivanna River Reservoir
It is of special interest 1o us that you have elected to base an alternate release
scenario on the measurement of"natural flows" of the Mechums and Moormans Rivers.
We proposed a similar measurement plan for the North and South Forks of the Moormans
River. Our '~proportional release plan" (attached), was suggested as a means of
measuring real time flow into the Sugar Hollow Reservoir in order to determine an
tmmunt tc be voluntarily released into the Moormans River during the months when
diversi OhS create dry conditions in the river bed below the Sugar HoLlow Dam.
At present, because of excessive summertime usage and the fact that the Sugar
Hollow Reservoir and Ragged. Mountain Reservoir are used as a system, with a combined
volmne of approximately 900 million gallons, and with a relatively small drainage area of
approximately 20 square miles, water is diverted tlmt would flow naturally into the
Moormans. In your report, you recommend the installation of streara gages on the
Moormans mad Mechums, just above their juncture with the South Fork Rivanna
Reservoir in order to measure their "natural flow". We question whether present
operating procedures would permit an accurate 'natural' flow measurement of the
Moormans River at this location.
Ed Imhoff, a certified professional geologist, points om that "the natural flow
which the Moormans contributes to the R_ivanna River at South Fork Dam would be the
amount of water that would flow down the Moorrnans, if drought inflows to Sugar
Hollow were not stored and diverted for municipal and industrial water supply.
'Reconstructing' the natural flow of the Moormans...is a necessary prelude to estimating
the natural flow to be released from South Fork Reservoir to tl~ Rivanna River, since the
Moormans is a major tributary." (see attachment) Mr. Imhoffrecommends the
installation of two additional stream gages on the North and South Forks of the
M oormans to measure natural flow into the Sugar Hollow Reservoir. Once this natural
flow is determined, he explain, the combined amounta would be releazed to the
Moormans, to be measured downstream at the proposed gaging position near the South
Fork Rivarma Reservoir. He observes 'daat "natural flow", including the North and South
Donna and Jirn Bennett
9
6430 Sugar Hollow Road
MoormansRtf.~msn. cam
Crozet, V~ 22932
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Frien&' of the Moormans River
10
Forks of the Moormans, would likely be lfigher than the flow scenario proposed in
Alternate #3.
Combined discussion of #10. Com~ersion of Ragged Mountain to Pumped Storage
Reservoir and #11. Pumpback to Mechums River
We would like to present a slightly different 'alternative", combining the conversion of
Ragged Mountain to a pumped storage reservoir and pumpback to the Mechums River.
However, our idea does not require the raising of the height of the Ragged Mountain
Reservoir. Use pumpback into Mechums River as described in #11. Once treated effluent
is pumped into upstream portion of Mechums, it becomes part of Mechums River flow.
Upgrade the existing pump station down river of the inlet point on the Mechums. Pump
'mn of the river' (combined river and effluent) to present Ragged Mountain Reservoir
(which has a total store capacity of 610 MG). With availability ofpmnped effluent, no
raising of the dam would be necessary. Wilt~ a new source of water for Ragged Mountain
Reservoir, the Sugar Hollow Reservoir could act independently of the RMR (to which it
is presently linked as a source of water). The Safe Yield of the P~elR would become
much larger than it is at present; thus, the present "safe yield" would no longer need to be
supplied by Sugar Hollow Reservoir. 'Ibis additional supply could be used for release
into the Moormans. It would be partially captured for use atthe SFRR and the Ragged
Mountain Reservoir could supplement supply to the Observatory Hill Treatment Plant.
There would be no need to raise the Ragged Mountain Dam 50 feet, because run of the
river flows could be made available when necessary--maintaining high volume storage
at Ragged Mountain.
Note on gl 1, Pumpback: You explain the benefits ofpumpback to the Mechums River in
the following way:
"gradual activation of the pumpback would result in mainlenance of normal stream fiows
during the most severe droughts that wouM otherwise co~npletely dry the ,~tream. This
would be a substantial benefit to many species that cannot migrate to other habitats
.during such stressful event~', "
We agree wholeheartedly with this statemem, bat are disappointed that similar logic was
not applied to the situation in the Moormans River.
Water Conservation and Drought Management: General Principles
The projected water supply deficit derives from a combination of three things:
projected increase in population served in the County Urban Ring, cominued per capita
water consumption based on lfistorical usages, and loss of SFRR safe yield due to
siltation. The issue of population growth control is beyond the scope of the present
analysis, and we have previously discussed the problem of restoring and maintaining the
SFRR. We now wish to comment on the lack of value placed on water conservation
practices as contributing to a drought management plan.
Donna and .]in, Bennett
10
6430 Sugar Hollow Road
MoormamR(¢msn. corn
Crozer. ~/f 22932.
Sent By: Friends of the Moormans River; 804 823 2636; Apr-18-O0 2:55PM;
Page 1'/17
Friend~ of the Moormans River
11
Recent historical usage patterns indicate a lack of reasonable controls on water
consumption during dry spells. The cool weather consumption rates of this community
are typically in the range of 10-11 MGD. Most recently, summertime consumptions have
reached 14.5 MGD, at the safe yield of the present system, without any attempts by
RWSA to intervene, This paradoxical 40% increase in consumption at a time when
reservoir recharge rates are at their minimum strongly suggests that this community has
not been properly informed of the problem, The response of this community in 1977 (a
20% reduction in. consumption rates) testifies to the rational behavior of the water
consumers when they are told that a problem exists. We do not understand the motives
behind the lack of encouragement to conserve water provided to the community during
dry weather, and we do not aecepi use of uncontrolled historical consumption rates as
predictors of ihture water needs,
The report suggests that an additional 5% reduction in indoor use and 25%
reduction in outdoor use is possible. This translates to about 1.5 MOD reduction in
summertime consumption (0.5 MOD of indoor and 1,0 MOD of outdoor usages). This
represents overall about a 10% reduction in peak summertime usage and a slightly larger
reduction in average summertime usage. This is unrealistically Iow and does not reflect
the historical capacity' of this community to reduce water consumption when asked.
Further, even dais proposed level of reduced summertime consumption (1,5
MGD) is adequate to provide flows in the otherwise, totally dry beginning of the
Moormans River below Sugar Hollo,.' Darn. Such a modest saving would easily allow
1.0 MGD to be released, with the expectation that the majority of released water would
be captured downstream at SFRR.
This community needs a more modern drought management policy than what is
proposed.. An immediate 10 % reduction in overall usage should be sought, and more
aggressive reductions in outdoor summertime usages achieved. This can be
accomplished by a combination of increased education and public awareness associated
with tiered usage pricing during dry seasons. Such policies could add an additional 2,5-
.3.0 MGD to the summertime supply without any capital costs.
#13. Water Conservation.
As we discussed earlier, water conservation strategies should be part of the
thinking about both water supply/demand and protection of natural resources.
Conserving water to preserve aquatic habitat should be given equivalent value in
planning for any water diversions. For this reason, conservation methods should be more
aggressive, especially in anticipation of drought. You state that "Conservation strategies
hold the potential to reduce the need for capital investments through the planing period,
,tand could also convey significant environmental benefits." Through conservation, water
'sources' could be developed which are adequate to provide flow into the Moormans,
provide flow into the R,ivanna, and avoid drawing down Chris Greene Lake. These axe
three desirable environmental benefits that could be achieved in abe immediate future if
aggressive conservation measures were adopted ri*~ht now.
In your earlier report (December 12, 1998), you described a more comprehensive
conservation strategy. Your present mmlysis is limited to few suggestions for actual
water savings and conservative estimates of actual savings from these meflaods. Greater
reductions in peak summer usage are more likely with modest rate changes, based on
Donna and .Jim Bennett
11
6430 Sugar Hollow Road
Mm~rmansR@jnsn. corn
Crozet, VA 22932
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Friem;k of the Moormans River
12
recent surveys of US municipal water consumption. These are discussed in more detail
in the analysis by Mr. Imhoff (attached) and the letter to him from Mr. Albani, one of the
authors of the study on which Mr. Imhoffbased his comments.
015. Drought Managemcnt Plan.
Drought management, like water con~rvafion, needs to become part cfa more
comprehensive strategy aimed at su.qtaining natural (water) resources. The value of
preservation of all beneficial uses of streams, i.e., river protection, should be considered
equivalent to water supply concerns. A modem drought plan should utilize the most
.sophisticated and technologically advanced methods of assessing such variables as
rainthll data and soil moisture retention data. A more modem plan would be 'predictive'
rather than reactive. Drought management strategies should represent coordinated efforts
between the two water customers (CWW and ACSA) and the Water Resources division
of the Albemarle County Engineering Department. The times when voluntary and
mandatory water restrictions are called for should be determined in the mo~t up to date
and scientific way with both resource and water aupply needs in mind. The idea stated in
#13 that conservation can "convey significant environmental benefits" should be applied
to Drought Management as well.
We hope you find these comments useful in your further analyses of the water
supply problems in our community.
Sincerely,
Donna Bennett
Attachments:
IrnholT review and letter
Proportional release plan
CC:
Mr. Joseph Hassell, DEQ
Mr. Thomas Wilcox, DGIF
Ms. Janet Norman, USFWS
Mr. James Brogdon, ACOE
Ms. Regina Poeske, EPA
Mr. Arthur Petrini_, RWSA
Albemarle County Board of Supervisors
Albemarle County Planning Commission
Charlottesville City Council
Jim Bennett
Donna and Jim Bennett
12
6430 Sugar Hollow J~oad
MoormansR ~,msn. corn
Crozet, VA 22932
Sent By: Friends of the Moormans River; 804 823 2636; Apr-18-O0 2:56PM;
Page 13/17
Imhoff Review Co~L~ents on
"Water Supply Project: Analysis of Alternatives," Feb. 2000
In the following discussion, I comment critically on the
analysis and description of two of the alternatives included in
this VHB report to the Rivanna Water & Sewer Authority (RWSA).
The alternatives I address are: "Alternative Release Scenarios at
South Fork Rivanna River Reservoir" (pp. 25-27), and "Water
conservation/Pricing structures," (pp. 52-54).
With respect to these alternatives, I consider the
consultant's analyses incomplete, some conclusions questionable,
and some statements contradictory.
A.- Releases downstream from South Fork .Res. durinq drouuhts~.
The consultant proposes a new water release scenario in
which "natural streamflow" in the estimated amount of 6.24 mgd
would be released to the Rivanna River, instead of the present
release of 8 mgd, an amount which the consultant states is not a
"regulatory requirement." The report estimates this change would
increase the year 2050 safe yield of South Fork by 1.6 mgd.
Although one could commend the consultant and RWSA for
raising the issue of "natural ~treamflow," this report is
incomplete without clarification--by a water rights expert (which
I am not)--of the range of possible interpretations of "natural
flow" under the riparian rights doctrine. The public officials
and citizens who read this report are owed a discussion of the
significance and likely outcome of introducing "natural flow"
considerations into the water supply planning process now
underway. It is my understanding that, under the reasonableness
test of the riparian doctrine, a wide range of interpretations of
natural flow are possible, including one I present below--that
has a different outcome than the scenario in the report.
To measure (not estimate) the natural flow of the Rivanna
River at South Fork Reservoir, VHB recommends installing single
stream gages, on the Moormans and Mechums Rivers, Just above
their respective junctures with South Fork Reservoir. In
recommending this action, VHB is implying that the "natural flow"
of the Moormans River during drought conditions will continue to
be that resulting from the present operating procedures of RWSA:
i.e., diversions from Sugar Hollow, which effectively dry up the
.~Moormans for months at a time below Sugar Hollow Dam.
Under a reasonableness test which is sometimes applied
during 4fought conditions--but a method not used by VHB in this
report--the natural flow which the Moormans contributes to the
Rivanna River at South Fork Dam would be the amount of water that
would flow down the Moormans, if drought inflows to Sugar Hollow
were not stored and diverted for municipal and industrial water
supply. "Reconstructing" the natural flow of the Moormans, of
course, is a necessary prelude to estimating the natural flow to
be released from South Fork Reservoir to the Rivanna River, since
the Moormans is a major tributary.
Sent By: Friends of The MooPmans RiveP; 804 823 2636; ApP-18-O0 2:57PM;
Page 14/17
Imhoff - 2
Under the scenario I am sketching, two additional stream
gages would be installed, one each on South and North Branches of
the Moormans River, to measure the natural inflow tc Sugar
Hollow. (Yes, there is flow in these streams, even during severe
droughts.) These combined amounts would be released to run the
MoOrmans down to the gage VHB would install just above South
Fork. The "natural flow" resulting at the VHB gage--even with
transit losses to evapotranspiration and recharge--would likely
be' higher under my version of natural flow than under VHB's
version. This higher value of natural flow would, in turn, appear
in the calculations of natural flow to be released from South
Fork Reservoir, so that the natural flow to be released to the
Rivanna River might even exceed 8 mgd.
Finally, on this subject, it is important to note the
contradiction between the following two statements appearing in
the VHB report:
On page 26, we find, "Under this alternative, the minimum
release would be 8 mgd or the rate of natural inflow to the
reservoir, whichever is less,"; while, on page 27, the reader is
advised, "Under this alternative, stream flows downstream of the
dam would be the same as natural streamflows into the reservoir
during severe drought events."
The reader is left asking just what is the point and
advantage of this alternative?
B.- Water Conservation/Pricinq Structures:
The consultant's treatment of this important subject has
several shortcomings which need to be corrected.
First, it is disingenuous to declare that the Albemarle
County Service Authority employs a uniform water rate structure
because "...only one system user exceeds the 4mg threshold... "
(The report indicates this user gets a 13% 9rice discount on the
overage.) This line of reasoning will cause reviewers of the
report to ask: What if this user's demands grow large, or, what
if several other users join this class? Do they still get
"rewarded" for using more water?
Having made the leap of logic to declare that uniform rates
really are in effect in RWSA service areas, the report terms the
present rate structures "transitional conservation." Logically,
reviewers will ask transitional to what? Is "real" or "final
stage" water conservation what they do in Los Angeles when, the
more you use the higher rate you pay per unit? Is it the reward
.(rebates) and punishment (surcharges) water users in Santa Fe
experience when water supplies run low? Yes, there are
conservation programs in effect in many places in the United
States in which incentive and disincentive programs lower water
demand by a large percent during peak use periods--which are
usually dry, hot su~u~er months.
The report preparers seem not to have found any data which
would support assertions such as the ones I've made above. To the
contrary, in evaluating increasing block rates (a form of
Sent By: Friends of the Moormans River; 804 823 2636; Apr-18-O0 2:58PM; Page 15/17
Imhoff - 3
surcharge), the VHB report concludes: "Because they are permanent
and can be somewhat complex, evidence suggests that increasiag
block rates may be less effective in reducing peak demand than
more simple methods described below." Then, the report moves on
to consider these simple methods, Seasonal Rates and Excess-use
Rates, and to conclude that "...it is estimated that savings of
1% could be realized by implementing a revised rate structure..."
In puzzling over this minuscule savings, I decided to review
a reference the VHB consultants used as authoritative for this
subject (Jordan and Albani, 1999). And, after studying the
referenced article and corresponding with one of the authors, I
am convinced VHB is presenting an overly pessimistic view of this
alternative.
Jordan and Albani report on a survey of the use of
conservation rate structures by twelve water utilities. There are
some very encouraging statements in the their report, e.g.: "The
average bill for peak months increased 31 percent for residential
customers...but average use in the peak period declined by 33
percent" (p. 71).
In studying the Jordan article, however, and reflecting on
my own professional experiences, I found myself agreeing with VHB
that, yes, structuring of water rates is a complex business and
that "Detailed calculations of demand and revenue impacts should
be performed prior to any rate change." (VHB, p.54).
That good suggestion should he expanded, however to include
a trial period, perhaps during the next drought, when surcharges
will be imposed and their effectiveness measured. To relegate the
water pricing alternative to the round file, without a trial
period is unwise. Building a dam or a pumpback system--or just
about any measure to increase water supply--is complex and full
of uncertainties. This subject of water pricing warrants a more
through and unbiased study than it has received.
Sincerely yours,
Edgar A. Imhoff
(certified professional geologist
Sent By: ;rien~s of the ~oormans River; 804 823 2636; Apr-18-00 ~:58PM; Page 16117
Hagler Bailly
Hegler I~ailly Services, inc.
15~0 Wilson ~oulevard
Arltn~Jton, Virginia 22209
March 26, 2000
Tel: (703) 351-03g0
Fax: (70.1) 351 0342,
Mr. Edgar A. Imhoff
1450 Bremerton Lane
Keswick, Virginia 22947
Deaf Mr. tmhoff:
I am in receipt of ),our letter of March 5, 2000 requesting clarification ufa point that was made in
m)' article that appeared in tbe AL:gust !999 AWWA Jo~.,'na!. ! apolo~z¢ in the delay in
responding to yom' tetter. Your letter was forwarded to mc. as I am ctaxently on a long-term
assignment to design conservation-based rates for the Alexander Caenerai Water Authority, here
in Alexandria, Egypt.
For tixe purpose of Table 5, on Page 69 cf the Joz~n~aL peak period does naean highest-use monttx.
However, peak period is most commonly used in technical articles to mean highest-use
Many of the respondents to the survey in the cit~ study expressed :heir data in terms of highest-
use quarter. In my analysis, I converted everTthing to lfighest usc month so that my comparison
between utilities was valid.
With respect to the VI-lB consultant's conclusion that a "savings of 1'5, could be realized by
implen~nting a revised rate structure in conjunction with other conservation measures," is too
general a statement and is not true universally among all water systems. In fact, our study shows
that the savings could be significantly greater under the right circumstances. The "savings" is
affected by such variables m~ air t~mperature, scarcity of supply, size of customer base, and
composition of customers (i.e., percent of residential ver;us other, classes of customers). For
example, here in Egypt where fresh watex ~s very scarce and air temperatures are very hot
(causing high evaporation), a 2% increase in rates during the high use sca.ion (April - October)
causes more than a [0% reduction in residential demand, because outside water use is curtailed so
that more water is available for agricultural irrigation.
If you do attempt a "trial ran" with a revised rate structure, the trial period should be at least two
years, so that you get t~ benefit of normalization of weather effects, becan.~ Virginia has such
variability in weather t~om year to year. I do agree with the, VFIB consultant that it is best to
implement other conservation measures, along with restructured rates, in o~der to maximize the
reduction in demand.
Jeff Jordan and I are pleased that you found our conservation rates study to be useful. If you have
any additional questica~s regarding rates or our. study, please e-rr~l me at:
~i~d- ~ rrs.eom~_eg or send me a,~oti~er'letter. I will be happy tO respond m your concerns. If
you wish to irk to someone at Hagler Bailly, you ca,, call David Earley in my absence... He can be
reached at 703-312-0376.
Best wishes in serving your citizens ~roup in Virginia.
Rick Albani
Professional services
Sent By: Friends of the Moormans R±ver; 804 823 2630; Apr-18-O0 2:59PM; Page 17/17
Proportional Release Plan for Moormans River
· Begin proportional release once water ceases to crest the Sugar Hollow dam
(usually early June).
· Rather than have fixed MIF rate during pedods of low flow, match release rate
to inflow rate, This links release rate to inflow rate and approximates natural
flow variations in this steep gradient mountain stream.
· Measure at weekly or twice weekly intervals the real-time inflow rates of North
and South Forks of Moormans dyer. This can be accomplished with modern,
portable electronic flewmeters in consultation with a hydrologist.
· Release 50% of the combined inflow into the Moormans below the Sugar
Hollow Dam. Cap maximum release rate at I mgd (millions of gallons/day).
This is half of average inflow measured during 1955-56 drought. If inflow truly
becomes zero, then zero is released.
· Release ceases if mandatory water restriction is ever imposed, or when water
once again regularly crests the dam.
Raw'Water
Supply
Facility
Permittin-g
Supply Analysis
Albemarle County and City of Charlottesville
Prepared for
Rivanna Water & Sewer Authority
Prepared by
O'Bden & Gem E~,gineerso
T~'.J~/vanasse Han~en E~rus~lin, inc.
DRAFT
October 1997
fred~a*.3~O2~raph~tcoue~OSO2c~pm5
Raw Water Supply Facility Permitting
Water Supply Analysis
Albemarle County/City of
Charlottesville,
Virginia
Prepared for
Prepared by
Rivanna Water and Sewer Authority
Charlottesville, Virginia
O'Brien & Gere Engineers
820I Corporate Drive, Suite 1000
Landover, Maryland 20785
and
Vanasse Hangen Brustlin, Inc.
477 McLaws Circle, Suite 1
Williamsburg, Virginia 23185
October 1997
O'Brien & Gere Engineers, Inc.
Table of Contents
Executive Summary
Introduction
System Description ................................................................................................................ 2
South Rivanna WTP ................................................................................................................... 2
Observatory WTP ....................................................................................................................... 2
North Fork Rivanna WTP ........................................................................................................... 2
Methodolo§y ........................................................................................................................... 5
Gauging Station Data ................................................................................................................. 5
Surrogate Watershed Selection .................................................................................................. 6
Safe Yield Analysis .............................................................................................................. 11
Rivanna Reservoir .................................................................................................................... 11
Sugar Hollow/Ragged Mountain Reservoir System ................................................................. 13
North Fork Rivanna River Intake .............................................................................................. 16
System-Wide Safe Yield ....................................................................................... ; ............. 18
References ............................................................................................................................. 20
i Table of Contents
~\willva~orojects\30502\obrien&ge re\Watersupply 1097
O'Brien & Gere Engineers, Inc.
,Figures
Figure No. Description Page No.
Urban Service Area .................................................................................. 3
1930 River Flows ...................................................................................... 8
RWSA System-Wide Safe Yield ............................................................. 19
ii Table of Contents
\\willva~projects\30502\obrien&gere\Watersupply1097
O'Brien & Gere Engineers, Inc.
Executive Summary
Vanasse I-tangen Brustlin, Inc. (VHB) has been authorized by the Rivanna Water &
Sewer Authority (RWSA) to prepare a raw water supply study to evaluate the future
water needs of the RWSA's Urban Service Area which includes the City of
Charlottesville and surrounding areas. O'Brien & Gere Engineers, Inc. serves as a
subcontractor to VHB on various aspects of the raw water supply study.
Among the initial efforts as part of this study are tasks to: (1) estimate the current and
future safe yield of the existing raw water supply system and, (2) project future water
demand through the year 2050. A comparison of safe yield and demand projections
will enable the RWSA to better understand whether and when it may face a water
deficit, and the magnitude of any such deficit. Subsequent studies will include an
analysis of alternatives to address any water deficit. Alternatives to be evaluated will
include, but will not necessarily be limited to, new sources of supply, water
conservation programs, demand control measures, and options to restore or increase
the safe yield of existing sources.
This report summarizes the results of a raw water safe yield review of the existing
RWSA Urban Service Area system as it has historically operated. This system
includes the (1) Rivarma Reservoir, (2) Sugar Hollow/Ragged Mountain Reservoir
system, and (3) North Fork Rivanna River Intake. For purposes of this analysis,
"safe yield" is defined as the maximum raw water yield that can be supplied
consistently over the long term. It is estimated by examining hydrologic data for as
long a time period as possible and then calculating the probable maximum yield of
the raw water supply resource during the most severe drought, also referred to as the
"critical period".
Previous safe yield estimates conducted for the same water supplies used differing
techniques and drought periods to estimate safe yield. For example, the recent Urban
Area Raw Water Management Plan (Black & Veatch, 1995) used synthesized flow
records simulating the period 1942 - 1991, and particularly the drought of 1954 to
estimate the yield of the Rivarma Reservoir. The Report on Water Works System
Charlottesville, Virgi~i~ (Polglaze & Basenberg, 1959) used the 1930 drought to
predict the safe yield for the Rivarma Reservoir. The Safe Yield of Municipal Surface
Water Supply Systems in Virginia Planrffng Bulletin #335 (Virginia State Water
Control Board, March 1985) used the 1953-54 critical period to estimate safe yield of
the Sugar Hollow/Ragged Mountain system.
Executive Summary
\\willva~projects\3OSO2\obrien&ge re\Watersupply1097
O'Brien gr Gere Engineers, Inc.
Methods employed for this analysis included a review of United States Geological
Survey (USGS) stream gage data for numerous gauging stationd in the region. This
data was used to select representative hydrologic data and to identify the critical
periods for all three water supply sources noted above. System-wide safe yield
evaluations were performed for the RWSA Urban Service Area system based on the
1930 drought, which was found to be the critical period for each of the water supply
systems (the Rivanna Reservoir, Sugar Hollow/Ragged Mountain Reservoir system,
and the North Fork Rivanna River). The system-wide safe yield was estimated by
adding the safe yield estimates for each component of the system. As no data exist to
directly evaluate the effect of the 1930 drought on the Sugar Hollow/Ragged
Mountain reservoir system, estimates of safe yield based on two surrogate
watersheds were used.
The estimated safe yield of the water supply system is currently 11.9 to 12.6 mgd.
This range in safe yield results from uncertainty regarding the 1930 safe yield of the
Sugar Hollow/Ragged Mountain system. As siltation reduces storage volume in the
reservoirs, this safe yield will decrease over time. Safe yield for the system in Year
2050 is estimated to be 4.5 mgd to 4.8 mgd. Current and future safe yield estimates
for the existing raw water supply system and for each component of the system are
summarized below.
RWSA Current And Future System-Wide Safe Yield Estimates
Source Current Safe
Yield
Year 2050 Safe Yield
Rivanna Reservoir
Sugar Hollow/Ragged Mtn.
North Rivanna River Intake
Total System
7.2 mgd 0 mgd
4.1 to 4.8 mgd (1) 3.9 to 4.2 mgd (~)
0.6 mgd 0.6 mgd
11.9 to 12.6 mgd 4.5 to 4.8 mgd
(1) Range corresponds to uncertainty regarding the 1930 drought event.
Executive Summary
\\willva~projects\30502\obrien&gere\Wate rsu pply1097
14
12
10
8
6
System-wide Safe Yield
4
2
0
1990 2000 2010
Sugar
Mountain
2020
Year
203O
2040
2O50
(*) range for uncertainty regardiag the 1930 drought evenrt
O'Brien & Gere Engineers, Inc.
Introduction
Vanasse Hangen Brustlin, Inc. (VHB) has been authorized by the
Rivanna Water & Sewer Authority (RWSA) to prepare a raw water
supply study to evaluate the future water needs of the RWSA's Urban
Service Area which includes the City of Charlottesville and surrounding
areas. O'Brien & Gere Engineers, Inc. serves as a subcontractor to VHB
on various aspects of the raw water supply study.
Among the initial efforts as part of this study are tasks to: (1) estimate the
current and future safe yield of the existing raw water supply system and,
(2) to project future water demand through the year 2050. A comparison
of safe yield and demand projections will enable the RWSA to better
understand whether and when it may face a water deficit and the
magnitude of any such deficit. Subsequent studies will include an analysis
of alternatives to address any water deficit. Alternatives to be evaluated
will include, but will not necessarily be limited to, new sources of supply,
water conservation programs, demand control measures, and options to
restore or increase the safe yield of existing sources (i.e. dredging).
This report summarizes the results of a raw water safe yield review of the
existing RWSA Urban Service Area system as it has historically operated.
This system includes the (1) Rivanna Reservoir, (2) Sugar Hollow/Ragged
Mountain Reservoir system, and (3) North Fork Rivanna River Intake.
For purposes of this analysis, "safe yield" is defined as the maximum raw
water yield that can be supplied consistently over the long term. It is
estimated by examining hydrologic data for as long a time period as
possible and then calculating the probable maximum yield of the raw water
supply resource during the most severe drought, also referred to as the
"critical period".
1 Introduction
\ \willva\pro~ects \30502\obrien&gere\Watersupply1097
O'Brien & Gere Engineers, Inc.
System Description
The Rivanna Water and Sewer Authority Urban Service Area system
includes three water treatment plants (WTP): (1) South Rivanna WTP,
(2) Observatory WTP, and (3) North Fork Rivanna WTP. These
treatment plants receive raw water from a water supply system which
includes reservoirs and a river diversion. Major system components are
shown in Figure 1.
South RivannaWTP
The South Rivanna WTP withdraws raw water from the Rivanna
Reservoir which is located on the South Fork of the Rivanna River. The
reservoir has a u2sable volume of 880 million2gallons (MG) and a drainage
area of 261 mi. However, since 18 mi of the Rivanna 'Reservoir
drainage basin flows to the Sugar Hollow Reservoir (see Observatory
WTP discussion below), a drainage basin size of 243 mi2 (261 mi2 minus
18 mi2 ) has been used to calculate safe yield at the Rivanna Reservoir.
ObservatoryWTP
The Observatory WTP is located in the City of Charlottesville and
withdraws water from the "Upper" and "Lower" Ragged Mountain
reservoirs via an 18 inch raw water pipe. These reservoirs were evaluated
as one with a total drainage area of 1.8 mi2 and a usable volume of 514
MG. The Observatory WTP also withdraws from the Sugar Hollow
Reservoir via another 18 inch raw water pipe. The Sugar Hollow
Reservoir is located at the confluence of the north and south fork of the
Moorman's River, has a drainage area of 18 mi2 and a usable volume of
360 MG. It is located entirely within the drainage basin of the Rivanna
Reservoir and can supply raw water to the Ragged Mountain Reservoir
by way of a weir overflow box that interconnects the system.
North Fork Rivanna WTP
The North Fork Rivanna WTP withdraws water from the North Fork of
the Rivanna River via a river intake. The drainage area for the river at
this point is 121 mi2. That number does not include the drainage area
located above Chris Greene Lake, an impoundment on Jacobs Run.
Jacobs Run is a tributary of the North Fork Rivanna River located
upstream of the RWSA's intake. The drainage area above Chris Greene
2 System Description
\ \willva\projects\30502\obrien&gere\WatersupplyI097
Observatory vtrrP
P~ntop~
Tank
North Fork Rlvanna w'rP
South Fork RIvanna WTP
u~oan ~ervlce Area
Water Treatment P]ant (WTP)
Water Storage Tank
Ragged Mountain 18" Raw
Water Line
Sugar Hollow 18" Raw
Water Line
Treated Water Lines
Existing Reservoir /
Water Supply
County Line
O'Brien & Gere Engineers, Inc.
Lake was not included in these calculations because the impoundment
historically has been used for recreational purpose~ and it has not
released water during times of severe drought. Thus, this drainage area
has not contributed to the safe yield of the North Fork Rivanna River
Intake. A full evaluation of using Chris Greene Lake and its upstream
drainage area for water supply purposes will be undertaken as part of the
analysis of alternatives available to the RWSA.
4 System Description
\\willva\projects\30502\obrien&gere\Watersupply1097
O'Brien & Gere Engineers, Inc.
Methodology
Gauging Station Data
Based on a review of available documents, it appears that recent safe
yield calculations ( Black & Veatch, 1994 and 1995) were not based on
the 1930 drought, an event which, in O'Brien & Gere's experience, has
been the most limiting in estimates of the safe yield of nearby water
supplies. However, during the1930 drought event, gauging stations were
not in operation at the WTP intake locations which are the focus of this
analysis. In order to estimate the effects of the 1930 drought on the water
supply system as previously described, streamflow data were obtained
from nearby gauging stations in the area which were in service during
1930. These gauging stations were evaluated to determine the suitability
of each for use as surrogates for the Rivanna River, the Moorman's
River, and the North Fork Rivanna River.
The search for compatible gauging stations encompassed the following
counties in Virginia which are topographically similar and are in close
proximity to the Rivanna System:
Amherst
Albemarle
Greene
Appomattox
Fluvanna
Madison
Nelson
Louisa
Culpeper
Buckingham
Orange
Rappahannock
Table 1 shows the gauging stations which were active in these counties
during the 1930 drought event. The gauging station which was active on
the Rivanna River below Moore's Creek (near Charlottesville) during the
1930 drought was moved upstream to a point near Earlysville near the
Route 29 bridge downstream from the Rivanna Reservoir dam. Data are
available from this location for the period from 1/1/53 to 12/31/57.
5 Methodology
\X. willva\projects\30502X, obrien&gere\water supply1097
O'Brien & Gere Engineers, Inc.
Table 1. Available gauging stations (1930 drought)
Gauging Station/River/Location County
Dates of Available Data
Drainage Area
Rivanna River below Moore's
Creek (later moved to a location
near Earlysville)
Slate River near Arvonia
Tye River near Roseland and
Lovingston
North Anna River near Doswell
Rapidan River near Culpeper and
Rapidan
Albemarle
Buckingham
Nelson
10/1/25-3/31/34
(No data for some months)
and (1/1/53- 12/31/57)
4/1/26-9/30/93
(No data from 1935-36)
10/1/27-9/30/93
(Station moved in 1938, no
data for some months of that
year)
507 mi2
(216 mi2 @
Earlysville)
226 mi2
68 mi2
Caroline 4/1/29-9/30/88 441 mi2
Culpeper 4/1/25-9/30/93 472 mi2
(Station moved downstream
in 1930)
Surrogate Watershed Selection
In determining the safe yield of the water supply system, supplies to the
three WTPs have been analyzed separately.
Rivanna Reservoir
Due to the fact that 18 mi2 of the Rivanna Reservoir drainage basin flows
to the Sugar Hollow Reservoir, which feeds the Observatory WTP during
a drought, the Rivanna Reservoir safe yield has been calculated using a
drainage basin size of 243 mi2 (rather than 261 mi2). Data are available
for the 1930 drought at a gage on the Rivanna River downstream of the
existing reservoir (Rivanna River below Moore's Creek). These data
were used to calculate a safe yield for the reservoir, and a surrogate
watershed (Slate River near Arvonia) was selected to confirm this
calculation.
There are two drought periods for which historical flow data are available
at all of the gauging stations described in Table 1: the 1930's drought of
record and the 1950's drought which was used in previous studies. To
assess the suitability of potential surrogates, average yields were
calculated and compared for each of these watersheds. The results of the
average yield calculations for each historical period are shown in Table 2.
6 Methodology
\\willva\projects\30502\obrien&gere\watersupply1097
O'Brien & Gere Engineers, Inc.
Table 2. Average yield at potential Rivanna River surrogates
Gauging Station/River/Location
County
Avg. Yield,
period of
10/1/29-3/31/34
(cf s/mi2)
Avg. Yield,
period of
111153-12/31/57
(cfslmi2)
Rivanna River below Moore's
Creek (t0/1/29-3/31/34) and near
Earlysville (1/1/53~12/31/57)
Slate River near Arvonia
Tye River near Roseland
and Lovingston
North Anna River near Doswell
Rapidan River near Culpeper
Albemarle 0.77 0.81
Buckingham 0.74 0.75
Nelson 1.41 1.93
Caroline 0.69 0.67
Culpeper 0.73 0.84
The average yield of the Rivanna, Slate, and North Anna rivers did not
vary significantly for the two periods (within each basin). The Slate and
Rapidan rivers have yields most similar to the Rivanna River.
More detailed review of the data for the specific drought period between
May and November of 1930, suggests that the Rapidan River had lower
yields than the Rivanna during the drought. (A comparison of daily flow
data is provided in Figure 2). The Rapidan River flow also recovered
more slowly from this drought. Daily data for the Rivanna and Slate
rivers compare more favorably. Because of the repeatability of the
average yield data and the similarities of flow patterns through the
drought, separate safe yield calculations were carded out using both the
Slate and Rivanna gauging station data.
Sugar Hollow/Ragged Mountain
Reservoir System
The Sugar Hollow and Ragged Mountain Reservoirs have been evaluated
as one system of reservoirs with a drainage area of 19.8 mi2. Since no
streamflow data are available for the Moorman's River during the 1930
drought, two surrogates were selected to use in safe yield calculations for
the Sugar Hollow/Ragged Mountain system. Since the Sugar Hollow
Basin lies entirely within the Rivanna River watershed, the Rivanna River
flows should closely mimic those in the Moorman's River. The Rivanna
River was therefore selected as one surrogate for the Moorman's River.
In order to evaluate other potential surrogates, the flow yield (flow
volume/drainage area) at the gauging stations was compared with that of
the Moorman's River during a period in which data are available for all
gages. The Slate River, which had a yield most similar to that of the
Moorman's, was also selected as a surrogate. Daily flow data for the
surrogates were adjusted for differences in drainage area and flow yield,
7 Methodology
\\willva\projects\30502\obrien&gere\watersupply1097
Figure 2:1930 River Flows
0.4
0.35
0.3
0.25
0.2
0.15
0.05
Rapidan River,'
Slate River
xj \x
---Rivanna River
05/22/30
06/21/30
07/21/30
08~20~30
Date
09/19/30
10/19/30
11/18/30
O'Brien & Gere Engineers, Inc.
and these adjusted data were used in a safe yield analysis based on the
1930 drought.
In order to verify the use of the Slate River, the evaluation was repeated
using 1954 data from the Slate River gage, and the results were compared
to the existing 1954 data from the Moorman's River gage. This
comparison revealed that simply using the Slate River as a surrogate for
the Moorman's River results in a significant overestimate of the
documented 1954 flows. This difference was used to develop a
correction factor for use in estimating safe yield.
No data are available for the Moorman's River (source for the Sugar
Hollow Reservoir) during the 1930 drought. Therefore, surrogate
watersheds, for which 1930's data are available, were selected for
estimating the safe yield of the Sugar Hollow/Ragged Mountain system
during this drought event. Since the Sugar Hollow Basin lies entirely
within the Rivanna River watershed, the Rivanna River flows should
closely mimic those in the Moorman's River. To determine the
similarities between the Moorman's River and the rivers which had
gauging stations during 1930, available data for the North Fork of the
Moorman' s River ( 1952-1963 and 1982-1983) were compared with data
for the same periods from these other rivers.
Although there is no period for which data are available from both the
Rivanna River gauging station and the Moorman's River gauging station,
the Rivanna River was selected for use as a surrogate because the
Rivanna River watershed includes the Sugar Hollow basin. The average
yields of the Moorman's River and the other potential surrogates are
shown on Table 3.
Table 3. Average yield of potential Moorman's River surrogates
Gauging County Avg. Yield,
Station/River/Location (cf s/mi2)
North Fork of the
Moorman's River near
White Hall
Slate River near Arvonia
Albemarle 1.50
Buckingham 0.92
Tye River near Roseland Nelson
and Lovingston
2.13
North Anna River near Caroline 0.84
Doswell
Rapidan River near Culpeper 1.02
Culpeper
The Rivanna River is not included because there is no period for which data is available from
both the Rivanna River station and the Moorman's River station.
9 Methodology
\ \willva \projects\30502\obrien&gere\watersupply1097
O'Brien & Gere Engineers, Inc.
Of the rivers analyzed, the Rapidan should be removed from
consideration because, as determined in the analysis and shown on Figure
2 of the Rivanna Reservoir, the Rapidan flOws did not mimic recorded
flows in the Rivanna River during the 1930 drought (the Moorman's
River Basin is located within the Rivanna Watershed). Of the remaining
rivers, none appear to have an average yield closely corresponding to that
of the Moorman's River. Therefore, the Slate River data, which indicate
a yield closest to that of the Moorman's River and closely resembled the
Rivanna River Basin during the 1930 drought, was used to estimate safe
yield for the Moorman's River. The Slate River data were adjusted with
a yield factor of 1.50/0.92 to correct for differences in yield.
North Fork Rivanna River
As previously noted, the North Fork watershed area is approximately 121
mi2 excluding the portion above Chris Greene Lake. The safe yield
calculation has been carried out based on the 1930 drought using the
same data set from the Rivanna River as was used for the Rivanna, Sugar
Hollow and Ragged Mountain reservoirs (Rivanna River below Moore's
Creek Gauge). Data from the North Fork Rivanna River near Proffit,
Virginia have also been used to calculate the safe yield of the system and
thus verify previous work.
Recent studies of the North Fork Rivanna River have relied on data from
a gauging station on the North Fork of the Rivanna River (at the Route
606 crossing) near the WTP intake. This gage is an excellent surrogate
but was not in place during the 1930 or the 1954 droughts. In order to
estimate the safe yield of this source during the 1930 drought, O'Brien &
Gere modeled the system using data from the Rivanna River gage which
was active during the 1930 drought (Rivanna River below Moore's
Creek).
10 Methodology
\ \willva \projects\30502\obrien&gere\watersupply1097
O'Brien & Gere Engineers, Inc.
Safe Yield Analysis
Rivanna Reservoir
Estimated safe yields were calculated for the Rivanna Reservoir using
adjusted data from two gauging stations: the Rivanna River below
Moore's Creek, and the Slate River near Arvonia. Daily flow data for
each of the rivers were adjusted for differences in drainage area.
The watershed area used for the Rivanna River at the reservoir was 243
mi2, a value used in the Interim Memoranda for the Urban Raw Water
Mana.g2ement Plan (Black & Veatch, 1994). This watershed area excludes
18 mi of the Rivanna Watershed which supplies the Sugar Hollow
Reservoir. It was assumed in the Black & Veatch report that the Sugar
Hollow Reservoir would supply water to the Ragged Mountain Reservoir
during drought conditions.
No adjustment of data for flow yield was necessary, as the yield values
were fairly similar for both the Rivanna and Slate rivers. A 1994
bathymetric survey found a usable storage volume of 880 mg and a
siltation rate of 13.01 mg/year. For current (1997) safe yield
calculations, the Rivanna Reservoir storage volume was assumed to be
841 MG. This value represents the volume between the spillway
elevation (382 ft.) and the lowest water intake gate elevation (367 ft.).
The available volume of 841 MG represents approximately 63% of the
total reservoir volume of 1333 MG (178 million cubic feet). To estimate
the future safe yield of the reservoir, continued loss of storage volume
due to siltation was considered.
In the December, 1959 Report on Water Works System Charlottesville,
Virginia by Polglaze & Basenberg, an evaporation factor of 44 inches per
year was applied. This corresponds to a loss of 1.28 mgd from the
Rivanna Reservoir.
The estimated current safe yield for the 1930 drought was calculated by
determining the date of drought initiation (the day that the net reservoir
inflow began to decrease according to the daily flow records) and
applying daily withdrawal rates and evaporation losses from that date
such that all available storage volume is emptied at the time daily inflows
begin refilling the reservoir. Results of the safe yield calculations are
shown in Table 4.
11 Safe Yield Analysis
\ \willva\project~\30502\obrien&gere\Watersupply1097
O'Brien & Gere Engineers, Inc.
Table 4. Current Rivanna River Unadjusted Safe Yield
Gauging station
Estimated watershed
current safe yield
(unadjusted)
Rivanna River below Moore's Creek
Slate River near Arvonia
15.2 mgd
15.0 mgd
As expected, the Rivanna River and Slate River results are quite similar.
O'Brien & Gere believes that the 15.2 mgd value is the best estimate of
unadjusted safe yield (based on the 1930 drought) for the current
reservoir volume, because the drainage area of the Rivanna River below
Moore's Creek Gauge includes the Rivanna Reservoir drainage area and
is considered a slightly better surrogate.
In determining available withdrawals for the South Fork Rivanna WTP,
this value has been adjusted to incorporate the minimum flowby currently
used for purposes of maintaining water quality on Moore's Creek
(downstream of the Moore's Creek Wastewater Treatment Plant). This
flowby is not mandated by a Minimum Instream Flow requirement.
Discussions with Virginia Department of Environmental Quality (VDEQ)
personnel indicate that the 8.00 mgd currently used is based on an old
modelling effort (from the 1970's) and suggest that additional modelling
could be performed as part of a study to establish a more accurate
estimate. Until such a study is complete, 8 mgd has been used as the best
existing estimate of the minimum flowby required to maintain water
quality. Therefore, the current safe yield for the Rivanna Reservoir is 8
mgd less (7.2 mgd) than the unadjusted 15.2 mgd estimate based on the
1930 drought.
The safe yield (based on the 1930 drought) was projected for the future
using reduced reservoir volumes as projected in the 1994 Black & Veatch
report. Black & Veatch used a bathymetric survey of the reservoir to
evaluate the amount of previously available reservoir volume which has
been displaced by siltation and to predict the future displacement of
storage. The estimated annual storage loss due to siltation was 13.01
MG/year. Siltation is caused by the settling of solids which are carried
into the reservoir by streams and rivers. Because the streams and rivers
typically enter the reservoir in the shallows, and because settling will
occur soon after entering the quiescent reservoir, the siltation typically
occurs in areas which are above the lowest intake (rather than at depths
which are not usable storage volume).
A cursory review of the bathymetric survey report supports the
assumption that the loss of volume is primarily in areas above the
elevation of the lowest intake gate. Therefore, the reservoir volume
would be reduced by 729 MG by the year 2050 (56 years x 13.01 MG/yr.)
to 151 MG. The safe yield calculation was repeated using this reservoir
volume and applying 1930 drought flow data from the gauging station at
the Rivanna River below Moore's Creek. This calculation predicts an
unadjusted safe yield of 6.6 mgd in 2050, using the Rivanna River Gauge
12 Safe Yield Analysis
\\willva \projects\30502\obrien&gere ~Watersupply1097
O'Brien & Gere Engineers, Inc.
as a surrogate and 7.7 mgd in 2050 using the Slate River Gauge.
Reducing this for the flow-by of 8 mgd provides an e~timated safe yield
of 0 mgd. As anticipated, this is lower than the 3.9 mgd safe yield
calculated for the Rivanna Reservoir in the year 2040 using 1954 drought
data as reported in the 1994 Black & Veatch report.
Current estimated safe yield for the Rivanna Reservoir, based on Rivanna
River data from the 1930 drought, is 7.2 mgd. This value is substantiated
by evaluating data from the Slate River, which resulted in an estimated
safe yield of 7.0 mgd. Since the 8 mgd flowby is greater than the 1930
drought flows, the estimated safe yield for the year 2050 is 0 mgd.
Sugar Hollow/Ragged Mountain Reservoir
System
To determine the likelihood that the 1930 drought was more severe than
the 1954 drought, minimum instream flows were compared for the four
gauging stations which collected data during both events. Minimum 30-
day average instream flows at these gauging stations are shown on Table
5.
Table 5. Comparison of average instrearn flows for 1930 and 1954 droughts
1930 Minimum 1954 Minimum
30-Day Average 30-Day Average
Gauging Station Instream Flow Instream Flow
State River near Arvonia
Tye River near Roseland and 6.0 cfs
Lovingston
North Anna River near Doswell 8.4 cfs
9.9cfs 22.9cfs
10.8 cfs
8.1 cfs
Rapidan River near
Culpeper and Rapidan
7.7 cfs 12.5 cfs
Rivanna River not shown because its gage was not active in 1954.
At three of the four gauging stations, the 1930 drought was significantly
more severe than the 1954 drought, and at the fourth station the droughts
were similar in magnitude. This evaluation suggests that the 1930 drought
was probably as severe, or more severe, than the 1954 drought in the
Moorman's River Basin. However, no data are available to directly
calculate the safe yield of the Sugar Hollow/Ragged Mountain Reservoir
system based on the 1930 drought.
In the absence of such direct data, O'Brien & Gere calculated an upper
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limit for the reservoir system's safe yield based on the less-severe 1954
drought (verifying previous studies) and an appr6ximation of the
probable safe yield during the 1930's event as described below.
Estimated safe yield for the Sugar Hollow/Ragged Mountain Reservoir
system during 1930 was calculated in several steps. First, the Slate River
flow data from 1930 were used as one surrogate for the Moorman's
River. Next, the Rivanna River flow data from 1930 were used as a
surrogate. A 19.8 mi2 drainage area was used for the reservoir system
which consists of 18 mi2 for Sugar Hollow and 1.8 mi2 for the Ragged
Mountain Reservoir. These values were taken from the Safe Yield of
Municipal Surface Water Supply Systems in Virginia Planning Bulletin
4/335 (Virginia State Water Control Board, March 1985).
The 44 inches/year evaporation factor (discussed above) corresponds to a
loss of 0.6 mgd from the Sugar Hollow/Ragged Mountain. System. The
State Water Control Board used 1953-54 streamflow data for the North
Fork of the Moorman's River to calculate a safe yield of 5.4 mgd.
O'Brien & Gere repeated this evaluation using the same data, and the
same reservoir volume. A safe yield of 4.8 mgd was calculated. The
difference is apparently a result of the evaporation factor.
A study of the dam at Sugar Hollow Reservoir has recently been
performed to determine the best operating elevation for the spillway
crest. Based on this study, RWSA has decided to operate the Sugar
Hollow Reservoir with crest gates at elevation 975. A recently conducted
hydrographic survey determined the volume of the Sugar Hollow
Reservoir to be 360 MG (with crest gates at elelvation 975). Reducing
this volume by the estimated siltation rate of 1.49 MG/year for three
years resulted in a 1997 volume of 356 MG. The Ragged Mountain
Reservoirs have a total volume of 514 MG. The Ragged Mountain/Sugar
Hollow system was evaluated as one reservoir with a total volume of 870
MG.
Analysis Using Slate River Gauging Station
An additional adjustment was made to the 1930 Slate River data for
differences in the average yield of the two rivers by applying, a yield
factor of 1.50/0.92 (based on comparable historical data for the two
rivers, as discussed above). This analysis resulted in preliminary safe
yield estimates for the Ragged Mountain/Sugar Hollow system, based on
Slate River data, of 6.0 mgd.
To assess the validity of the 6.0 mgd estimate, the methodology applied
to the 1930 data was applied to the 1954 data and compared to actual
recorded flows. The safe yield was calculated using Slate River flow
data from 1953-54, adjusted to the Moorman's River by watershed size
and yield, and using the 944 MG reservoir volume (the volume prior to
loss of 70 MG of storage). This calculation resulted in a safe yield
estimate of 8.5 mgd for the Sugar Hollow/Ragged Mountain Reservoir
system during the 1953-54 drought event. Existing Moorman's River
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flow data indicate a safe yield of only 4.8 mgd. The methodology plainly
is overestimating the flows in the Moorman's River.
Accordingly, a correction factor was estimated by comparing the safe
yield calculated using the recorded flows in the Moorman's River during
the 1950's drought (4.8 mgd) with the safe yield calculated using the Slate
River data corrected for drainage area size and yield (8.5 mgd). By
applying this correction factor (4.8/8.5) to the previously calculated safe
yield based on the 1930's drought (6.0 mgd), a safe yield estimate of 3.4
mgd is obtained.
Analysis Using Rivanna River Gauging Station
The Rivanna River has a drainage area of 507 mi2 at the gauging station
versus 19.8 mi2 for the Sugar Hollow Reservoir. Therefore, a correction
factor of 19.8/507 was used in this analysis. This analysis resulted in
preliminary safe yield estimates for the Ragged Mountain/Sugar Hollow
system, based on Rivanna River data, of 4.1 mgd.
Based on the above, O'Brien and Gere believes that 4.1 mgd should be
used for the present safe yield estimate of the Sugar Hollow/Ragged
Mountain reservoir system. However, this report shows the 4.8 mgd
estimate from the 1954 drought to indicate the upper end of the potential
safe yield. This range reflects the uncertainty in the 1930's hydrologic
data.
No flow-by requirement is currently applicable to this reservoir system.
Therefore, no reduction in safe yield has been employed and it is
assumed that the entire basin flow may be used for water supply
purposes. Based on that assumption, the numbers shown above are
estimates of reservoir safe yield at present.
The estimated current safe yield of the Sugar Hollow/Ragged Mountain
Reservoir system based on the 1930's drought is 4.1 mgd. Safe yield
estimates are shown on Table 6. The 1954 safe yield (4.8 mgd) and the
1930 Slate River safe yield (3.4 mgd) are also shown in this table for
informational purposes.
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Table 6. Sugar Hollow/Ragged Mountain Current Safe
Yield Estimates
Reservoir volume
1930 1954
1930 Rivanna Moorman's
Slate River River River
analysis analysis analysis*
944 MG (prior to any 4.3 mgd
siltation)
4.8 mgd
874 MG (including siltation
through I
3.4 mgd 4.1 mgd 4.5 mgd
* adjusted from Polglaze & Basenberg estimates for evaporation
The reservoirs were constructed with a volume of 944 MG. Recent
studies indicate that this volume has been reduced by 70 MG due to a
recent landslide and general siltation. To account for projected loss of
storage in estimating future safe yield, calculations were carded out using
various reservoir volumes and applying all three methodologies described
above (1930 Rivanna River Data, Slate River Data, and 1954 Moorman's
River Data.) A 1.49 MG/year siltation rate (70 MG loss of storage over
the 47-year reservoir life) was applied for projections of future 'safe yield
of the Ragged Mountain/Sugar Hollow Reservoir system. The results of
these calculations are shown in Table 7.
Table 7. Ragged Mountain/Sugar Hollow future safe
yield estimates (year 2050)
Reservoir volume
1930 Rivanna 1954
1930 River Moorman's
SIZe Riveranalysis analysis River
analysis
794 MG 3.1 mgd
3.9 mgd 4.2 mgd
North Fork Rivanna River Intake
Estimated safe yields were calculated for the North Fork Rivanna River
using adjusted data from two gauging stations: the Rivanna River below
Moore's Creek and the Slate River near Arvonia. Daily flow data for
each of the rivers were adjusted for differences in drainage area.
The watershed area of the North Fork Rivanna River at. the WTP intake
(exclusive of the Chris Greene Lake portion of the watershed) is 121 mi2.
This value was used in the "Technical Memoranda for the Safe Yield of
the North Fork Rivanna Water System" (Black & Veatch, 1995).
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In determining available withdrawals for the North F6rk Rivanna WTP,
this value may need to be adjusted for a minimum instream flow
requirement. There is currently no minimum instream flow (MIF) but it
is possible that one may be imposed in the future.
The estimated safe yield of the North Fork Rivanna River at the WTP
intake, during the 1930 drought, was calculated to be 0.6 mgd using the
Rivanna River Gauge and 0.7 mgd using the Slate River Gauge. Because
no storage volume is required for a run of the river intake (like the one at
the North Fork Rivanna WTP), the estimated future (year 2050) safe
yield at the North Fork Rivanna River Intake source is unchanged from
the estimated current safe yield (0.6 mgd).
If the existing Chris Greene Lake and its drainage area were used for
water supply purposes, this safe yield would be increased. The amount of
that increase in safe yield would depend on the balance struck between
use of Chris Greene Lake for recreational purposes, an its use for water
supply purposes. O'Brien & Gere will fully evaluate the potential safe
yield that may result from use of Chris Greene Lake for water supply
purposes in the upcoming analysis of alternatives.
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System-Wide Safe Yield
System-wide safe yield evaluations have been performed for the Rivanna
Water and Sewer Authority Urban Service Area system based on the
1930 drought, which was found to be the critical (drought) period for the
Rivanna, Sugar Hollow/Ragged Mountain Reservoirs and the North Fork
Rivanna River. The system-wide safe yield has been estimated by adding
the safe yield estimate for each component of the system. As no data exist
to directly evaluate the effect of the 1930 drought on the Sugar Hollow
and Ragged Mountain Reservoirs, estimates of safe yield based on two
surrogate watersheds have been used.
The estimated safe yield of the current system is 11.9 to 12.6 mgd
depending on uncertainty regarding the 1930 safe yield of Sugar
Hollow/Ragged Mountain. As siltation reduces storage volume in the
reservoirs, this safe yield will decrease. Safe yield for the system in Year
2050 is estimated to be 4.5 mgd to 4.8 mgd. Current and future safe yield
estimates for the system and for each component of the system are shown
in Table 8 and on Figure3.
Table 8. RWSA current and future system-wide safe yield estimates
Source
Current Safe Yield
Year 2050
Safe Yield
7.2 mgd 0 mgd
Rivanna Reservoir
Sugar Hollow/Ragged 4.1 to 4.8 mgd o) 3.9 to 4.2 mgd o)
Mountain
North Rivanna River 0.6 mgd 0.6 mgd
Total System 11.9 to 12.6 mgd 4.5 to 4.8 mgd
(1) Range for uncertainty regarding the 1930 drought event
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14
12
10
8
6
4
2
Figure 3: System-wide Safe Yield
\
__ ~
1990 2000 2010
Sugar
Mountain
T~tal (*)
2020 2030
Year
2O4O
2050
(*) range for uncertainty regarding the 1930 drought even[
O'Brien & Gere Engineers, Inc.
References
Black & Veatch, 1994. Interim Memoranda for the Urban Raw Water Management
Plan, November 1994, 116 pp.
Black & V~eatch, 1995 (Revised). Urban Raw Water Management Plan Summary
Heport, Revised August 1995, 24 pp.
Polglaze ,a. nd Bas,..enbur~l, 1959. Report on Water Works System, Charlottesville,
Virginia, vecemuer 1959, 101 pp.
Virginia S~tate,W~ater. Cont.ro Board~,1985. Safe Yield of Municipal Surface Water
~upply systems, virginia ~anning Bu erin #335.
20 References
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