HomeMy WebLinkAboutWPO201900051 Correspondence 2021-07-02DEq Virginia Runoff Reduction Method Re -Development Compliance Spreadsheet -Version 3.0
02011 BMP Standards and Specifications 112013 Draft BMP Standards and Specifications
Project Name: Scottsville Elementary School Addition dabinputaells
®
Date: 9/5/2019 constunvalues
Linear Development Project? No calculation cells
Site Information
Post -Development Project (Treatment Volume and Loads)
Enter Total Disturbed Area (acres)
3.04
Check:
BMP Design Specifications List:
2011 St
& Specs
Maximum
reduction required
F®'.
Linear project? No
The site's net increase in impervious
cover (ac ts�Land
cover areas entered correctly?
Post-DevelopmentTotal
disturbed area entered?
Pre-ReDevelopment land Cover (acres)
ASoils BSoils CSoils
DSoils
Totals
Forest/Open Space (acres) -- undisturbetl
D.10
forest/o enspace0.10
Managetl Tuff (acres) -- disturbed, graded for
2.47
rds or other turf to be mowed/man etl
2.47
Impervious Cover(acne)
047
0.47
3.04
Post -Development Land Cover (acres)
ASoils
BSoils
cSoils
DSoils
Totals
Forest/Open Space (acres) --undisturbed,
0.07
rotectetl forest/o space or reforeted land
0.07
Manned Tuff (acres) disturbed, graded for
yards or other turf to be mowetl/man etl
1.68
Impervious Caver(acres)
1.29
Area Check
OK.
OK.
OK.
OK.
• Forest/Opin Spare areas mustbe protected
in accordance with the Virginia RunaRReduaian
Method
M�lls
Constants
Runoff Coefficients Rv
Annual Rainfall (inches)
43
A Soils
C Soils
D Soils
Target Rainfall Event(inches)
1.00
Forest/Open Space
0.02
0.D4
0.05
Total phosphorus(IT) EMC(mg/L)
0.26
Managed Tuff
0.15
0.22
0.25
Total Nitrogen (TN) EMC(mg/L)
1.86
Impervious Cover
0.95
0.95
0.95
ME
Target TP Load (lb/acre/W)
OAl
Pj(unitless correction factor)
0.90
LAND COVER SUMMARY -- PRE
-REDEVELOPMENT•
COVER
SUMMARY POST DEVELOPMENT
Wnd Cover SummaOVPdA
Post-ReDevelopment
agagagal
fond CoverSummory-Pre
Land Cover Summary-Post(FinaO
Lard Cover, summary -Post
Pre-ReDevelopment
Liven!
Adjusted'
Post ReDew. Is New Impervious
Post -Development New lmperviaus
pen pace (acres)
Forest/Open s Cover
0.10
O.OJ
Forest/Open Space
0.07
Forest/Open Space
Cover acres
Cover(acres)0.07
Weighted Rv(forion)
ou
0.04
Weighted Rv(fimn s0
0.04
Weighted Rv(forest)
0.04
%Forest
3%
3%
%Forest
2%
%Forest
3%
Managed Tuff Cover (acres)
2.47
168
Managed Tuff Cover
1.68
Managed TurfCover
acre
168
Weighted Rv(turf)
0.22
0.22
Weighted Rv(turf)
0.22
Weighted Rv (turf)
0.22
%Managed Tuff
81%
76%
%Managetl Tuff
55%
%Managetl Tuff
76%
Impervious Cover (acres)
0.47
0.47
ImperviousC r
129
ReDev. Impervious
047
New Impervious Cover 0.82
(acres)
cover (acres)
(acres)
Rv(impervicus)
0.95
0.95
Rv(impervimo)
0.95
Rv(impervious)
0.95
Rv(impervious) 0.95
%lmperviaus
15%
21%
%Impervious
42%
%lmperviaus
21%
Total She Area (acres)
3.04
2.22
Final Site Area (acres)
3.04
Total need. She Area
acres
2M
site Rv
0.33
0.37
Final Port Dew Site Rv
0.53
ReDev She Rv
037
Treatment Volume and
Nutrient Load
Treatment
Volume and
Nutrient Load
Post -Development
Final Post-
Post-ReDevelopment
Pre-ReDevelopment Treatment Volume
0.0828
0.0682
Development
0.1332
TrentmentVolume
0.0682
Treatment Volume
0.0649
(acre it)
TreMmentVolume
(acre -It)
lacre-ft)
(acre-h)
Port-Development
Final
Port-ReDevelopment
TreTreatmentPost-
Pre-ReDevelopment Treatment Volume
3,608
2,873
Development
5,800
TreatmentVolume
2,973
Trentmert Volume (cubic
2,828
(cubic tent(
TreMmeM Volume
(cubic feet)
feet)
(cubic feet)
mentT
Pre-ReDevelopment TP Load
Final Post-
Port-ReDevelopment
(Ib/yrl
227
1.87
Development TP Load
3.64
Load lTPl
Lill
d
ad (
Wa
Loatl lbMl
178
(lb/yr)
(IbM)'
PmArDevelopmwn TP Lead per acre
Final Part ievelopment TP
PostArDeveloparentlP
(Ib/acre/yr)
O75
a."
Load per acre
1.20
Load per acre
(lb/arre/yr)
(lb/-m/yr)
Baseline TP Load (IbM)
Max. Reduction Required
(BAl lbs/ave/yr applied to pre- redevelopment area ertluding pervious
0.91
(Below Pre-
20%
land imposed for new impervious cosreQ
ReDevelopment Load)
'Adjusted Land CoverSummary:
TP Load Reduction
TP Load Reduction
Pre ReDevelopment landcoverminuspervious landcover Boresv pen sparem
Required for
0.37
Required for New
1.44
managed for]) acreageproPasedfor new impervious cover.
Redeveloped Area
Impervious Area (ib/yr)
(lb/yr)
Adjustedunal acreage is consistent with PosbneDevelopmentarrimV (minus
acreage of new impervious cover).
Column I shows load reduction requdementfor new imyervloue cover (based on new
development load limit 0.41 Ibs/acre/year).
Post -Development
TP Load Reduction Required (Ib/yr)
1.81
Nitrogen Loads (Informational Purposes
Only)
Final Post-Develapment TN Load
Pre-ReDevelopment TN Load(lb/yr)
16.22
(Post-ReDevelopment&New
26.07
Impervious) (IbM)
a�� sacra seems
Site Results )Water quality Compliance)
area a.n
m.—PREEN, a—D.l
a ay.l
rtulsl
m Col
rtuly
E.
o.
SIDE TMmmtt Volume lXal
R.
Runoff u. W.R. aM R By Onimp Nea
vt
m
ale a
rural Fnurynu ua
naesirp
"IDNEGETTTotal
ox mnrx
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Virginia Runoff Reduction Method Wora heel
DEQ Virginia Runoff Reduction Method Re -Development Compliance Spreadsheet - Version 3.0
LIMP Design Specifications List: 2011 Stds & Specs
Site Summary
Project Title: Scottsville Elementary School Addition
Date: 43713 Total Rainfall (in): 43
Total Disturbed Acreage: 3.04
Site Land Cover Summary
Pre-ReDevelopment Land Cover (acres)
Asoils
BSoils
CSolis
DSoils
Totals
%of Total
Forest/Open (acres)
O.
0.00
0.10
0.00
0.10V'810so
Managed Turf(acres)
0.00
0.00
2.47
0.00
2.47Impervious
Cover(acres)
0.00
0.00
0.47
0.00
0.473.04
Post-ReDevelopment Land Cover (acres)
Asoils
!.Solis
CSolis
DSolis
Totals
%of Total
Forest/Open (acres)
0.00
0.00
0.07
0.00
0.07
2
Managed Turf (acres)
I coo
0.00
1.68
0.00
1.68
55
Impervious Cover (acres)
1 0.00
0.00
1.29
0.00
1.29
42
'Forest/Open Space areas must be protected in accordance with the Virginia Runoff Reduction Method
3.04
100
Site Tv and Land Cover Nutrient Loads
Final Post -Development
Post-
Post
Adjusted Pre-
(Post-ReDevelopment
Development
& New Impervious)
ReDevelopment
NewImpervious)
ReDevelopment
Site Rv
0.53
0.37
0.95
0.37
Treatment Volume(ft)
5,800
2,973
2,828
2,973
TP Load (lb/yr)
3.64
1.87
1.78
1.87
Total TP Load Reduction Required (Ib/yr) 1.81 0.37 1.44
Final Post -Development Load
(Post-ReDevelopment & New Impervious)
Pre-
ReDevelopment
TN Load (lb/yr)
26.07
16.22
Pre-
ReDevelopment
Final Post -Development
Post-ReDevelopment TP
TP Load per acre
TP Load per acre
Load per acre
b/acre/ r
(Ib/acre/yr)
(Ib/acre/yr)
0.84
1.20
0.84
Summary Print
Virginia Runoff Reduction Method Worksheet
Site Compliance Summary
Maximum% Reduction Required Below 2M
Pr ReDevelopment Load
Total Runoff Volume Reduction (R)
2,705
Total TP Load Reduction Achieved (Ih/yr)
2.03
Total TN Load Reduction Achieved (Ih/yr)
15.49
Remaining Post Development TP Load
(Ih/yr)
1.62
Remaining TP Load Reduction (Ih/yr)
Required
0.00
'*TARGET TP REDUCTION EXCEEDED BY 0.21 LB/YEAR **
Summary Print
Virginia Runoff RecJalion Method Woftheet
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Drainage Area Summary
D.A. A
D.A. B
DA. C
DA. D
D.A. E
Total
Forest/Open (acres)
0.02
0.05
0.00
0.00
0.00
0.07
Managed Turf(acros)
0.90
0.16
0.00
0.00
0.00
1.06
Impervious Corer(acres)
0.37
0.67
0.00
0.00
0.00
1.04
Total Area (acres)
1.29
0.88
0.00
0.00
0.00
2.17
Drainage Area Compliance Summary
D.A. A
DA. B
DA. C
D.A. D
D.A. E
Total
TP Load Reduced Ib/ r
0.65
1.38
0.00
1 0.00
0.00
2.03
TN Load Reduced (lb/yr)
5.42
10.07
0.00
1 0.00
0.00
15.49
Summary Print
Virginia Runotf Reduction Method Worksheet
Runoff Volume and CN Calculations
1-yearrtorm 2-yearstorra 10-yearstorra
Target Rainfall Event (in) 0.00 0.00 0.00
Drainage Areas
RV&CN
Drainage AreaA
Drainage AreaB
Drainage Ari
Drainage Areal)
Drainage AreaE
CN
81
92
0
0
0
RR(fte)
7S
1,951
0
0
0
1-year return period
RV was R0.(wzin)
0.00
0.00
0.00
0.00
0.00
RV w RR (ws-in)
0.00
0.00
0.00
0.00
0.00
M adjusted
100
100
0
0
0
2-year return period
RVwo RR(wzin)
0.00
0.00
0.00
0.00
0.00
RV w RR (ws-in)
0.00
0.00
0.00
0.00
0.00
M adjustedl
S00
100
0
0
0
10-year return period
RVwo RR(wzin)
0.00
0.00
0.00
0.00
0.00
RV w RR (ws-in)
0.00
0.00
0.00
0.00
0.00
M adjusted
100
100
0
0
0
Summary Print