HomeMy WebLinkAboutSUB200700302 Study 2008-01-15WELL YIELD & WATER QUALITY REPORT
RED HILL SCHOOL WELL NO. 5
ALBEMARLE COUNTY, VIRGINIA
PREPARED FOR:
ALBEMARLE COUNTY
401 MCINTIRE RD.
CHARLOTTESVILLE, VIRGINIA 22902
IN ASSOCIATION WITH:
WDEQ
VIRGINIA DEPARTMENT OF ENVIRONMENTAL QUALITY
VALLEY REGIONAL OFFICE
4411 EARLY ROAD
HARRISONBURG, VIRGINIA 22801
PREPARED BY:
Golder
ASSoCl2►#eS
GOLDER ASSOCIATES INC.
3719 SAUNDERS AVENUE
RICHMOND, VIRGINIA 23227
GOLDER PROJECT NO. 033 -66$8
File: G:�j,—Wb.,lnRNHilhWell Yield Re.ftaed Hill Wdl Yield Re- -Fie .,I-
Well Yield and Water Quality Report August 29, 2006
Red Hill School Well No. 5 -i- 033 -6658
TABLE OF CONTENTS
1.0 INTRODUCTION ........................................................................ ..............................1
2.0 WELL DRILLING AND CONSTRUCTION PROCEDURES .............................3
2.1 WELL SITE LOCATION AND VDH APPROVAL ........................... ..............................3
2.2 WELL DRILLING AND CONSTRUCTION PROCEDURES ................ ..............................3
3.0 WELL YIELD AND WATER QUALITY TESTING ............... ..............................6
3.1 48 -HOUR AQUIFER TESTING PROCEDURES ............................... ..............................6
3.2 AQUIFER RESPONSE TO PUMPING ............................................. ..............................6
3.2.1 Aquifer Coefficient Estimates ........................................ ..............................7
3.2.2 Predictive Simulations .................................................. .............................10
3.3 SOURCE CAPACITY ESTIMATES ............................................... .............................10
3.4 WATER QUALITY SAMPLING RESULTS .................................... .............................11
4.0 CONCLUSIONS .......................................................................... .............................17
5.0 REFERENCES ............................................................................ .............................18
Appendix A — Red Hill Well 5 Data
(VDH Well Site Approval Letters, Water Well Completion Report, VDH Engineering
Description Sheet for Red Hill School)
Appendix B — Well Yield and Water Quality Data
(48 -hour Well Yield and Drawdown Data and Water Quality Results)
Golder Associates Inc.
Well Yield and Water Quality Report
Red Hill School Well No. 5 -ii-
LIST OF FIGURES
Figure No. and Title
1. Area and Well Location Map ..................... ...............................
2. Well Construction Diagram ....................... ...............................
3. Hydrograph of 48 -Hour Pump and Recovery Test ...................
4. Aquifer Test Analysis and Predictive Simulations .....................
LIST OF TABLES
Table No. and Title
1. Water Quality Results ......................... ...............................
2. Bacteriological Water Quality Results ...............................
Golder Associates Inc.
August 29, 2006
033 -6658
Page
...... ..............................2
...... ..............................5
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Page
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Well Yield and Water Quality Report August 29, 2006
Red Hill School Well No. 5 -1- 033 -6658
1.0 INTRODUCTION
Golder Associates, in association with Dewberry and Davis, B &L Water Specialists and
C.R. Moore Well Drilling Company, have completed drilling and testing of a new public
community water supply well for a residential community located in the Red Hill/North
Garden area of Albemarle County. Residential wells within this community have been
impacted by multiple petroleum hydrocarbon releases primarily from The Trading Post
gas station. The Virginia Department of Environmental Quality (DEQ) is funding
remediation of the contaminated groundwater through its Petroleum Storage Tank
Reimbursement program. As part of the remediation efforts, the DEQ in conjunction
with Albemarle County are developing this new community water system to provide a
long -term solution to the water quality issues caused by the releases of gasoline at The
Trading Post.
The new well was drilled on the Oakey property located just to the east of the affected
area. The well has a tested yield of 29 gallons per minute (gpm), which is more than
sufficient to support the estimated water supply needs of the impacted community. The
new well will be added to the existing public water system located at the Red Hill
Elementary School (PWSID #2003660) and is referred to as Red Hill School Well No. 5,
or simply Well 5. The Red Hill School public water supply consists of three drilled wells
(Wells 2, 3 and 4), a 6,000 - gallon hydropneumatic tank, chlorination plus soda ash and
phosphate treatment. The new well will provide additional source capacity and will be
capable of supporting the school and the additional 11 residences and 1 commercial
facility (e.g., Trading Post) that have impacted wells. Combining the two water systems
will result in considerable cost savings by reducing the amount of new infrastructure
(water treatment building and storage) and reducing long -term operational costs.
Figure 1 shows the locations of Well No. 5, the Red Hill Elementary School, and the
impacted residential wells to be served by this expanded public community water system.
Golder Associates Inc.
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' r TRADING POST GAS STATION !
0 125 250 500 750 — Project: 033 -6658 Title
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Legend uller 08/29/2005 LOCATION MAP
Design: PWN Red Hill Water Supply Study
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File: Review: BBW Client Albemarle Count Virginia Fi ure 1
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Legend uller 08/29/2005 LOCATION MAP
Design: PWN Red Hill Water Supply Study
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File: Review: BBW Client Albemarle Count Virginia Fi ure 1
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0 125 250 500 750 — Project: 033 -6658 Title
Feet (Bussociates Date. RED HILL WELL 5
Legend uller 08/29/2005 LOCATION MAP
Design: PWN Red Hill Water Supply Study
Parcels
File: Review: BBW Client Albemarle Count Virginia Fi ure 1
Figure 1 -Well 5 Locations.mxd Ye g g
Well Yield and Water Quality Report August 29, 2006
Red Hill School Well No. 5 -3- 033 -6658
2.0 WELL DRILLING AND CONSTRUCTION PROCEDURES
2.1 WELL SITE LOCATION AND VDH APPROVAL
Several potential well site locations for the Red Hill School well were inspected and
tentatively approved by Mr. James Simons, Environmental Health Specialist for the
Virginia Department of Health (VDH) for construction of a Class IIB well and minimum
offset requirements. The well locations initially proposed were designated TW2 -27,
TW2 -19 and TW4 -35. The well site meets the minimum lot requirements in accordance
with Section 12 VAC 5- 590 -840A of the Commonwealth of Virginia's Waterworks
Regulations. A copy of the VDH approval letter dated April 20, 2006 is provided in
Appendix A with the proposed well locations. The well site was later relocated to its
current location (designated TW4 -35) based on the results of initial test well drilling
efforts. The alternative site was inspected and tentatively approved by Mr. Carl
Christiansen of VDH. A copy of the VDH approval letter dated June 26, 2006 is also
provided in Appendix A. The well location is shown in Figure 1. A recorded survey plat
of the well lot and a recorded dedication of the well lot for use only as a waterworks
facility will be provided with the final engineering report. The well lot will be graded to
divert surface drainage away from the well casing. An all- weather access road will be
provided to the well lot.
2.2 WELL DRILLING AND CONSTRUCTION PROCEDURES
Two exploratory wells were drilled at the locations previously described as TW2 -27 and
TW2 -19 (Appendix A, VDH topographic maps). Test well TW2 -27 was dry. Test well
TW2 -19 was drilled to 500 feet and yielded 20 gpm based on air -lift yield estimates. The
well was completed as a monitoring well and designated as MW -1. The well was not
completed as a public water supply well at the request of the property owner. The new
well was relocated approximately 320 feet to the east of MW -1 as shown in Figure 1 and
is referred to as Red Hill Well No. 5, or Well 5, due to its incorporation into the Red Hill
School public water system.
The test wells and Red Hill Well 5 were drilled by B &L Water Specialists utilizing air
rotary drilling methods between June 30 and July 7, 2006. A 10 -inch diameter borehole
was drilled and cased through approximately 50 feet of unconsolidated soil and
weathered bedrock and was completed into competent rock to a depth of 63 feet. Welded
Well Yield and Water Quality Report August 29, 2006
Red Hill School Well No. 5 -4- 033 -6658
6 -inch diameter Schedule 40 steel well casing was set into the borehole to a depth of 63
feet. Portland cement grout was pumped under pressure into the annular space between
the casing and the borehole using a side - discharging tremie pipe set at a depth of 50 feet.
After allowing sufficient time for the cement grout to cure, a 6 -inch diameter open rock
hole was drilled to a completion depth of 500 feet. The bedrock encountered consisted of
grey, medium - grained, biotite and feldspar rich granitic gneiss. The main water - bearing
fracture zones were identified by the driller at 380 -385 and 420 -430 feet below grade.
The well was developed for a minimum of one hour. During this time, the well was
producing an estimated 25 gpm. A Water Well Completion Report (Form GW -2) is
provided in Appendix A. A well construction diagram is shown in Figure 2.
WELL CONSTRUCTION DIAGRAM - ALBEMARLE COUNTY
RED HILL SCHOOL WELL NO. 5
'TOP OF BEDROCK
.95' STATIC WATER LEVEL (7/31/2006)
" DIAMETER BOREHOLE TO A DEPTH OF 63 FT
1NULAR SPACE FILLED WITH CEMENT GROUT
'OF WELDED 6" ID, 0.322" WALL
'EEL WELL CASING
:OLOGY:
ZANITIC GNEISS
;ACTURE ZONES: 73, 380 -385, 420 -430 ft btoc
WIFER TEST INFORMATION:
4SED ON 72 -HOUR PUMPING TEST)
IMPING RATE:
29 GPM
IMPING LEVEL:
149.97 FT
tAWDOWN:
105.13 FT
'EC. CAPACITY:
0.28 GPM /FT
kTER QUALITY INFORMATION:
-al Bacteria: Not Detected
,1: 0.27 mg /L
uene: 0.0006 mg /L
.ST PUMP INFORMATION:
)ULDS SUBMERSIBLE PUMP MODEL 18GS30
,3 hp, 19 STAGE, 460V, THREE PHASE)
:T TO A DEPTH OF —400 FT
OPEN ROCK HOLE TO 500 FT
Title:
nnTF nRroaignnF WELL CONSTRUCTION DIAGRAM Figure
Golder Prepared By: PN RED HILL SCHOOL WELL NO.5 No.
Approved By: BBW Albemarle County, Virginia 2 mr;.s.oci.te,
Well Yield and Water Quality Report August 29, 2006
Red Hill School Well No. 5 -6- 033 -6658
3.0 WELL YIELD AND WATER QUALITY TESTING
3.1 48 -HOUR AQUIFER TESTING PROCEDURES
Following construction of the well, C.R. Moore Well Drilling Company installed a 4 -inch
diameter, 3 -hp submersible turbine pump on 1-1/4-inch galvanized column pipe. The
intake of the pump was set to a depth of 400 feet. Following the installation of the pump,
the well and pump assembly was disinfected using a concentrated mixture of calcium
hypochlorite. The chorine solution was pumped through the pump bowls and column
pipe and was flushed out into the fractures surrounding the well bore by gravity pressure.
The well pump assembly was set up with a sampling port, flow control valve, and
totalizing flow meter. Water level and pumping rate measurements were monitored and
recorded throughout the test by Golder personnel. Discharge water was routed away
from the wellhead approximately 50 feet downgradient to prevent possible recharge to
the well.
Water levels were monitored in Well 5 and MW -1 using automated Solinst Leveloggers
prior to, during, and after the 48 -hour aquifer test. A 300 -foot datalogger was installed in
Well 5 and recorded water levels at 1- minute intervals throughout the test period. A 100 -
foot datalogger was installed in MW -1 and recorded water levels at 5- minute intervals.
The 48 -hour aquifer test commenced on July 31St, 2006 at 13:44 PM and ended on
August 2nd, at 14:00 PM (2896 minutes). A pumping rate of approximately 31.5 gpm
was initially established. The pumping rate was reduced to 29 gpm after 1,300 minutes
to maintain back - pressure on the pump. The flow rate remained at 29 gpm throughout
the remainder of the 48 -hour test. A total of 87,327 gallons was pumped during the 48-
hour period resulting in an average discharge rate of 30 gpm for the test. Recorded water
level and discharge measurements are provided in Appendix B.
3.2 AQUIFER RESPONSE TO PUMPING
Figure 3 presents a hydrograph of water levels measured in the pumping well. During
the test, groundwater levels drew down rapidly at first then stabilized for a short period of
time when water levels reached 73 feet below the top of the well casing (ft, btoc). For
Well Yield and Water Quality Report August 29, 2006
Red Hill School Well No. 5 -7- 033 -6658
approximately 100 minutes water levels in the well remained essentially unchanged then
continued a relatively rapid drawdown rate of approximately 9 feet per hour. After
approximately 500 minutes, the drawdown rate decreased to approximately 1.5 feet per
hour and continued to decline throughout the test and was only 0.17 feet per hour at the
end of the test. The static water level at the beginning of the pumping test was 33.95
feet. At the end of the test, the pumping water level was 149.90 feet. This equates to a
total drawdown of 115.95 feet and a calculated specific capacity' of 0.25 gpm/ft.
Monitoring well MW -1, located approximately 320 feet northwest of Well 5, did not
drawdown during the test. Water levels remained constant at 44.65 feet below ground
during the first day of pumping and decreased to 44.45 feet by the end of the test.
3.2.1 Aquifer Coefficient Estimates
Aquifer characteristics were estimated using straight line methods (Cooper- Jacob, 1946),
and residual drawdown (recovery) methods for confined aquifers (Theis, 1935). On
semi -log graphs drawdown data should plot as a straight line if the aquifer is behaving in
a manner consistent with assumptions made by Theis (i.e., radial flow towards a well
from isotropic, homogeneous, porous media aquifer of infinite extent). A semi -log plot
of time - drawdown from the Well 5 test is shown in Figure 4. As shown, there are several
deviations from a straight line plot. These deviations are attributed intersection of
various boundary conditions and changes in fracture flow geometry as the drawdown
cone expanded away from the well. The flattening of the drawdown curve at the
beginning of the test is likely from recharge due to the storage conversion and gravity
drainage of a fracture zone situated at a depth of approximately 73 ft, btoc. After the
pumping level dropped below the fracture, the drawdown slope steepened reflecting the
loss of this shallow water - bearing fracture zone. After 500 minutes, the drawdown slope
decreased slightly and followed a linear trend for the remainder of the test expect when
the pumping rate was lowered to 29 gpm. This suggests that the drawdown cone
intersected additional water - bearing fractures as it expanded away from the well
(recharge boundary) and indicates that the fractured rock aquifer is behaving in a manner
consistent with Theis.
1 Specific capacity is a measure of well capacity per unit of drawdown. It is typically expressed in gallons per minute per foot of
drawdown.
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7/31/06 12:00 8/1/06 0:00 8/1/06 12:00 8/2/06 0:00 8/2/06 12:00 8/3/06 0:00 8/3/06 12:00
DATE
Title:
DATE: 0 By: 2006 48 -Hour Drawdown and Recovery Test Figure
Prepared By: PWN Red Hill Well 5 Aquifer Test No.
(F�,USSOCj*ateS i�l(� q Approved By: BBW Albemarle County, Virginia 3
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Anticipated drawdown
trend at 9 gpm
50
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90
100
110
120
Anticipated drawdown
trend at 29 gpm
130
-
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140
10 100 1000 10000 100000
Elapsed Time (min)
Title:
DATE: 08/28/2006
48 -Hour Pump Test Analysis Figure
(F�,Gold Prepared By: PWN Red Hill Well 5 Aquifer Test No.
ssvlci tes Approved By: BBW Albemarle County, Virginia 4
Well Yield and Water Quality Report August 29, 2006
Red Hill School Well No. 5 -10- 033 -6658
Drawdown data from the pumped well typically do not provide accurate estimates of
aquifer coefficients due to fluctuations in the pumping rate and head losses near the well
bore from turbulent flow and well bore skin effects. Often this produces greater
drawdown in the well compared to the actual drawdown in the aquifer immediately
surrounding the well, and therefore results in a lower calculated transmissivity. For these
reasons, recovery data from the pumping well and drawdown data from observation wells
are primarily used to estimate aquifer transmissivity and storage. In this case, recovery
data from the pumping well was used to estimate an aquifer transmissivity of 123 gpd/ft.
The aquifer coefficient analysis plot is provided in Appendix B. Note that late recovery
data is affected by the fracture system encountered at approximately 73 feet and was not
used by this analysis. Similar affects are seen in Figure 3 as the recovery rate slows as
the shallow fracture zone is re- saturated by rising water levels.
3.2.2 Predictive Simulations
Predictive simulations of drawdown in the well and the surrounding aquifer were
performed to estimate the likely water level response in the Red Hill Well to long -term
pumping. The results are shown in Figure 4 and indicate that sustained pumping of this
well at 29 gpm for 30 days would result in a drawdown of approximately 137 feet and a
pumping level of approximately 170 ft, btoc. The first recorded water - bearing fracture
was encountered at 380 feet, well below the projected pumping level. This along with
the low drawdown rate at the end of the 48 -hour pumping test suggests that the well has a
sustainable yield in excess of 29 gpm. The predicted trend at the anticipated required
yield of 9 gpm based on the well specific capacity is also shown on Figure 4. After
continuous pumping at this rate for a period of 30 days, the estimated pumping level is
approximately 93 ft, btoc.
3.3 SOURCE CAPACITY ESTIMATES
Based on the results of the 48 -hour yield test, the Red Hill Well 5 can be pumped for
sustained periods at a rate of 29 gpm. This is equivalent to 41,760 gallons per day (gpd),
which represents the tested capacity of Well 5. To assure adequate long -term capacity of
a groundwater source, VDH requires 0.5 gpm of tested well capacity for each equivalent
residential connection (ERC). As such, VDH will likely determine the source capacity of
Red Hill Well 5 to be equal to 58 ERCs. VDH calculates source capacity on the basis of
400 gpd per ERC, therefore the source capacity of this additional well is equal to 23,200
Well Yield and Water Quality Report August 29, 2006
Red Hill School Well No. 5 -11- 033 -6658
(see calculations below). The design capacity of the Red Hill School system with the
new well is shown below. Note that the actual permitted capacity of the public water
system will be based on the lesser amount of the source capacity, pump capacity,
treatment capacity, or storage capacity. The most recent VDH Engineering Description
Sheet is provided in Appendix A.
Source Capacity Estimate — Red Hill School System
Design Capacity
Source/Pump Capacity: Well Numbers 1 and 2 — Unknown
Well Number 4 = 5.8 gpm (pump limited)
Well Number 5 = 29 gpm (may be limited by pump)
34.8 gpm x 2 ERCs /gpm = 69.6 ERCs
69.6 ERCs x 400 gpd/ERC = 27,840 gpd
Storage Capacity: 6,000 - gallon hydropneumatic tank
6,000 _ 3 = 2,000 gallons effective storage
2,000 gallons - 200 gallons/ERC = 10 ERCs
10 ERCs x 400 gpd /ERC = 4,000 gpd
Existing Condition: 300 students /staff
11 residential connections
1 commercial connection (Trading Post)
Therefore, the design capacity of the Red Hill School waterworks is limited by storage to
a design capacity of 4,000 gpd.
3.4 WATER QUALITY SAMPLING RESULTS
Water samples were collected at the end of the 48 -hour constant rate test and were
submitted to the Division of Consolidated Laboratory Services in State Lab in Richmond
for inorganic, metals, volatile organic and radiological analyses. In addition, a series of
twenty bacteriological samples were collected approximately every hour over a 20 hour
period and analyzed for total and fecal coliform using the most probable number (MPN)
method.
Well Yield and Water Quality Report August 29, 2006
Red Hill School Well No. 5 -12- 033 -6658
The laboratory analytical data sheets are provided in Appendix B. Summaries of the
water quality results are presented in Tables 1 and 2. The analyses indicate that the water
source complies with all state and federal water quality standards. Iron concentrations
were measured at 0.27 mg/L, which is only slightly less than the secondary maximum
contaminant level (SMCL) for iron of 0.3 mg/L. Iron standards are esthetic and can
cause staining of porcelain bathroom fixtures and laundered goods, and may impart a
bitter taste in heated beverages such as tea and coffee. Treatment for iron and manganese
generally involves filtration and ion exchange using greensand filters or by the addition
of a sequestering agent (i.e. AquaMag or NAPCO 204) that prevent iron and manganese
from precipitating out in the distribution system. The existing water treatment system
utilizes AquaMag for corrosion protection, which should prevent the presence of
dissolved iron from becoming a water quality problem.
Toluene, a petroleum substance found in gasoline, was detected slightly above the the
minimum detection limit at a concentration of 0.6 micrograms per liter or parts per billion
(ug /l or ppb). The drinking water standard for toluene is 1,000 ug /1. The concentration is
well below current standards and are not believed to pose a risk. In addition, because
there are no likely sources near the well site, it is believed that the detection of toluene
may be due to cross contamination of the sample from on -site vehicles or the generator.
The source should be re- sampled prior to start up. If the compound is still present, then
VDH should be consulted on a monitoring program to insure that concentrations remain
below maximum concentration limits.
The results of the bacteriological sampling summarized in Table 2 indicate that total
coliform bacteria was detected in one sample at a concentration of 5.2 colonies per 100
ml and that no fecal bacteria was detected. Based on these results, VDH will not likely
require continuous chlorine disinfection of this water source.
Well Yield and Water Quality Report
Red Hill School Well No. 5 -13-
TABLE 1
WATER QUALITY RESULTS
Red Hill and School Wells, Red Hill, VA
(Shaded indicates value exceeds MCL)
August 29, 2006
033 -6658
PARAMETER
Drinking
Water
Standards
(PMCL or SMCL)
RED HILL
SCHOOL UNITS
WELL NO. 5
INORGANICS
6.83
pH
8.5
mg /I
Alkalinity -Total
19
Alkalinity- Bicarbonate
19
mg /I
Alkalinity- Carbonate
0
mg /I
Ammonia
-
mg /I
Chloride
250
<5
mg /I
Color PCU
15
0
PCU
Corrosion Index
-
AGGR
Dissolved Solids - Total
500
45
mg /I
Dissolved Solids - Volatile
500
4
mg /I
Dissolved Solids - Fixed
500
41
mg /I
Fluoride
<0.2
mg /I
Hardness - Calcium
7.42
mg /I
Hardness -Total
8.69
mg /I
Langlier Index
-
LANG
Nitrate +Nitrite as N
10
0.63
mg /I
Nitrite as N
2
-
Ortho Phosphate as P
-
mg /I
Silica (as Si02)
-
mg /I
Specific Conductance
49.1
umhos /cm
Sulfate
250
<5
mg /I
Sulfide
0
mg /I
Turbidity
-
NTU
METALS
Aluminum
0.077
mg /I
Antimony
0.006
<0.002
mg /I
Arsenic
<0.002
mg /I
Barium
2.0
<.20
mg /I
Beryllium
0.004
<0.002
mg /I
Cadmium
0.005
<0.002
mg /I
Chromium
0.1
<0.01
mg /I
Copper
1.3
<0.20
mg /I
Iron
0.3
0.27
mg /I
Lead
0.015
<0.002
mg /I
Manganese
0.05
<0.01
mg /I
Mercury
0.002
<0.0002
mg /I
Nickel
0.1
<0.01
mg /I
Selenium
1 0.05
<0.01
I mg /I
Well Yield and Water Quality Report
Red Hill School Well No. 5 -14-
TABLE 1
WATER QUALITY RESULTS
Red Hill and School Wells, Red Hill, VA
(Shaded indicates value exceeds MCL)
August 29, 2006
033 -6658
PARAMETER
Drinking
Water
Standards
(PMCL or SMCL)
RED HILL
SCHOOL UNITS
WELL NO. 5
Sodium
20.0
<5.0
mg /I
mg /I
mg /I
ug /I
Thallium
0.002
<0.002
Zinc
5.0
<0.20
<0.5
VOLATILE ORGANIC COMPOUNDS
Dichlorodifluoromethane
Methyl Chloride (Chloromethane)
<0.5
ug /I
Vinyl Chloride
2
<0.5
ug /I
Methyl Bromide (Bromomethane)
<0.5
ug /I
Chloroethane
<0.5
ug /I
Trichlorofluoromethane
<0.5
ug /I
1, 1 -Dichloroethene
7
<0.5
ug /I
Dichloromethane
<0.5
ug /I
trans- 1,2- Dichloroethene
100
<0.5
ug /I
1, 1 -Dichloroethane
5
<0.5
ug /I
1,2- Dichloroethane
5
<0.5
ug /I
cis- 1,2- Dichloroethene
70
<0.5
ug /I
Chloroform
THM
<0.5
ug /I
1, 1, 1 -Trichloroethane
200
<0.5
ug /I
Carbon Tetrachloride
5
<0.5
ug /I
1,2- Dichloroethane
<0.5
ug /I
Trichloroethene
5
<0.5
ug /I
1,2- Dichloropropane
5
<0.5
ug /I
Dibromomethane
<0.5
ug /I
Bromodichloromethane
<0.5
ug /I
cis- 1,3- Dichloropropene
<0.5
ug /I
trans -1,3- Dichloropropene
<0.5
ug /I
1,1,2- Trichloroethane
5
<0.5
ug /I
Tetrachloroethylene
5
<0.5
ug /I
Dibromochloromethane
<0.5
ug /I
Chlorobenzene
100
<0.5
ug /I
1,1,1,2- Tetrachloroethane
<0.5
ug /I
Bromoform
THM
<0.5
ug /I
1,1,2,2- Tetrachloroethane
<0.5
ug /I
o- Chlorotoluene (2- Chlorotoluene)
<0.5
ug /I
p- Chlorotoluene (4- Chlorotoluene)
<0.5
ug /I
m- Dichlorobenzene
<0.5
ug /I
p- Dichlorobenzene
75
<0.5
ug /I
o- Dichlorobenzene
600
<0.5
ug /I
1,2,4- Trichlorobenzene
8*
<0.5
ug /I
1,2,3- Trichlorobenzene
<0.5
1 ug /I
Well Yield and Water Quality Report
Red Hill School Well No. 5 -15-
TABLE 1
WATER QUALITY RESULTS
Red Hill and School Wells, Red Hill, VA
(Shaded indicates value exceeds MCL)
August 29, 2006
033 -6658
PARAMETER
Drinking
Water
Standards
(PMCL or SMCL)
RED HILL
SCHOOL UNITS
WELL NO. 5
Benzene
Toluene
Ethylbenzene
Isopropyl benzene
5
<0.5
0.6
<0.5
ug /I
ug /I
ug /I
ug /I
ug /I
1,000
700
<0.5
<0.5
n- Propylbenzene
t- Butylbenzene
<0.5
<0.5
ug /I
ug /I
s- Butylbenzene
Naphthalene
<0.5
ug /I
Bromochloromethane
<0.5
ug /I
n- Butylbenzene
<0.5
ug /I
1,2- Dibromo -3- chloropropane
<0.5
ug /I
1,2- Ethylenedibromide
<0.5
ug /I
1,3- Dichloropropane
<0.5
ug /I
2,2- Dichloropropane
<0.5
ug /I
1,1- Dichloropropene
<0.5
ug /I
Hexachlorobutadiene
<0.5
ug /I
4- Isopropyltoluene
<0.5
ug /I
Styrene
100
<0.5
ug /I
1,2,3- Trichloropropane
<0.5
ug /I
1,2,4- Trimethylbenzene
<0.5
ug /I
1,3,5 - Trimethylbenzene
<0.5
ug /I
Total Xylenes
10,000
<0.5
ug /I
Methyl t -butyl ether (MTBE)
<0.5
<0.5
ug /I
ug /I
Bromobenzene
RADIONUCLIDES
Gross Alpha 15
Gross Beta 50
Radium 228
1.1 +/-0.2
pCi /L
2.9+/-0.3
pCi /L
pCi /L
0.0+/-0.6
PMCL- Primary Maximum Contaminant Level
SMCL- Secondary Maximum Contaminant Level
- Not Analyzed
Well Yield and Water Quality Report August 29, 2006
Red Hill School Well No. 5 -16- 033 -6658
TABLE 2
BACTERIOLOGICAL WATER QUALITY RESULTS -
RED HILL WELL NO. 5
Sample ID/
LIMS #
Date /Time Total Fecal
Coliform Coliform
1402991
8/1/200616:00
<1.0
<1.0
1402992
8/1/200617:00
<1.0
<1.0
1402993
8/1/2006 18:00
<1.0
<1.0
1402994
8/1/2006 19:00
5.2
<1.0
1402995
8/1/2006 20:00
<1.0
<1.0
1402996
8/1/2006 21:00
<1.0
<1.0
1402997
8/1/2006 22:00
<1.0
<1.0
1402998
8/1/2006 23:00
<1.0
<1.0
1402999
8/2/2006 0:00
<1.0
<1.0
1403000
8/2/20061:00
<1.0
<1.0
1403001
8/2/2006 2:00
<1.0
<1.0
1403002
8/2/2006 3:00
<1.0
<1.0
1403003
8/2/2006 4:00
<1.0
<1.0
1403004
8/2/2006 5:00
<1.0
<1.0
1403005
8/2/2006 6:00
<1.0
<1.0
1403006
8/2/2006 7:00
<1.0
<1.0
1403007
8/2/2006 8:00
<1.0
<1.0
1403008
8/2/2006 9:00
<1.0
<1.0
1403009
8/2/200610:00
<1.0
<1.0
1403010
1 8/2/200611:00
1 <1.0
<1.0
Well Yield and Water Quality Report August 29, 2006
Red Hill School Well No. 5 -17- 033 -6658
4.0 CONCLUSIONS
A new public water supply well has been drilled and tested for the Red Hill School water
system (PWSID #2003660). The purpose of the new well is to provide sufficient source
capacity to serve residents near the school that are impacted by petroleum releases from
the former Trading Post gas station. The results of the well drilling, construction, and
yield and water quality testing are documented in this report. The primary conclusions
are presented below.
• The Red Hill Well 5 is constructed as a Class IIB public water supply well with 63
feet of pressure grouted 6 -inch diameter steel casing and nominal 6 -inch open well
bore drilled to a total depth of 500 feet.
• Significant water - producing fracture zones were encountered at depths of 380 -385
feet and 420 -430 feet. The air -lift yield of the well during drilling operations was
estimated at more than 25 gpm.
• A 48 -hour aquifer test was completed at a pumping rate of 29 to 31 gpm. The static
depth to water at the beginning of the test was approximately 34 feet and the
maximum pumping level at the end of the test was 149 feet.
• Based on the results of the 48 -hour aquifer test, the Red Hill Well has a sustainable
yield of 29 gpm (41,760 gpd). Using VDH guidelines of 0.5 gpm per ERC, the well
will likely have a permitted source capacity of 23,200 gpd on an annual average
basis. This is equivalent to 696,000 gallons per month and 8.468 million gallons per
year.
Water quality analyses indicate that the water source complies with all state and
federal water quality standards.
Well Yield and Water Quality Report August 29, 2006
Red Hill School Well No. 5 -18- 033 -6658
5.0 REFERENCES
Cooper, H.H. and C.E. Jacob, 1946, A generalized graphical method for evaluating
formation constants and summarizing well field history, Am. Geophys. Union Trans.,
vol. 27, pp. 526 -534.
Theis, C.V., 1935, The relation between the lowering of the piezometric surface and the
rate and duration of discharge of a well using groundwater storage, Am. Geophys.
Union Trans., vol 16, p. 519
Well Yield and Water Quality Report
Red Hill School Well No. 5 -19-
APPENDIX A
RED HILL SCHOOL WELL NO. 5
VDH WELL SITE APPROVAL LETTERS
WATER WELL COMPLETION REPORT
August 29, 2006
033 -6658
RED HILL SCHOOL VDH ENGINEERING DESCRIPTION SHEET
Well Yield and Water Quality Report
Red Hill School Well No. 5 -20-
APPENDIX B
RED HILL SCHOOL WELL NO. 5
August 29, 2006
033 -6658
48 -HOUR WELL YIELD AND DRAWDOWN TEST DATA
WATER QUALITY RESULTS