Chloride Concentrations in Hampton Roads Drinking Water Sources

Home , Saltwater intrusion

Salt Water Intrusion and Potential Impacts to Community Water Systems

Prepared for the: HAMPTON ROADS PLANNING DISTRICT COMMISSION DIRECTORS OF UTILITIES COMMITTEE

Prepared by the: STAFF OF THE HAMPTON ROADS PLANNING DISTRICT COMMISSION

SEPTEMBER 2014

Chloride Concentrations in Hampton Roads Drinking Water Sources

Salt Water Intrusion and Potential Impacts to Community Water Systems

Prepared for the: HAMPTON ROADS PLANNING DISTRICT COMMISSION DIRECTORS OF UTILITIES COMMITTEE

Prepared by the: STAFF OF THE HAMPTON ROADS PLANNING DISTRICT COMMISSION

SEPTEMBER 2014

Acknowledgements

This report was prepared by the Hampton Roads Planning District Commission (HRPDC) in cooperation with the

U.S. Geological Survey (USGS) Virginia Water Science Center. HRPDC would like to acknowledge the hydrologic and spatial data analysis provided by USGS in support of this document.

Chloride Concentrations in Hampton Roads Drinking Water Sources

Table of Contents Executive Summary ...... iii Introduction ...... 1 Chloride Concentrations Across Hampton Roads ...... 3 Chloride Trends Over Time ...... 14 Chloride Monitoring and Implications for Water Resource Management ...... 16 Tables Table 1. Significance of Chloride Concentrations ...... 3 Table 2. Distribution of Small Capacity Private Drinking Water Wells among Selected Drinking Water Aquifers ...... 3 Table 3. Estimated Number of Small Capacity Private Drinking Water Wells in the Yorktown-Eastover Aquifer ...... 4 Table 4. Estimated Number of Small Capacity Private Drinking Water Wells in the Piney Point Aquifer ...... 6 Table 5. Estimated Number of Small Capacity Private Drinking Water Wells in the Aquia Aquifer ...... 8 Table 6. Estimated Number of Small Capacity Private Drinking Water Wells in the Potomac Aquifer ...... 10 Figures Figure 1. Saltwater Interface...... 1 Figure 2. Coastal Plain Aquifers...... 2 Figure 3. Selected Wells Included in the Chloride Trend Analysis ...... 15 Maps Map 1. Chloride Concentrations and Groundwater Users for the Yorktown-Eastover Aquifer ...... 5 Map 2. Chloride Concentrations and Groundwater Users for the Piney Point Aquifer ...... 7 Map 3. Chloride Concentrations and Groundwater Users for the Aquia Aquifer ...... 9 Map 4. Chloride Concentrations and Groundwater Users for the Potomac Aquifer ...... 11 Map 5. Private Community Water Systems in Hampton Roads with Unknown Source Aquifers ...... 13

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Chloride Concentrations in Hampton Roads Drinking Water Sources

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Chloride Concentrations in Hampton Roads Drinking Water Sources

Executive Summary

The primary drinking water aquifers in Hampton Roads are at risk of degradation from saltwater intrusion. Local governments should support DEQ’s groundwater monitoring strategy for improving the existing chloride monitoring program. In Hampton Roads, 19 municipal water systems and 51 private water systems are supplied partially or completely by groundwater from four primary drinking water aquifers. Additionally, about 77,200 private wells provide water from these aquifers to homes and small businesses in the region. A comprehensive chloride monitoring program with “sentinel” monitor well sites is needed to effectively assess: • Saltwater intrusion at the coast; and • Upconing of saltwater related to well pumping.

There are strategies to mitigate saltwater intrusion, such as changing rates and locations of pumping or injecting water into the aquifer. Early detection of saltwater intrusion or upconing through a properly designed chloride monitoring network will allow water utilities to apply management strategies and plan for extensions of municipal systems.

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Chloride Concentrations in Hampton Roads Drinking Water Sources

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Chloride Concentrations in Hampton Roads Drinking Water Sources

Introduction water pressure pushing saltwater inland; large groundwater withdrawals reduce water pressure and allow groundwater to In Hampton Roads, many homeowners and communities rely on move inland to fill the void and equalize water pressure across the wells to provide their drinking water. If the well water becomes aquifer. salty, additional treatment is necessary to make the well water drinkable. The treatment can be very expensive for individual Large withdrawals from wells can also cause upconing in the homeowners and small communities and often there is not a aquifer. Upconing is the process by which saline water underlying viable alternative because the public water system does not freshwater in an aquifer rises upward into the freshwater zone as provide service to the area. From 2000 to 2012, the Hampton a response to well pumping. Upconing will cause wells to become Roads Planning District Commission (HRPDC) partnered with the saltier. Upconing can cause localized short-term changes in water United States Geological Survey (USGS) to monitor chloride quality that reverse when pumping is discontinued, but prolonged concentrations in the region’s groundwater. Since 2012, pumping may result in increasingly saltier water. monitoring has been conducted by the Virginia Department of Environmental Quality (DEQ). Chloride monitoring provides the data needed to evaluate the potential for wells in the region to become salty.

Because we live along the coast, seawater encroaches on the fresh groundwater and some wells may become salty over time as the seawater moves inland. Because seawater has a higher density than freshwater, the freshwater typically sits on top of the seawater. The point where seawater and freshwater meet is called the saltwater interface. The saltwater interface doesn’t move very quickly because groundwater in Hampton Roads moves very slowly (often less than a few feet per year). However, large wells that pump out millions of gallons of water can cause the saltwater interface to move faster and may cause the groundwater to start flowing towards the well instead of towards the ocean. If the rate of sea level rise increases, the saltwater interface may also move inland at a faster rate. The interface Figure 1. Saltwater Interface. The zone where freshwater meets seawater is moves because of water pressure. Increased sea level rise adds called the saltwater interface, which can be disturbed by upconing.

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Chloride Concentrations in Hampton Roads Drinking Water Sources

HRPDC partnered with the USGS and DEQ to evaluate all of the was able to estimate the chloride concentration in the historic chloride data available for eastern Virginia (see groundwater all across Hampton Roads. Some wells in the “Groundwater-quality data and regional trends in the Virginia monitoring network were tested every few years. At those wells, Coastal Plain” (PP-1772)). By mapping the wells that were USGS could determine whether or not the well water was getting monitored and the chloride concentrations at those wells, USGS saltier over time.

ED ED’ Groundwater flows through 200 layers of sand and gravel 0 CHESAPEAKE BAY STUDY YORKTOWN-EASTOVER AQUIFER VIRGINIA AREA called aquifers. Under AQUIA AQUIFER -200 PINEY POINT AQUIFER Hampton Roads, there are

MARYLAND -400 several aquifers separated by layers of clay (McFarland -600 and Bruce, 2006). -800 POTOMAC AQUIFER Groundwater barely moves ALTITUDE, IN FEET IN ALTITUDE, -1,000 through these clay layers. ED

-1,200 The clay layers are called ED’ OUTER BEDROCK CRATER GD confining units because they -1,400 GD’ act as barriers to the NORTH CAROLINA movement of groundwater 0 10 20 SECTION LOCATIONS MILES GD 200 between aquifers. Figure 2 kwater River

Nottoway River Bla GD’

Nansemond River 0 Elizabeth River illustrates a cross-section of AQUIA AQUIFER YORKTOWN-EASTOVER AQUIFER the aquifers under Hampton -200 EXPLANATION Surﬁcial aquifer Roads. At any location, the -400 Yorktown-Eastover aquifer PINEY POINT AQUIFER Piney Point aquifer chloride concentrations are Aquia aquifer -600 Virginia Beach aquifer different at different depths POTOMAC AQUIFER Potomac aquifer -800 Basement bedrock because each aquifer has a VIRGINIA BEACH AQUIFER ALTITUDE, IN FEET IN ALTITUDE, different chloride -1,000 0 10 20 BEDROCK MILES concentration. Typically,

-1,200 VERTICAL EXAGGERATION 130X deeper aquifers have higher

-1,400 chloride concentrations.

Figure 2. Coastal Plain Aquifers. Beneath Hampton Roads, sand and gravel aquifers are separated by confining units of clay. Page 2

Chloride Concentrations in Hampton Roads Drinking Water Sources

Chloride Concentrations across Hampton Roads Table 2. Distribution of Small Capacity Private Drinking Water Wells among Selected Drinking Water Aquifers Maps 1 through 4 show the estimated chloride concentrations in Estimated Distribution of Small Private Wells (number, %) four Hampton Roads Drinking Water aquifers: the Yorktown- Number of Locality Small Yorktown Piney Eastover aquifer, the Piney Point aquifer, the Aquia aquifer, and Aquia Potomac Private -Eastover Point Wells (2000) Aquifer Aquifer the Potomac aquifer. Each map shows the chloride concentrations Aquifer Aquifer across the aquifer, the location of public and private water system Chesapeake 12,617 10,472 0 126 0 wells withdrawing from that aquifer, and the portions of the (83%) (1%) region where all homes and businesses rely on individual wells. Franklin 0 0 0 0 0 Most wells only withdraw water from one aquifer. Chloride Gloucester 9,478 8,246 569 0 0 concentrations are represented by contour lines ranging from (87%) (6%) 50 to 10,000 milligrams per liter (mg/l). The significance of the Hampton 0 0 0 0 0 chloride concentrations are described in Table 1: Isle of Wight 5,359 107 54 375 3,430 (2%) (1%) (7%) (64%) Table 1. Significance of Chloride Concentrations James City 7,183 718 2,011 3,376 1,006 Chloride Concentration Significance (10%) (28%) (47%) (14%) 1 - 250 mg/l Freshwater Newport News 0 0 0 0 0 250 - 400 mg/L Water tastes salty Norfolk 0 0 0 0 0 500 - 5,000 mg/L Brackish water that needs treatment Poquoson 0 0 0 0 0 19,400 mg/L Seawater Portsmouth 0 0 0 0 0 Additionally, Maps 1 through 4 show the estimated number of Southampton 3,188 96 0 64 2,072 small capacity private drinking water wells (small private wells) in (3%) (2%) (65%) each locality and aquifer. This information is also provided in Suffolk 6,019 181 0 120 1,986 (3%) (2%) (33%) Table 2. Small private well data is summarized from the USGS Surry 1,952 683 0 98 527 report, “Private Domestic-Well Characteristics and the (35%) (5%) (27%) Distribution of Domestic Withdrawals among Aquifer in the Virginia Beach 15,306 9,490 0 0 0 Virginia Coastal Plain” (SIR 2007-5250). The report estimated the (62%) Williamsburg 0 0 0 0 0 number of drinking water wells serving homes and businesses; it does not address wells used only for irrigation. York 16,137 11,941 4,196 0 0 (74%) (26%)

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Chloride Concentrations in Hampton Roads Drinking Water Sources

Map 1. Chloride Concentrations and Groundwater Users for the Table 3. Estimated Number of Small Capacity Private Drinking Water Wells in the Yorktown-Eastover Aquifer Yorktown-Eastover Aquifer. Although the Yorktown-Eastover Small Private Wells in the Aquifer is not a drinking water source for any municipal water Total Number of Small Yorktown-Eastover Aquifer systems, the aquifer provides water for five private community Locality Private Wells (Estimated, Year 2000) water system wells and many small private wells serving homes Number Percent and businesses throughout Hampton Roads. In Gloucester, 87% Chesapeake 12,617 10,472 83% (8,246) of small private wells in the County rely on the Yorktown- Franklin 0 0 0% Eastover Aquifer. In the City of Chesapeake and York County, 83% (10,472) and 74% (11,941) of small private wells in these Gloucester 9,478 8,246 87% localities, respectively, are supplied by the aquifer. Small private Hampton 0 0 0% wells in James City County (718 wells, 10%), Isle of Wight County Isle of Wight 5,359 107 2% (107 wells, 2%), Southampton County (96 wells, 3%), the City of Suffolk (181 wells, 3%), Surry County (683 wells, 35%), and the James City 7,183 718 10% City of Virginia Beach (9,490 wells, 62%) are also dependent on Newport News 0 0 0% the aquifer (see Table 3). Norfolk 0 0 0% Chloride concentrations of 250 mg/l estimated at the top of the Poquoson 0 0 0% aquifer appear in portions of Chesapeake, Gloucester, Hampton, Norfolk, Poquoson, Virginia Beach, and York. Based on the Portsmouth 0 0 0% location of the 250 mg/l chloride contour and the extent of areas Southampton 3,188 96 3% served by municipal water systems, a few private water systems and some homes and businesses in Gloucester, Chesapeake, and Suffolk 6,019 181 3% Virginia Beach may be producing water that is salty to the taste. Surry 1,952 683 35%

Virginia Beach 15,306 9,490 62% Williamsburg 0 0 0%

York 16,137 11,941 74%

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Hanover Goochland King William King And Queen Middlesex Map 1. Chloride Concentrations and Legend Accomack Groundwater Users for the Chloride ConcReinchtrmaotniod nCity Yorktown-Eastover Aquifer (Saltwater Intrusion into Aquifer) 50 mg/l New Kent Henrico 250 mg/l 50 mg/l 1000 mg/l Gloucester Mathews Y 10000 mg/l O (8,246) R K

Chesterfield Charles City R Community Water Systems I 250 mg/l V (Drinking Water) Withdrawing E James City R Bray's Point LLC Northampton from the Yorktown-Eastover !. (718) Aquifer R & L Trailer !. !. Park C Municipal SysCtoelmonsia (l0 H)ghts Cty Williamsburg H 10000 E

!. S Private Systems (5) York mg/l A

P (11,941) 1000 mg/l Municipal WaterP Setyesrstbeumrg Prince George E

Service Areas K

Areas Outside Community Water A System Service Areas Y Newport News Poquoson Areas Served by Small Surry CaDpianwcidtyd iPe rivate Drinking (683) Water Wells J A M E S Hampton Estimated Number of Small R I V Private Drinking Water Wells E R Withdrawing from the Yorktown- Sussex 1000 mg/l Eastover Aquifer: Chesapeake 10,472 Franklin 0 Gloucester 8,246 Norfolk 50 mg/l Hampton 0 Isle of Wight ATLANTIC Isle of Wight 107 (107) Portsmouth James City 718 OCEAN Newport News 0 Norfolk 0 !. 250 mg/l Virginia Beach Poquoson 0 Portsmouth (9,490) Portsmouth 0 Aqua Virginia, Inc. Southampton 96 Suffolk 181 Surry 683 Southampton Virginia Beach 9,490 (96) Suffolk Chesapeake Emporia (10,472) Williamsburg 0 Franklin (181) York 11,941

Greensville St. Brides Correctional Center Scale 50 mg/l !.

0 5 10 United States - Dept. of the Navy Miles ° !. Chloride Concentrations in Hampton Roads Drinking Water Sources

Map 2. Chloride Concentrations and Groundwater Users for the Table 4. Estimated Number of Small Capacity Private Drinking Water Wells in the Piney Point Aquifer Piney Point Aquifer. The Piney Point Aquifer is an important water Small Private Wells in the source for the York-James Peninsula, supplying 23 municipal Total Number of Small Piney Point Aquifer water system wells operated by the James City Service Authority Locality Private Wells (Estimated, Year 2000) and 3 municipal water system wells operated by Newport News Number Percent Waterworks. The aquifer also provides water to one private Chesapeake 12,617 0 0% community water system and 28% (2,011) of small private wells in Franklin 0 0 0% James City County. In York County, 26% (4,196) of small private wells rely on the Piney Point Aquifer. Some small private wells in Gloucester 9,478 569 6% Gloucester County (569 wells, 6%) and Isle of Wight County Hampton 0 0 0% (54 wells, 1%) are also dependent on the aquifer (see Table 4). Isle of Wight 5,359 54 1% Chloride concentrations of 250 mg/l estimated at the top of the James City 7,183 2,011 28% aquifer appear in portions of the Cities of Chesapeake, Newport Newport News News, Norfolk, Portsmouth, and Suffolk, and the Counties of 0 0 0% Gloucester County and York. Most of the areas with chloride Norfolk 0 0 0% concentrations of 250 mg/l or higher are served by municipal Poquoson 0 0 0% water systems that use surface water or treated groundwater. The southern portion of Gloucester County is the only area in Portsmouth 0 0 0% Hampton roads where small private wells in the Piney Point Southampton 3,188 0 0% aquifer may be producing water that is salty to the taste. Suffolk 6,019 0 0%

Surry 1,952 0 0%

Virginia Beach 15,306 0 0%

Williamsburg 0 0 0%

York 16,137 4,196 26%

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Legend Middlesex Map 2. Chloride Concentrations and Chloride Concentration King William Groundwater Users for the (Saltwater Intrusion into Aquifer) King And Queen Piney Point Aquifer 50 mg/l 250 mg/l 1000 mg/l New Kent 10000 mg/l Community Water Systems 50 mg/l Mathews (Drinking Water) Withdrawing 250 mg/l from the Piney Point Aquifer #0 #0 #0 #0#0 James City Service Authority 1000 mg/l Wells (23) #0 #0 #0 Gloucester (569) "/ #0 10000 mg/l Newport News Waterworks #0 Y #0 #0 O Wells (3) R K !. #0 Private System Wells (1) #0 "/ R I "/ "/ V E #0 R Municipal Water System Charles Shodon Mobile !. Service Areas City Estates #0 250 mg/l Areas Outside Community Water #0#0 #0 System Service Areas James City (2,011) Areas Served by Small Capacity Private Drinking York #0Williamsburg C Water Wells (4,196) H 1000 mg/l Prince George E S Estimated Number of Small A P

Private Drinking Water Wells 10000 mg/l

50 mg/l Withdrawing from the K Piney Point Aquifer: E

B Chesapeake 0 A Franklin 0 Y Gloucester 569 Hampton 0 Isle of Wight 54 Newport News James City 2,011 Surry Poquoson Newport News 0 Norfolk 0 Poquoson 0 Portsmouth 0 J A M Southampton 0 E S

Suffolk 0 R mg/l 250 I V Surry 0 E R Virginia Beach 0 Hampton Williamsburg 0 York 4,196 Sussex

Isle of Wight

Scale (54) 50 mg/l 50 Miles Southampton 0 2.5 5 ° Norfolk 1000 mg/l

Suffolk Chloride Concentrations in Hampton Roads Drinking Water Sources

Map 3. Chloride Concentrations and Groundwater Users for the Table 5. Estimated Number of Small Capacity Private Drinking Water Wells in the Aquia Aquifer Aquia Aquifer. The Aquia Aquifer is the source for two wells Small Private Wells in the operated by the Western Tidewater Water Authority, which Total Number of Small Aquia Aquifer supplies municipal water systems in the City of Suffolk and Isle of Locality Private Wells (Estimated, Year 2000) Wight County. Although no private community water systems Number Percent have wells in the Aquia Aquifer, many homes and businesses Chesapeake 12,617 126 1% throughout Hampton Roads depend on the aquifer for drinking Franklin 0 0 0% water. Approximately 47% (3,376) of small private wells in James City County pump water from the Aquia Aquifer. Some small Gloucester 9,478 0 0% private wells in the City of Chesapeake (126 wells, 1%), Isle of Hampton 0 0 0% Wight County (375 wells, 7%), Southampton County (64 wells, Isle of Wight 5,359 375 7% 2%), the City of Suffolk (120 wells, 2%), and Surry County (98 wells, 5%) also utilize the aquifer (see Table 5). James City 7,183 3,376 47% Newport News Chloride concentrations of 250 mg/l estimated at the top of the 0 0 0% aquifer appear in portions of the Cities of Chesapeake, Norfolk, Norfolk 0 0 0% Portsmouth, and Suffolk and the Counties of Gloucester and York. Poquoson 0 0 0% Most of these areas are served by municipal water systems. The southern portions of Chesapeake and Suffolk are the only areas Portsmouth 0 0 0% where small private wells in the Piney Point aquifer may be Southampton 3,188 64 2% producing water that is salty to the taste. Suffolk 6,019 120 2%

Surry 1,952 98 5%

Virginia Beach 15,306 0 0%

Williamsburg 0 0 0%

York 16,137 0 0%

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Henrico New Kent

New Kent Legend Map 3. Chloride Concentrations and Chloride Concentration GroMuatnhedwswater Users for the Y Chesterfield (Saltwater Intrusion into Aquifer) O Aquia Aquifer R 50 mg/l 50 mg/l K Gloucester Charles City R I 250 mg/l V E 1000 mg/l James City R 10000 mg/l (3,376)

250 Community Water Systems Williamsburg mg/l (Drinking Water) Withdrawing from the Aquia Aquifer !. Prince George C Western Tidewater Water H

Authority Wells (2) York E S

!. Private System Wells (0) P

A Municipal Water System K E Service Areas Newport News Poquoson B Surry A Y Dinwiddie Areas Outside Community Water (98) J System Service Areas A M E S Areas Served by Small R Hampton Capacity Private Drinking I V E R Water Wells

Estimated Number of Small Private Drinking Water Wells Sussex Withdrawing from the Aquia Aquifer: Chesapeake 126 Franklin 0 Gloucester 0 Isle of Wight Norfolk Hampton 0 (375) Portsmouth Isle of Wight 375 James City 3,376 Newport News 0 0 Norfolk Portsmouth Virginia Beach Poquoson 0 Southampton Portsmouth 0 (64) 10000 Southampton 64 50 mg/l mg/l Suffolk 120 250 mg/l Surry 98 Chesapeake Virginia Beach 0 Emporia Suffolk (126) Williamsburg 0 1000 mg/l York 0 Franklin (120)

Greensville

Scale !.!. Miles 0 5 10 °

Currituck Currituck Chloride Concentrations in Hampton Roads Drinking Water Sources

Map 4. Chloride Concentrations and Groundwater Users for the Table 6. Estimated Number of Small Capacity Private Drinking Water Wells in the Potomac Aquifer Potomac Aquifer. The Potomac Aquifer, the largest and most Small Private Wells in the heavily used source of groundwater in the Virginia Coastal Plain, Total Number of Small Potomac Aquifer provides water for 88 municipal water supply wells. A total of Locality Private Wells (Estimated, Year 2000) 30 private community water system wells utilize the Potomac Number Percent Aquifer. The aquifer also provides water to a significant portion of Chesapeake 12,617 0 0% small private wells in Isle of Wight County (3,430 wells, 64%), Franklin 0 0 0% James City County (1,006 wells, 14%), Southampton County (2,072 wells, 65%), the City of Suffolk (1,986 wells, 33%), and Gloucester 9,478 0 0% Surry County (527 wells, 27%). Hampton 0 0 0%

Chloride concentrations of 250 mg/l estimated at the top of the Isle of Wight 5,359 3,430 64% aquifer appear in portions of the Counties of Gloucester, York, James City 7,183 1,006 14% and James City and the Cities of Newport News, Norfolk, Newport News Portsmouth, Chesapeake, and Suffolk. Based on the location of 0 0 0% the 250 mg/l chloride contour and the extent of areas served by Norfolk 0 0 0% municipal water systems, there may be some small private wells Poquoson 0 0 0% in Suffolk may be producing water that is salty to the taste. Portsmouth 0 0 0%

Southampton 3,188 2,072 65%

Suffolk 6,019 1,986 33%

Surry 1,952 527 27%

Virginia Beach 15,306 0 0%

Williamsburg 0 0 0%

York 16,137 0 0%

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Lancaster Goochland Legend Hanover Middlesex Map 4. Chloride Concentrations and Community Water Systems King William King and Queen (Drinking Water) Withdrawing Groundwater Users for the Powhatan from the Potomac Aquifer Potomac Aquifer !. Richmond Private System Wells (30) Henrico Laurelwood Estates Municipal Wells: Trailer Pk New Kent !.

%9 Chesapeake (6) C

50 mg/l H 250 mg/l "S E Franklin (4) 1000 mg/l %, S %, Gloucester (2) 0# A P $8 E Isle of Wight (13) Y Mathews A 0# O Gloucester 0# James City Service Authority (8) R K Charles 0# K E

"/ B Newport News Waterworks (6) Chesterfield City R I A V Northampton +$ James City E Y Norfolk (4) R (1,006) ") %, *# Portsmouth (4) Hopewell Colonial !. !( Brooks' Duplexes Chloride Concentration ASmmeliiathfield (6) Heights Williamsburg 10000 mg/l (Saltwater Intrusion !> Southampton (10) 0# into Aquifer) !. Western Tidewater Water XW Petersburg !. 50 mg/l NottowayAuthority (10) Guilford Heights ") Prince George Subdivision York 250 mg/l Williamsburg (1) !. "/"/ Scotland Heights "/ != Windsor (1) XW Subdivision 1000 mg/l 10000 mg/l XW Towns: Newport News Capron (1) XW Poquoson Claremont (2) Surry Rushmere Shores Courtland (3) (527) !. Dinwiddie J Dendron (2) Owens Subdivision !. A M $8 E Ivor (3) S XW R Surry (2) I Smithfield Apartment Company !. $8$8 V E Hampton Municipal Water System !. R Wrenns Mill Estates $8 Rescue Waterworks Service Areas !. !( !.James River Shores !(!( !( !. Areas Outside Community Water $8 !( Bob Steele Waterworks System Service Areas $8!. !. Sussex Deer Run !.Cannon Acres Areas Served by Small Turner Property Springfield XW !. Downs Hobson Civic

Capacity Private Drinking !. !. !. mg/l 10000 White Tail Park!. !. Water Corp Water Wells Isle of Wight !. Longview !.Cherry Grove $8 (3,430) Acres !.Acres Portsmouth Norfolk Estimated Number of Small Private !. Drinking Water Wells Withdrawing Clydes Dale Mobile Home Park +$ Virginia from the Potomac Aquifer !=!. +$$+$ !. Portsmouth Beach Brunswick Southampton + Chesapeake 0 Suffolk 1,986 !. !. %9 Franklin 0 Surry 527 Southampton County !. (2,072) !. Sedley Water Company %9 Correctional Complex 50 mg/l 250 mg/l Gloucester 0 Virginia Beach 0 Darden's Mills Estates *# Hampton 0 Williamsburg 0 *# Isle of Wight 3,430 York 0 !> XW XW Scottswood !> $8 Byrdtown *#*# Emporia XW !. $8 Subdivision James City 1,006 !. "S"S !. Newport News 0 Franklin !. 1000 mg/l Silverleaf Corp "S Chesapeake Norfolk 0 "S Suffolk Poquoson 0 (1,986) Portsmouth 0 Greensville !> !. Kingsdale Moseley Southampton 2,072 Kingsdale Artis Southampton !> Meadows !. %9 Scale !> !> %9%9 Miles %9 0 5 10 ° Nottoway Shores !. Chloride Concentrations in Hampton Roads Drinking Water Sources

Map 5. Private Community Water Systems in Hampton Roads with Unknown Source Aquifers. This map shows the general locations and names of fifteen private community water systems for which source aquifer information is unavailable. This may be because the information was not reported during the permitting process, the system withdrawals are too small to require a groundwater withdrawal permit from the Department of Environmental Quality, or the information is not available from the Department of Health’s public water system records. Without water quality monitoring data or source aquifer information for these wells, it is difficult to anticipate current or future impacts of chloride concentrations to these private community water systems.

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Henrico Hanover King William Legend King And Queen Middlesex Map 5. Private Community WaterAccomack Systems in Hampton Roads !. PRriicvhamteon Cd oCmitymunity Water Systems (Drinking Water) Withdrawing from with Unknown Source Aquifers New Kent Unknown Source Aquifer Public Water Henrico System ID System Name Municipal Water System Mathews Service Areas 3093220 Duck's Trailer Court 3093225 Edwards Trailer Park Hampton Roads Localities Gloucester 3175800 Fieldcrest Manufactured Homes 3095320 Greensprings Mobile Village Y Heaths Mobile O 3095590 Heaths Mobile Homes Charles City R Chesterfield Homes K 3800290 Hobson Artesian Well Assn

!. R Northampton Scale I 3175520 Nottoway Gardens V E 3093347 Oaks Mobile Estates James City R 0 5 10 Hopewell City 3550705 Plantation Mobile Home Park Miles ° Greensprings !. 3093316 Red Oaks Mobile Home Community Colonial Hghts Cty Mobile Village Williamsburg 3093306 Smithfield Mobile Home Park 3550775 Sunray Artesian Water Supply York 3550800 Sunray Water Co. Petersburg 3093850 Willing Workers Club Prince George 3093952 Zuni Presbyterian Homes

Newport News Poquoson Surry C H Dinwiddie E S A P E J A A Edwards Trailer !. M K E Hampton E Park S B R A I Y V E Smithfield Mobile R Home Park !. !. !. Willing Workers Club Sussex Red Oaks Mobile Home Community Norfolk ATLANTIC !. Isle Of Wight OCEAN Hobson Artesian Zuni Presbyterian Well Assn Duck's Trailer Court Homes !. !. Virginia Beach Portsmouth !. Oaks Mobile !.!.!. Plantation Mobile Home Park Southampton Estates Sunray Artesian Water Supply Sunray Water Co. Emporia !. Fieldcrest Manufactured Franklin Chesapeake Homes Suffolk

Greensville !. Nottoway Gardens Chloride Concentrations in Hampton Roads Drinking Water Sources

Chloride Trends over Time Potomac aquifer. The remaining two wells (61B 15 SOW 091H and 59F 1 SOW 027) withdraw water from other aquifers. Chloride data from selected wells in the Chloride Monitoring Network and the DEQ Groundwater Withdrawal Permitting DEQ Groundwater Withdrawal Permitting Program Data Program were analyzed for changes in chloride concentrations over time (see Figure 3). The results are summarized in the Chloride data is required by DEQ as part of groundwater following sections. A detailed analysis of groundwater quality in withdrawal permits. Data from 24 wells was analyzed (see the Virginia Coastal Plain is provided in the USGS report, Figure 4). Each of the 24 wells is an active water supply well with “Groundwater-Quality Data and Regional Trends in the Virginia at least 10 chloride samples taken over a period of at least Coastal Plain, 1906-2007” (PP-1772). 3 years. Only 24 wells in DEQ’s program have been sampled this frequently. The total time span of all chloride data analyzed is Chloride Monitoring Network Well Data 1980-2012. The analysis of DEQ Groundwater Withdrawal Permitting Program data is summarized below: Chloride data was analyzed from 22 monitoring wells in the Hampton Roads region (see Figure 4). The total time span of all • 3 of the 24 wells showed increasing chloride concentrations, chloride data analyzed is 1969-2012. Each of the 22 wells has at all in the Potomac least 4 chloride samples collected at least 1 month apart over a • 13 wells showed decreasing chloride concentrations span of at least 3 years. There are over 100 wells in the chloride • 8 wells showed no clear trend up or down. monitoring network, but only 22 wells have been sampled this consistently.

The analysis of well data from the Chloride Monitoring Network is summarized below: • 10 of the 22 wells showed increasing chloride concentrations • 3 wells showed decreasing chloride concentrations • 9 wells showed no clear trend up or down.

Of the ten wells where chloride concentrations were observed to be increasing, eight of these wells withdraw water from the

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Chloride Concentrations in Hampton Roads Drinking Water Sources

Figure 3. Selected Wells Included in the Chloride Trend Analysis. Samples from 22 Chloride Monitoring Network wells and 24 wells in the DEQ Groundwater Withdrawal Permit Program were analyzed for changes in chloride concentrations over time. Page 15

Chloride Concentrations in Hampton Roads Drinking Water Sources

Chloride Monitoring and Implications for Water Resource Management

Because groundwater levels in the major Hampton Roads aquifers are below sea level, saltwater intrusion should be monitored. Chloride monitoring provides an early warning system for saltwater intrusion into water supply aquifers. By regularly collecting chloride measurements, water resource managers can focus on sensitive areas and important water supply wells with increasing salinity.

DEQ is developing a groundwater quality monitoring strategy, which includes improving the chloride monitoring program in the Coastal Plain aquifer system. The current chloride monitoring network is inadequate. A better understanding of how groundwater withdrawals impact chloride concentrations is needed to support resource management decisions. DEQ’s draft strategy recommends identifying areas of potential saltwater intrusion, siting of monitoring wells to intercept intrusion, and sampling at more frequent intervals.

When saltwater intrusion is found, there are strategies to manage it such as changing rates and locations of pumping or injecting water into the aquifer. Early detection of saltwater intrusion or upconing may allow utilities time to plan for extensions of municipal systems. Proper management of groundwater resources requires monitoring data to maintain an up-to-date understanding of water quality.

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Chloride Concentrations in Hampton Roads Drinking Water Sources

References

McFarland, E.R., and Bruce, T.S., 2006, The Virginia Coastal Plain Hydrogeologic Framework: U.S. Geological Survey Professional Paper 1731, 118 p., 25 pls. (available online at http://pubs.water.usgs.gov/pp1731/)

McFarland, E.R., 2010, Groundwater-quality data and regional trends in the Virginia Coastal Plain, 1906–2007: U.S. Geological Survey Professional Paper 1772, 86 p., 14 pls. (available online at http://pubs.usgs.gov/pp/1772/)

Pope, J.P., McFarland, E.R., and Banks, R.B., 2008, Private domestic-well characteristics and the distribution of domestic withdrawals among aquifers in the Virginia Coastal Plain: U.S. Geological Survey Scientific Investigations Report 2007–5250, 47 p. (available online at http://pubs.water.usgs.gov/sir2007-5250)

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Chloride Concentrations in Hampton Roads Drinking Water Sources

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