HB 2050 is Law

Occoquan Reservoir PFAS Reduction Program; and introduced by: David L. Bulova (Chief Patron) passed the general assembly during last winter's session. It was signed into law by the Governor.

This law creates the Occoquan Reservoir PFAS Reduction Program to reduce excessive levels of perfluoroalkyl and polyfluoroalkyl substances (PFAS) in public drinking water that comes from the Occoquan Reservoir. The bill requires certain facilities to monitor for PFAS and to report all results to the Department of Environmental Quality (DEQ). For any facility that measures exceedances in its discharge of the maximum contaminant level (MCL) for PFAS in drinking water, the DEQ shall amend their Virginia Pollutant Discharge Elimination System permits to require that the facility’s  discharge water does not exceed that MCL. The law requires the modified permit to provide a compliance schedule to meet the EPA’s drinking water MCL compliance schedule.

In April 2024, the EPA announced the final national primary drinking water standards for six poly- and perfluoroalkyl substances (PFAS). Public water systems have five years (by 2029) to implement solutions that reduce these PFAS if monitoring shows that drinking water levels exceed the maximum contaminant levels (MCLs). For PFOA and PFOS the U.S. EPA is setting enforceable Maximum Contaminant Levels (MCLs) at 4.0 parts per trillion for PFOA and PFOS, individually.   PFNA, PFHxS, and HFPO-DA (GenX Chemicals), EPA is setting MCLGs of 10 parts per trillion.

Based on the most recent quarterly sampling the Occoquan (Griffith Water Treatment Plant) does not currently comply with the EPA 2029 planned MCL for PFOA. Compliance for PFOS is only marginally below the regulatory limit. Additional treatment processes will be required to comply with regulations and Fairfax Water has stated that they will ensure their water meets these standards by the regulatory date.

Fairfax Water hopes to use this law to identify and remove enough of the sources of PFAS in the water that arrives at the Occoquan Reservoir to meet the EPA MCL without requiring Fairfax Water and their rate payers to foot the bill for compliance which at this point is estimated to be about $400,000,000 in capital investment and $24,000,000 per year in operating costs. This law will force all the current permitted dischargers to see if they are contributing to the PFAS problem. If PFAS is identified in their waste streams and stormwater discharges then they can be required to remove it at their expense.

The water in the Occoquan Reservoir comes from the Occoquan Watershed. Our water supplies are connected to each other and the land. Two thirds of the Occoquan Watershed that supplies the Occoquan Reservoir is in Prince William County. The former Rural Crescent allowed rainwater to flow gently over vegetation, feed the aquifers that provide water to the private wells and the Evergreen water system, but also feeds the tributaries to Bull Run and the Occoquan River assuring the base flow to the rivers and streams that feed the Reservoir.

The Upper Occoquan Service Authority, UOSA, the wastewater treatment plant also delivers up to 40 million/day of recycled water that originated in the Potomac River to the Occoquan Reservoir. Supplementing the supply. Keeping PFAS out of the source water is a real challenge when PFAS is in our diet and wastewater is reused in our drinking water supplies. To stay within the regulatory limit, Fairfax Water will have to identify the PFAS content in the various sources of water and can either mix them to minimize exposure or remove them.

On the occasion of the Governor signing the bill into law, Fairfax Water press release said;  “This new law takes an essential and proactive approach to safeguarding our region’s drinking water by requiring polluters to monitor and remove harmful PFAS chemicals from one of Northern Virginia’s most critical drinking water sources. It represents meaningful progress toward maintaining the safety and quality of our drinking water supply.” What it does is help identify the sources of PFAS in our water supply and if possible make those responsible bear the cost and  responsibility of removing the PFAS from the water.

Sampling data for the Potomac River water supply indicate that the Corbalis Water Treatment Plant will comply with the PFAS regulations without additional treatment. So, Fairfax Water has been focusing on ways for the Occoquan Reservoir to meet the MCL and is also moving ahead with designing a water treatment train to remove PFAS from the water drawn from the Occoquan Reservoir.

In January of this year, Fairfax Water filed a lawsuit in the Circuit Court of Fairfax County against several manufacturers of aqueous film-forming foam chemicals. The lawsuit seeks to hold companies responsible for PFAS contamination in the Occoquan Reservoir and recover costs associated with water treatment and environmental remediation. (There have been several spills of aqueous film-forming foam chemicals at Manassas airport alone.) 

PW Water Academy Registration is Open

 

HL Mooney Advanced Wastewater Treatment Plant is licensed to operate at around 24 million gallons a day. Over the years it has been expanded as Prince William Counties’ population grows. In addition, to the HL Mooney plant, Prince William owns a share of the capacity of the UOSA plant in Fairfax. Prince William’s share of UOSA is 19.8 million gallons a day. HL Mooney serves the easter population of Prince William County. The UOSA plant serves the western portion.

Water Academy is a program hosted by Prince William Water. The program is a three session annual event that provides a behind-the-scenes look at water reclamation (wastewater treatment)  through tours of the H.L. Mooney facility, hands-on activities and conversations with PW Water professionals.

This past winter PW Water’s Water Academy received the 2025 National Environmental Achievement Award (NEAA) from the National Association of Clean Water Agencies (NACWA). This award recognizes individuals and NACWA member agencies that have demonstrated exceptional contributions to environmental protection and the clean water community.

The Water Academy is designed for adults and high school seniors who live or work in Prince William County. A few years back I took my STEM club seniors and we really learned a lot and enjoyed the experience. The program offers a unique educational experience to see how wastewater is treated. The program is free (and they give you a neat graduation gift). There are three-sessions- one is at the H.L Mooney Advanced Water Reclamation Facility and the other two are is at the Raymond Spittle office Building at 4 County Complex Ct at the county complex in Woodbridge.

Past participants have included local elected officials, homeowners’ association representatives, business owners, engineers, retirees and teachers who have earned continuing education credits through the program.

“Prince William Water is truly honored to receive the NACWA 2025 National Environmental Achievement Award for our Water Academy,” said General Manage/CEO Calvin D. Farr, Jr., P.E. “This award highlights our efforts to educate the community about our mission, engage our stakeholders in protecting water resources and inspire Water Academy participants to serve as environmental ambassadors.”

Sign up at this link.

Water Academy 2025 Application Survey

Attending the Water Academy is FREE, and will be held on June 18, June 25, and July 2 from 4:30-7:30pm. The class is limited to 28 people.  For the full syllabus, go to www.princewilliamwater.org/water_academy.

Drought Continues to Expand in Virginia

 

Drought Advisory Update from Virginia Department of Environmental Quality 05/02/2025.

After days of teasing, last night it finally rained and hopefully start up again today. However, we are still in moderate drought. On Friday, the Virginia Department of Environmental Quality (DEQ), in coordination with the Virginia Drought Monitoring Task Force, expanded the drought watch advisory to include 44 counties in Virginia.

The drought watch advisory includes the following areas:

• Eastern Shore: Accomack and Northampton counties
• Northern Coastal Plain: Caroline, Essex, Gloucester, King George, King William, King and Queen, Lancaster, Mathews, Middlesex, Northumberland, Richmond, and Westmoreland counties
• Northern Piedmont: Culpeper, Greene, Louisa, Madison, Orange, Rappahannock, Spotsylvania, and Stafford counties
• Northern Virginia: Arlington, Fairfax, Fauquier, Loudoun, and Prince William counties
• Roanoke River: Bedford, Campbell, Charlotte, Franklin, Patrick, Halifax, Henry, Mecklenburg, Pittsylvania, and Roanoke counties.
• Shenandoah: Augusta, Clarke, Frederick, Page, Rockingham, Shenandoah, and Warren counties

Soil moisture and groundwater deficits continue to worsen in Northern Virginia and the Shenandoah Valley despite localized rainfall like last night. 

Precipitation continues below normal

Groundwater levels and stream flows likewise have seen a decline in portions of the Northern Neck, Middle Peninsula, and Roanoke River Basin. The dry conditions have impacted agricultural activities in the Northern Shenandoah Valley (rye crops) and within the Roanoke River Basin (spring planting of no-till corn and soybeans). The forecast for the next two weeks suggests below normal rainfall and greater than average temperatures over much of the Commonwealth. Storage at major water supply reservoirs remains within normal ranges.

groundwater has fallen below the historical range

DEQ is working with local governments, public water works, and water users in the affected areas to ensure that conservation and drought response plans and ordinances are followed. All Virginians are encouraged to protect water supplies by minimizing water use, monitoring drought conditions, and detecting and repairing leaks. According to the Washing Metropolitan Area Council of Governments  the Potomac River Basin and our regional supply of drinking water has been under a drought watch since 2024.

According to the latest condition report from the Interstate Commission on the Potomac River Basin (ICPRB):

Rain: Since November, the Potomac River basin has received only 12 inches of rain, which is 6 inches below average. Some relief is in the forecast, with 2-4 inches of rain expected over the next week.

Drought: The basin is DRY with 57% of the area in Moderate Drought and 30% in Severe Drought.

Flow: The river’s flow at the USGS gage at Point of Rocks is around 4,500 cubic feet per second (cfs). The lowest recorded flow at this time of year is 3,000 cfs in 1896. While its of concern, it can get much worse. 

After two very dry summers and an exceptionally cold winter, I lost two trees that had been struggling had to come down and I lost my roses and plantings on the side of the garage. Until this drought passes I will not replant the bed. I am still watering the 6 caliper maple and the smaller redbud I planted 3 years ago to ensure their survival. I will not add foundation plantings that will need to be watered. 

Bloom-How to contaminate your yard with PFAS

DC Water is marketing its EPA-certified “Exceptional Quality” Class A Biosolids as a retail soil additive called Bloom. Biosolids are merely the sludge that comes out of a wastewater treatment plant. DC Water is not the first wastewater utility or DC area utility to turn its wastewater biosolids into a soil additive for home gardeners and crops for human consumption. AlexRenew sells their Class A Exceptional Quality bio-solids to farmers in Virginia; and some of the Class A Biosolids are combined with wood fines, creating a soil amendment product that they are calling “George’s Old Town Blend.”

At DC Water’s  Blue Plains and other sewer treatment plants primary treatment uses screens to remove large solids from wastewater which then sits in settling tanks, which are designed to hold the wastewater for several hours. During that time, most of the heavier solids fall to the bottom of the tank, where they become a thick slurry known as primary sludge.

The sludge is separated from the wastewater during the primary treatment is further screened and gravity is allowed to thicken the sludge in a tank. Then the sludge is mixed with the solids collected from the secondary and denitrification units. The combined solids are pumped to tanks where they are heated to destroy pathogens and further reduce the volume of solids. With treatment sludge is transformed (at least in name) to Biosolids.

In 2015 DC Water unveiled the newly completed and operational sludge treatment system. Blue Plaines now has Cambi thermal hydrolysis trains, four digesters, dewatering equipment and a combined heat and power plant that cost $470 million. The new digestor system uses thermal hydrolysis (heating to over 160 degrees under high pressure) followed by anaerobic digestors. This takes care of the pathogens.

Bloom is an “EPA approved Exceptional Quality Class A biosolids.” This means that Bloom has been tested for a limited list of contaminants.   Class A biosolids can provide essential plant nutrients, including slow-release nitrogen, and organic matter, by slowly add nutrients to the soil by naturally breaking down and decomposing into a plant-available form which is helpful in building healthy soil. However, we do not actually know what other contaminants are in the biosolids and  there are other ways to build healthy soil. The real need addressed is disposing of the biosolids. DC Water encourages the use of Bloom for water holding capacity, improving and establishing lawns, remediating poor soils, planting trees and shrubs, and establishing flower and vegetable gardens. I don’t think this is a good idea.

U.S. EPA regulations limit metals and pathogens in biosolids intended for land applications, but no organic contaminants are currently regulated under 40 CFR Part 503 Rule created in 1989 and still in effect today. Only metals and pathogens are tested for. It categorizes Biosolids as Class A or B, depending on the level of fecal coliform and salmonella bacteria in the material and restricts the use based on classification. There turns out to be many more contaminants in sewage sludge. Over the years controversy associated with potential impacts of Biosolids and the land disposal or reuse of Class B and even Class A Biosolids have grown.

The presence of other contaminants in the Biosolids has not been tracked, but has become an emerging area of concern. Previously, research at the University of Virginia found that organic chemicals persist in Biosolids and can be introduced into the food chain. Land application of biosolids is a widespread practice across the US and remains an approved method by the US EPA. This practice is now being questioned.

In April 2024, the EPA announced the final national primary drinking water standards for six poly- and perfluoroalkyl substances (PFAS). Public water systems have five years (by 2029) to implement solutions that reduce these PFAS if monitoring shows that drinking water levels exceed the maximum contaminant levels (MCLs). The limit for PFOA and PFOS at or near the MCL of 4.0 parts per trillion (ppt) individually. For PFNA, PFHxS, and HFPO-DA (GenX Chemicals), EPA is setting MCLs of 10 parts per trillion combined. Per- and Polyfluoroalkyl Substances (PFAS) do not occur in nature, they are an entirely synthetic substance and are highly stable which is how they got their nickname “forever chemicals.”

DC Water reports that they have tested Bloom for various PFAS chemicals. They have found concentrations of PFOS and PFOA within ranges of 4.60 to 16.1 parts per billion (ppb) and 1.7 to 3.7 ppb respectively – a thousand of times higher than the primary drinking water standard, but lower than than in food packaging materials; and cosmetics; and lower than the levels measured in dust. Bloom’s total combined PFAS levels average 130 ppb. Though very water soluble, PFAS are resistant to degradation and simply flow through the wastewater treatment plant. PFAS remains in the biosolids and effluent.

Though PFOS and PFOA have been eliminated from production, exposure to them is still occurring. Almost all of the PFOS and PFOA ever manufactured is out there still circulating in the hydrologic cycle. According to the National Institute of Environmental Health Sciences (part of the NIH): “People are most likely exposed to these chemicals by consuming PFAS-contaminated water or food, using products made with PFAS, or breathing air containing PFAS. Because PFAS break down slowly, if at all, people and animals are repeatedly exposed to them, and blood levels of some PFAS can build up over time.”

One report by the Centers for Disease Control and Prevention, using data from the National Health and Nutrition Examination Survey (NHANES), found PFAS in the blood of 97% of Americans. Even when/ or if the source of exposure is removed, measurable levels of PFASs may be detected in humans due to the relatively long half-life of these chemicals. The estimated half-life for PFOS, PFOA, and PFHxS in humans ranges from 3.8 to 8.5 years.  

Practically everyone has been exposed to PFAS and DC Water seems to want to assure that the PFAS out in the environment continues to spread. There are thousands of PFAS chemicals, and they are found in many different consumer, commercial, and industrial products.  PFOS and PFOA were used in Scotch Guard, the manufacture of Teflon and traditional Aqueous Film-Forming Foam (AFFF) - the Class B firefighting foam used to fight aviation and other chemical.

After AFFF is deployed in an emergency or training exercise, it can seep into the ground, or flow to the storm drain system and contaminate soil, surface water and groundwater. Then there was the wastewater from the manufacture of flame retardants, Teflon, Gortex, Scotch guard and other coating that was buried, ponded or simply released into streams. PFAS began to spread in the environment.

Then onto consumer products. Coatings were sprayed onto cans and food packaging. Wash water from light manufacturing or processing. Treatments for fabrics. The companies that applied the stain resistant and flame resistant treatments to carpeting, upholstery, clothing sent their wastewater to the wastewater treatment plants which cannot remove PFAS. PFAS containing packaging picked up traces of PFAS and it was passed onto people that way, too.

The PFAS ended up in the effluent and the biosolids. The reach and spread of PFAS was increased because effluent from wastewater treatment is released to rivers and used as source water for drinking water. Out it went to rivers and streams ultimately to the oceans. Fish and seafood were exposed to PFAS through the wastewater effluent as are we. The wastewater effluent is often upstream of drinking water plant intakes or intentionally reused. The Occoquan receives up to 40 million gallons a day of treated wastewater from UOSA.

Wastewater treatment plants generate biosolids which also are contaminated with PFAS. Biosolids were land applied in agriculture (cheap "natural" fertilizer in Maine) and buried in landfills. Animals grazed on the land, food grown on the land picked up some of the PFAS and passed traces into food. People passed it onto other wastewater treatment plants and the circle widened.

When our analytical methods were less precise and PFAS had less time to permeate our environments, we used to think that only people living near the industrial manufactures of PFAS, their industrial waste disposal sites or airports were exposed. The ability to measure parts per trillion disabused us of that belief and allowed us to understand we have helped spread PFAS almost everywhere .

We discovered that we are all exposed to PFAS in everyday life. Stain-resistant carpeting, nonstick cookware, grease- and water-proof food packaging, fabric softeners, waterproof clothing, cosmetics, and through our diet and water. PFAS- forever chemicals -are washed out of our clothing, carpeting, pans, skin and end up in our wastewater. There are numerous sources of exposure including: industrial emissions, PFAS-containing consumer products, contaminated drinking and surface water, house dust and food. I do not think it is appropriate to sell this product to spread it on our lawns (my pets lie on the lawn and eat the grass) and use it to grow the vegetables in my garden. We need to begin to extinguish the contaminants from the environment, and that should start by not spreading it further.

Climate Change and Drought

 It rained a bit over the weekend, but we remain in drought and a significant precipitation deficit. . 

Data from rain gauge PW VA-15, 5.5 miles N of Haymarket

The long predicted impacts of climate change are arriving. Not only is Earth’s temperature increasing, polar ice melting, and the northern U.S. is seeing increased summer heat. We have all seen the impacts of wildfires. Hurricane intensity has increased. Droughts are becoming more intense. There is tremendous uncertainty in projecting the future climate of the earth, especially at the regional scale. Though global climate models are continually being refined and improved, they do not capture complexity of the interrelations of earth’s land, water, and atmospheric systems that we do not yet fully understand.

Nonetheless about a decade ago, the Interstate Commission on the Potomac River Basin (ICPRB) engaged the U.S. Geological Survey to  complete a study of water supply availability and the health of the Potomac Watershed for various climate scenarios. The focus of their study was the Potomac River, which supplies water to the Washington Aqueduct, Washington Suburban Sanitary Commission (WSSC), and Fairfax Water who all funded the study. 

The climate models predict that precipitation will increase on a global scale, when dealing with only the Potomac River basin, the models differed on whether precipitation will increase or decrease. The models project that the total annual precipitation varies from plus 9% to minus 9% meaning that rainfall will stay within 4 inches of that average. It is to be noted, that year to year weather variations in rainfall in the region are very large, precipitation has varied from over 80 inches to below 20 inches in the past century.

Though annual rainfall increases in half of the climate change scenarios, flow in the Potomac River falls in most scenarios. Changes in both temperature and precipitation affect stream flows. Changes in rain or snow affect the amount of water that runs off the land surface and enters streams during rainfall. Precipitation also affects the amount of water recharging groundwater aquifers, which are the primary source of stream flow during dry weather periods. Increasing temperatures will cause more rain to be lost to evaporation from the soil, streams, and will increase transpiration, the water released to the atmosphere by plants. These increases in evaporation and transpiration will tend to reduce flow in streams which in turn reduces flow in the Potomac.

With rising population and land use and land cover changes -cutting down streamside vegetation and woodland buffers that once slowed and absorbed rains. Covering the ground with compacted and/or impervious surfaces.  The faster flow of storm water will not only reduce groundwater availability for private well owners like me, but reduce stream and river flow, cause floods and property damage. This will in turn require more and larger reservoirs to store the flood waters and  supply  water to the region, and additional water treatment to make the floodwaters suitable as water supply.

The study also predicted that average annual basin-wide evaporation and transpiration is predicted to increase by 6-8%. Groundwater recharge decreases under 83% of the climate scenarios.  The groundwater monitoring well up the road has experienced slow but continuous decline of one foot per decade over the last 20 or so years. The monitoring well east of Leesburg which has seen more development has fallen about 3 feet per decade over the same period after the change from open space to development. Land use and land cover change may be the cause. 

According to study results, the seasonal pattern of groundwater recharge does not change significantly under climate change, with January, February, and March remaining the months of greatest recharge. However, the average annual amount of groundwater that provides base flow to streams and the water in my well, is predicted to decrease in 16 out of the 18 scenarios by as much as 34% in one case. Looking below at what is happening over the last 20 years in Loudoun county is not a comforting picture. 

The U.S. Drought Monitor shows 62.39% of Virginia is experiencing abnormally dry to moderate drought conditions. Northern Virginia groundwater wells continue to exhibit much below normal water levels. The Shenandoah and Northern Virginia regions remain in emergency status for groundwater indicators, and the Roanoke and Northern Coastal Plain regions’ groundwater indicators were in warning status.

graph from David Ward, Loudoun County Presentation 10/2024

Location of the Wells

Loudoun Water

The following is excerpted from various Loudoun Water reports:

Loudoun Water is very much a reflection of its past, present and future. It buys water, treats its own water, manages the small water systems of semirural hamlets and provides reclaimed and potable water to the industrial demand of data center alley.

 Loudoun Water central system delivers water to its customers through a water distribution system consisting of 1,467 miles of water mains and 8 storage tanks with a storage capacity of over 18 million gallons. Loudoun Water currently purchases the majority of its drinking water from Fairfax Water which supplies approximately 18 million gallons per day (MGD).

The remainder of the water is supplied by the Trap Rock Water Treatment Plant drawn from the Potomac River. In the case of need Loudoun Water can also draw from Goose Creek Reservoir. The Trap Rock Water treatment plant is part of Loudoun Water’s Potomac Water Supply Program (PWSP). This includes an intake on the Potomac River, transmission lines, quarry storage and the treatment plant. The new plant has the ability to produce up to 20 MGD. Trap Rock became fully operational in January 2019 and currently produces approximately 10 MGD. As demands on the Loudoun Water system increase, it is currently assumed that the additional water will be purchased from Fairfax Water, as Loudoun Water anticipates continuing to operate Trap Rock at 10 MGD in the immediate future.

The cost of purchasing wholesale water from Fairfax County Water Authority (FCWA) has increased substantially over the past few years with the cost of purchased water increasing 42% between 2021 and 2024.  Loudoun Water will be increasing their water rates about 7% a year over the next few years to keep up with the costs of operating the system.

Loudoun Water also provides reclaimed water to data center customers located within the reclaimed water service area. The reclaimed water is produced at the Broad Run Water Reclamation Facility. The reclaimed water is distributed through a distribution system consisting of 22 miles of reclaimed mains. The reclaimed water system has delivered an average day amount of approximately 2.1 MGD of reclaimed water during 2024. It is anticipated that the volume of reclaimed water will grow to 3 million gallons a day on average in the next four years.

Loudoun Water also sells finished drinking water to data centers. It was reported that in 2023 Loudoun Water sold an average of 2.46 million gallons of water a day to data centers and that just keeps growing faster than the reclaimed water which is limited by location.

Loudoun Water has also taken over management of several community water systems. Community Water and Wastewater Systems are free-standing water and wastewater systems that generally draw from groundwater and utilize packaged waste systems. They are not connected to the central system. The community systems are: Beacon Hill, Creighton Farms, Selma Estates, The Reserve at Rokeby, and Village Green at Elysian Heights.

Loudoun Water Service Area

 

Assuring the Water Supply in the DMV

 Since the mid 1800’s, the Potomac River has been the source of drinking water for Washington DC. Today the Potomac River supplies 78% of the Washington, DC, metropolitan area’s water, with public water supply intakes for WSSC, the Washington Aqueduct, Fairfax Water and Loudoun Water located in the river upstream of the city. (For security reasons the exact locations of the water intakes is not disclosed and is blocked on Google Maps).

The Potomac River belongs to Maryland. In 1632 King Charles I granted to Lord Baltimore land from the “first fountain” of the Potomac River and along its south shore to the bay. There have been numerous legal cases over the centuries tightening up that boundary, but the fundamental ownership of the Potomac has not changed. There is; however, a multijurisdictional agreement to share the waters of the Potomac.

This agreement established the Interstate Commission on the Potomac River Basin (ICPRB) to cooperatively preserve water quality and to conserve and share water and related land resources of the Potomac River Basin. ICPRB is a non-regulatory agency that promotes water quality through watershed-based approaches. In 1979, the Commission created the Cooperative Water Supply operations on the Potomac (CO OP), which provides water usage forecasts and coordinates water management of the Upper Potomac Reservoirs and with the operations of the water utilities in the Washington metropolitan area.

The ICPRB was one of the first organizations with a congressional mandate to consider water resources on a watershed basis, rather than along political boundaries. However, now, we have reached the point in population density and development that during times of drought, natural flows on the Potomac are not always sufficient to allow water withdrawals by the utilities (including power generation which takes an awesome amount of water) while still maintaining a minimum flow in the river for sustaining aquatic resources. 

Current threats to the region’s water supply include severe droughts due to climate change, population and demand growth from data centers; increasing salinization of the Potomac and the watershed, and potential spills intentional or accidental polluting the Potomac River.  The region’s water supply relies heavily on the Potomac River and would be faced with moderate to severe water shortages in the event of an interruption in the Potomac River water supply.  Washington DC has the least storage. A shutdown of Potomac River intakes is predicted to result in a critical loss of water in some areas of the region after just one day.

During drought, water from three upstream reservoirs can be released if necessary to increase river flow, but it would take nine days for the water to reach the river intakes for the water treatment plants and be treated. Use of these upstream reservoirs would not be feasible in the case of an accidental or intentional spill. Plus, drought response in made tricky because of the time delay and that during an extreme drought the Jennings Randolph Reservoir is unlikely to be refilled. The ICPEB needs to carefully pick their moments for release. 

The public water suppliers in the region utilize the Potomac River as a source of raw water and distribute treated water to homes, businesses, and critical government facilities. Combined, they serve five million residents and over three million workers in the District and surrounding Maryland and Virginia. DC Water distributes the water treated from the Washington Aqueduct to Washington DC and only has enough water storage to supply the District for 24 hours, if not less. Without water, every facet of the city and government is affected. This vulnerability, though well-known regionally was laid bare last summer, when an algal bloom on the Potomac River overwhelmed the Dalecarlia Water Treatment Facility run by the Washington Aqueduct.

Drought remains a significant threat. We have not had a severe drought in this region in over 30 years, but the water basin has been in a low level drought for two years. The ICPRB allocates and manages water resources of the river through the management of the jointly owned Jennings Randolph Reservoir (built in 1981), Potomac River Low Flow Allocation Agreement (1978) and the Water Supply Coordination Agreement (1982) which designated a section of the ICPRB as responsible for allocating water resources during times of low flow. These steps improved reliability of the water supply and ensured maintenance of in-stream flows to meet minimum aquatic habitat requirements as defined by the Maryland Potomac River study in 1981. The section of ICPRB responsible for all this is known as the Section for Cooperative Water Supply Operations on the Potomac (CO-OP), and is formally empowered in its duty by the Water Supply Coordination Agreement. 

Currently,  for a limited period of time Fairfax Water can supply their entire system from the Occoquan Reservoir and that is one of the most powerful tools available for supply management. Fairfax Water is engaged in a long term plan of expansion of their water storage. The Vulcan Quarry almost adjacent to the Occoquan Reservoir will be converted to a reservoir in phases and continue to operate during phase 1 which will convert a portion of the quarry to a reservoir with storage of of about 1.8 billion gallons by 2035. Quarry operations will end with Phase II which will convert the remaining area to Fairfax Water reservoir with storage capacity of up to 15 billion gallons by 2085. The Vulcan Reservoir will store water from the Occoquan Watershed.  Loudoun is adding the Luck Quarry as a reservoir to store water diverted from the Potomac River. 

The ICPRB’s 2017 study, Washington Metropolitan Area Water Supply Alternatives, evaluated a suite of options to address increased drought severity in the face of climate change and identified use of a local quarry to create a backup supply for WSSC and the Washington Aqueduct to complement the Occoquan. This could allow the entire DMV to step off the Potomac for a period of time.  Another study, the National Capital Region Water Supply and Distribution System Redundancy Study, completed in 2016 for the Metropolitan Washington Council of Governments, also concluded that raw water storage in a local quarry was an effective solution to the threat of water shortages or disruptions to use of the Potomac River.

An existing quarry, Travilah Quarry, located in Montgomery County, Maryland, could be converted to a regional raw water storage reservoir with tunnels to carry water by gravity to  the Washington Aqueduct and WWWC  water treatment plants, bypassing the Potomac River. The estimated project cost was $800 million. Black & Veatch was retained by the Interstate Commission on the Potomac River Basin to perform the feasibility study of potential prerequisites for use of the Travilah Quarry as a raw water supply storage facility, to supplement the existing water supply for the Washington Suburban Sanitary Commission and the Washington Aqueduct.

The assessment was divided into two phases. The first phase of the study focused on studying characteristics of the quarry for water storage potential and water quality aspects. The study found the quarry suitable for raw water storage:

• The current storage available in the Quarry is approximately 7.3 billion gallons (smaller than the Occoquan Reservoir).
• However, the ultimate storage in the Quarry could reach 17.4 BG, based on the mining plans and quarry reservoir pool elevation. This capacity is expected to be available sometime around 2060
• It is expected that stored water will be in the range of available water treatment technologies. The management of water quality can be accomplished through inlet/outlet design and pumping strategies.

The second phase assessed potential options for conveyance, pumping and presents life cycle costs for different alternatives. It includes a conceptual design and layout of the infrastructure necessary to convey water from the quarry and plant to the Washington Aqueduct and ultimately concluded that the Conveyance Tunnel connection to the Great Falls was the better solution in terms of constructability, operations, cost and community acceptance. The tunnel can be built without much interference with the existing utilities and surface features. Because of the existing infrastructure at Great Falls, the consultant expected that this alternative offers a relatively compact system in terms of ease of system integration and O&M.