Sunday, October 29, 2023

The Spiderweb of the Planned expansion of the Grid in Virginia

 Data centers are the bricks and mortar of the internet. These buildings store servers, digital storage equipment, and network infrastructure for large-scale data processing and storage.  Our increasingly digital world has an ever-growing need for data creation, processing, and storage from businesses, online platforms, video streaming, smart and connected infrastructure, autonomous and driver assist vehicles, and artificial intelligence. 

Data centers use an incredible amount of power, which has been growing as demand for data storage and computing power has skyrocketed. The Piedmont Environmental Council (PEC)  reports the current power demand for data centers is 60-90 megawatts per building, which is more than the power used by 15,000 households at their most energy intense or peak use. Data center power usage is a flat constant demand. In the future the power use for data centers may increase due to the integration of AI since their more powerful chips require more power to run and more cooling.

The United States houses nearly 30% of data center servers, more than any other country; and northern Virginia houses more data centers than any other locality. In May when Dominion Energy filed its 2023 Integrated Resource Plan (IRP) with the State Corporation Commission (SCC) it essentially showed that Virginia plans to decarbonize the grid under the VCEA had collided with the exploding demand of the unconstrained growth of the data centers in Northern Virginia. 

The IRP plan presented by Dominion would increase carbon emissions from current levels, instead of dropping to zero by 2040, as required under the VCEA. In the IRP submitted to the SCC Dominion forecasted that power demand would rise 80% and that peak load will rise from a bit more than 17,000 megawatts now to 27,000 megawatts by 2037. You cannot plan that amount of electricity use growth while eliminating generation capacity. It has never been done, and Dominion admits that they need to not only keep all their fossil fuel power generation operating but are asking to build more fossil fuel generation to meet this forecast demand.

All that power must be delivered to the data centers. PJM Interconnection, our regional transmission grid operator, works behind the scenes to ensure the reliability of the power grid to keep the data centers humming and keep the lights and heat on. The PJM extends into 13 states and the District of Columbia: Delaware, Illinois, Indiana, Kentucky, Maryland, Michigan, New Jersey, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia, and West Virginia. PJM balances the loads and makes sure the grid can deliver the power when it is needed.

 PJM is currently looking at proposals to deliver more power to data center alley, which it now defines as an area stretching from Ashburn to south of Manassas. This would encompass the PW Digital Gateway which has yet to receive its rezoning, but will be heard by the Planning Commission on November 8th beginning at 2 pm. To meet the power demands of data centers PJM plans to expand the grid with hundreds of miles of new high-power lines that sit atop 100-foot towers.

Last month, PJM Transmission Expansion Advisory Committee (TEAC) posted a list of 72 project proposals as part of their data center load planning.  The PEC took all  those proposals and digitized as many of the paths as they could from the project descriptions to create a map  you can find at this link. The PEC held an informational meeting in Upperville last week to inform residents who thought the data centers would not impact them that people can see what’s being considered and the communities and resources that might be impacted. 

As you can see in the thumbnail map above, the power is being brought to the Ashburn to Manassas Alley from both east and west. If you look at the larger map the power comes from New Jersey, Pennsylvania and West Virginia. This is the PEC map prepared for a Fauquier audience. The red lines will be areas a new power corridors of 100 meter tall power towers, the purple are the power corridors that will be rebuilt with bigger and better towers, the black are right of ways that will be expanded.

That little corn by Hickory Grove caught my eye

According to the PEC: “The PJM TEAC requested proposals for transmission expansion projects to help address modeled “overload violations on the grid” caused by currently operating data centers and to meet immediate load requests for electric service through the planning period (2022-2027). Although not all of these proposals will likely move forward through this “2022 RTEP Window 3” period, it is likely that we will see those not selected return in the next 2023 RTEP Windows. As a result of the massive data center boom occurring in Virginia, we believe this is only the beginning of the massive transmission line proposals we are likely to see over the next few years.”

If you open the PEC map (give it time it loads slowly) you can enter your address and see how these proposal might impact your neighborhood or view shed, or simply take a look at overall impact. When I did, I got a nasty surprise: 100 foot towers bisecting my neighborhood creating a 52 foot wide utility corridor between homes
The enlarged section of bottom right at Hickory Grove

All images are from PEC presentation

Wednesday, October 25, 2023

Prince William Adopts Sustainability Plan

 During their regular meetings on Tuesday afternoon the Board of County Supervisors voted 5-3 to adopt the Community Energy and SustainabilityMaster Plan “to strive to meet the Climate Mitigation and Resiliency Goals established by the Board through Resolution Number 20-773.”

 A little background: On November 17, 2020, the Prince William County Board of Supervisors adopted Climate Mitigation and Resiliency goals and authorized the creation of a Sustainability Commission.  The Commission was charged with advising on potential enhancements to the Community Energy and Sustainability Master Plan (CESMP), which is intended to provide the map for how the county will reach its climate goals that includes Prince William County achieving 50% of 2005 CO2 emissions by 2030 and net-zero by 2050; but also include plans for adaption to climate change.

Let me get this out of the way first, if you read the plan you will see that there are no realistic scenario that Prince William achieve those goals in the stated time frame. “It was found that due to limited span of control, all five goals will not likely be met through County action alone. It is expected that there would be a gap in emissions reductions needed to hit our 2030 target even if all 25 high priority actions are implemented. It is recommended that the actions are implemented to the best of the County’s ability and to evaluate whether or not to bridge the potential remaining emissions reductions gap using high quality carbon offsets in 2030.”

Carbon credits or offsets represent carbon emission reductions or removal and are traded in on various exchanges or markets. Offsets are tool that companies use to reduce their net greenhouse gas (GHG) emissions and live up to their environmental, social and governance (ESG) goals, as well as promises made to customers and consumers. They can be problematic in ensuring that they are “real” and non-duplicative.

Our inability to meet the climate goals is that many factors are simply out of the nexus of control of the County, but also the decisions made within the counties nexus of control have been made and continue to be made without regard for the climate impact or the sustainability of Prince William County. Growth and industrial development grow’s the carbon footprint of the county. The problem is predominately the millions of square foot of data centers, already built, under construction and in the pipeline.

Data centers are the physical factories of the internet. Standard data centers are warehouses filled with row upon row of servers, routers, wires, and other information technology hardware spanning hundreds of thousands of highly cooled square feet per building and sucking up incredible amounts of power. Data centers operate 24/7 and increase the baseload needs for power generation. When Dominion Energy filed its 2023 Integrated Resource Plan (IRP) with the State Corporation Commission (SCC) it essentially showed that Virginia plans to decarbonize the grid under the VCEA had collided with the exploding demand of the unconstrained growth of the data centers in Northern Virginia.

In the submission, Dominion details how it plans to meet electricity needs and demands over the next 15 years. The picture they paint is that Dominion cannot both meet the power demand of the exploding number of data centers in Virginia and the mandates of the Virginia Clean Economy Act (VCEA).

Also, building more roads and thousands of acres of industrial buildings where there was once woodland and open fields exacerbates the impacts we are already seeing from climate change. Increased rain storm intensity and  more impervious surfaces increases dangerous flash flooding, damages our perennial streams, and negatively impacts our water supply while increasing demand for water by millions upon millions of gallons of water a day.

As a member of the Sustainability Commission I vote to recommend the adaption of the CESMP with several caveats. You can read our entire comments on beginning on page 207 of the attachments. The Sustainability Commission recommended the immediate adoption of all seven adaptation measures listed below (A.1-A.7), as these measures are almost exclusively within the control of the county and are necessary for the future we will have.

A.1.  Develop Adaptation Plans for Critical Facilities
A.2.  Manage Stormwater Flooding Outside of the Floodplain
A.3.  Improve Power Resiliency for Critical Infrastructure
A.4.  Assess Shoreline Protection and Nature[1]Based Solutions
A.5.  Restore Streams to Reduce Flooding
A.6.  Encourage Technology for Residents to Make Homes Adaptive
A.7.  Plan Alternate Evacuation Routes for Flood[1]prone Areas

Sunday, October 22, 2023

Saltwater Intrusion

Heavier saltwater from the Gulf of Mexico is moving up the Mississippi River as a growing wedge beneath the freshwater moving downstream. This is primarily because of the lack of rainfall in the Midwest (in the tributary valleys and along the Mississippi itself) during August and September. This lack of rainfall results in a reduced river flow that is not powerful enough and deep enough to prevent the denser and heavier saltwater from moving inland and upriver.

When the Mississippi River flow falls below 300,000 cubic feet per second, it cannot prevent salt from coming up from the Gulf of Mexico. Flows on the Mississippi River fell to 145,000 cubic feet per second at the end of September and is expected to fall even lower in coming weeks. It would require approximately 10 inches of rain across the Mississippi and Ohio River valleys, to return the river to a high flow rate capable of driving the saltwater wedge back to the Gulf.

The saltwater wedge is expected to reach the New Orleans water intake area in the next couple of weeks. When it does the drinking water will exceed the U.S. EPA Safe Drinking Water Act standard of 250ppm sodium chloride (salt)  and  people will not want to drink it due to taste, and those on low-salts diets should not exceed 20 ppm sodium chloride. Desalination is not part of this or any river water treatment systems and the New Orleans water treatment system cannot remove the salt. New Orleans is looking to piping or barging fresh water from up river to mix with the New Orleans water and dilute the salt.

Saltwater intrusion is the leading edge of climate change ahead of sea level rise. Saltwater intrusion precedes tidal inundation of low-lying lands, and dramatically changes the chemistry of tidal freshwater wetlands. Although there always has been a swath of coastal land adapted to salt, interactions among sea-level rise, climate change and coastal water infrastructure (overuse of groundwater and surface water) is causing saltwater to reach further and further inland.

As our climate is changing we are seeing dramatic pictures of increases in storm driven flooding, and higher-amplitude tidal inundation associated with sea-level rise. The effects of saltwater intrusion on ecosystem services, has received less attention, probably because changes in water chemistry are invisible to the public. However, the addition of marine salt to previously freshwater systems have profound impacts not only on our drinking water systems but on ecosystem balance, leading to coastal forest loss, species replacements, reductions in agricultural productivity, declines in coastal water quality, and marsh migration.

Saltwater intrusion and the degree of upland salinization are driven by five main factors: the position of sea-level relative to the land and water table, the frequency and magnitude of storms and tides, the frequency and duration of drought, surface and groundwater water withdrawals for drinking water and irrigation, and hydrologic connectivity the presence of tide gates, levees, agricultural diversions, and reservoirs.

In the U.S., the Chesapeake Bay region is the third most vulnerable area to sea level rise, behind Louisiana (New Orleans) and southern Florida.  Our region’s coastal plain is subsiding along with sea level rising. Over the past 100 years, due to the combination of global sea level rise and regional land subsidence sea level has risen by approximately one foot within the Chesapeake Bay.  This combined with the low lying flat geography with increase saltwater intrusion and inundation.  

The Potomac Watershed of the Chesapeake Bay watershed has the Interstate Commission on the Potomac River Basin (ICPRB) to help manage the Washington metropolitan area water supply system by coordinating withdrawals from the Potomac River and off-river reservoirs and recommending releases from upstream reservoirs when forecasted flow in the river is not sufficient to meet expected needs and prevent saltwater intrusion. The river flow for this is measured at Little Falls dam near Washington, D.C. and must meet the water utilities demands and an environmental flow-by of 100 million gallons per day (MGD). Hopefully, this system will prevent the Washington Metropolitan Area from experiencing the same problems as New Orleans is facing right now.

Sea level rise is occurring and will continue to do so into the future. The salinity effects from sea level rise could potentially be mitigated to some extent but cannot be reversed. Coastal storms and associated flooding occur several times each year, but are increasing in intensity and frequency with each passing decade.  Depending on the intensity of coastal storms, salinity effects due to over wash of tidal waters onto land can last for several months. The frequency of droughts are expected to remain the same occurring every few years, but are expected to increase in duration causing worsened salinity impacts due to reduced freshwater flows during those times. However, those effects will reverse once precipitation returns to normal levels. Conversely, periods of excessive precipitation that we are also forecast to have will mitigate salinity impacts.

Tidal  saltwater intrusion is not are only salt problem. We are experiencing inland salinization and have had saltwater intrusion into the Potomac aquifer from overuse. The Potomac River and Occoquan Reservoir are experiencing salinization.  Analyses from three different studies at multiple locations have found increasing freshwater salinization in Northern Virginia and the Occoquan Reservoir. Regionally, as salt levels have risen, WSSC is seeing discolored water problems related to winter deicing when chloride levels were observed to spike from 40mg/L to 100 mg/L. Increasing chloride levels is from sodium chloride (salt) due to rising sea levels, increased direct and indirect potable reuse of wastewater, the increased amount of pavement and the salting of roads in the winter. Nearly all road salt is eventually washed into adjacent rivers, streams, and groundwater aquifers - road salt is considered the largest contributor to rising salt levels.  

The ICPRB, the Virginia Department of Environmental Quality (VDEQ) and the Northern Virginia Regional Commission have joined together to develop a voluntary Salt Management Strategy published in 2020 to reduce the largest source of salt/ chloride to the Potomac, its tributaries and the Occoquan Watershed, but this alone may not slow the increasing salinization of our source water for drinking as road construction continues at an alarming pace. While trying to encourage the adoption of the voluntary salt management strategy, we keep building roads and paving over the county.

Road salt impacts not only potability of water, but also impact drinking water infrastructure in terms of lifetime and leaks. Water contamination is an emerging and increasing problem for both private well owners and municipal water suppliers. Salt, sodium chloride, spikes have caused changes in water chemistry triggering the lead in solder to be released into the water. Chloride is an aggressive ion that exacerbates corrosion, especially galvanic corrosion in hot water heaters and at solder points where pipes are joined.

Wednesday, October 18, 2023

Atmospheric River Envy

Last winter after three years of drought California experienced an unprecedented wet winter in Water Year 2023 with a deluge from what were described as 19 atmospherics rivers which made landfall in California. According to the California Department of Water Resources “Statewide the annual precipitation in water year 2023 totaled 33.56 inches, which is about 141% of the long-term (1901-2000)annual average precipitation statewide,” though rainfall varied across the state from 16.99 inches in Fresno to 78.92 inches in the gauge in Miranda and over 45 inches in Piedmont and Eureka.

According to the April 1 snow survey, the statewide snowpack was at 237% of normal for the date and the deepest on record since the state’s network of snow sensors was established in the mid-1980s. The snowpack was so deep that it contained roughly 30 million acre -feet of water, or more water than 1.7 times the annual average groundwater use (about 18 million acre-feet)in California. The subsequent snowmelt runoff filled surface water reservoirs and caused historic flooding.” Though this was only a single wet winter. The state’s groundwater basins, which supply more than 40% of the state’s total water supply, in an average year, remain seriously depleted despite the wet winter because the groundwater basins require a much longer time frame to recover and through mismanagement of groundwater resources California has experienced land subsidence in many areas and the groundwater basins can never recover.

Here in Haymarket, Virginia we had a relatively dry winter and a very dry summer and fell into drought in August. Besides lawns turning brown (my lawn and my neighbors are either watered by rain or not at all) there were also signs of concern. The Bull Run Mountain Conservancy recorded that the perennial streams: Little Bull Run and Catlett’s Branch were dry. Catharpin Creek, another perennial stream, appeared to have been reduced to a series of puddles. Then September came, and my rain monitoring station recorded a series of intense storms that brought 13.57 inches of rain (and hail) most of it over a 4 day period. Because the area around my home is semi-rural and wooded, flooding was not a problem. The ground just drank up the water. We ended the water year on September 30th at over 45 inches of rainfall above the average of 44 inches per year. I was shocked to realize that Piedmont and I had about the same amount of rain. I experienced it as a dry year. Yet, the intense rains in September were very localized and the region remains abnormally dry, but my lawn is green.

Catlett's Branch from BRM Conservancy, M. Kieffer

Generally, groundwater in the Culpeper Basin is renewed each year through precipitation. The groundwater has always been able to feed the perennial streams during dry periods, but not this year. In the past, the water stored in the watershed has been able to provide adequate water in droughts because historically the withdrawal of water was within the average recharge rate. However, the only nearby US Geological Survey groundwater monitoring well is no longer stable. The fall seasonal lows have been getting lower and the recharge even in 2018, the wettest year on record, did not reach the level of recharge during the drought that occurred in 2007-8.

We appear to have a growing problem in this area. We need information to find out. Prince William County and Loudoun County need to engage the USGS and DEQ to study the groundwater in our region expanding on the study they have been performing for Fauquier County. Little is known about the sustainability of our groundwater basins, but potential problems can still be addressed before it is too late.

Groundwater models and data from more monitoring wells can help develop a picture of the volume of the water within the groundwater basin and at what rate it is being used and at what rate it is being recharged. We need to know if the current and planned use of our lands, groundwater and surface water is sustainable even in drought years. We need to understand how ground cover by roads, parking lots and buildings will impact groundwater recharge and what level of groundwater and surface water withdrawals are sustainable to determine if a proposed change in land use or additional use of water resources is sustainable before it is granted. Without coordinated and proactive management, the aquifers and rivers supplying our region will be depleted. Through mismanagement we can turn ourselves into California.

Sunday, October 15, 2023

The Chesapeake Bay Preservation Act & Allowed Development

Daniel Moore, Principal Environmental Planner from the Office of Watersheds and Local Government Assistance at DEQ (Virginia Department of Environmental Quality). Spoke to the Potomac Watershed Roundtable at our last meeting.

Mr. Moore, first went over a little history of efforts to protect and restore the Chesapeake Bay (the Bay). Through it’s history the Bay has played an important role in Virginia and the region by providing valuable economic, environmental and recreational resources. However, the health of the Bay began to decline in the 1950s, when underwater grasses started to disappear, and fish and shellfish populations decreased. The deteriorating water quality of the Bay is caused by pollution, which can be divided into two categories: point source pollution and non-point source pollution.

In 1986-1987 Virginia formed the Chesapeake Bay Land Use Roundtable to address the deterioration of water quality and damage to aquatic life in the Chesapeake Bay. The group realized that Virginia needed to address non-point source pollution into the Bay. In 1988, Virginia's General Assembly enacted the Chesapeake Bay Preservation Act (Bay Act) to improve the water quality of the Chesapeake Bay and its tributary streams.

The Bay Act created a cooperative program between the Commonwealth of Virginia and 86 local governments to protect and enhance water quality through environmentally responsible land use management. Each local government created local land use requirements and ordinances which seek to minimize the non-point sources of pollution into the Bay.

The regulations for the Bay Act were created in 1991and subsequently amended in 2001 and 2014 step by step tightening the requirements to reduce nutrient and sediment pollution carried in stormwater from reaching the Bay. The Chesapeake Bay Preservation Act in Virginia was amended in 2001 to expand the Resource Protection Areas of the Act to all tidal wetlands, tidal shore, perennial flow bodies of water, non-tidal wetlands connected and contiguous to tidal wetlands and buffer lands within 100 feet of any of those features. All other areas of the Tidewater were named Resource Management Areas as was all of Prince William County.

Under the Bay Act all localities are required to identify and map RPA’s as part of their local Bay Act programs. Resource Management Areas (RMAs) are defined as lands that, if improperly developed, may result in substantial damage to the water quality of the Bay and its tributaries. The zoning maps of each locality are required to show the general boundaries of the RMA. Resource Protection Areas (RPAs) are vegetated areas along water bodies, such as lakes, streams, rivers, marshes or shoreline, also known as riparian buffers. These buffers are RPAs under the Bay Act. RPAs include the land area within 100 feet of a perennial stream bank or edge of wetlands adjacent to the perennial stream. RPA areas are protected under state law and local ordinances. In general, no development, land disturbance, or vegetation removal is allowed in an RPA. RPAs were designated along all perennial streams in Prince William County.
Current regulations prevent further development of RPA lands beyond minor additions to existing residences and structures and impose broad standards for septic regulations. A Water Quality Impact Assessment (WQIA) is required for any development or redevelopment proposed within an RPA, or for modification (clearing, grading, etc.) of any portion of the 100-foot RPA buffer greater than 2,500 square feet. The Bay Act also requires that all septic systems within a RMA be pumped out at least once every five years. This applies to all existing homes and businesses, as well as new development. In addition, a reserve septic drain field is required for all new development. Requirements for maintenance of existing septic systems are necessary to protect ground water quality, and also protect the water quality of the Bay.

In their natural condition, RPAs protect water quality, filter pollutants from stormwater runoff, reduce the volume of stormwater runoff, prevent erosion, and perform other important biological and ecological functions. As such the goals of the Bay Act ordinances are to minimize land disturbance, preserve indigenous vegetation, minimize impervious cover, assure compliance with Virginia stormwater regulations and septic regulations, and assure that any agricultural disturbance have a conservation assessment.
A lot of what Mr. Moore does is make sure that the local programs meet the requirements of the regulations and that the locality has an adequate and appropriate review process.  

Wednesday, October 11, 2023

Water Supply and Source Water Protection

The Potomac Watershed Roundtable met last week at Fairfax Water Griffith Water Treatment Plant. The host speakers were: Greg Prelewicz, Manager-Planning for Fairfax Water and Nicki Bellezza, Watershed Protection Specialist for Fairfax Water. Mr. Prelewicz and Ms. Bellezza spoke about ensuring an adequate water supply into the future and protecting the quality of source water especially at the Occoquan Reservoir and the Griffith Water Treatment Plant.

Fairfax Water founded in Fairfax County in 1957 is now the largest drinking water provider in the Commonwealth of Virginia and one of the largest in the nation. They supply drinking water to 2 million Virginians -1.13 million retail customers through their 4,000 miles of water distribution pipes and 988,000 people through their wholesale customers - Prince William Service Authority, American Water and Loudoun Water. About 40% of the water supply comes from the Griffith Water Treatment Plant that obtains it’s water from the Occoquan Reservoir.

The Occoquan Reservoir consists of 1,400 acres containing 8.5 billion gallons of water that provides 40% of the daily water supply for Fairfax Water which in turn supplies Prince William Service Authority and a significant portion of Loudoun County. The reservoir’s water quality is a reflection of its watershed; spills, roadway runoff, stormwater carrying oil, salt and dirt are all carried into the Occoquan Reservoir. The water from the reservoir is then treated by the Griffith Water Treatment Plant and piped out to customers.

Source water protection is the first step to ensuring safe drinking remains available. By the early 1970’s Occoquan Reservoir began to experience problems with water quality and became that something had to be done to protect the water supply. Studies at that time concluded that inadequately treated sewage discharged by eleven secondary treatment plants in the Occoquan Watershed was largely responsible for the serious water quality problems in the Occoquan Reservoir. To remedy the problems, the predecessor of the DEQ adopted a comprehensive policy for the Occoquan Watershed in 1971. A principal requirement of the Occoquan Policy was the construction of a regional wastewater treatment facility to replace the eleven existing treatment plants. UOSA was created to treat the wastewater to such an extent that it could be recycled for use in the reservoir. UOSA was designed to recycle water that originated in the Potomac River and Lake Manassas into the Occoquan Reservoir. The Virginia Tech run Occoquan Watershed Laboratory continuously monitors the quality of the water.

To meet needs resulting from increases in population (both past and future) and the wastewater flows in its service area, UOSA developed an expansion program that  expanded the treatment plant capacity to 54 million gallons a day that was completed in  2005. Though the construction of UOSA was a huge step forward in restoring and maintaining water quality, it was not enough.

When the Occoquan Reservoir was first built 1957 it was located in a rural and forested area and the water was pristine. The unrelenting growth and development in this region has changed that.  When natural land is cleared to make way for commercial, residential, or industrial uses, vegetation is removed and resulted in increases in impervious which causes stormwater to flow at higher velocity and volume and damages and erodes stream banks. In addition to the damage done to streams by increased storm flows, urban/suburban runoff brings with it many types of pollution, mostly of the type that come from diffuse large geographic areas (called nonpoint source pollution). All sorts of pollutants can be carried in stormwater reflecting the land use- oil, grease, solvents, fertilizer, trace toxins from roadways, etc. The next steps to protect the Occoquan Reservoir was to develop the Occoquan Non-Point Source Program. Fairfax County down zoned 41,000 acres to 1 house per five acres or to parkland and created the Water Supply Protection Overlay District. Though 40% of the 570 square miles of the Occoquan Watershed including the headwaters of the Occoquan are in Prince William County, they did nothing to protect the Occoquan Reservoir. In addition, Prince William specifically chose not to create a Occoquan Watershed Overlay district in 2022.   

Nonetheless, Fairfax Water continues to work to improve water quality in the rivers, streams, and Occoquan Reservoir ahead of the Griffith Plant intakes. Fairfax Water is hoping in this way, despite the lack of cooperation and coordination from Prince William County it is possible to keep some contaminants out of the water and make the treatment process easier, and less expensive for all their water customers in Fairfax, Prince William and Loudoun.

Climate forecasts for the region indicate that by 2040 precipitation in the Potomac River Basin is projected to increase 8% and temperatures are forecast to increase 2.2 degrees Celsius from preindustrial times. While rainfall and storm intensity is expected to increase overall, droughts are also forecast to increase. Though water sales have been relatively flat from 1990-2020, due primarily to the expansion of water demand management in the form of more efficient water fixtures, the spread of conservation practices and reductions in water loss,  it is expected to grow in the future. Population is expanding and industrial use is growing in the form of data centers and semi-conductor chip manufacturing.

To meet the forecast demand for water and the climate uncertainties, Fairfax Water acquired the Vulcan Quarry in Lorton, VA right next door to the Griffith Plant. The Quarry 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 2080. 

Fairfax Water is panning for the future, but needs Prince William County to join them. The way to protect source water is land use controls (such as zoning ordinances and growth controls) Regulations, permits, and inspections. Land conservation and green infrastructure solutions utilizing plantings and open areas to manage stormwater. However, Prince William County is going in the opposite direction. Rezoning agricultural and woodland to industrial, stripping the land of natural vegetation that served as natural green infrastructure.

The entire Potomac watershed is being challenged by freshwater salinization syndrome and the expansion of roadways and impervious surfaces that require salting will make it worse. Sodium mass loading to the reservoir is primarily from watershed runoff during wet weather and reclaimed water from UOSA (where Micron Semi-Conductor discharges their process water) during dry weather, sodium concentration in the reclaimed water is higher than in outflow from the two watersheds in the current historical data, but development in the Bull Run and Occoquan watershed has been accelerating, increasing salinity. Currently, the Occoquan watershed is far less developed than the Bull Run Watershed, but Prince William is considering massive development in the watershed.  Rising salinity in the Occoquan Reservoir implies that its salt budge is out of balance and needs to change.

Sunday, October 8, 2023

Fairfax Water's Griffith Water Treatment Plant

from Fairfax Water

Last Friday I had the opportunity to tour the Fairfax Water Frederick P Griffith , Jr Water Treatment Plant on the northern edge of the Occoquan Reservoir in Lorton, Virginia. I had never visited the plant before and was really delighted to have the opportunity to tour the facility with a group from the Potomac Watershed Roundtable. We were fortunate enough to have Chad Coneway, the Manager of the Griffith facility act as our tour guide.

Fairfax Water is the largest drinking water provider in the Commonwealth of Virginia and one of the largest in the nation. They supply drinking water to 2 million residents (1.13 million retail customers and 988,000 people through their wholesale customers - Prince William Service Authority, American Water and Loudoun Water).

The Frederick P Griffith , Jr Water Treatment Plant was completed in 2006 to replace a series of older water treatment facilities. It’s design capacity is 120 million gallons of water a day, but it can be expanded to 160 million gallons a day if regional water demand grows. Despite growing population in the region, water demand from Fairfax Water has remained fairly level for over 25 years as water conservation habits and appliances have been adopted regionally and Loudoun has built a water treatment plant that draws directly from the Potomac River.

The Griffith plant is operated by a team of operators in a control room with two rows of screens that monitor operations and water parameters watching for an unusual or out of parameter. The Griffith plant does testing in the process to ensure that the water treatment operations remain consistently within parameters. As Mr. Coneway pointed out there is no ability to dump a “bad batch” of water. Around 100 million gallons of water is treated every day at Griffith and it all has to be good.

The Fairfax Water Quality Laboratory which is housed in the Corbalis Plant monitors the water from both the Potomac River and Occoquan Reservoir throughout the water treatment process and at various points in the distribution system for almost 300 parameters including the Federal Safe Drinking Water Act, SDWA primary and secondary contaminants for which there exist maximum contaminants limits and also for a list of emerging contaminants such as Endocrine Disrupting Compounds (EDCs), Pharmaceuticals, and Personal Care Products (PPCPs) that have been found in water nationally. Fairfax Water tests their source and treated waters for a list of 25 substances, hexavalent chromium and perchlorate have recently been added to the list.

The technology used for chemical analysis has advanced to the point that it is possible to detect and quantify nearly any compound known to man down to less than a nanogram per liter or parts per trillion (1/1,000,000,000,000), but Fairfax Water and all water treatment plants are struggling to get ahead of PFAS regulations. In the meantime, research has shown that using the combination of ozone and granular activated carbon filtration that is used by Fairfax Water is very effective in removing broad categories of personal care products and pharmaceuticals as well as the more dangerous Cryptosporidium organism from the source water. Though, no method of filtration is 100% effective all the time.

The Griffith plant also uses an unusual water quality monitoring system. Blue gill fish are part of an aquatic biomonitoring system. A water-monitoring device electronically analyzes the behavior of eight captive young bluegill fish to detect the presence of chemical toxins or other contaminants. The system uses bluegills because the fish are both sedentary and because there exists a large database showing how various toxins affect them. Although adult bluegills can grow to be over a foot long, the system relies young fish that are generally no longer than four inches. It requires that they remain in the chamber, unfed, for two-to-three-week tours and then are retired to the aquariums to breed more bluegills.

Water from Fairfax Water is distributed through approximately 4,000 miles of water pipes in to the homes and businesses in Fairfax County. On average, Fairfax Water produces 160 million gallons of water per day from both the Corbalis plant and the Griffith plant. The combined total capacity of both plants is 345 million gallons/day. The system must be sized to deliver the peak demand on a hot summer day when everyone is doing laundry and watering their lawns and everything else we do with water on hot summer days. This past summer the peak demand day was 238 million gallons. The peak demand day ever was 259.1 gallons of water delivered. To ensure the continuation of water supply during droughts, Fairfax finalized a regional drought response plan in 2001 that included a low flow allocation agreement with the members of the Interstate Commission on the Potomac River Basin, ICPRB. In addition, Fairfax bought the rights to 14 billion gallons of water from the Jennings Randolph Reservoir. Planning for the future Fairfax Water has obtained the Vulcan Quarry in Lorton. It will be converted to a reservoir in phases and continue to operate. Phase I 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 2080.

The Griffith Plant draws its water from the Occoquan Reservoir down the hill. The Occoquan Reservoir is fed by the Occoquan River which receives on average over 30 million gallons a day of the treated discharge of the Upper Occoquan Sewage Authority treatment plant. (The peak for that plant is 54 million gallons a day.) A significant portion of the flow (especially during dry periods) into the reservoir is recycled sewage. This treated wastewater is from areas supplied by the Corbalis plant or lake Manassas. In addition, the reservoir receives stormwater runoff, precipitation from the Occoquan Watershed which covers portions of Loudoun, Fairfax, Fauquier, and Prince William counties and feeds the streams and creeks that feed Bull Run and the Occoquan River.

Bars and giant screens on the pipes are used to prevent the intake of trash, debris and fish. Potassium permanganate (KMnO4) is added to the water at the intake to control taste and odors, remove color, prevent biological growth within the water treatment plant, and remove iron and manganese. The raw water is then pumped to the Griffith plant where is treated in a series of slow and elegantly simple steps to produce clean and clear drinking water.

Once at the plant the water is pumped to the first of a series of continuously monitored water chambers where the pH is adjusted by adding either caustic soda or sulfuric acid and the primary coagulant, polyaluminum chloride. This coagulant is used to remove small particles of dirt suspended in the water by causing them to stick to one another aided by the coagulant polymer. The water moves from the first water chamber where it is mixed through a series of chambers (which are really just a series of open rectangular water pools) with slower and slower mixing to allow the particles to coagulate into larger and larger particles until dirt floc is formed. Finally, the water arrives in the sedimentation basins that are not mixed at all and the floc is allowed to settle to the bottom of basins by gravity where they are removed. The floc is filtered out pumped to the quarry where the water separated out. Mr. Coneway call the sediment basins the workhorses of the plant.

The next step in the water treatment process is ozonation, the infusing of the water with ozone gas and the first of two disinfection steps. This step is still very much leading edge in water treatment technology. Ozone is the only chemical made on site, and is highly effective in eliminating the Cryptosporidium bacteria and other naturally occurring microorganisms present in water. Unlike ultraviolet and chlorine disinfection systems, there is no re-growth of microbes after ozonation. This step improves the taste and smell of the water. Ozonation also reduces the formation of trihalomethanes (chlorine breakdown products) because of the reduction of organic materials in the water before chlorination. Fairfax water converts liquid oxygen to ozone by an electrical discharge field created in a series of tanks. I was able to  be able to see the purple corona in the one operating tank. The Griffith plant has the capacity to treat a much higher level of cryptosporidium bacteria than is typically found in the Occoquan Reservoir.

Ozonation is followed by filtration through granular activated carbon. One cup of GAC has the surface area of about 25 football fields (1,300,000 square feet). Billions of pores in GAC absorb the organic substances removing them from the water and is very effective in removing biological and physical impurities that occur in broad categories of personal care products and pharmaceuticals from the water. Slow flow through the filter tanks improves the effectiveness of the filtration. The filter water wash, all runoff from the plant and the water from the dewatering process are reclaimed and returned to the raw water control chamber. The GAC is regularly backwashed, but lasts about 20 years before it has to be replaced. Mr. Coneway told us that the cost to replace the GAC in each bay is currently around $400,000.

The final steps in the water treatment process is the second disinfection, fluoridation and the addition of a ammonium hydroxide to adjust the pH slightly to prevent corrosion of piping and fixtures in customer homes to prevent the leaching of lead into water. Nine months of the year Fairfax Water uses chloramine (created by mixing sodium hypochlorite and ammonia) as the final disinfection step. However, during April, May and June of every year Fairfax Water flushes the entire 3,200 miles of water main and uses chlorine during that time to disinfect the delivery network. Flushing the water system entails sending a rapid flow of water through the water mains. As part of the flushing program, fire hydrants and valves are checked and cleaned. Flushing of the water distribution system is performed to remove sediment in pipes and helps to keep fresh and clear water throughout the distribution system. Chlorine is used as the disinfectant during this time so that after the system is flushed, a chlorine residual is maintained in the distribution system to provide a persistent disinfectant to prevent the re-contamination of water before your water tap.

Wednesday, October 4, 2023

The Rappahannock River, Data Centers and our Future

On a random day last week I took a look at the online USGS stream gauge on the Rappahannock River near Fredericksburg VA. My intention was to get a typical flow number to make a quick calculation. However, the flow on that day was at 11% of normal. That stopped me in my tracks. That meant that at that moment the flow of the Rappahannock River was about 142 million gallons/day.  

The Rappahannock River headwaters are in the Piedmont, fed by rainfall and snowmelt. The Rapidan, Robinson and Hedgeman rivers all come together and connect with the Rappahannock about 10 miles northwest of Fredericksburg. The river is subject to seasonal variations in flow, with higher levels in the spring due to snowmelt and rainfall and lower levels in the summer due to decreased rainfall, but this summer’s flow reduction seems very extreme. Even in Piedmont, the drought was only moderate in a portion of Fauquier County.

The Rappahannock River’s upper reaches, from the headwaters to Mayfield Bridge in Fredericksburg, are designated a Virginia State Scenic River. In addition to being one of Virginia’s top destinations for fishing, the river is a favorite for outdoor recreation on and off the water along the unspoiled river corridor. The river has been free flowing since the Embrey Dam was breached. The Dam was constructed in 1910, replacing a type of earth and timber dam called a crib dam that was built in 1853. The dam at one time provided water to a Virginia Electric Power Company’s hydraulic power station. The dam made the Rappahannock River impassible above Fredericksburg to spawning fish. With the dedicated work of Friends of the Rappahannock and Senator Warner, and a federal grant the dam was removed in 2004. allowing migratory fish like American shad and striped bass gained access to spawning grounds in the upper Rappahannock and its tributaries.

Today, much of the river’s watershed is rural and forested but is facing increasing pressure from development and population growth and a new challenge-data centers. Back in the day counties and cities used to submit water-supply plans to the state every 10 years, but that’s changed to regional planning, and there are five different water planning regions in the Rappahannock watershed with none of them coordinating with each other. The relatively recent increase in development in the suburbs southeast of Washington D.C. and the rapid expansion of data centers and planned data centers into Fauquier, Spotsylvania, King George and Caroline Counties all wanting to stick a straw into the river to supply the 1-5 million gallons of water a day those massive industrial buildings need to operate could challenge the river and farming’s survival in the region.

Even before data centers Caroline and King George counties had water troubles. By the early 2000’s it became clear that the Potomac Aquifer that the counties depend on for potable water was beginning to fail. Caroline and King George counties are within the current groundwater management areas of Eastern Virginia and Eastern Shore which were created by the DEQ to curb withdrawals from the aquifer’s biggest users. However, it has failed to preserve that resource for those counties.

Over half of reported groundwater withdrawals in Virginia are located within the groundwater management areas and are permitted. Despite all the efforts by DEQ, the groundwater level in the Potomac Aquifer has continued to decrease due to the historic over allocation of the water that has resulted in a deterioration in both water quality and quantity in Caroline and King George counties. Despite DEQ reducing permit limits by 52% the groundwater aquifer cannot long support growth in Caroline and King George counties and they have been forced to look to the Rappahannock River for water. The problems is that the Rappahannock River is not unlimited and that accessing surface water requires much more water infrastructure and that costs money.

Caroline County wants to build a water-intake facility that could withdraw up to 13.9 million gallons of water a day from the river, treat that water then, build the pipelines that would carry the water across the county for some residential and business growth, but mainly for the industrial projects proposed in Carmel Church and Ladysmith. King George County has been considering different approaches to tapping the Rappahannock River. 

The King George Board of Supervisors recently approved rezoning to build 19 data centers for Birchwood Power Partners, which presented the plan on behalf of Amazon Web Services. The Birchwood site already has a permit to withdraw water from the river, dating from when it was an operating coal-fired power plant. The residual cooling water from the data centers would be treated and returned to the Rappahannock however it is unclear the salinity limits and treatment parameters that would be applied and if the permit would have to be reapplied for. Amazon plans $35 billion investment to establish data center campuses throughout Virginia by the year 2040.

So, back to the flow of the Rappahannock River- on that day, at that spot, the flow of the Rappahannock River was about 142 million gallons/day.  Nineteen data centers use between 19 and 95 gallons a day of water, Caroline County wants 14 million gallons a day, and Prince George is talking about 4 million gallons a day. Motts Drinking water plant is designed to produce up to 24 million gallons a day. Then there is irrigation, ecological need and other users being approved each day. This summer people walked across the Rappahannock River on rocks revealed when the river level fell as the river was reduced to puddles and wetlands below Fredericksburg. We need to manage and properly allocate our water resources in a changing climate and economy to assure that Virginia has a future during both wet years and drought.


Sunday, October 1, 2023

Where Our Water Comes From

The Potomac River, its tributaries, reservoirs and the associated groundwater resources are the source of drinking water for the over 6,000,000 people in the Washington Metropolitan area. The Washington Aqueduct, WSSC, Fairfax Water and Loudoun Water directly draw from the Potomac River. The Occoquan River is a downstream tributary to the Potomac River.

The Interstate Commission on the Potomac River Basin (ICPRB) coordinates water supply/withdrawal operations for the Potomac River during times of drought and recommends releases of stored water from the jointly owned reservoirs. This is to ensure sharing of the water resources among the large Washington metropolitan area water companies and to meet minimum environmental flow levels that were jointly agreed to.


Water management in the Potomac basins requires preparation for summers and autumns when river flow is typically lowest and water demand is at its highest. This seasonality may be made worse by the changing climate and  expansion of data centers that require more cooling in the summer-typically using water which is more cost effective than air cooling.

The need for water is constant and grows with population, industry and wealth. A community or society becomes unstable if water resources are “used up” –inadequate to meet the needs of the community by growth in demand or reduction in supply- often both. Land use decisions that result in increasing impervious cover impacts our water resources. 

Fairfax Water owns and operates the two largest water treatment facilities in Virginia with an average daily water production of 167 million gallons and a combined maximum capacity of 376 million gallons per day. The James J. Corbalis Jr. treatment plant is at the northern tip of Fairfax County and the Frederick P. Griffith Jr. treatment plant is on the northern edge of the Occoquan Reservoir in the southeast part of Fairfax County.

Within Fairfax, Prince William and Loudoun Counties are a number of residents who still obtain their water from private wells or community wells that draw from the groundwater. However, most residents are served by the large pubic water companies and that water comes from two sources: the Potomac River and the Occoquan Reservoir.

The Occoquan Reservoir is an essential part of our water supply. It is fed by Bull Run and the Occoquan River which receives up to 40 million gallons a day of the treated discharge of the Upper Occoquan Sewage Authority treatment plant (UOSA). The UOSA treatment plant  is located south of Centreville and west of Route 123. It discharges all the treated water upstream of the Occoquan Reservoir so, a significant portion of the flow (especially during dry periods) into the reservoir is recycled sewer water. This treated wastewater is from areas supplied by the Corbalis plant or lake Manassas so you do not end up with constantly recycling and concentrating the same impurities, but it also makes the water in the Occoquan Reservoir dependent on the Potomac River.  

In addition, the Occoquan Reservoir receives stormwater – snow and rain from the Occoquan Watershed which covers portions of Loudoun, Fairfax, Fauquier, and Prince William counties and feeds the streams and creeks that feed Bull Run and the Occoquan River. As we change the land use in the region, it has a significant impact on our regional water resources. The extent of development in a watershed impacts stream health. Development results in increased impervious surface area, as new roads are built to access new buildings. Urbanization and industrial development brings a variety of pollutant sources such as oils, paints, salts, loose sediment, and other contaminants which are deposited on the impervious surfaces. Rainwater then washes these materials and other contaminants (e.g., heavy metals, pesticides, fertilizers, etc) from the land into nearby streams, either directly or through the storm drain network.

During development the primary impact is erosion and sediment that are carried by stormwater into the streams. Post-development the primary impact is increased stormwater volume and velocity that is caused by the removal of tree canopy cover and the replacement of pervious surfaces of plants and grass with the impervious surfaces such as roads, parking lots, rooftops, driveways, patios, etc. The increased impervious surface area result in increased stormwater runoff that increases erosion of stream banks and reduces infiltration of water in to the ground. 

Generally, groundwater in the regional Culpeper Basin is renewed each year through precipitation. The water stored in the watershed has always been able to provide adequate base flow to the rivers and streams in droughts because historically the withdrawal of water was within the average recharge rate. However, the nearby US Geological Survey groundwater monitoring well in the Occoquan watershed is no longer stable. The water level has been slowly falling since before the last drought- despite a series of wet years.

The Potomac River and the Occoquan Reservoir are the main supply of water for Fairfax Water which also supplies Prince William Service Authority, Loudoun Water and American Water. Public water supply in Prince William County is a mix of water from the Occoquan Reservoir, the Potomac River, groundwater and Lake Manassas. Public water supply in Loudoun County is a mix of groundwater, Goose Creek, and the Potomac River. The groundwater is an essential part of that mix. 

Never forget our water supplies are connected to each other and the land. How we treat the land will impact our water supplies. As the climate changes, our region is predicted to grow wetter with more intense storms and also have more severe droughts. More water storage (additional reservoirs) and better management of our water supplies and land are required to ensure there will be enough water for our region into the future.