Sunday, February 27, 2022

Bull Run Mountain/ Evergreen Water System

Last week the Prince William Service Authority held a virtual meeting to update the community on the progress of the modification to the Bull Run Mountain/ Evergreen water system that are necessary to bring the water system up to Virginia Department of Health standards and increase the potentially available water supply so that the system will be able to respond to and recover from emergency situations such as water main breaks.

The project will include:

  • Adding a new well on Evergreen County Club land to increase the water supply;
  • Modifying existing and new wells to add chemical feed for disinfection; and
  • Connecting the new well to the existing distribution system

The Bull Run Mountain/ Evergreen Water System currently consists of a series of groundwater wells and a distribution systems serving Bull Run Mountain and Evergreen Estates some of the wells and much of the distribution system are more than 40 years old, others parts are much younger. The Service Authority took over ownership and operation of the system in 1990. According to the Service Authority, the system is experiencing diminishing yields from some of the wells. The Service Authority did not explain the causes of the diminished yield which can be due to age of the wells, biological or mineral encrustations, or diminishing yield from the groundwater in the fractured sedimentary rock system.

According to the Service Authority two major factors are affecting the yield of the existing wells: All wells have a “safe yield” pumping rate, which is the rate that water can be extracted from the aquifer over a long period of time without producing unacceptable effects. As the geology has changed over time and the area has seen more development, the yields of the wells have decreased; possibly due to declining aquifer transmissivity. Age is also a factor. Some of the wells are more than 40 years old and their yields have been impacted by encrustation and in part, by the development of other private wells around them.

The quantity and quality of groundwater in Prince William County varies across the county depending on the geologic and hydrogeologic group you are in. The wells of the Bull Run Mountain/ Evergreen supply system are east of Bull Run Mountain in the western part of Prince William County. The Service Authority hired Emery & Garrett Groundwater, Inc. to study further development of the groundwater resources to expand the water supply for the system.

 Hydrogeologic group B underlies most of the western part of Prince William County and consists of sedimentary rocks of the Culpeper Basin. The predominant rock types are conglomerates, sandstones, siltstones, shales, and argillaceous limestones. Rocks within hydrogeologic group B tend to have moderate to excellent water-bearing potential because it is a fractured rock system with very little overburden. The highest reported yields in the county are from wells located in this hydrogeologic group B. The downside is that the hydrogeologic group is susceptible to contamination- the fractures that carry water can easily spread a contaminant and without adequate overburden spills could flow to depth through a fracture.  

Hydrogeologic group C, which is interspersed throughout this area of group B in the western part of the County, consists of igneous rocks (basalt and diabase) of the Culpeper Basin. The rocks of group C are Early Jurassic in age. The predominant rock types are basalt, sandstone, siltstone, diabase, hornfels, and granofels. Rocks within hydrogeologic group C tend to have generally poor water-bearing potential because of the wide spacing between fractures, mineralization of fractures, and random fracture orientations. In other words, unless you hit a good fracture, you are unlikely to have the water yield the system needed. 

Thus, in this area of Prince William County it is necessary to drill test wells to identify the locations with the best yield. The Service Authority was looking to locate wells that will provide a total of 40 to 100 gallons per minute of capacity for the system serving Bull Run Mountain and Evergreen Estates and to improve the system redundancy by augmenting water supply. The Service Authority converted two of the test wells drilled in 2019 into production wells. One well located on Evergreen Country Club and drilled to 330 feet below grade produced 60 gallons per minute and will be the new supply well. The second well located north west of the Country Club only yielded 10 gallons per minute and will be closed  and held as a reserve well.

The Service Authority ran a 72 hour pump test to determine if pumping this well would have an impact on nearby private wells. The aquifers underlying Bull Run Mountain and Evergreen are regional and interconnected. Every well that draws water from these aquifers has some effect, even if very small, on other wells drawing water from the same aquifers. This impact can take years to express. The 72 hour pump test was run to see if a cone of depression would for drawing down the water level in nearby wells in the short term. The Service Authority found “no impact” during 72 hour  pumping tests to the nearby wells they were granted permission to monitor. True long term impact will not be seen for years and the Service Authority should maintain monitoring well or wells in the area to document any changes in the groundwater over decades to come to have a greater understanding of the sustainability of the groundwater use.

This project does not expand the service area for the Bull Run Mountain/ Evergreen water system. It is intended only to ensure the continued level of service to existing customers and to provide sufficient water for others within the existing service area who decide to become Service Authority customers.

Wednesday, February 23, 2022

In Warrenton a Smell in His Hot Water

We went to Warrenton to drop off some very late gifts and visit with some relatives including  our nephew and get a glimpse of his new house. It is a really nice house still undergoing customization by him. He happened to mention that his hot water has a sometimes faint smell of rotten eggs. The symptom he described is typical of well water not so much surface water, and the house is on Warrenton “town water.”  So, I checked and it turns out that Warrenton uses both wells and the reservoir for source water. Only one of the town wells is treated with chlorine-That makes sense with his complaint.

Hydrogen Sulfide gas (H2S) gives water that awful “rotten egg” taste and smell and can be a fairly common occurrence in parts of the country, like around here where the groundwater is naturally high in sulfate. This problem can be solved, but let’s back up and start at the beginning. You have to first have sulfate present to have hydrogen sulfide (though a “faint smell” has sometimes been associated with iron bacteria).  Hydrogen sulfide naturally occurs in shale, sandstone, and near coal or oil fields, but can also be created by sulfur reducing bacteria “eating” the sulfate. According to the EPA, sulfur-reducing bacteria pose no known health risks. Sulfur-reducing bacteria live in oxygen-deficient environments such as deep wells, plumbing systems, water softeners, and water heaters.  Sulfate reduction can occur over a wide range of pH, pressure, temperature, and salinity conditions and produce the rotten egg smell and the blackening of water and sediment by the formation of iron sulfide if iron is also present in the groundwater or plumbing system. 

Hydrogen Sulfide gas (H2S) with its characteristic “rotten egg” taste and smell can actually be detected as an off smell at 0.5 parts per million (ppm) by most people. At less than 1 ppm, hydrogen sulfide will give water a musty odor. At 1 to 2 ppm, it will have an odor similar to rotten eggs. Levels encountered in wells are usually less than 10 ppm, because high levels of gas will not remain in solution in the water. Though toxic and potentially lethal at 800 parts per million after 5 minutes of exposure, the Occupation Safety and Health Administration, OSHA, OSHA has established 10 ppm (20 times the concentration that you can smell it at) as the safe limit. Hydrogen sulfide is heavier than air and can accumulate in pits and basements and can potentially create a health and explosive hazard (though the smell might kill you first). Hydrogen sulfide can be corrosive to metals such as iron, steel, copper, and brass, and it can cause yellow or black stains on kitchen and bathroom fixtures, but the big problem is the smell, the water is undrinkable and unpleasant with that smell. Some water treatment systems can actually create the problem within the plumbing system. Most hydrogen sulfide problems can be solved if the correct solution is implemented. So if you smell Hydrogen sulfide in your water you need to figure out what is going on to correctly identify a solution.

Hydrogen sulfide can end up in your tap water by four different routes. (1) It can occur naturally in groundwater especially in oil rich shale and coal seams. (2) It can be produced within the well or plumbing systems by sulfur reducing bacteria (bacteria that essentially eat sulfate in areas that have a high natural level of sulfate in the rocks. It is only guessed at how the bacteria enter the well or plumbing system, but the DEQ in recent studies of wells has found these bacteria in all older wells. (3) Hydrogen sulfide can form in hot water heater by either supplying a pleasant environment for the sulfate reducing bacteria to thrive or the energy for the magnesium rod intended to prevent corrosion of the heating tank to react with the sulfate naturally occurring in the water. (4) Finally, there are instances where the hydrogen sulfide gas is due to contamination of the well with septic waste. Since this instance is public water that is extremely unlikely.

Because hydrogen sulfate is so easily smelled by the typical human being, just this one time, that is all you need to identify the problem.  If the smell is only from the hot water faucet as reported by our nephew and not from the cold water or the hoses, then the problem is in the hot water heater. It is either sulfate reacting with the magnesium anode rod, or sulfur reducing bacteria (flourishing) in the hot water tank. 

Unless you are very familiar with operations and maintenance of hot water heaters, you should call a plumber. There is no standard test for sulfur reducing bacteria, so it is difficult to differentiate between a bacteria problem and something that might be solely sulfate reacting with the magnesium. You might  need to treat the hot water tank for both situations, but I suggested my nephew start with the assuming that bacteria took up residence in the hot water heater before he moved in. In that case the first thing to do is kill off the bacteria then flush the hot water tank. The easiest thing is to start by raising the temperature in the hot water heater to 160 degrees Fahrenheit for three hours. This will generally kill the sulfur reducing bacteria and all other bacteria. At this point you might want to flush the hot water heater a couple of times and let it refill and heat back up and see if the problem is gone. This cure probably won’t last, if iron bacteria are being reintroduced from the water system, but keeping your hot water heater above 150 degrees will constantly kill the reducing bacteria. If you do not want to keep your hot water heater set so high, then move on to disinfecting the hot water heater by chlorine shocking and replacing the anode rod.

Either turn off the hot water heater if it is electric or put it on pilot if it is gas and drain off a few gallons of water after you close the cold-water inlet valve. Make sure that you have drained off a gallon or so and pour a half gallon of household bleach (5.25% hypochlorite) into the tank. Use either the temperature and pressure valve, anode rod opening, or hot water outlet pipe opening to pour the chlorine into the hot water heater. Let the chlorine sit in the tank for at least two hours. Then open the cold-water inlet valve, drain the hot water heater and turn the heat back up. If the problem is sulfate reacting with the magnesium anode (corrosion protection rod), it can be replaced with an aluminum rod that is not as reactive as the magnesium and may still serve to protect the metal components of the tank from corrosion. Most hot water tanks take a standard size anode rod and there are aluminum replacements available from several manufacturers. Generally, you should check the condition of the anode rod when you pour the bleach into the tank. Be aware that some high end tanks have two anode rods and replacing just one with aluminum will not solve the problem because the remaining magnesium rod will continue to react with the sulfate.  

As a side note, according to recent research, increase salinization and resulting source water contamination has widespread implications for corrosion of drinking water infrastructure, including chloride acceleration of galvanic corrosion of water infrastructure and other premature plumbing  failures. Chloride can corrode and rupture hot water heaters.  Chloride potentially enhances hydrogen gas production which is explosive at higher levels, but at low levels also be food for bacteria – Harmless and smelly H2 S and far more serious Legionella. Warrenton does use a water softener (which adds sodium chloride) to control the elevated radium on one of the town’s wells, so that is a potential source of the problem.

Sunday, February 20, 2022

Sea Level Rise and Coastal Flooding


See full report
Last week NOAA Released the 2022 update to the Sea Level Rise Technical Report. Sea level along the U.S. coastline is projected to rise, on average, 10 - 12 inches (0.25 - 0.30 meters) in the next 30 years (2020 - 2050), matching the rise measured over the last 100 years (1920 - 2020). Sea level rise will vary regionally along U.S. coasts because of changes in both land and ocean height. The east coast is expected to have the most significant rise in the next three decades projected to be, on average: 10 - 14 inches (0.25 - 0.35 meters).

The sea level rise hot spot along the east coast extends from Cape Hatteras, North Carolina to Boston, Massachusetts with the Southern Chesapeake Bay region will experiencing the most significant rise. In the last century this area experienced the highest rate of sea level rise in the nation and is forecast to continue to have the highest sea level rise in the next 30 years due to land subsidence on top of the rising sea levels.

Our local land subsidence is due to glacial rebound after the Laurentide ice sheet melted, excessive groundwater extraction from the coastal aquifers, as well as the effects of the meteor impact near Cape Charles, Virginia (about 35.5 million years ago). Combined, they are all causing the sea level rise. The Aquifer-system compaction from non-sustainable groundwater extraction accounts for more than 50% of the land subsidence observed in the coastal region. 

Virginia is experiencing tidal erosion and rising sea levels (or sinking land) along the 5,000 miles of tidal shoreline in Virginia. Nearly six million people, or 70% of the state’s population, call coastal Virginia home. Between rising sea levels and changing precipitation patterns, Virginia has already recorded changes to the frequency and intensity of floods that pose increasingly greater risks to our communities.

from NOAA

The NOAA report finds that by 2050, the expected relative sea level (RSL) will cause tide and storm surge heights to increase and will lead to a shift in coastal flood regimes, with major and moderate high tide flood events occurring as frequently as moderate and minor high tide flood events occur today. Without additional risk-reduction measures, Virginia coastal infrastructure, communities, and ecosystems will face significant consequences.

Wind events and seasonal high tides are already regularly flooding our Tidewater communities, and they will do so to an ever greater extent in the next few decades, affecting homes and businesses, overloading stormwater and wastewater systems, infiltrating coastal groundwater aquifers with saltwater, and stressing coastal wetlands and estuarine ecosystems.

NOAA states that regardless of the emissions pathway we will experience a higher regional sea level rise at 2050 than previously reported (Sweet et al., 2017). Flooding already affects many Virginians but does not do so equally. Each community faces varying levels of flood exposure, vulnerability to harm or damage, and associated risks, tied to its individual socioeconomic, historical, and physical context.

from NOAA whos says dry weather flooding is increasing

Wednesday, February 16, 2022

The Latest in Covid-19 News

 Last Friday by the CDC released a report on the vaccine protection after 2 doses of mRNA vaccine after two and three doses. A waning of vaccine protection after two doses observed during the period when the delta variant predominated had prompted CDC to recommend that all persons older than 12 years receive a booster dose of COVID-19 mRNA vaccine 5 months or more after completion of a primary mRNA vaccination series and that immunocompromised persons receive a third primary dose.

This study was done during the period of the Covid variant predominance moved from the Delta to the Omicron and is a preliminary look at the effectiveness of the booster regime for the mRNA vaccines.

The CDC used data from emergency department/ urgent care visits and hospitalizations among U.S. adults aged ≥18 years at various time points after receipt of a second or third vaccine dose. A weakness in the data is that people who received 3 doses included those who received a third dose in a primary series because they were immunocompromised or high risk and a third dose as booster dose after a 2 dose primary series.

Among 241,204 encounters of people with COVID-19 like illness seeking care, 185,652 (77%) and 55,552 (23%) occurred during the Delta- and Omicron predominant periods, respectively. Among the people 46% were unvaccinated, 44% had received 2 doses of vaccine, and 10% had received 3 doses.

During the Delta-predominant period, vaccine effectiveness was higher after receiving a third dose than after a second dose; however, vaccine effectiveness declined with increasing time since vaccination. Among recipients of 3 doses, vaccine effectiveness was 97% within 2 months of vaccination and declined to 89% among those vaccinated ≥4 months earlier.

However, the effectiveness of the mRNA vaccines against Omicron was vastly different. During the Omicron-predominant period, vaccine effectiveness at preventing COVID-19 was lower overall compared with that during the Delta-predominant period and waned much faster after the second dose, from 69% within 2 months of vaccination to 37% at ≥5 months after vaccination.

Though during the Omicron-predominant period, mRNA vaccination was still highly effective against more severe disease. When looking only at COVID-19–associated emergency department/ urgent care visits and hospitalization for Covid-19 vaccine effectiveness was 87% and vaccine effectiveness against hospitalizations for COVID-19 vaccine effectiveness was 91% within 2 months after a third dose. Once more effectiveness waned, declining to 66% for prevention of COVID-19 emergency department/ urgent care visits by the fourth month after receipt of a third dose and to 78% for hospitalizations by the fourth month after receipt of a third dose. The finding of lower vaccine effectiveness for 2 or 3 doses during the Omicron-predominant period is consistent with previous reports and studies in Israel.

Right now the greater concern in our society is the rising mental-health problems, drug overdoses, violent crime, loss of learning and harm to our children. We need to turn the focus to protecting the young. As David Leonhardt of the New York Times pointed out over the weekend “At this point in the pandemic, there is a strong argument that a targeted approach — lifting restrictions while taking specific measures to protect the vulnerable — can maximize public health. ...” Read David Leonhardt’s newsletter here

As a final note, yesterday, Governor Glenn Youngkin signed SB739, which allows a parental opt-out from local school mask mandates and ensures five day a week in-person instruction. The change will take effect after a transition period by March 1, 2022.


Sunday, February 13, 2022

Eliminating the Rural Crescent

 Last week Prince William County held an informational meeting at the Manassas Campus of George Mason University and online to introduce residents to the county’s draft land use map, released the week before. As the county planners had telegraphed, the county proposes eliminating the “rural area” designation from the planning map-truly eliminating the Rural Crescent.

The county proposes replacing the Rural Crescent with a new “Agricultural and Forestry” designation that would up zone the land with that designation to one home per 5 acres area rather than the current one home per 10 acres. In addition, the county would add two new  designations of “Village Mixed Use” and “Hamlet Mixed Use” as well as designation most of the land from the Dutch Land Farm in Nokesville (House family) and Smith Family Farms in Gainesville as Conservation Residential Cluster.

Residential Cluster development allow one home per two acres but concentrates development at higher densities on a limited footprint within a site while conserving open space on at least 60% of the land. It is imagined that the homes will be connected to public water and onsite septic.  Land uses within Hamlets and Villages sounded exactly the same to me only differing in size, Hamlets are smaller. They may include “small-scale retail/commercial uses, infill residential uses, civic/institutional uses (e.g., libraries, schools, post offices, places of worship, and other government buildings and facilities), outdoor civic and recreational spaces, or other community-serving uses that are compatible with the rural character.”

According to the planning department about 75,000 acres of land in total will fall under the new “Agricultural and Forestry” designation, and another 1,600 acres would fall under the Hamlets and Villages designation with higher residential densities.  The Conservation Residential Cluster will encompass about 3,500 acres.

Agriculture and Forrestal district is designed to protect and enhances agricultural and forested land as an economic and environmental resource. Planning intends that the Rural Area will be served by public water, but not public sewer. It was unclear if the intension is to deliver public water to the existing development in the newly named Agriculture and Forrestal district designated in light green in the map or only the higher density Conservation Residential, Hamlet Mixed Use and Village Mixed Use. Planning said only that they would “Permit all future development within the Rural Area to connect to public water facilities. However, they would “require new development utilizing public water systems to fund – in coordination with the Prince William County Service Authority and Virginia American Water – the capital costs associated with expanding the water facility, including line extensions and plant capacity expansions.”

Link to the entire map

The large grey area is the PW Digital Gateway currently under consideration for Industrial Use

Planning states that the Agricultural and Forrestal District designation and Conservation Residential designation encourages primarily residential use. Though the planning department says that “this district is designed to encourage conservation and proper use of large tracts of real property in order to assure available sources of agricultural products, …” 5 acres is hardly a large tract of land, Possibly they were talking about the Conservation Residential designation. Planning also stated: “The Rural Area also protects Prince William Forest Park and Manassas National Battlefield Park County Registered Historic Sites, which serve as key anchor points within the Rural Area classification.”

Wednesday, February 9, 2022

What happens when Salinity Rises

In 2021, Dr. Marc Edwards the Charles Edward Via Professor of Civil and Environmental Engineering at Virginia Tech and MacArthur Fellow gave a talk at a virtual meeting of the ICPRB about some of the consequences of rising salinity in our source water. This was one half of a program about rising salinity in the Occoquan Reservoir.  In addition, research that has highlighted the corrosive effects of salt on private and public infrastructure has been published in recent years.

The Occoquan Reservoir is an important part of our region’s drinking water supply, providing about 40% of the clean drinking water for around 2 million people. The reservoir’s current storage capacity is estimated by ICPRB to be 8.3 billion gallons. Prince William land accounts for 40% of the Occoquan watershed which contains 1,300 stream miles, Lake Jackson and Lake Manassas as well as the Occoquan Reservoir.  Water from the Occoquan Reservoir is distributed to customers in Fairfax and Prince William Counties. This water is essential, but we are not adequately protecting it from the damage of increasing development and growth in the region. The salinity in the reservoir has been rising over time and may be reaching a critical stage. 

With rising salinity comes rising chloride concentrations, after all, salt is sodium chloride which forms a solution in water with available free chloride. According to recent research, increase salinization and resulting source water contamination has widespread implications for corrosion of drinking water infrastructure, including chloride acceleration of galvanic corrosion of water infrastructure and other premature plumbing failures. Chloride can corrode and rupture hot water heaters.  Chloride potentially enhances hydrogen gas production which is explosive at higher levels, but at low levels also be food for bacteria – Harmless and smelly H2 S and far more serious Legionella.

The rising salinity is also associated in some areas with changing water chemistry. Sulfate levels are decreasing and alkalinity is rising. These are other factors that influence corrosion  in our infrastructure.  According to Dr. Edwards a chloride-to-sulfate mass ratio (CSMR) > 0.58 can trigger catastrophic galvanic corrosion of lead solder. The thresholds for the catastrophic galvanic corrosion of other metals is not yet known.

Regionally, as salt levels have risen, WSSC is seeing colored water problems related to winter deicing when chloride levels were observed to spike from 40mg/L to too mg/L. Increasing chloride levels is from rising sea levels, increased direct and indirect potable reuse of waste water, the increased amount of pavement and the salting of roads in the winter. Nearly all road salt eventually enters adjacent rivers, streams, and aquifers.  

Road salt’s impact on drinking water infrastructure in terms of lifetime, leaks, and water contamination is an emerging problem for both private well owners and municipal water suppliers These spikes have caused changes in water chemistry triggering the release of lead in solder to be released. Chloride is an aggressive ion that exacerbates corrosion, especially galvanic corrosion in hot water heaters and at pipe joining’s.

Dr. Edwards stated that every $1 of road salt applied produces $46 in public infrastructure damage. This figure excludes private plumbing damage.  Chloride levels are rising nationally in freshwater sources. We increasingly need to reuse water to meet water demand and increased pavement and road building increases the use of road salt for de-icing.  Road salt is applied to de-ice roads in the winter for highway safety, with more than 18 million metric tons applied annually and most used in northeastern and midwestern states to ensure public safety. The more paved roads we build, the more salt is used in the winter.

Sunday, February 6, 2022

UOSA Contribution to Increasing Salinity in the Occoquan

The information is from the article cited below and a presentation to the ICPRB in 2021. 

Bhide, S.V., Grant, S.B., Parker, E.A. et al. Addressing the contribution of indirect potable reuse to inland freshwater salinization. Nat Sustain 4, 699–707 (2021).

A partnership between Virginia Tech, University of Maryland, Vanderbilt University, and North Carolina State University under a $3.6 million grant from the National Science Foundation has been studying freshwater salt pollution in the Occoquan Reservoir. This research is still in its first half examining the historical data from the Occoquan Reservoir.  So far the team has examined the 25 years of data collected by the middle of the last decade by the Occoquan Watershed Monitoring Lab’s mission of monitoring water quality associated with augmenting the water supply to the reservoir by adding the highly treated wastewater (reclaimed water) from the Upper Occoquan Service  Authority, UOSA, to surface waters from Bull Run and the Occoquan River.

The scientists quantified the contributions of the three salinity sources; UOSA, and two urbanizing watersheds; Bull Run and the Occoquan. This study is part of the National Science Foundation’s Growing Convergence Research (GCR) program, which “aims to catalyze solutions to societal grand challenges by the merging of ideas, approaches, and technologies from widely diverse fields of knowledge to stimulate innovation and discovery.” According to Dr. Stanley Grant Co-Director of the Occoquan Watershed Monitoring Lab and an affiliated faculty member at Virginia Tech, and his collaborators whose first half findings were published in Nature Sustainability last winter, the rising salt pollution in the reservoir is primarily from watershed runoff during wet weather and highly treated wastewater during dry weather. 

Across all timescales evaluated, sodium concentration in the treated wastewater is higher than in outflow from the two watersheds, but only during dry weather periods is the UOSA water the majority. Sodium in the treated wastewater originates from chemicals added during wastewater treatment, industrial and commercial discharges, human excretion and down-drain disposal of drinking water and sodium-rich household products. However, the source of more than half the sodium measured is unknown and could be attributed to the cyclical nature of the water supply.

The Occoquan Reservoir is an important part of our drinking water supply. The Occoquan supplies about 40% of the clean drinking water for around 2 million people and, in an emergency, can supply all for a short period of time. The reservoir’s current storage capacity is estimated by ICPRB to be 8.3 billion gallons. Prince William land accounts for 40% of the Occoquan watershed which contains 1,300 stream miles, Lake Jackson and Lake Manassas as well as the Occoquan Reservoir.  Water from the Occoquan Reservoir is distributed to customers in Fairfax and Prince William Counties. This water is essential, but the salinity in the reservoir has been rising over time and may be reaching a critical stage. 

Inland freshwater salinity, a phenomenon called the freshwater salinization syndrome (FSS), is rising nationwide. Though sodium mass loading to the reservoir is primarily from watershed runoff during wet weather and reclaimed 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.

Salt sources during wet weather

salt contribution during dry periods

The first part of the NSF grant has been to examine the contribution of UOSA to the rising sodium level.  Hopefully by the completion of this phase of the research the scientists will have quantified all sources of the sodium in reclaimed water which originates from chemicals added during wastewater treatment, industrial and commercial discharges, human excretion and down-drain disposal of drinking water and sodium-rich household products like water softening systems. Thus, numerous opportunities exist to reduce the contribution of indirect potable reuse to sodium pollution at this site, and the FSS more generally. These efforts will require deliberative engagement with a diverse community of watershed stakeholders and careful consideration of the local political, social and environmental context.

Dr. Stanley hopes this research will foster collaborative learning and discovery leading to stakeholder driven bottom-up management of the salt budget for the Occoquan Reservoir. The researchers will be presenting their findings to date to the NSF later this year in hopes of obtaining phase II funding and the “moonshot” desire to host one of three NSF Engineering Research Center locations for the freshwater salinization research.

Thursday, February 3, 2022

Other Options for Dominion Energy

I read in Inside NOVA that Senator Surovell and Supervisor Baily do not support the idea that an onsite landfill should be built to properly dispose of the coal ash a Possum Point. I have concerns about their suggestions.  Senator Surovell stated that the power station at Possum Point will be closed in 15 years and Possum Point should be redeveloped and that the land value should be used to offset the cost of removing the coal ash from Possum Point and disposing of it elsewhere.  While I agree with the Senator and Supervisor that building a landfill may not be the best idea, redeveloping an industrial parcel of land that is sinking into the bay while sea level is rising is not a better idea, and hauling almost 4 million cubic yards of coal ash to another site is not a better idea.

Moving waste from one site to another simply creates another location for potential contamination from coal ash. Turning one contaminated site into two. The existing coal ash ponds have been open to the elements and taking on water for decades. Trace contaminants and metals in the coal ash have already leached into the soil and groundwater, Quantico Creek and Potomac and no doubt spread throughout a significant portion of the 780 acre site.

from Dominion energy

Creating a landfill on site would require continual monitoring and maintenance.  Though Dominion is proposing a landfill with two liners, all physical barriers fail over time this is addressed requiring monitoring and maintaining the systems. Possum Point has been an industrial property for over 70 years. We do not have the technology to restore land and water resources to a pristine state.  Environmental cleanups are crude and imperfect.          

Consider what happened in  Hinkely, California located in the Mojave Desert. The groundwater in Hinkley became contaminated with hexavalent chromium from the compressor plant operated by Pacific Gas and Electric (PG&E). You may have heard of Hinkely or hexavalent chromium because of the movie “Erin Brockovich.”

In 1993, a legal clerk named Erin Brockovich investigated an elevated cluster of cancer in Hinkley that were linked to hexavalent chromium. Average hexavalent chromium levels in Hinkley were recorded as 1.19 parts per billion (ppb) with an estimated peak of 20 ppb. The PG&E Compressor Station averaged 7.8 ppb and peaks at 31.8 ppb based on the PG&E Background Study.

Though the U.S. Environmental Protection Agency (EPA) regulatory limit of total chromium at 100 ppb, and the EPA does not regulate hexavalent chromium at this time, and Dominion Energy has not tested for hexavalent chromium at Possum Point. The maximum contaminant level (MCL) for hexavalent chromium in California was lowered to 0.01 ppb in drinking water in 2014. Hexavalent chromium in drinking water is not regulated in Virginia, only total chromium.

Chromium is an element that is found naturally in coal in what is called the trivalent oxidation state, Cr(III). Chromium exists in nature as either a component in clay minerals such as illite or chlorite, or as its oxidized components; small-particle chromium oxide (Cr2O3) or oxyhydroxide (CrOOH) carbonaceous components of coal, or more rarely as chromite (FeCr2O4), as a result of special geology. Chromium is a metallic element found in rocks, soils, plants, and animals.

Cr(III) is relatively non-hazardous to humans and is in fact an essential nutrient. Chromium in coal is not considered a serious health risk. However, during commercial coal combustion, coal is burned with excess air to raise heat to generate steam for turbines that produce electricity. In the process, significant quantities of ash are created from the incombustible inorganic components in coal. That ash can contain not only hexavalent chromium, but also arsenic, selenium, lead, copper, antimony, and thallium. These are the contaminants likely present a Possum Point.

Furthermore, there is the potential for greatly increasing the health risk associated with chromium because not only can its concentration in the ash be increased by up to 10 times compared to that in the original coal, but Cr(III) can also be oxidized during coal combustion to form Cr(VI), which poses a much greater threat to public health.

Hexavalent chromium is commonly referred to as: chromium 6, chromium VI, Cr(VI), Cr+6, or hex chrome. Hexavalent chromium in the form of chromates is very soluble and, because of the six available electrons it has a high oxidizing capability, and can have severe adverse effects on the human body, including cancerous tumor formation and gene damage.

Research by the National Toxicology Program (NTP) has found that hexavalent chromium causes cancer in laboratory animals following oral ingestion at high doses (NTP, 2008). California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment (OEHHA) analyzed data collected from China that found increased rates of stomach cancer in people who were exposed to very high levels of hexavalent chromium in drinking water (OEHHA, 2010). Redevelping Possum Point for anything other than industrial use seems unwise.

Northern Virginia has become the data center capital of the world. Prince William County already home to a significant number of data centers and with the majority of the 2,400 acres in the existing Data Center Overlay district not yet built out, but owned by data center development companies or directly by data center operators. In addition, the County Board of Supervisors is considering doubling that available land.

The total amount of proposed data center space in Prince William County is twice of the existing data center square footage in Loudoun County (the current data center capital of the nation and the world). It took Loudoun County 14 years to build out the existing data centers and Loudoun County still has approved data centers that have not yet been built. That is a tremendous amount of 24/7 power demand that Dominion Energy is required to meet while also required to convert to 100% renewable energy.  Given the existing grid infrastructure and forecast of massively increasing demand, Dominion Energy is going to have to generate some form of power from Possum Point, but possibly a significant portion of the 780 acres could be redeveloped using coal ash to pave and create foundations for industrial buildings, like data centers.  They are near a non-potable source of water and power lines.