Thursday, October 27, 2016

5 Counties Offer Financial Assistance in Maintaining Septic Systems

At the last housing census about 28% of Virginia households had septic systems. This is a bit higher than the average of 25% for all U.S. households. It is widely accepted, but not well documented that improperly managed septic systems contribute to major water quality problems. In 2003 EPA reported that 168,000 viral and 34,000 bacterial illnesses occur each year from drinking water contaminated by waterborne pathogens from fecal contamination due primarily from failed septic systems. Unfortunately, many homeowners are unaware of how septic systems work, what is necessary to maintain them, or lack the financial resources to properly maintain their systems.

Now for five counties in Virginia- Orange, Madison, Culpeper, Rappahannock and Green- financial assistance is available to all residents with septic system. Through a grant funded by the Commonwealth of Virginia, the Culpeper Soil and Water Conservation District is offering financial assistance to all residents in their 5 county conservation district to pump septic tanks, fix septic system malfunctions and perform preventative maintenance. This program will reimburse participants who sign up before the work is done up to $150 for a septic system pump-out and 50% of any required repair or replacement expenses, including full system replacement. For low income households up to 75% of the cost of a septic system replacements or new installations can be reimbursed.
* up to 75%  is available for low income households

This money could allow residents in Orange, Madison, Culpeper, Rappahannock and Green counties to get their tanks pumped and septic systems repaired. Proper maintenance of septic systems (both traditional and alternative) is essential for protection of public health and local water resources and maintaining the value of your home. The regulations for septic systems are limited. For traditional systems located within a Chesapeake Bay Preservation Area once a system is built, the responsibilities for the owner are to have the system pumped out at a minimum every five years. However, there are no regulations that require the inspection of a traditional system, so you may not know your system is no longer functioning properly. For alternative septic systems called AOSSs there are more requirements including annual inspections. Here is a little tip, systems are less likely to back up into your basement or percolate out of the drain field if you pump them out frequently.

The drain field does not have an unlimited capacity. The more water your family uses, the greater the likelihood of problems with the septic system, so it is important to fix all leaks, and stop toilets from running and practice water conservation. In the Chesapeake Bay watershed many homes are within areas designated resource protected areas that requires a septic tank pump out at least every five years, but that may not be frequent enough depending primarily on the size of your tank, the number of people in the household contributing to the volume of your wastewater, the volume of solids in your wastewater and whether you use a garbage disposal or have a water treatment system. Excess water flow through the septic system can cause the solid sludge buildup and floating scum (grease, oil, dead skin cells, etc.) to flow out of the tank and travel into the leach field area. Some newer systems have screens and filters to keep solids from entering the leach field. These filters and screens become clogged and need to be cleaned out regularly or the system will back up into the house.

The septic tank is a buried, watertight container typically made of concrete, fiberglass, or polyethylene. It holds the wastewater long enough to allow solids to settle out (forming sludge) and oil and grease to float to the surface (as scum). It also allows partial decomposition of the solid fecal materials. Anaerobic (without oxygen) digestion takes place with the aid of bacteria that came from human digestive tracks and most of the fecal solids are converted to carbon dioxide, water and other byproducts. The process is not completely efficient and fecal solids and other materials that find their way into the septic tank will accumulate over time. To keep a septic system operating optimally, a septic tank must be pumped every few years to remove the scum and solid layers. Steady use of water throughout the day and water conservation should be practiced because too large a flow of waste water and the solids in the tank will be stirred up and be carried out to the drain field.

If you are in the five counties of Orange, Madison, Culpeper, Rappahannock and Green and have a septic system call the Culpeper Soil and Water Conservation District for more information at 540-825-8591 or 540-948-7531.

Monday, October 24, 2016

Alexandria Estimates $10-$15/month Increase in Sewer Rates

Alexandria's Combined Sewer Area

Like many old cities in the United States, Alexandria, Virginia has an area of the City, mostly around Old Town that has a Combined Sewer System. This combined system is a piped sewer system in which there is one pipe that carries both sanitary sewage and stormwater to the local wastewater treatment plant. This was how sewer systems were commonly built in the days before waste water treatment systems. There was no need to consider capacity of waste water treatment plants, because there were none. This was a time when sanitation was simply moving sewage out of the city to the rivers and streams. Back then one piping system was cheaper and adequate for the job.

However, today when sewage is treated by waste water treatment plants, the rain water that falls in the street and enters the storm water drains is combined with the sanitary waste water entering the sewers from homes and businesses. The combined flow can overwhelm the waste water treatment plant. The water coming from the combined sewer system is the most dilute. It has already had rainwater mixed in with the sewage. So, to protect the sewage system as a whole, the combined sewage and rainfall is released into the local creeks in a controlled and planned fashion out of the “Combined Sewer Overflows” which are release locations permitted and monitored by the regulators.

The U.S. Environmental Protection Agency (EPA) requires that each city have a Long Term Control Plan to address its combined sewer system overflows. In Virginia that program is managed by the Department of Environmental Quality (DEQ). Alexandria has been operating its combined sewer system under an approved Long Term Control Plan since 1999. Nonetheless, these overflows impact local water quality and over the years these regulations have been tightened. The Virginia Department of Environmental Quality (VDEQ) determined that Hunting Creek, Cameron Run, and Holmes Run watersheds where Alexandria is releasing the mixed stormwater and sewage water exceeded water quality standards for E. coli bacteria and put a limit on the amount of E. coli that can be released. This limit is called a Total Maximum Daily Load (TMDL) is the maximum amount of a pollutant that a waterbody can receive during a storm and still meet water quality standards. The City was issued a new combined sewer system discharge permit in 2013 that requires Alexandria to update its Long Term Control Plan by August 2016 to meet the Hunting Creek E. coli limit no later than 2035.

Alexandria has submitted its plan that is a combination reducing stormwater flow, increasing system storage and separating the stormwater from the sanitary sewer system as areas are redeveloped. Specifically, Alexandria’s long term plan calls for the following:
  • Construction of a 1.6 million gallon storage tunnel in the area of Hooffs Run. This tunnel will be 10-feet in diameter and be approximately 1/2 mile in length. Construction activities would be limited to a few tunneling shafts, but is still estimated to cost $80,000,000-$120,000,000. 
  • Construction of a 3 million gallon storage tank at the south end of Royal Street. This is estimated to cost $35,000.000-$53,000,000
  • Utilize green infrastructure to reduce stormwater runoff as a complementary strategy to be implemented citywide. This is estimated to cost $5,000,000-$7,500,000. 
  • Targeted sewer separation as a complementary strategy to be done as a condition of redevelopment in the Old Town area. These targeted separations are estimated to cost $5,000,000-$7,500,000.
  • Other potential opportunities including evaluating incentives for private property owners, including rebates for installation of water-saving fixtures to reduce overall sewage flow. 

The total cost of the combined sewer long term control plan is estimated to be $125,000,000-$188,000,000. This strategy of a Storage Tunnel for Hoofs Run and Storage Tank at Royal Street complemented by green infrastructure was selected as the preferred strategy because it had the lowest capital and operating costs, and was determined by stakeholders to be least disruptive to the community . These projects will be funded by issuing bonds which are paid back through the sanitary sewer rates. Currently, the average household in Alexandria pays $45-50 per month on their sewer bill. Studies are underway to determine the impact of these projects on the sewer rates, but preliminary estimates by the city indicate that the expected impact will be an increase of $10-$15 per month on the monthly sewer bill for these projects. These increases to the billing will be implemented over time.

These project when implemented will address the TMDL on Hunting Creek, Cameron Run, and Holmes Run watersheds, however; there is another combined sewer overflow at the end of Pendleton Street. This outfall discharges into Oronoco Bay, which is a Virginia waterway that is tidally influenced by the Potomac River. The Potomac River and Oronoco Bay are not part of the Hunting Creek TMDL and currently there is no regulatory requirement to reduce overflows there. However, because it is part of the combined sewer system, it is subject to the EPA’s existing Long Term Control Plan approved in 1999. Additionally, sewer separation and stormwater controls are a requirement of redevelopment in the combined sewer areas.

So, following the implementation of Hunting Creek, Cameron Run, and Holmes Run watersheds infrastructure projects and the Old Town North Small Area Plan, the City will reassess the need for additional controls at Pendleton Street.

Thursday, October 20, 2016

Bifenthrin Not Safe at Any Concentration

According to a new study by the U.S. Geological Survey (USGS) Bifenthrin, a pyrethroid insecticide, is widely used in agriculture and as an urban pesticide. Pyrethroids are manmade versions of pyrethrins, which come from chrysanthemum flowers; and though that sounds very safe bifenthrin  is harmful to aquatic ecosystems at levels that were previously considered safe. Bifenthrin is already a Restricted Use Pesticide (RUP) which means it can be sold only to “certified applicators.”

Bifenthrin is used to combat common household pests like ants and termites, to control mosquitos that could spread diseases like West Nile and Zika and on crops to kill aphids and other agricultural pests. About 1.2 million pounds of bifenthrin were used in the United States in 2014. Globally in order to improve crop yields as arable land declines the use of pesticides and fertilizers is increasing. In addition, the urban use of pesticides is increasing, in part to mitigate the spread of insect carried disease like Zika and West Nile.

Use of pyrethroids like bifenthrin has increased dramatically over the past 20 years in the United States and elsewhere; driven by the need to replace organophosphate insecticides. Pyrethroids have always been considered less toxic, but it is becoming increasingly clear that these pesticides are now agents of global ecological change. Ecological impact is beyond the breeding of resistance that results from spraying pests with pesticides that are significantly less than 100% effective .

Bifenthrin is insoluble in water and can persist in stream sediments. A USGS survey across the continental United States detected bifenthrin in 58% of the streams sampled. The USGS found concentrations of bifenthrin as high as 23.9 μg bifenthrin/g organic carbon (OC) in stream sediment. In global surveys, regional freshwater biodiversity was decreased in areas where pesticides were used, and pesticides, especially pyrethroids, were detected above regulatory thresholds at a greater frequency than expected.

In this study the USGS scientists evaluated the effects of bifenthrin on natural communities of stream invertebrates, such as mayflies and midges, using artificial streams. Exposure to bifenthrin concentrations previously thought benign caused the insect populations to become less abundant and diverse, and caused an increase in algal growth as the larvae that feed on algae decreased. The insecticide also altered the timing of insect emergence from the larval state to become adults and complete their life cycle.

According to Travis Schmidt, a USGS ecologist and the lead scientist on the study “The results of this experiment demonstrate that not only do aquatic insects die at concentrations of bifenthrin previously thought nontoxic, but that bifenthrin changes the way that stream ecosystems function. Bifenthrin disrupts the ability of insects to control algal blooms, and disrupts the emergence of flying aquatic insects that are a food source for bats, birds and other animals in and around rivers.”

There are over 600 products containing bifenthrin available in the United States.When you have pesticides applied to your home be aware of what the company is using. Product names of bifentrhin include Talstar, Bifenthrine, Brigade, Capture, FMC 54800, OMS3024, Torant (with Clofentezine), and Zipak (with Amitraz), but ask for the product information sheet for any pesticide used in or around your home. 

To read more of this study:
Schmidt, T.S., Rogers, H.A., Hladik, M.L., Dabney, B.L., Mahler, B.J., Van Metre, P.C., 2016, Bifenthrin causes trophic cascade and altered insect emergences in mesocosms: implications for small streams: U.S. Geological Survey data release,

Monday, October 17, 2016

WSSC to Help Prince George Residents Prepare for Winter

Washington Suburban Sanitary Commission (WSSC) is taking part in the inaugrial Prince George’s County Snow Summits- a series of public meeting to help residents prepare for the upcoming snow, ice, water main break and frozen pipe winter season. The summits will take place on the evenings of October 17, 18 and 20 2016.
  • Monday, October 17, the meeting will be 6:30 pm – 8:30 pm at Harmony Hall Regional Center located at 10701 Livingston Road in Fort Washington, MD. 
  • On Tuesday, October 18, the meeting will be held also at 6:30-8:30 pm at Laurel Beltsville Senior Center 7120 Contee Road in Laurel, MD.
  • On Thursday, October 20th the meeting will be held at 7:00 pm. – 8:30 pm at Palmer Park City Community Center located at 7720 Barlowe Road in Landover, MD.

WSSC will join the Department of Public Works and Transportation, Office of Emergency Management, Department of Health and Human Services, Department of Permitting, Inspections and Enforcement, Office of Community Relations/311 and the Prince George’s County Police and Fire departments to provide and share information.

Winter’s lower temperatures increase the chances of water main breaks in Prince George’s and Montgomery counties by about 60% compared to warmer months. Breaks can not only leave hundreds of people without service, they can also cause traffic problems. That’s why WSSC takes winter preparations very seriously and is participating in the Prince George County Snow Summits. The chart below shows the pipe break history in for WSSC over the past two years. Light blue is 2015 and dark blue is 2016.
from WSSC
Residents will learn how to prepare and winterize their homes and what to expect if a water main breaks in their neighborhood. Other organizations will provide information about the snow removal operations and services available during snow events, as well as answer questions. The snow summits are the first of their kind hosted by the county, and will serve as a great opportunity for the residents to proactively plan for the winter weather. WSSC is engaged in a PR campaign ahead of the 2017 rate increase necessary to support its aging infrastructure.

The WSSC provides water and sewer service to nearly 1,000 square miles in Prince George’s and Montgomery counties in Maryland. Established in 1918, WSSC is one of the largest water and wastewater utilities in the nation, with a network of nearly 5,600 miles of fresh water pipeline and over 5,400 miles of sewer pipeline. WSSC supplies water and sewer service to 1.8 million residents in approximately 460,000 households and businesses.

Much of the WSSC’s service areas was built out in the building boom of 1960s and continuing through the late 1980s. The pipes installed in 1960 are 55 years old and typically break at a higher rate than newer pipes. Though age alone is not the only factor that determines the likelihood of a pipe breaking it is a big one.  WSSC has begun a program to replace a significant portion of their piping systems and will us the rate increase to pay for it. Over the next 10 years WSSC plans to replace over 2,000 miles of water pipe and similar amount or sewer pipes at an average cost of $1.4 per mile of pipe (2009 WSSC figure) that is almost $6 billion to replace the piping that has exceeded it design life.

WSSC is moving forward with their program to replace both lateral line and repair water mains.

Thursday, October 13, 2016

What Virginia Has Spent on Meeting the TMDL So Far

At the October 7th 2016 meeting of the Potomac Watershed Roundtable the Deputy Secretary of Natural Resources for the Chesapeake Bay Russ Baxter reviewed Virginia’s costs and accomplishments towards achieving our U.S. Environmental Protection Agency, EPA, mandated reductions in nitrogen, phosphorus and sediment flowing into the Chesapeake Bay. Excess nitrogen, phosphorus and sediment from waste water treatment plants, agricultural operations, urban and suburban runoff, wastewater facilities, septic systems, air pollution and other sources have impaired the Chesapeake Bay and its tidal waters. These pollutants cause algae blooms that consume oxygen and create dead zones where fish and shellfish cannot survive, block sunlight that is needed for underwater grasses, and smother aquatic life on the bottom.

The EPA mandated a contamination limit called the TMDL (total maximum daily load for nutrient contamination and sediment) to all the states in the Chesapeake Bay Watershed and Washington DC. The TMDL sets a total limit for the entire watershed of 185.9 million pounds of nitrogen, 12.5 million pounds of phosphorus and 6.45 billion pounds of sediment per year 25% reduction in nitrogen, 24% reduction in phosphorus and 20 % reduction in sediment from the 2011 levels. The pollution limits were then partitioned to the various states and river basins based on the Chesapeake Bay computer modeling tools and monitoring data.

The six states and Washington DC with EPA oversight created plans of how they intend to achieve their assigned pollution reduction goals. These plans are called the Watershed Implementation Plans, WIPs, and lay out a series of pollution control measures that need to be put in place by 2025 to achieve the goals. While it will take years after 2025 for the Bay and its tributaries to fully heal, EPA expects that if 60% of the pollution controls are in place by 2017 and the rest of the pollution control measures are in place by 2025 the Chesapeake Bay ecosystem can heal itself. Management of the Chesapeake Bay is accomplished by using a model that has been continuously updated and improved and is now in its Phase 6.

About half of Virginia’s 39,490 square miles are part of the Chesapeake Bay watershed, and two-thirds of the state's population lives within the watershed area that impacts the Chesapeake Bay. To make the process manageable, EPA reviews Virginia’s progress every two years against what they call milestones -short-term goals. So far Virginia has met their state-wide milestone targets for nitrogen and phosphorus, but failed to meet its state-wide target for sediment. However, the Commonwealth presented plans to “catch up” and meet the important 2017 targets to the EPA.

From now on, achieving the goals becomes more difficult. The obvious targets for reduction have been taken as part of the 2017 reductions. The 2017 goals for nitrogen and phosphorus will be met by Virginia by having completed wastewater treatment plant improvements and expansions ahead of population growth. In total Virginians will have spent about $2 billion from 1998-2017 to upgrade the waste water treatment plants in the watershed. Half the money came from the state and the other half came from the individual waste water treatment plants that issued bonds and ultimately increased sewer rates for residents. That was expensive, but easy to achieve reductions- we knew how to do it.

The remaining areas for reducing nitrogen, phosphorus and sediment for the midpoint evaluation and ultimately the 2025 goals are in the agricultural, suburban and urban storm water management. These are harder targets to hit because the sources of pollution in these areas are non-point source pollution (NPS), diffuse sources of pollution. These pollutants do not come out of a pipe, but are carried to streams and rivers by runoff of rain and snowmelt.

The way to reduce non-point source pollution on the environment is to control stormwater and implement what is called “best management practices” (BMPs). BMPs have mostly been used in the agricultural sector. Virginia made great progress towards the EPA goal in management of livestock. A huge program carried out by the Soil and Water Conservation Districts to induce all animal operations to fence all pastures to exclude all livestock from rivers and streams and provide alternate sources of water for the animals away from rivers and streams. This is being accomplished by the state paying for 100% of the fencing for projects approved in the first two years and 80% combined with federal money for current projects. All the committed projects need to be installed by 2017 to meet the goal.

In total, the Soil and Water Conservation Districts will have provided technical assistance worth $178,000,000 and financial incentives (paying for all or part of the cost to install these agricultural mitigations) totaling $200,000,000 to minimize the use of fertilizers and pesticides; to reduce runoff and slow rain water, and exclude animals from rivers and streams over time period (1998-2017).

To achieve the next set of TMDL goals, Virginia is going to have to expand BMP programs and induce homeowners and business owners to change how they take care of their lawns and take action one yard at a time to reduce stormwater runoff to meet tightened stormwater goals. The Soil and Water Conservation Districts together have estimated that it will take and additional $1,740,119,000 for the technical assistance and cost sharing needs to meet these goals expanding our existing programs and using such innovative programs as the Virginia Conservation Assistance Program designed for suburban homeowners.

In addition, Virginia is making a big push to address urban stormwater. The Commonwealth has created a Stormwater Assistance Fund with a first round of $40,000,000 in funding. Total costs to upgrade the urban and suburban stormwater systems throughout the watershed are not yet known. You have heard about rain taxes and pavement taxes that local governments are struggling with to pay for the improvements in their stormwater management systems. There will have to be significant improvements in the stormwater systems to meet the EPA 2025 goal and it will be expensive.

Monday, October 10, 2016

Dominion Power Agrees to More Monitoring Wells at Possum Point

Last week Dominion Power agreed to install additional groundwater monitoring wells and conduct bi-weekly monitoring of the new wells. When these wells are installed it will bring the total number of monitoring wells at Possum Point to 24 and provide enhanced monitoring and protection for Quantico Creek, the upstream neighbors and the Potomac River from the dewatering of the coal ash ponds at Dominion’s Possum Point Power Station.

If you recall, Dominion Power has been moving forward with a plan to “close in place” 3.7 million cubic yards of coal ash under the finalized U.S. EPA Coal Ash regulation. The plan for Possum Point is to consolidate all of the on-site coal ash into one impoundment. There is estimated to be 3.7 million cubic yards of coal ash. Dominion has collected more than 1 million cubic yards of ash from four smaller ponds, put them in a 120-acre pond that already contains 2.6 million cubic yards of coal ash that they have begun to dewater. The plan calls for the pond to be capped with an impermeable membrane to prevent future infiltration of rain.

These coal ash ponds have been open to the elements and taking on water for decades. Trace contaminants and metals in the coal ash may have already leached into the groundwater, Quantico Creek and Potomac. The State Water Control Board and Virginia Department of Environmental Quality (DEQ) are the regulating agencies that oversee the dewatering of the ponds, though the U.S. EPA maintains authority to review applications and permits for "major" dischargers, a distinction based on discharge quantity and content. In January 2016 DEQ and the Water Control Board approved the modifications to Dominion’s Virginia Pollutant Discharge Elimination System (VPDES) Permit allowing the treatment and subsequent discharge of the coal ash waters to Quantico Creek, which flows into the Potomac River.

The Virginia Department of Environmental Quality (DEQ) issued a discharge permit in 2013 authorizing Dominion Power to discharge wastewater from coal ash ponds D and E at Possum Point through a designated outfall. On August 18, 2015, Dominion Power applied for and received a permit modification from DEQ seeking authorization to drain wastewater stored in ash pond D into either a tributary of Quantico Creek or Quantico Creek directly. This wastewater includes high levels of arsenic (960 µg/L, as compared to the EPA freshwater standard of 150 µg/L) and other metals. DEQ staff estimated that pond D holds approximately 150 to 200 million gallons of wastewater, and estimated that dewatering of coal ash pond D will take two years.

On January 19, 2016, DEQ issued a final modified permit for the Possum Point Power Station authorizing the release of wastewater from coal ash pond D into a tributary of Quantico Creek or Quantico Creek directly and authorizing the discharge from the toe drain. This was followed by The Potomac Riverkeepers (represented by the Southern Environmental Law Center) and Prince William County Board of Supervisors filed appeals to the permit.

Last spring an agreement was negotiated between Dominion Power and the Prince William County Board of Supervisors. The county would withdraw their appeal and Dominion Power agreed to reduce contaminant levels in the discharged water and independent testing of the levels:
  • ​Dominion agrees to provide advanced treatment of all water from the coal ash ponds prior to discharge, regardless of whether this treatment level is needed to meet the required VPDES Permit levels.
  • Dominion agrees to take additional hourly samples, and if any of the samples exceed more stringent triggers for certain elements (arsenic, selenium, lead, copper, antimony, and thallium), Dominion agrees to provide an additional enhanced treatment step, thus assuring the final effluent concentrations will be considerably lower than required by the VPDES Permit. 
  • Dominion will only use a State accredited third-party independent laboratory for its VPDES Permit-required sampling and testing.
  • Dominion will implement Standard Operating Procedures and Quality Assurance/Quality Control protocols. 
  • Dominion will regularly post on a publically accessible website all permit-required test results for public review.
  • Dominion and the County will work collaboratively to coordinate on solid waste permitting during the next phase of the closure of the inactive coal ash ponds to ensure that the Board’s and Dominion’s commitments to groundwater quality and environmental protection continue to be met.
  • Dominion will reimburse the County for its costs of outside technical consultation services regarding this state and federal regulatory matter pertaining to the water discharge and the solid waste permit application review. As such, the County and its citizens will not be responsible for these costs. 

Three weeks ago, the Potomac Riverkeeper Network argued to have the courts set aside the modified VPDES permit for Possum Point and remand the matter to the State Water Control Board and DEQ . The court failed to set aside the permit, but the court declined. Nonetheless, DEQ requested the additional monitoring wells. DEQ’s media spokesperson, Bill Hayden, said the request is part of the normal solid waste permitting process. Since Dominion Power has reported elevated groundwater concentrations of certain heavy metals associated with coal ash, additional monitoring wells were necessary to identify the extent of the contamination.

Possum Point Power Station is located in Dumfries Virginia in the eastern part of Prince William County that borders the Potomac River and the Quantico Creek. Dominion Virginia Power has not burned coal at Possum Point for 13 years and is unlikely to burn coal to generate power in the future. Possum Point is downstream from nearby drinking water supplies and is unlikely to impact local residents beyond what has already taken place over the decades. Though, let me clearly state that when coal ash is stored in ponds without proper and effective liners, harmful pollutants from coal ash can leach or dissolve into the water and move into the groundwater, streams, rivers and bay.
Dominion’s monitoring has shown that the coal ash ponds at Possum Point have leaked cadmium, zinc, and other pollutants into the on-site groundwater, but no off-site monitirng has been carried on before now so the extent of the environmental impact is not known.

The Potomac Riverkeepers are pushing to have the coal ash waste removed from the site and disposed of in a lined landfill far from any surface waterways. I disagree, because I am concerned about protecting our groundwater as well as our surface water. I do not believe in hauling one environmental problem to another location to become a second environmental problem. Closing the coal ash on site when properly done is the best solution. A safe closure requires a fully lined pond, ongoing monitoring and maintenance that is best accomplished at an operating and regulated plant rather than at a remote cap and leave it location. All physical barriers fail over time this is addressed by monitoring and maintaining the systems.

Thursday, October 6, 2016

Is My Groundwater Being Used Up?

I breathed a big sigh of relief when the rains came last week. I live in the northwest corner of Prince William county that is often shielded from rain; it can be pouring 5 miles down the road in Haymarket and dry here. Earlier this month the groundwater level in the U.S. Geological Survey (USGS) monitoring well up the road from my home recorded its lowest level in 86 years and I began to worry about my water supply. Now, water levels have crawled back up to the 10th percentile and I am watchful but not worried.

Groundwater is water beneath the surface of the earth. It is one of our Nation's most important natural resources and is often taken for granted. According to the U.S. Geological Survey (USGS) groundwater is the provides 38% of public water supplies in our country. In addition, groundwater is the sole source of drinking water for more than 97% of the rural population who are not connected to city or community water systems. I am one of the 46 million Americans who depend on a private well for their water, so I care very much about groundwater, its sustainability and its protection.

My well draws on an unconfined aquifer. A water-table, or unconfined, aquifer is an aquifer whose upper water surface (water table) is at atmospheric pressure, and thus is able to rise and fall with moisture that is contained in the earth. Water-table aquifers are usually shallower than confined aquifers are. Because they are shallow, they are impacted by drought conditions much sooner than confined aquifers. A confined aquifer is an aquifer below the land surface that is saturated with water. Layers of impermeable material are both above and below the aquifer, causing it to be under pressure so that when the aquifer is penetrated by a well, the water will rise above the top of the aquifer.

The water level in the aquifer that supplies a well does not always stay the same. Droughts, seasonal variations in rainfall, and pumping affect the level of the water table. If a well is pumped at a faster rate than the aquifer around it is recharged by precipitation or other underground flow, then water levels in the well can fall. This is what happens during times of drought and happened this summer when there was little or no rain in our little micro-climate. A well is said to have gone dry when the water level falls below the pump intake. This does not mean your well will never have water in it again, as the water level may come back through time as recharge increases. If drought has caused the water level to fall, then precipitation can restore the well.

There are other forces that can impact the recharge of a well. Land use changes that significantly increase impervious cover and stormwater velocity can prevent water from soaking into the earth and reduce recharge of the groundwater making existing wells more susceptible to drought. Significant increases in groundwater use for irrigation of crops or playing fields, or commercial or industrial purposes can overtax and aquifer and dry out neighboring wells. Unless there is an earthquake or other geological event groundwater changes are not abrupt and problems with water supply tend to happen slowly as demand increases with construction and recharge is impacted by adding paved roads, driveways, houses and other impervious surfaces.

The water level in a groundwater wells naturally fluctuates during the year. Groundwater levels tend to be highest in the early spring after winter snowmelt and spring rainfall when the groundwater is recharged. Groundwater levels begin to fall in May and typically continue to decline during summer as plants and trees use the available shallow groundwater to grow and streamflow draws water. Natural groundwater levels usually reach their lowest point in late September or October when fall rains begin to recharge the groundwater again. It is concerning that the monitoring well recorded its lowest level in 86 years.

The natural fluctuations of groundwater levels are most pronounced in shallow wells that are most susceptible to drought. Older wells tend to be shallower. However, deeper wells may be impacted by an extended drought and take longer to recover. My well is fairly shallow in a fractured rock system with little overburden. During dry periods, I can watch the water level fall. The chart below is from a nearby USGS monitoring well.

Private wells draw their water from groundwater. Geology, climate, weather, land use and many other factors determine the quality of the groundwater; and the water level in your well depends on a number of things, such as the depth of the well, the type (confined or unconfined) of aquifer the well taps, the amount of pumping that occurs in this aquifer, and the amount of recharge occurring. Within Prince William County Virginia there are four distinct geologic provinces: (1) the Blue Ridge, (2) the Culpeper Basin, (3) the Piedmont, and (4) the Coastal Plain. The northwestern part of Prince William County down the hill from Bull Run Mountain, consists of sedimentary rocks of the Culpeper Basin. The predominant rock types are conglomerates, sandstones, siltstones, shales, and argillaceous limestones. This geology tends 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 in this geology.

It is concerning that the seasonal lows are getting lower. This is a sign that the present groundwater use is not sustainable. Since we do not know what the total available water is, it is impossible to know how critical the overuse or diminished recharge of the aquifer is. According to studies by a group of researchers at the University of California, Irvine, the University of Texas, and the Hydrological Sciences Branch at NASA GSFC using satellites to perform real world groundwater monitoring Virginia’s aquifers are under stress. That means that we are using up the groundwater faster than it is recharging. That is exactly what an 86 year low level of groundwater is telling us.