The Piedmont and Blue Ridge Groundwater

About half of the nation’s population relies on groundwater for drinking water. As the nation’s population grows, the need for high-quality drinking-water supplies becomes ever more urgent. The USGS has identified 68 principal aquifers in the United States, these are regionally extensive aquifers that are used as sources of drinking water.

Groundwater pumped from these primary aquifers provides nearly 50% of the nation’s drinking water. Twenty of these principal aquifers account for about three quarters of the nation’s groundwater pumped for public supply. These aquifers also provide 85 % of the groundwater pumped for domestic (private) supply. Three of these principal aquifers are in Virginia and were evaluated by the USGS National Water-Quality Assessment Project, which began in2012 and continued through 2021. Below are excerpts from the evaluation of the Piedmont and Blue Ridge aquifers and information taken from the USGS Groundwater Atlas of the United States.

The Piedmont and Blue Ridge crystalline-rock aquifers underlie an area with a population of more than 25 million people in 11 states (map). The Piedmont and Blue Ridge crystalline-rock aquifers, together with the other rock types in the Piedmont and Blue Ridge regions, rank second in the Nation as a source of groundwater for private domestic supply, providing about 360 million gallons per day (Arnold and others, 2017a).

These aquifers are also an important source of public supply, and about 92 million gallons per day are pumped for that use. Land use overlying the Piedmont and Blue Ridge crystalline-rock aquifers is mostly undeveloped (71 %) and agricultural (19 %). The cities of Atlanta, Georgia, and Charlotte, North Carolina, overlie the aquifers, as well as suburbs of Richmond, Virginia; Washington, D.C.; Baltimore, Maryland; and Philadelphia, Pennsylvania.

The Piedmont and Blue Ridge Provinces are underlain by three principal types of bedrock aquifers. In order of decreasing area, these are crystalline-rock and undifferentiated sedimentary-rock aquifers, aquifers in early Mesozoic basins, and carbonate-rock aquifers. Unconsolidated aquifers that are part of the surficial aquifer system overlie the bedrock aquifers locally in Pennsylvania and northern New Jersey.

Crystalline-Rock and Undifferentiated Sedimentary-Rock Aquifers are the most widespread aquifers in the Piedmont and Blue Ridge Provinces. These aquifers extend over about 49,000 square miles, or about 86 % of the area, of these provinces. Most of the rocks that make up crystalline-rock and undifferentiated sedimentary-rock aquifers are crystalline metamorphic and igneous rocks of many types. The main types of crystalline rocks are coarse-grained gneisses and schists of various mineral composition; however, fine-grained rocks, such as phyllite and metamorphosed volcanic rocks, are common in places.

Unconsolidated material called regolith overlies the crystalline-rock and undifferentiated sedimentary-rock aquifers almost everywhere. Because the regolith material varies greatly in thickness, composition, and grain size, its hydraulic properties also vary greatly. However, the regolith is more permeable than the underlying bedrock. Water in the bedrock is stored in and moves through fractures, which form the only effective porosity in the bedrock.

Early Mesozoic rift basins are spread out in the Piedmont Province and occupy about 9 % of the combined area of the Blue Ridge and the Piedmont Provinces. Aquifers in early Mesozoic basins are primarily in three major basins-the Newark Basin in New Jersey and Pennsylvania is the largest basin and the one from which the most ground water is withdrawn; second largest is the Gettysburg Basin of Pennsylvania and Maryland; and third is the Culpeper Basin of Virginia.

The Culpeper Basin of northern Virginia and Maryland is an elongate, fault-bounded trough that trends north-northeast from the southern border of Madison County, Va., about 90 miles to Frederick County, Md. All the formations in the basin are part of the Culpeper Group. The lower part of the group consists of sandstone, siltstone, and conglomerate of Late Triassic age; the upper part consists of Lower Jurassic sedimentary rocks and interbedded basaltic lava flows.

The water in the Culpeper Basin is the least impacted by iron, manganese and sulfate in the region and of only moderate hardness. My home overlies a section of the Culpeper basin that runs through all but one small corner of northwestern Prince William County. I chose this area for the water. It requires no treatment.

Carbonate-Rock supports the largest aquifers in the Piedmont and Blue Ridge. Limestone, dolomite, and marble of Paleozoic and Precambrian age form carbonate-rock aquifers that extend over about 3 % of the Piedmont and the Blue Ridge Provinces. Although these carbonate rocks are of small extent, they are significant local sources of water. Carbonate-rock aquifers are in five areas of the Piedmont and the Blue Ridge Provinces. In addition to these areas, small, isolated elongate stringers of limestone and marble form minor aquifers locally, particularly in Virginia, and generally trend parallel to the Blue Ridge front.

Recharge is highly variable in the Blue Ridge and the Piedmont Provinces because it is determined by local precipitation and runoff, which are highly variable and are influenced by topographic relief, ground cover, compaction and the capacity of the land surface to accept infiltrating water. 

Most of the Piedmont and the Blue Ridge Provinces are covered by regolith. Compared to the Blue Ridge, the gentler topographic relief of the Piedmont and less precipitation make the Piedmont less subject to rapid denudation than the Blue Ridge and thus favor the accumulation of a thicker regolith. The combination of large areas of thin regolith and dense bedrock with minimal permeability in the Blue Ridge Province do not favor large amounts of ground-water recharge. These areas have a limited ability to provide water.

Almost all recharge is from precipitation that enters the aquifers through the porous regolith. Much of the recharge water moves laterally through the regolith and discharges to a nearby stream or depression during or shortly after a storm or precipitation event. Some of the water, however, moves downward through the regolith until it reaches the bedrock where it enters fractures in crystalline rocks and sandstones or solution openings in carbonate rocks.

The USGS Aquifer Studies were designed to evaluate groundwater used for public supply prior to any treatment. Groundwater quality was assessed by comparing contaminant concentrations to regulatory limits established for drinking water quality.  Trace elements and major and minor ions are naturally present in the minerals of rocks, soils and sediments, and in the water that comes into contact with those materials.

The USGS sampled 60 wells at depths that a used for public supply wells: 150-700 feet beneath grade. Samples were analyzed for 90 VOCs, of which 38 have human-health benchmarks. VOCs were detected at moderate concentrations in 5 percent of the study area but were not detected at high concentrations. Compounds detected at moderate concentrations were the disinfection byproduct chloroform and the solvent trichloroethylene (TCE).

Manganese was found to be present at high concentrations relative to the SMCL in about 15 % of the study wells. Iron was present at high concentrations relative to the SMCL in about 12 % of the wells.

Samples were analyzed for 227 pesticide compounds (pesticides and their breakdown products), of which 119 have human-health benchmarks. Pesticides were not detected at high or moderate concentrations in the study

In some areas, the pH of the groundwater was not in the SMCL range of 6.5 to 8.5. The pH did not meet the standard in 35 % of the study area, typically because it was less than 6.5, which is acidic and potentially corrosive.

The total dissolved solids (TDS) concentration is a usually considered a measure of the salinity of the groundwater, though all water naturally contains TDS as a result of the weathering and dissolution of minerals in rocks and sediments. Concentrations of TDS can be high because of natural factors or as a result of human activities such as applications of road salt, fertilizers, or other chemicals to the land surface in urban or agricultural areas. Concentrations of TDS were high in about 3 % of the study area. Chloride, fluoride, and sulfate—constituents that also contribute to TDS concentrations—were detected at moderate, but elevated concentrations.

Radioactivity is the release of energy or energetic particles during spontaneous decay of unstable atoms. Most of the radioactivity in groundwater comes from the decay of isotopes of uranium and thorium that are naturally present in minerals in aquifer materials. Samples were analyzed for eight radioactive constituents, of which four have human-health limits for drinking water. The USGS found radioactive constituents were present at high levels in about 30 % of the study area and at moderate levels in about 17 %. Radon (using the proposed alternative maximum contaminant level of 4,000 picocuries per liter) and gross-alpha activity were the only constituents that were present at high concentrations. Radium (combined concentration of Ra-226 and Ra-228 isotopes) was detected at moderate concentrations in 2% of the study area.

Nutrients are naturally present at low concentrations in groundwater; high and moderate concentrations (relative to human-health benchmarks) generally result from human activities. Samples were analyzed for five nutrients, of which two have human health benchmarks. Common sources of nutrients, aside from soils, include fertilizer applied to crops and landscaping, seepage from septic systems, and human and animal waste. No nutrients were detected at high concentrations in the study area. Nitrate was detected at moderate concentrations in about 3% of the study area.

 

Pharmaceutical Contamination Impacting Our Groundwater

Water is neither created nor destroyed. All the water on earth is between 4-5 billion years old, dating from around the time when the Earth was formed. There is no mechanism on Earth for creating or destroying large quantities of water. What we've got is recycled through the water cycle over and over again. Mankind leaves contaminants in the wastewater we return to streams. For most of history this was not important because contaminants were natural and biological, populations were sparse and the water ultimately flowed to the sea and rainwater returning to our rivers was free of contamination. As populations increased we treated our wastewater to remove the biological contamination with increasing efficiency to reduce disease and environmental impact. Wastewater reuse has become an important and measurable portion of downstream water supply while becoming a complex mix of chemical and biological contamination characteristic of our modern society. This contamination is spreading to all of our water supply including groundwater.

Groundwater is the largest and most reliable source of freshwater on earth. In the United States 26% of public supplied water is from groundwater in addition, 15% of households in the United States with private wells pump directly from groundwater for their drinking water. Groundwater and surface water are connected in many ways, not all of them fully understood. When streamflow is low due to lack of precipitation (drought) or withdraws (pumping for irrigation or water supply), groundwater serves to help maintain the baseflow. When conditions are dry, rivers, streams and ponds can serve to recharge groundwater.

In addition wastewater from agricultural irrigation is used to recharge groundwater and effluent discharge from wastewater treatment plants is intentionally and accidently finding its way into groundwater. In Los Angeles waste water effluent is used to recharge the groundwater, septic systems return their effluent water to groundwater and several studies by the U.S. Geological Survey (USGS) scientists Paul M. Bradley and Larry B. Barber (and others) have shown that waste water contaminants including pharmaceuticals are carried not only downstream into drinking water intakes, but into the shallow groundwater at least 65 feet from the stream.

The most recent study by Bradley and Barber et. al. was carried out at Fourmile Creek, near Des Moines, Iowa in October and December 2012. Fourmile Creek has been extensively studied by these scientists because wastewater dominates the streamflow. (Wastewater also dominates the flow of the Occoquan River and many others in our area.) Due to a drought in the Des Moines area, the wastewater represented 99% of streamflow in October and 71% of streamflow in December. Scientists chose to track the movement of pharmaceuticals between the stream and shallow groundwater because pharmaceuticals are bioactive, can be highly mobile, are good indicators of domestic wastewater, and wastewater is the only source of pharmaceuticals in Fourmile Creek.

Both stream and shallow groundwater samples were analyzed for 110 pharmaceuticals. The scientists found that 43% and 55% of pharmaceuticals analyzed for were detected in the stream’s water in in October and December, respectively. Fewer pharmaceuticals were detected in shallow groundwater; however, 16% and 6% of the pharmaceuticals were detected at a distance of 65 feet from the stream bank during October and December, respectively. The pharmaceuticals detected included antivirals and antibiotics, muscle relaxants, and antidepressants and tranquilizers, as well as medications for treating cancer, diabetes, and hypertension; in concentrations as high as 87 nanogram per liter (ng/L).

Both carbamazepine and sulfamethoxazole (a common antibiotic) were found in shallow groundwater at detectable levels at 65 feet from the river bank. The levels of these pharmaceuticals were higher close to the riverbank during the drier period, and appeared to fluctuate in response to drought; the larger portions of the river flow were made up of wastewater the higher the concentrations of sulfamethoxazole and carbamazepine in the groundwater. However as distance increased, the concentrations dropped, but it appeared that the rate of biodegradation of wastewater contaminants in groundwater is slower than in surface water and trace contamination of the groundwater may become ubiquitous.

USGS scientists have previously documented adverse impact to trace levels of sulfamethoxazole far below levels used to treat diseases on native soil bacteria. Since many studies by the USGS have found sulfamethoxazole in surface waters, the scientists conducted a series of laboratory experiments to determine the effect of the antibiotic on native soil bacteria. They found that sulfamethoxazole concentrations commonly found in aquatic environments (approximately 1 microgram per liter [ug/L]) delayed the start of cell growth, limited denitrification (a critical component of global nitrogen cycles), and altered bacterial community composition. In short, our contamination of water supplies with traces of antibiotics may impact the ability of the earth to feed us.

Other impacts of water pollution have been to the aquatic ecology. For over 15 years the USGS has been studying fish kills. Work done by Vicki Blazer and others has documented endocrine disruption and immune-suppression in aquatic life as contributing to fish kills. The earliest work did not find a cause. Dr. Blazer and others believe that methodology used to detect these chemicals in past studies may not have been sensitive enough, and may indeed be above the concentration thought to impact these fish. Dr. Blazer and others believe based on research studies in more than 25 fish species, that 1 ng/L (parts per trillion) may be the “no effects level” for estrogen concentrations in stream water on fish. We eat the fish, we drink the water, and we intentionally recharge groundwater with our waste water and pass all manner of chemicals and pharmaceuticals through our septic systems. For many of us, the closest septic system to your well is our own septic system. Any drugs you take (or flush down the toilet), chemicals you spray in your yard, use or pour down the drain may reappear in trace levels in your well especially during dry months or drought.

Water is our most valuable resource and how we manage its use or allow its abuse may determine the fate of our country and mankind. Groundwater is an important natural resource, especially in those parts of the country that don't have ample surface-water sources, such as the arid West and in times of drought. Groundwater is a renewable resource, but not in the way that sun light is. Groundwater recharges at various rates from precipitation and surface water. Wastewater reuse is necessary to meet water supply needs, but we are contaminating our environment and our drinking water supplies with what we do not remove from our wastewater.

Wastewater has become a complex mixture of chemical and biological contamination. Pharmaceutical contamination in wastewater is a particular problem because the pharmaceuticals are highly soluble in water, highly mobile in the water compared to other wastewater contaminants, and pharmaceuticals are designed to be highly bioreactive with long shelf-lives. At the low levels found they can be toxic to stream ecology, cause endocrine disruption, immune-modulation and suppression and serve for antibiotic resistance selection. Water contamination will challenge mankind’s survival long before climate change.

Related blog posts and articles:

Endocrine Disruption and What’s in the Potomac River Watershed

Is Our Drinking Water Safe?  

Barber, L., Keefe, S., LeBlanc, D., Bradley, P., Chapelle, F., Meyer, M., Loftin, K., Kolpin, D., Rubio, F., 2009. Fate of sulfamethoxazole, 4-nonylphenol, and 17bestradiol in groundwater contaminated by wastewater treatment plant effluent. Environ. Sci. Technol. 43, 4843e4850.

Barber, L., Antweiler, R., Flynn, J., Keefe, S., Kolpin, D., Roth, D., Schnoebelen, D., Taylor, H., Verplanck, P., 2011a. Lagrangian mass-flow investigations of inorganic contaminants in wastewater-impacted streams. Environ. Sci. Technol. 45, 2575e2583.

Barber, L., Keefe, S., Brown, G., Furlong, E., Gray, J., Kolpin, D., Meyer, M., Sandstrom, M., Zaugg, S., 2013. Persistence and potential effects of complex organic contaminant mixtures in wastewater-impacted streams. Environ. Sci. Technol. 47, 2177e2188.

Bradley, P., Barber, L., Kolpin, D., McMahon, P., Chapelle, F., 2007. Biotransformation of caffeine, cotinine, and nicotine in stream sedimentseImplications for use as wastewater indicators. Environ. Toxicol. Chem. 26, 1116e1121.

Bradley, P., Barber, L., Kolpin, D., McMahon, P., Chapelle, F., 2008. Potential for 4-nnonylphenol biodegradation in stream sediments. Environ. Toxicol. Chem. 27, 260e265.

Bradley, P., Barber, L., Duris, J., Foreman, W., Furlong, E., Hubbard, L., Hutchinson, K., Keef, S., Kolpin, D., 2014. Riverbank filtration potential of pharmaceuticals in a wastewater-impacted stream. Environ.Poll. 193, 173-180.

Fairfax County, Collecting Real Data to Model the Watershed

Potomac Watershed Round Table met on Friday, April 4th in the Fairfax County Herrity Building. The meetings are open so you are welcome to attend. As usual there were several stimulating presentations about programs operating in the Potomac Watershed and threats to our watershed. Shannon Curtis an Ecologist with the Fairfax Count Stormwater Planning Division spoke to the group about the evolution of the water monitoring program in Fairfax County Virginia and the long-term monitoring partnership between Fairfax County and the United States Geological Survey (USGS) that began in 2007.

Back in the 1980’s ecosystem monitoring by Fairfax County and others discovered that there is an ecosystem response time lag of 10-15 years (either positive of negative) to changes in the landscape. Traditional development practices cover large areas of the ground with impervious surfaces such as roads, driveways, sidewalks and buildings. Slowly, but surely this changes the ecosystem. The paved and impervious surfaces prevent rainwater from infiltrating into the ground, causing it to runoff site at velocities and volumes that are much higher than would naturally occur, carrying with it pollutants, oil and grease, and litter.

The collective force of high velocity rainwater scours streams and over time erodes stream banks carrying sediment and other pollutants into the streams, rivers, estuaries and bays. The US EPA believes that sediment and nutrient pollutions contained in runoff from urban areas is the largest source of water quality impairments to estuaries (areas near the coast where seawater mixes with freshwater) in the United States and has turned its water quality focus on these areas starting with the Chesapeake Bay Watershed and moving forward with the Gulf Coast estuaries.

Nationally, billions of dollars are being spent to implement stormwater best management practices and low impact development strategies based on computer simulations and models. In Virginia alone millions upon millions of dollars are expect to be spent on stormwater best management practices in the next 10 years. Fairfax county programs are helping to understand how well these programs work. The Fairfax County Stormwater Planning Division performed a baseline study of the condition of all the streams in Fairfax County in the late 1990;s and found at the time that three quarters of the streams were in fair, poor or very poor condition. The deterioration of the streams had resulted from the development of the county over the previous 40 years.

This finding was used to develop the stream protection and management plan. Then in 2007 Fairfax County Stormwater Planning Division and the USGS began a long-term monitoring effort to identify countywide conditions and trends in stream water quality and quantity. The first five years of data has been accumulated by the program. The information collected will be used to evaluate the benefits of past and future watershed improvement projects. There are currently twenty monitoring stations (recently expanded from 14) in the county collecting data. Fifteen of these sites are monitored manually on a monthly basis; the remaining five sites are equipped with automated stream gages which are monitored continuously.

Stream gage in Fairfax from USGS

Instruments at the five automated gages measure six indicators every 15 minutes and during storm events: water temperature, dissolved oxygen, pH, specific conductance (a measurement of the dissolved solids in the water), turbidity, and during the storm events sediment and nutrient (nitrogen and phosphorus) concentrations. The manual stations are sampled monthly. These gages cover and area of less than six square miles. It is hoped that this data will allow the USGS and Fairfax County to observe small and subtle changes over time.

The first five years of data (when there were only 14 gages in operation) has recently been accumulated and analyzed by the USGS and provides a baseline of the condition of the watershed based on real data and not US EPA’s Chesapeake Bay Model. The Urban loading modules of the Chesapeake Bay Model are believed to have the greatest uncertainties and this is a great opportunity to perform a “reality check” on the EPA’s oversight of the water quality in the Chesapeake Bay. EPA is using the Total Maximum Daily Load (TMDL) for nitrogen, phosphorus and sediment mandated to the six Chesapeake Bay Watershed states (Virginia, Maryland, Delaware, New York, Pennsylvania and West Virginia) and the District of the Columbia to manage contamination in the Chesapeake Bay Watershed.

The TMDL sets a total Chesapeake Bay watershed limit for the entire region of 185.9 million pounds of nitrogen, 12.5 million pounds of phosphorus and 6.45 billion pounds of sediment per year which is a 25% reduction in nitrogen, 24% reduction in phosphorus and 20 %t reduction in sediment from the current levels. The pollution limits are then partitioned to the various jurisdictions and river basins based on the Chesapeake Bay modeling tools. Now, the data that the USGS Gages Partnership with Fairfax County can provide a baseline of the condition of the watershed based on data not modeling by the EPA. So far they have discovered that high phosphorus in the western portion of the county is a naturally occurring deposit that was formed about 200-250 million years ago during the Triassic period and unlikely to be remediated by any stormwater or agricultural best management practices.

In addition, the monitoring has shown that stream conditions within the county have not changed much since 1998 when the Stream Protection Strategy base study was performed, though Mr. Curtis pointed out that there might be a subtle improvement in the data, but it could be a function of weather conditions, time will tell. However, during the past 15 years the county has grown in population and development increasing the pressure on the streams, so a steady stream condition might be a small victory.

Cleaning stormwater runoff is very expensive. Preventing stormwater runoff using green infrastructure and low impact development strategies appears to be effective, but is difficult to implement and maintain. Low Impact Development and green infrastructure are a series strategies for stormwater management emphasizing water capture and conservation using natural features to mimic as closely as possible natural hydraulic properties of a site. The idea is to reduce runoff with strategies like green roofs and rain gardens and move water slowly through open unpaved areas to allow infiltration of rain water into the earth. This reduces the quantity and velocity of stormwater as it leaves a site reducing the damage that uncontrolled stormwater runoff created by building roads, sidewalks, playgrounds, and structures and compacting soil can cause.

Nonetheless, the data gathering and work performed in Fairfax raises the question of whether it is possible for urban streams to ever fully recover. Those cleanup goals may not be realistic or attainable. Fairfax County is looking to discover what is the “best attainable conditions” for its streams. In addressing pollution from runoff each step requires consistent and sustained behavior modification of individual citizens working with government. Human behavior is very slow to change and maintaining stormwater best management practices is something each individual must do for the plan to succeed.

Landslide in Oso Washington Death Toll Grows

At about 11 am a large landslide occurred in northwest Washington State last Saturday. According to the U. S Geological Survey, USGS, the recent heavy rain conditions and soil saturation of the glacial deposits in that area led to the landslide. This was a falling rock, mud and debris flow-the most common type and often the most deadly type of landslide. The hillside collapsed at a speed that caught the local community unaware. Landslide debris covered about 30 houses and 0.8 miles of State Route 530. Flow also dammed and partially blocked the North Fork Stillaguamish River, creating a potential for flooding at the blockage. A pool of water currently 20-30 feet deep has formed behind the blockage a naturally formed dam. There is danger of flooding when this dam gives. There are still over 100 people reported missing the number is reported to be up to 176, but that number contains many duplicates from consolidating all the lists of the missing. It is unlikely any will be found alive. According to the Snohomish County Twitter feed, 16 bodies have been recovered and they believe that they have located an additional 8 bodies.

There are many types of landslides, and this event in Washington was a “debris flow,” also commonly referred to as a “mud slide” or “mud flow.” A debris flow is a flowing mixture of water-saturated debris that moves downslope under the force of gravity. Debris flows consist of material varying in size from clay to boulders that are tens of meters in size. When moving, they resemble masses of wet concrete and tend to flow downslope along channels or stream valleys. These mud slides can flow at up to 30 miles an hour and gives people little time or warning to get out of the way. These types of landslides occur most frequently in California, but the glacial deposits of sand and silt and weeks of rain created the conditions for a landslide. The hillside that collapsed had a history of slides and a study performed for the Washington Department of Ecology in 1997 identified the potential for a large catastrophic failure of the slope. Nonetheless, development of the area proceeded.

Hundreds of thousands of landslides of some scale occur in the United States each year from the tiny to the massive. Landslides occur in all 50 states and U.S. territories, and cause $1-2 billion in damages and more than 25 fatalities on average each year. Falling rocks, mud, and debris flows are the most common and deadly of the landslides, and yet there is still much to learn about how and why they happen. Any area composed of very weak or fractured materials resting on a steep slope can have a landslide when the conditions are right. Those conditions are predominately excess weight from heavy rains and melting snow that causes the slopes to fail. The rock and soil slopes are weakened though saturation by snowmelt and of heavy rains and literally begin to flow. Earthquakes of magnitude 4.0 and greater have been known to trigger landslides.

There is so much we do not know about our earth. The USGS science is helping answer questions such as where, when and how often landslides occur, and how fast and far they might move. USGS scientists produce maps of areas susceptible to landslides and identify what sort of rainfall conditions will lead to such events. You can watch the video about the USGS Landslide Program and check the maps to know if your area is suspect able to landslides.

Groundwater Awareness Week

It’s National Groundwater Awareness Week (March 10-16, 2014). According to George Harlow at the US Geological Survey (USGS) in Richmond, VA about 34% of all drinking water in Virginia is supplied by groundwater and there are 1.7 million Virginians whose drinking water is sourced from groundwater and supplied by their own private wells. Well ownership comes with the responsibility of keeping the water well in good working order and managing your own water supply. Ensuring that your water is safe to drink, of good quality is your responsibility and should be done annually. Managing your water use is an on-going challenge.

The groundwater aquifer you tap for water is not seen so you have to be aware of your water budget and live within it, something that transplants from the suburbs and city are not always aware of. Many who are on public water on the east coast are very accustomed to thinking of water supply as unlimited. Your well is not unlimited and living with a well you need to be aware of your water use and water budget. A diminished water supply can be caused by drop in water level in the well due to drought or over pumping of the aquifer, or the well could be failing (though equipment problems are the most common cause of well failure). Groundwater supply and quality can and do change because groundwater systems are dynamic.

The National Ground Water Association (NGWA) and most health departments recommend that private well owners test their water annually for at a minimum bacteria and nitrate. When you bought your house in all probability you only tested your water for was bacteria, that is not adequate to ensure your water supply is safe. There are many other contaminants that might be of local concern that you could test for and there are common contaminants that can be health hazard or water quality issue; however, not every contaminant needs to be tested for each year. The quality of your water will be determined by the source of the groundwater, the ability of your local geology to protect or impact your aquifer and the absence or presence of a potential local source of contamination. According to the US EPA actual events of groundwater contamination have historically been rare; however, as population density increases and we use more and more chemicals, pesticides and drugs, there are more opportunities to contaminate our groundwater. The most common sources of pollution to groundwater supplies come from two categories; naturally occurring ones and those caused by human activities. Naturally occurring contamination are produced from the underlying soil and rock geology.

Human activities can also contaminate groundwater. Improperly constructed and sealed wells can allow surface contamination to enter the well. Improperly maintained septic systems containing human waste and any chemical you flush down the drain, horses, and backyard poultry can contaminate the groundwater. Leaks from underground storage tanks, excessive use of fertilizers and pesticides, surface disposal of solvents, motor oil, paint, fuel, or nearby landfills or industrial operations can contaminate groundwater. While a confining geological layer can protect groundwater from surface contaminants, there is very limited natural protection in karst terrain and fractured rock systems that are very common in Virginia. So while we have rich supplies of groundwater our aquifers can be very susceptible to contamination.

The Virginia Household Water Quality Program out of Virginia Tech recommends that wells be tested for 14 chemical and bacteriological contaminants: iron, manganese, nitrate, lead, arsenic, fluoride, sulfate, pH, total dissolved solids, hardness, sodium, copper, total coliform bacteria and E. Coli bacteria. The Virginia Cooperative Extension (VCE) Office will be holding a drinking water clinic for well owners on March 31, 2014 in Prince William County and will perform the 14 analysis listed above analysis for just $49. (The water clinics are subsidized by a grant to the Virginia Household Water Quality Program.) That is enough information to address most water problems and ensure that your water is safe for your family to drink. To sign up for the program please call 703-792-7747 or email master_gardener@pwcgov.org.

If your water is supplied by a well, you also need to be aware of the factors that impact your water supply and respond to them, making sure to live within your water budget. There are dry years and wet years and you need to know which you are in. Direct determination of the groundwater level in your well requires a water level meter which can cost hundreds of dollars, but the condition of the aquifer can be obtained from a proxy well. The U.S. Geological Survey, USGS, maintains a group of 20 groundwater monitoring wells in Virginia that measure groundwater conditions daily and can be viewed online. One of the Virginia wells is just up the road from me in the same groundwater basin and is currently measuring at normal groundwater levels. As a matter of fact, all twenty of the Virginia monitoring wells are currently at or above normal groundwater levels, so if you are in Virginia it doesn’t look like there are going to be any problems with water supply this year.

groundwater conditions in Virginia

The water level in a groundwater well usually fluctuates naturally during the year. Groundwater levels tend to be highest in the early spring in response to 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. The natural fluctuations of groundwater levels are most pronounced in shallow wells that are most susceptible to drought. However, deeper wells may be impacted by an extended drought and take longer to recover.

In the fractured rock systems of the Piedmont where I live, most wells draw groundwater from vertical fractures in the bedding plane. Fractures can run dry or become clogged with sediment over the years. In unconsolidated sediments of the coastal plain ground water is pulled from the saturated zone. Prince William County is divided between these two areas. To provide a reliable supply of water, a drilled well must intersect bedrock fractures containing ground water and recharge at a rate greater than the typical domestic demand of 5 gallons per minute during periods of water use or have adequate storage within the well itself. In the typical 6 inch diameter well each foot of depth equals about a gallon and a half. So a 200 foot deep well that recharges at 1 gallon a minute could easily serve a family if the water demand were spread out throughout the day.

Failure of the well itself is rarely sudden, but happens especially in drought. A drought caused well failure may be restored when the drought ends. All problems with private wells break down into equipment failure, depletion of the aquifer or other groundwater problems and failing well design and construction. Though not as common as equipment failure, there are times that the problem is the well and the water supply. If the well cannot recharge at the same rate at which water is being pumped out of the well, you will experience intermittent episodes of severe water pressure loss or possibly loss of water entirely. If you have water first thing in the morning and again when you get home from work, but the supply seems to run out especially when doing laundry or taking a shower. Then you may have a groundwater problem or a well problem. Knowing the condition of the local aquifer will allow you to know which.

NASA to Help Manage California’s Water Resources

Water is fundamental to life on Earth. Knowing where and how much rain and snow falls is vital to understanding how weather and climate impact our environment, including the effects on agriculture, fresh water availability and natural disasters. Nowhere is this better seen than in California. The California Water Plan, a regular analysis published by the California Department of Water Resources (DWR) is the major guide book for water planning within the state. The latest version of the Plan was released for public review in January 2009 and updated in 2013. It stated: “We must adapt and evolve California’s water systems more quickly and effectively to keep pace with ever changing conditions now and in the future. Population is growing while available water supplies are static and even decreasing.”

The powerful Pacific storm that brought rain and snow late last week through much of California. Communities endangered by wildfire just weeks ago, faced mud and debris landslides and flash floods. The much prayed for rain came in a massive deluge as it often does. On Friday 4.3 inches of rain fell on Los Angeles almost three times as much rain as had fallen in the region since July. The parched ground and hillsides stripped bare by wildfires were less able to absorb water and several communities experienced mudslides and flash floods. The storm front moved on to the east bringing more snow to the east coast.

Despite the enormity of the deluge, these storms will not rescue the region from the three years of below-normal rainfall, California still looks to be facing its most severe drought in decades. It would take rainfall of almost biblical proportions to make up the water shortfall that California faces. If you recall Governor Jerry Brown has declared a drought emergency and water allocations had been cut to zero by state and federal water manages. Though, this storm did bring some relief to rural and smaller communities especially in Northern California whose water supply was forecast to run dry in the next two months.

In the past California’s state water agencies could not even track how much water is actually being used, where it is being used, where it is being diverted to, how much is being diverted, or how many diversions are illegal. The ability to track water usage and accurate long range forecasts of precipitation would allow California water manages to better capture and store the precious water. The California DWR announced last week that they will be working with NASA to apply new technology to better understand, monitor and manage the state's water resources and respond to its droughts and changing water needs. NASA scientists, university researchers and DWR water managers will work together to apply advanced remote sensing and improved forecast modeling to better assess water resources, monitor drought conditions and water supplies, plan for drought response and mitigation, and measure drought impacts.

DWR first began working with NASA on the Gravity Recovery and Climate Experiment (GRACE) and Global Land Data Assimilation System (GLDAS) to quantify groundwater depletion. A group of researchers at the University of California, Irvine, the University of Texas, and the Hydrological Sciences Branch at NASA GSFC have worked in partnership to apply GRACE and GLDAS to various real world groundwater monitoring with funding from the 2009 American Recovery and Reinvestment Act. The GRACE scientific team will launch the next generation of GRACE satellites able to monitor groundwater changes on a weekly basis and to be able to monitor groundwater and river basins that are 1,000 square miles in area. In addition, this partnership will provide the resources to interpret the date in a more timely fashion so that communities can use it to manage water resources in real time.

In California's Central Valley groundwater was pumped to such an extent that the ground subsided more than 75 feet in some places. The area was identified by the research efforts of Joseph Poland in the 1970’s as the location of maximum subsidence in the United States due to groundwater mining. Once the land subsides, it loses its water holding capacity and will never recover as an aquifer. Recent GRACE data has indicated that the groundwater level is once more falling due to over pumping. The groundwater resources of the state need to be managed with the surface water resources and the partnership with NASA holds promise of providing tools to do just that.

In addition, NASA is now planning on using their remote sensing data and research to monitor the California delta levees; map fallowed agricultural lands; and improve estimates of precipitation, water stored in the winter snowpack, and changes in groundwater resources. The agencies also are working to combine data from NASA satellites and DWR's network of agricultural weather stations to improve estimates of crop water requirements for California farmers seeking to better manage irrigation.

Next month, NASA and DWR will resume flights of NASA's Airborne Snow Observatory to map the snowpack of the Tuolumne River Basin in the Sierra Nevada and the Uncompahgre watershed in the Upper Colorado River Basin. The Tuolumne watershed is the source of the water supply for 2.6 million San Francisco Bay Area residents. The airborne observatory measures how much water is in the snowpack and how much sunlight the snow absorbs, which in turn affects how fast the snow melts. This information would allow NASA and DWR to make accurate estimates of how much water will flow out of a basin when the snow melts. Last year, observatory data helped water managers optimize reservoir filling and more efficiently allocate water between power generation, water supplies and ecological uses.

Another pilot project is demonstrating the feasibility of using satellite imagery to track the extent of fallowed land -- cultivated land intentionally allowed to lie idle during growing season. NASA is working with DWR, the U.S. Department of Agriculture, the U.S. Geological Survey (USGS) and California State University at Monetary Bay to establish a fallowed land monitoring service as part of a California drought early warning information system. New methods using time-series of crop data from NASA and USGS satellites can provide information on land fallowing and reductions in planted acreage early in the year. The team is preparing to produce data and maps of fallowed acreage in the Central Valley beginning this April to help monitor the impacts of the ongoing drought.

Over the next seven years NASA plans to launch four additional water-related satellites to add to the more than a dozen NASA satellites focused on understanding detailed Earth science processes. NASA also monitors Earth from ground-based observation posts. NASA is working to develop new ways to observe and study Earth's interconnected natural systems using the long-term data records and computer analysis tools to better see how our planet is changing and contribute to understanding and protecting our home planet.

These programs are not going to increase the water available to California, and they will likely reduce individual choice, but they may allow the state to rationally manage the resources available to it. I say maybe because California and its population has demonstrated an inability to face and accept harsh truths and plan rationally for the future. There seems to be a tendency to engage in magical thinking. Hope for the best, plan for the worst and carefully monitor the facts of the situation.

Wells, Geology and Contamination

from USGS

A well is simply a hole dug or drilled into the ground from which water can be removed. The hole is called the borehole and is lined with a well casing, which is typically a plastic or metal pipe. The well casing prevents the side walls of the borehole from collapsing into the well and closing the hole. The casing is sealed into place with grout which is usually neat cement or bentonite that was pumped into the annular space between a well casing and the borehole. This grouting seals the well and prevents water from flowing into the well directly from land surface down the side of the well casing pipe or from the shallowest part of the aquifer where the water quality may be less desirable.

Depending on geology, the casing will be open at the bottom or perforated at a specific depth with a screen, allowing water to flow into the well where it can be pumped to the surface. In sandy soils well screens are common. In fractured rock systems and bedrock screens are not necessary on low volume domestic wells. In clay or loam coarse sand or gravel can be placed around the well screen to help improve the flow of water into the well. These sand or gavel packs create larger pore spaces for water to accumulate. Gravel or sand packs are rarely used for domestic wells.

In the United States almost half of all drinking water is supplied by wells. About a third of the population obtains its drinking water from public supply wells which they never think about, and about 15% of the population obtains their household water from private domestic wells. Domestic well owners need to think about their wells and the groundwater that supplies them. Domestic wells have pumps that can pump 10-15 gallons a minute into the pressure tank when needed for household use. These pumps draw groundwater from the area immediately surrounding the well. Depending on the depth of the well and the local geology groundwater drawn into a private domestic drinking water well is typically young water-it could be weeks, months or several years old.

Typically rain water and snow melt percolate into the ground and the deeper the well the further away is the water origination and the older the water. The groundwater age is a function of the depth of the well, the geology of the area, the precipitation, recharge of the aquifer and pumping rates of the aquifer that control the rate of flow of water to a well. The age of the water in an aquifer provides insight into the likelihood of contamination from both anthropogenic and natural sources. Very young groundwater that has recently infiltrated into the aquifer is more vulnerable to contamination from human activities near the land surface than older, deeper groundwater that has had more time to be filtered by soils. Old groundwater, however, is not necessarily free of contaminants. The older groundwater can contain naturally occurring chemical elements and contamination from years past. The land surface through which groundwater is recharged must remain open and uncontaminated to maintain the quality and quantity of groundwater.

Though the most common sources of pollution to groundwater supplies come from two categories; naturally occurring and human activities, groundwater and domestic well water vulnerability to contamination depends on three factors:

1. The presence of man made or natural contaminant sources; for example, a failing septic system or chemicals poured down the drain, or underlying sediments can be sources of contaminants entering groundwater. From the underlying rocks radionuclides and heavy metals can enter the groundwater. There are areas with natural occurring arsenic, cadmium, chromium, lead, selenium and fluoride. 
2. The natural processes in the subsurface that can filter or cleanse the groundwater; for example, microorganisms can break down some chemical contaminants in groundwater like nitrate, contaminants can attach to soil particles and unsorted sediments can cause dispersion of contaminants as they move through an aquifer. 
3. The ease with which water and contaminants can travel to and through an aquifer; for example microorganisms in the soil and from wildlife can travel into groundwater supplies through cracks, fissures, other pathways of opportunity or even through sedimentary and basaltic rocks that are highly fractured and overlain by a thin cover of overburden, while a dense clay layer can reduce groundwater vulnerability by acting as a barrier to the movement of water and contaminants.

The vulnerability and water quality of a well can be vastly different from the quality and productivity of nearby wells. The most common sources of pollution to groundwater supplies come from two categories; naturally occurring ones and those cause by human activities. Naturally occurring contamination are those that are produced from the underlying soil and rock geology and wildlife. Once within an aquifer, contaminants that dissolve in water will travel with the flowing groundwater. What happens next is dependent on the chemical properties of a contaminant, the geology of the area and the flow rate of groundwater. Natural processes such as sorption/desorption, dissolution/precipitation, ion exchange, or biodegradation can reduce contaminant concentrations to effectively clean the groundwater. Many contaminants in the shallow groundwater remain in solution because of presence of oxygen, and the short travel times between the water table and the domestic wells allows contaminants to easily reach the well. In addition, a well might have one or more pathways of opportunity. One of the most common contaminant pathways is the failure of the grouting on the well casing allowing rainwater and snowmelt (carrying dirt and other contaminants) directly enter the well.

Nitrate concentration are often elevated in shallow groundwater because of agricultural and suburban development. Bacteria and nitrates contamination to groundwater can be caused by human and animal waste. In our own neighborhoods septic systems, horses, backyard poultry can cause these problems perculating into the ground or finding an opportunistic pathway through a fissure or other geological entry. On a regional level small lots and dense population of septic systems or large animal or fertilized farm operations can cause problems. Heavy local use of pesticides for ornamental gardens, leaks from underground fuel tanks can be sources of contamination. Households can introduce solvents, motor oil, and paint, paint thinner, water treatment chemicals and others substances by not maintaining our septic systems, or pouring chemicals into the ground or down the drain. Groundwater-quality protection depends on the entire community, what my up gradient neighbor does could impact my water quality. If residents and businesses take steps to reduce input of anthropogenic contaminants to the groundwater, water quality can be improved because of the short travel times between the water table and the well. The opposite is also true. 

from USGS

Groundwater Drought in Western Prince William

USGS monitoring well 49V1

It seemed that all of last week we had rain here in western Prince William County, my garden blooms and I am getting my garden in shape. As I was considering planting three trees that would need to be watered until they became established, I checked the water level in the U.S. Geological Survey (USGS) groundwater monitoring well up the road and was shocked at the water level. The median groundwater level for May based on 39 years of data is 9 feet below grade. The monitoring well’s groundwater level had fallen to just about 14 feet below grade. This was the lowest level of groundwater recorded for that well during May over the entire 39 years of data that had been recorded. The USGS maintains a group of 20 groundwater monitoring wells in Virginia that measure groundwater conditions daily and can be viewed online. One of the Virginia wells, 49V1 is just up the road from me in the same groundwater basin and serves as the proxy of the condition of my well.

The water level in a well usually fluctuates naturally during the year. Groundwater levels tend to be highest in the early spring in response to 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, though the lowest level ever recorded at the monitoring well up the road was in July 2011 at 15.38 feet below land surface. If the groundwater level in May is already this low, I am very worried about July and the general health of the aquifer. The natural fluctuations of groundwater levels are most pronounced in shallower wells like mine that are the most susceptible to drought.

The USGS has been using long-term groundwater monitoring data, combined with groundwater models, to improve our understanding of the storage and flow of groundwater. Whenever you pump water from a well it has to be balanced by a loss of water from storage in the groundwater aquifer. Groundwater is recharged from rain and surface infiltration from things like septic. If too much water is pumped, water tables can drop in unconfined aquifer like the one here in the Piedmont region of Virginia. The growing population and the effects of recent droughts have made the need for an updated status on the availability of the groundwater necessary and the USGS has been expanding their groundwater studies nationally.  I called the USGS Virginia Water Science Center in Richmond, Virginia and spoke to David Nelms the groundwater specialist. I happen to catch him right after the Drought Taskforce Meeting and so he was able to give me a well-considered opinion of what might be causing the low groundwater levels.

Mr. Nelms confirmed that this is the lowest groundwater level recorded in this region in May in 39 years. Though the Virginia Department of Environmental Quality, DEQ, has listed the groundwater conditions for Northern Virginia (including Prince William County) as normal, according to the USGS there is a small area in the Piedmont that just did not get enough rain last fall and over the winter to overcome the soil moisture deficit from the drought of 2012. According to Mr. Nelms this area of the Piedmont did not catch enough rainfall during the rains last fall even with Hurricane Sandy passing through. Though the water levels in the past couple of years have fallen to levels lower than recorded over the previous 39 years, the USGS did not think that anything other than a lack of rainfall was causing the low water levels. Mr. Nelms noted that the seasonal variation in groundwater levels seemed to be more extreme in recent years, and that the ownership of the property where the monitoring well is located had changed hands and could indicate a change in use could have impacted the apparent static pumping level by increasing the cone of depression if for instance the well had been used for irrigation or a sprinkler system. The USGS was not aware of any change in water use. As Mr. Nelms pointed the water level needs to be watched because it impacts not only the wells in western Prince William (including the Evergreen public water supply system), but also the surface water tributaries to the public water supply systems drawing from the Occoquan Reservoir and the Potomac River. Potomac River flow was also low for this time of year. Data from the National Weather Service’s Middle Atlantic River Forecast Center shows that the Potomac basin upstream of Washington, D.C. had a precipitation total which for the year to date is 1.5 inches below normal. We need to keep an eye on the water level and rainfall this summer.

USGS Data for 49V1

New York Fracking Report Leaked to the New York Times

Extent of Marcellus Shale within the Devonian Shale of the Northeast- USGS

Last Thursday the New York Times reported that an analysis on fracking prepared in early 2012 was leaked to their paper. This analysis was prepared last year after the New York Department of Environmental Conservation’s 2011 draft environmental impact statement (EIS) on drilling comment period was closed and might have been prepared in response to the comments received. The 8 pages obtained by the New York Times were characterized by the paper as containing an analysis that showed that hydraulic Fracturing, or fracking, could be safely done in New York by implementing the proper mitigation measures. The report, obtained by the New York Times from and “expert who did not believe it should be kept secret,” was characterized by State Department of Environmental Conservation, DEC, as an out of date summary that was nearly a year old and will undergo significant changes. The revised version of the Environmental Impact Statement has not yet been completed or released and the DEC’s health assessment is being reviewed by three outside experts. I think someone may have violated the terms of their consulting contract.

The report (or summary) the New York Times had seems to be in agreement with the recommendations made in the report of the Shale Gas Subcommittee of the Secretary of Energy Advisory Board in 2011. That report had a rational approach to regulation recommending disclosure, testing, evaluation and modification of regulation and practices based on the information and data obtained. It assumes information and data will be gathered and analyzed and seems to be the accepted view, but fracking is a highly complex issue whose greatest risks are to our water resources. There needs to be much more data collected over time and analyzed. That has not being done in the past and until extensive data is collected and studied we will not truly know. The data needs to be collected on a state by state basis and provided to the US Geological Survey (USGS) and US EPA to consolidate on a national level. It is essential that the USGS be involved because of the unique expertise and research in geology and water resources.

In 2011, the EPA began a series of research projects into the impacts and potential impacts of fracking on water that are scheduled for completion in late 2014. These projects will be the basis of their actions and future regulations for oil and gas operations. Whether the EPA will regulate oil and gas exploration nationally or leave the oversight in the hands of the states is an open question. There is an argument that water resources and geology are very local phenomena and cannot be generalized over the nation and that hydraulic fracturing should remain under local oversight. According to the New York Times the leaked report rejects performing a quantitative risk assessment because such an assessment would ‘involve making a large number of assumptions about the many scenario-specific variables that influence the nature and degree of potential human exposure and toxicity.”

The EPA research projects may help with that though all the answers will not be known in 2014.  The current fracking projects at the EPA are a series of studies. Existing Data from multiple sources have been obtained for review and analysis. Well construction and hydraulic fracturing records provided by well drillers are being reviewed for 333 oil and gas wells across the United States; data within these records are being examined to assess the effectiveness of current well construction practices at containing gases and liquids before, during, and after hydraulic fracturing.

Computer models are being developed (or expanded) to identify conditions that may lead to impacts on drinking water resources from hydraulic fracturing. The EPA has created hypothetical scenarios for water acquisition, well injection, and wastewater treatment and waste disposal stages of the water cycle that they hope to have the models evaluate. Computer models are also being used to explore the possibility of subsurface gas and fluid migration from deep shale formations to overlying aquifers in different scenarios. The effectiveness of the models would be dependent on how closely the model predicts transport behavior in rock and shale and the similarity in behavior of different formations.

Laboratory studies are being performed to identifying potential impacts of inadequately treating hydraulic fracturing wastewater and discharging it to rivers. Experiments are being designed to test how well common wastewater treatment processes remove selected contaminants from hydraulic fracturing wastewater, including brines, heavy metals, radionuclides and organic contaminants. Since wastewater treatment plants are not designed to remove more than biological waste and bacteria, any removal of fracking chemicals and contaminants would be incidental.

The EPA has identified chemicals used in hydraulic fracturing fluids from 2005 to 2011 and chemicals found in flowback and produced water. The EPA is performing toxicity assessments based on chemical, physical, and toxicological properties for chemicals with known chemical structures and using exiting toxicology models to estimate properties in cases where information is not available. The important thing that EPA is doing is bringing together all the data and previous work to get as complete picture of what we know about how hydraulic fracturing may be impacting our water resources and that would allow a broad quantitative health risk assessment to be performed along the identified routes of exposure.  

New York placed a moratorium on drilling in the Marcellus Shale in 2010 while it assessed the effects of fracking. New York DEC’s draft environmental impact statement (EIS) on drilling was released in the fall of 2011 and recommended that drilling be permitted, but with conditions. The comment period was extended and the DEC began a revision to the EIS that has been going on for over a year. The leaked report indicates that the DEC is recommending lifting the ban on hydro fracking in New York, but that is not certain and fracking remains controversial for good reason.

A large swath of southwestern New York sits atop the Marcellus Shale, which is the third-largest natural gas field currently known in the world. The Marcellus Shale alone is estimated to be 500-trillion-cubic-feet of gas reserve. This resource could heat our homes for a generation or more, and power our electrical generating plants, even fuel cars either directly or through plug in hybrids. The possible impacts to our economy and environment are far reaching. The potential risks are also far reaching.

Our ability to recover natural gas buried a mile or more beneath the earth has increased. Advances in horizontal drilling which allows a vertically drilled well to turn and run thousands of feet laterally through the earth combined with advances in hydraulic fracking, the pumping of millions of gallons of chemicals and water into shale at high pressure have increased our ability to recover natural gas from shale. Hydraulic fracking while old has made tremendous advances in the past 15 years have made it possible to economically access this gas. Our knowledge of the impacts from fracking has lagged behind our ability to access the gas.

 

In hydraulic fracking on average 2-5 million gallons of chemicals and water is pumped into the shale formation at 9,000 pounds per square inch and literally cracks the shale or breaks open existing cracks and allows the trapped natural gas to flow. Each stage of the fracking water cycle is a potential area for impact to drinking water supplies especially from human error and irresponsibly and improperly handling chemicals and contaminated water and poorly managing and protecting our water resources. Water used for fracturing fluids is acquired from surface water or groundwater in the local area. Billions of gallons of water will be used in each region for fracking. Wastewaters from the hydraulic fracturing process (flowback or water produced in the well) needs to be properly treated before it is returned to the waters of the earth. The reality is all water on earth has been here for 4.5 billion years and no new water is being created. The fate of the water that flows back after fracturing has to be addressed, but not all fracturing fluids injected into the geologic formation are recovered. The EPA estimates that the fluids recovered range from 15-80% of the volume injected depending on the site. The long term fate of any residual fluid has not been studied.

 There have been documented cases of seepage into drinking water wells through improperly sealed or abandoned drilling wells.  An ongoing monitoring and data collection program needs to be part of the permitting process. Potential impacts to our water supply from hydraulic fracking needs to be studied over time and regulations modified to better protect our water supplies and natural resources as fracking expands in the region. Our water resources are sacred and irreplaceable. The gas will be there when we know how to access it safely.  The least risky course might be to delay lifting the moratorium until the US EPA finishes its research in late 2014 and then slowly allow a limited number of wells that will include monitoring over decades of the groundwater resources in the area with all the data given to the USGS for analysis.  Any area in consideration for fracking should have several years of quarterly groundwater testing and analysis before fracking begins to establish a base line for groundwater study. Now would be a good time to start developing groundwater monitoring programs.    

After Your Well Goes Dry-What Can Be Done

In my corner of Northern Virginia there seem to be a slew of well failures lately-maybe more than usual or maybe it just seems that way. There was no snow melt this year and we flirted with drought all summer. Even if an aquifer is sound a well may fail. In a well, a diminished water supply is characterized by a short period of adequate water in the morning (or after resting the well for hours or days) and then almost a complete loss of water. Another typical symptom is loss of water after doing a load of laundry. (A top loading washing machine uses about 51 gallons of water and a front loader uses 27 gallons.) What is happening is overnight the well bore hole is filling with as much water as it can still produce and the pressure tank gets filled- a tenth of a gallon a minute will still be able to fill the pressure tank overnight and give you enough water for a bit of a wash up (depending on whether you have low flow toilets, sinks and showers). This low flow to the well can be caused by drop in water level in the well due to drought or over pumping of the aquifer, or the well could be failing due to a buildup of dirt, sediment and gravel reducing the flow to the well. There are times that the steel casing that lines the first 40-60 feet of a well does not extend deep enough and the well walls crumble over time filling the well with dirt and gravel. One or more of these factors could be the cause of a well problem.

The natural fluctuations of groundwater levels are most pronounced in shallow wells and wells that are failing, both tend to go dry in the fall of a drought year. Groundwater levels are usually highest in the early spring in response to winter snow melt 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 streams draws water from the groundwater aquifer to keep flowing. Natural groundwater levels usually reach their lowest point in late September or October when fall rains begin to recharge the groundwater again.Geology also impacts groundwater, fractured siltstone is very porous and filled with water while diabase stone has very low yielding wells.

Groundwater supply can change because groundwater systems are dynamic. The Piedmont where I live is bordered by the “fall zone” on the east and the Blue Ridge Mountains on the west. The Piedmont is the largest geological region in Virginia and has a diverse geology largely dominated by igneous and metamorphic rocks, with some areas of sedimentary rocks. The fractures and fault lines formed in the rocks store and transmit groundwater. The size and number of water bearing fractures decrease with depth so significant supplies of water are generally located in the first few hundred feet. There is a wide variation in groundwater quality and yield ranging from under 1 gallon per minute to over 50 gallons a minute depending on location and specific site geology. The largest yields are obtained where fracture and fault system are extensive. In other areas of the Piedmont there are carbonate rocks within the areas of Karst terrain with the most robust and easily contaminated wells and finally there are also area where disintegration of the granite bedrock forms a zone of granular material with slow recharge and relatively high and annoying amounts of iron and sulfur. To be productive a well must be located within a fracture or pass through them.

In the Valley and Ridge of Virginia the geology is characterized by unconsolidated overlay underlain also by fractured rock. Fractured rock systems tend to be water rich areas of Virginia, but not uniformly so. Fractures can run dry. In unconsolidated sediments of the coastal plain ground water is pulled from the saturated zone which is being overtaxed and may be significantly impacted by drought. In the Appalachian Plateau which is a flat layered rock system with horizontal fractures, the coal seams are typically the aquifer and groundwater is typically shallow. Coal country is the location of many shallower dug wells which tend to follow the weather and be noticeably drier every fall.

If your well has gone dry or is down to a dribble you have four basic options: do nothing and hope the well replenishes after the winter, drill a new well, hydrofracture the existing well, or re-drill the existing well down to a lower aquifer. What is the best solution is dependent on geology, the condition of the aquifers, whether there is another likely location for a well on your property, and your financial resources. In many parts of the Piedmont, with enough money you can fix a well. Many wells draw water from more than one aquifer- there is more than one water zone. If you look at the water well completion report that you can obtain from the County Department of Environmental Health, VA DEH, you will see more than one water zone. Recently, I have seen wells where the shallow water zone appears to be dry and the lower aquifer still has some water, but is not providing enough flow to support a household.

It is impossible to look at a well and know if the aquifer has failed or just the well. The best proxy is the U.S. Geological Survey, USGS, monitoring wells and other wells in the neighborhood. Checking with VA DEH, the USGS and neighbors and the HOA will give a better picture of the aquifer. Several wells in a particular neighborhood in Prince William County have failed, though it did not seem apparent to individual homeowners, the problem was with the shallow aquifer. According to the nearest U.S. Geological Survey monitoring wells the lower aquifer appeared to be fine, and there is a possibility that there is some flow left in the shallow aquifer (around 60 feet) foot aquifer even in the drought water levels have fallen only about 10-12 feet in the USGS monitoring well. The aquifer itself cannot be seen so intelligent speculation is the best that can be done.

In Prince William County, the aquifers are not over pumped, but wells can still fail. Over time debris and deposits can build up in a well and the small earthquake that occurred last fall could have increased the deposits then this year’s drought reduced the water quantity and suddenly the well has failed. Fall and winter rains might recharge the shallow aquifer and the problem could be a seasonal or drought related problem, but drought can go on for years and living with limited water for months or having the well bore dry out even more is not an good solution. Using hydrofracking to flush out the hole by might get enough flow back into the well now to function adequately to keep the well itself full of water. Every two feet of well can hold just under 12 gallons of water, so a well producing half a gallon a minute with 100 feet of well below the static water level can support a household.

Hydrofracturing, commonly referred to as hydrofracking, is a well development process that injects water under high pressure through the well into the bedrock formation. This process is intended to flush and remove fine particles and rock fragments from existing bedrock fractures and/or increase the size and extent of existing fractures, resulting in an increased flow of water, and a larger network of water bearing fractures supplying water to the well. The procedure is often used to increase well yields of new deep drilled wells with inadequate water production rates. It may also be used for older wells that have diminished water recovery rates over time, which is usually caused by the build up of minerals and fine particles in the rock fracture over time. It can be very successful in parts of the Piedmont and other bedrock rock formations, but the improvement may not last beyond a few weeks or months. In diabase hydrofracking may do nothing and in siltstone it is unpredictable what may happen to the fractured system. I could not find statistics on long term failure rates for hydrofracking (only the impressions and experience of the VA DEH and USGS), but hydrofracking could work at least for a period of time- whether that time is weeks, months or years can not be predicted. Hydrofracking a water well should cost $3,000-$4,000. It is a good first step in trying to restore a well with a viable aquifer, and that is structurally sound.

If restoring an existing well does not work or does not appear to be an option because of geology or the condition of the aquifer, then it will be necessary to drill a new well or re-drill the existing well to a lower aquifer. There are times on a small property with only an acre or two of land that there are no other likely locations for a new well or that the cost to pipe the water from a distant corner of the property makes using the existing well bore the best choice. With the right equipment, an existing well can be re-drilled to a lower aquifer. Not every well driller has the expertise and equipment to hydrofrack or re-drill wells, and locally based well drillers are familiar with the geology of a region. Well drilling equipment is expensive to move great distances- if your hire an out-of-town well driller, chances are they will subcontract the actual drilling anyway. Stay local when hiring well drillers. Get references, check insurance, and licenses. Since 1992 private drinking water well construction has been regulated in Virginia and well drillers have to be licensed. In many other places well drilling and water wells are still not regulated. Generally speaking, a new well or re-drilled well costs $12,000-$20,000 plus other costs for piping to the house, pumps and pressure tanks.

If a property has a low producing well in the neighborhood of 0.5 gallons, there are ways to deal with it. First is water conservation and the second is to increase water storage within the system. Water conservation involves changing water–use behavior such as taking shorter showers, but usually involves installing water saving devices like a front-loading washer (saves over 20 gallons of water for each load- about half), low flush toilets, flow restricting faucets and shower heads. Installing water saving appliances can reduce household water use by up to 30%. Water conservation may solve the problem of a 4 gallon a minute well, but increasing water storage can make a reliable 0.5 gallon a minute well viable for a modern household. An intermediate storage system can either be the well itself if deep enough or a storage tank, reservoir or cistern that can be installed between the well and pressurized distribution system. The reservoir or storage serves as the primary source of supply for the pressure pump supplying peak demand. Ideally, the storage tank or cistern should be able to hold at least a day’s water supply and be regulated by a float switch or water level sensor. A 0.5 gallon a minute well can pump 720 gallons per day more than adequate for a household. The rule of thumb is to size a storage tank or cistern at 100 gallons per person in the household. Every two feet of well below the static water level holds almost 3 gallons so that 120 feet of well below the static water level will hold about 175 gallons this may be adequate only if water use is spread out throughout the day.

Using Up the Ogallala- The Groundwater Footprint of the U.S.

The High Plains aquifer commonly known as the Ogallala aquifer (because the Ogallala formation makes up about three quarters of the aquifer) became news and burst into public awareness due to the protests associated with the Keystone XL Pipeline. The Keystone XL Pipeline has been very controversial. Most of the environmental controversy has focused on the porous soils of the Sandhills and fears of a possible oil leak into the Ogallala aquifer which is one of the nation's most important agricultural aquifers. Moving the pipeline away from the aquifer or piping the Canadian oil through British Columbia should mitigate concern for contamination to the Ogallala, but oil leaks are a minor problem. Really, the oil does not move quickly or spread easily through the sedimentary deposits of the High Plains aquifer. There is a much bigger threat to the Ogallala; the aquifer is being depleted because the groundwater within it is predominately non-renewable. This groundwater aquifer that spans and estimated 174,000 square miles is the primary source of water for the High Plains. This was open range land until the groundwater from the aquifer was used to turn the range land into irrigated crops. However, according to John Opie in “Ogallala: Water for a Dry Land” this is essentially fossil water that was generated 10,000-25,000 years ago by the melting of the glaciers of the Rockies.

Water level declines in the High Plains Aquifer since 1958 

The High Plains aquifer is the most intensively used aquifer in the United States and 97% of the water is used for irrigation. Groundwater withdrawals from the High Plains aquifer represent about 20% of all groundwater withdrawals within the United States and have turned the dry range land in the center of the country into the breadbasket of the world. There are only about 2.5 million people living within the High Plains aquifer. With the grains we grow and export we are exporting our water reserves and possibly the future of the region. The High Plains aquifer is being depleted (and contaminated) by irrigation. In the central and southern High Plains water levels have fallen from 50 to more than 150 feet primarily in parts of Kansas, Oklahoma, New Mexico and Texas.  

In  the past year Drs. Tom Gleeson, Yoshihide Wada, Marc F.P. Bierkens and Lodovicus P.H. van Beek each a distinguished voice in groundwater research have pulled together to try to popularize the concept of Groundwater Footprint in order to focus attention on the sustainability of groundwater use. While I think the “global groundwater footprint” is not particularly useful beyond seeing how important groundwater use is globally, their groundwater footprint concept may end up being a very powerful tool. Water is regional and while the authors of “Water Balance of Global Aquifers Revealed by Groundwater Footprint” point out that some groundwater consumption can be transferred to an adjacent aquifer (they use the Upper and Lower Ganges aquifers in India as their example) more often water use and recharge are a dictated by local conditions. An excess of water along the Amazon basin is not particularly useful to Saudi Arabia. However, the authors measurement of “groundwater footprint” is really a measure of groundwater sustainability. A groundwater footprint is a simplified tool to see the water balance between recharge and use of an aquifer and could be used to include groundwater sustainability in developing water, economic and agriculture policies using the virtual water and water footprint analysis. If the water use is not sustainable, then ultimately we are not sustainable.

Groundwater footprint, as the authors point out, could be used with the satellite-based Gravity Recovery and Climate Experiment (GRACE) and Global Land Data Assimilation System (GLDAS) to quantify groundwater depletion. Researchers at the University of California, Irvine, the University of Texas, and the Hydrological Sciences Branch at NASA GSFC have worked in partnership to apply GRACE and GLDAS to real world groundwater monitoring. As these tools develop, the groundwater footprint could end up being an intuitive management tool. The authors found that 80% of the world’s aquifers are not being depleted, but that of the 20% that are being depleted are being depleted at such a vast rate that the global average footprint is of unsustainable groundwater use. In the United States the High Plains and the Central Valley aquifers are being depleted. We as a nation need to examine our agricultural policies and incentives, even our energy policies (corn for ethanol is squandering 40% of the corn crop and the non-renewable water in it to dilute gasoline) and the way we value and price water to ensure that we will have food in the future.