Monday, November 30, 2015

Well Problems Lead to Destroying a Well- VAMWON Notes from the Fieldg

VAMWON Notes from the Field are the stories of the questions I’ve encountered as a volunteer with VAMWON that might be helpful to you. The Virginia Master Well Owner Network (VAMWON) is an organization of trained volunteers and extension agents dedicated to promoting the proper construction, maintenance, and management of private water systems (wells, springs, and cisterns) in Virginia. The Cooperative Extension Services in Virginia manages the program and have numerous publications and fact sheets that can help homeowners make educated decisions about their drinking water. The VAMWON volunteer or Agent can help you identify problems with the water system and provide information on suggested treatments options and other solutions. You can find your VAMWON volunteer neighbor through this link by entering your county in the search box.

I received a homeowner inquiry recently from someone in Loudoun County who found me from my blog, Green Risks, while search for information on wells and groundwater. Two days earlier their well had gone dry. The homeowner had moved into their newly built home in Lovettsville, VA in the fall of 2014. By the fall of 2015 they would lose all water pressure after using the water, especially at night. After this had happened several times, they called a license Well Driller I was not familiar with to come out and check it. They choose the company that had drilled the well and filled the well completion report back in 2006. Despite the well being drilled in 2006, the house was not built until 2014 and during the past couple of years during which time  80 homes were built as a clustered development.

The information on private wells performance and location can be obtained from the water well completion report on file with the department of health. Be aware though, that private well construction was not regulated in Virginia until 1992 and is still not regulated in many places. The “stabilized yield” is the recharge rate at the time of installation. However, groundwater can change over time and it is commonly reported that the recharge rate falls over time from the initial recharge rate. According to the well completion report from 2006 the well stabilized yield was 5 gallons per minute, The well was drilled to 300 feet below grade and the pump placed at 275 feet below grade. Five gallons a minute is not a robust well, but an almost 300 foot deep well would serve as good storage. Each foot of a typical 6 inch well can provide 1.46 gallons of water storage (7.45 gallons of water per cubic foot).

The home owner was told by the Well Driller that her well ran dry because of all the drilling in the surrounding area. That is very possible. The home is located in in a clustered community of 80 recently built homes, all build on an acre or more. The homes are clustered together and a lot of open space is beyond the homes. The Well Driller told the home owner that sediment had filled up the fissures in the bedrock and they recommended hydro-fracking.

I began to write her a response, but felt, finally, that it would be more effective to call her. We talked about her situation. Essentially, the symptom she described of losing water after using it for a little bit is a classic symptom of a well with a diminished water supply- the well was going dry. In the well, 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 due to mineralization or sediment filling up the fissures and cracks in the bedrock as the Well Driller had thought. It is difficult to tell the underlying cause without checking the condition of all the nearby wells. Groundwater systems are both invisible and dynamic and can be impacted by many things.

Modern wells are drilled past the water table to draw water from water bearing fractures in the bedrock. The groundwater that feeds the wells exists in water–filled and interconnected fractures, pores and cavities in the rock. The size and density of the pores and fractures vary with rock type, depth and location.  In most cases when a well pumps, a cone of depression develops in the water table around the well as the water is pumped out of the well. When many wells are operated in a limited area the cone of depression in one well may affect the water level in another or they can simply pump water out of the aquifer faster than it is recharging. Eighty homes in the development might pump 32,000 gallons a day within the 80 acres of the clustered portion of the development.

In addition, a significant portion of the clustered areas is covered with buildings, patios, walks, driveways, roads and other impervious surfaces that will changed the hydrology of the site reducing ground water recharge in the immediate area around the homes at the same time increasing the demand for water. With reduced groundwater recharge in the immediate area, there is a real possibility that the pumping from all the homes could overdraw the aquifer and dry out several homes over time, beginning with the least robust and shallowest wells.

Because there are natural fluctuations in groundwater levels it is easy to mask or ignore signs of the beginnings of destruction of the water resources that we depend on. Fluctuations in climate or rainfall and imperfect measurements and vantage points mask trends from clear view. While groundwater is a renewable resource it is NOT unlimited. The sad truth is that we do not know how much water we have available in the Culpeper Basin that servers the region, nor do we know what the sustainable rate of ground water use is. The USGS tells us that our groundwater basin is under stress. Sustainability of groundwater is hyper-local and adequacy of water resources would vary from neighborhood to neighborhood..

The homeowner decided to take the Well Driller’s advice and hydro-frack the well. The cost of hydro-fracking a well is around $4,000 and the cost of a new well varies by depth and other factors. Around here it is usually $10,000 to $20,000 for a single family home. Home owners insurance never covers well failure either by equipment or groundwater drying up.

 Hydro-fracking usually involves the installation of an inflatable or mechanical packer that is placed in the well bore at least 40 feet below the well casing and drive shoe seal, and at least 60 feet below the ground surface to ensure that the process does not "break" the seal or allow surface water contaminants to enter the well. Fist the well pump is pulled from the well, then the packer is inflated or locked into position and water is pumped through the packer under pressure. Most applications require between 500 and 2,000 pounds per square inch (psi) pressure and in some cases 3,000 psi pressure may be needed in tight rock Formations, the artistry comes into play in knowing the formations and the amount of pressure needed. This could flush particles and rock fragments from existing bedrock fractures or bust open more fractures, resulting in an increased flow of water, and a larger network of water bearing fractures supplying water to the well. This technique has been very successful in bedrock formations. In the wrong geology it could collapse the well.

Unfortunately, things went from bad to worse. When the well driller went to pull the pump, they used a pickup truck with a winch. This essentially pulled the pump at a slight angle and the pump hooked the casing and dislodged it, destroying the well.  The pump should have been pulled from directly above to smoothly remove it. Pulling a pump requires more skill than dropping one in. The well Driller was careless in pulling the pump and pulled out the casing destroying a well that could have potentially been salvaged. After all, the Well Driller had suggested fracking the well to restore flow, which would indicate at the time they believed that the well could be salvaged.

The training and knowledge that well drillers have are limited and based primarily on experience.Experience can be a good teacher, but is often not a consistent one. There are few other sources of information and help. Hydro/ geological engineering and groundwater consulting  are really geared to industrial work and community supply wells where the costs of modeling the ground water flow, geological studies, obtaining data can be recovered, but even then it is experience and an engineering degree.  I recommended the homeowner give a local consultant (and neighbor) a call and contacting a lawyer and going after the Well Drillers errors in pulling the pump. At last report they were working with Loudoun County to identify a location for a new well while exploring recourse against the builder and well driller. .

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