Thursday, December 10, 2015

More Well Stories- VAMWON Notes from the Field

VAMWON Notes from the Field are the stories of the questions I’ve encountered as a volunteer with VAMWON. 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, but there are times all we can offer is a framework on how to gather information and think about your problem. You can find your VAMWON volunteer neighbor through this link by entering your county in the search box.

I regularly receive contacts from people and sometimes all we do is talk about wells. I collect data from all the contacts to increase my knowledge, get current prices of having a well drilled and hear about which well drillers people were satisfied with.  This is the story from Lloyd.

I live in Fort Valley VA, about an hour West of Haymarket.  I have had this home for about 3 years and recently ran into a problem with my well water turning very cloudy, almost muddy.  The well for the house is about 40 years old and from what I know from a neighbor is somewhere between 225 and 300 feet deep.  When it was drilled they rarely used much of a casing and apparently the pump and all tubing is original.   I had no problems with the water at all until recently. “

At this point I would like to interrupt his story with some observations. First this is a drilled well. Drilled wells are typically more than 100. In Virginia well drillers are required to file a drilling log with thecounty and comply with drilling regulations since 1992. If the well was drilled before 1992 you have to think that sooner rather than later you will have to replace not only the  well components, but also depending on your geology the well.  While many wells will last decades, it is reported that 20 years is the average age of well failure. Pumps, pressure tanks, switches and other equipment tend to last about 15 years or so. Mechanical equipment has a limited life and will fail sooner or later.  Well casings are subject to corrosion, pitting and perforation.

A second note is that just because your neighbor’s well is at 225-300 does not mean that your well is. My well is at 150 feet below grade and my nearest neighbors are at 250 and 175 feet below grade. On our county land the wells are drilled from 150 to 450 feet below grade. (Yes, I looked up the well completion report for every home in my surrounding 360 acres.) Back to Lloyd’s story.

In July I started construction of an addition to my house which required excavation.  The fill was placed on the side of a hill on our property, perhaps 50 feet from the well.  A few days later, we had 4” of rain in a very short period of time and our water was muddy for several days.  I chalked it up to infiltration from the water mixing with the fill and penetrating the water table by getting around the casing.  A few weeks ago we had a quick 2” rainfall and once again we had cloudy water (unsuitable for drinking) for a few days.  But I had the problem again this week and we had no rain.  I did do some power washing and the water went down a drain which drains who-knows-where but there really should not have been enough of this water to stir things up.  If it was infiltration it should clear up in a day or two, but I think this time could be different.

Prior to the construction I had my water tested to see if I would benefit from a water softener.  I was told my water was pretty good and there would be little benefit to adding a water conditioner.  Given the age of the well and equipment I realize it could be about anything, particularly the casing (or lack thereof) creating a problem.  I am a bit gun shy about calling a well driller in since obviously he will want to re-drill the well, replace all the equipment and the connection to the house which would involve pulling apart a very expensive patio which sits over the pipe (or hose) coming from the well.  It won’t matter if that is the real problem.  So do you have any recommendations for someone to call who might be a bit more impartial about diagnosing the problem?”

Dear Lloyd,
               You are right, given the age of the well and the complete lack of information on construction, geology and yield it could be anything. Not all well drillers will immediately suggest a new well if your well is functional (is not going dry or collapsing), but some will indeed. You are really going to have to get help on the ground where you are. I would suggest paying for a service call from more than one well driller after talking to the health department. What I can tell you is that your problem may be a geological one.

Massanutten Mountain in the Shenandoah Valley of Virginia is in the Valley and Ridge regional aquifer system. The Valley and Ridge regional aquifer systems are within the Valley and Ridge Physiographic Province. The carbonate rocks in the Valley and Ridge where you are have unique hydrogeologic features like karst topography, solution channels, and caves. Ground water in the carbonate rocks of the Valley and Ridge flows (1) in the regolith (alluvium, colluvium, and residuum); (2) along fractures, joints, and bedding plane partings in the bedrock; and (3) in solution channels and cavities (caves) formed by the dissolution of carbonate minerals.

It is possible that your problem is caused by a solution channel that has formed in the karst terrain. This could have been created by time, water flow or the weight of the excavating equipment and soil piled up on the ground. If this is the cause the filtration and potentially secondary treatment is the solution not a new well and the water might just begin to clear up on its own. However, your well casing could be collapsing from rust, you could be pumping Virginia clay to the surface or you could have a significant amount of surface infiltration from the dirt piled on the hill and being mobilized by all the rain.

Well production and a careful analysis of the water (not one of the free tests to see if the water is hard by test strips) can help you determine if your well is failing or has been impacted by the creation of a channel or cavity or if you have surface infiltration. Surface infiltration would be characterized by the presence of coliform bacteria. However, the creation of a solution channel in karst terrain could bring surface water into contact with the ground. A Ground penetrating sonar can identify voids (that is not always available in small towns it is used typically for commercial projects and re-development), but you need to figure out what is going on with your well.

Start with the health department in your county. Here in Prince William we have practiced solutions to many of our typical problems. Talk to the health department, talk to at least two well drillers, do a complete water analysis on your well. Samples should be analyzed for at least: iron, manganese, nitrate, lead, arsenic, fluoride, sulfate, pH, total dissolved solids, hardness, sodium, copper, total coliform bacteria and E. Coli bacteria. The bacteria could identify a surface infiltration, the pH an acidic condition that would over time impact the well casing, etc...It would also be helpful to test the yield on your well to make sure that your well is not going dry. Also, wells often have fine mesh filter socks that fit tightly over the slotted screen in a well and are designed to allow water to pass through while preventing fine sand and clay from entering the well screen. These days they are made of knitted polyester, which is more inert and resistant to degradation than nylon which was used in the past. Remember, if you pull the pump, you should replace it. No use paying to pull a pump from the ground and then putting an old piece of equipment back in.  Good luck and let me know how you do,

“Thank you so much for that detailed response.  I suspect your solution channel explanation caused by the full is very likely. The water is slowly clearing up.“

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