Fresh water spring at cabin

 

I guess I took the spring for granted in the plans we have been developing for the innovative water recycling system proposed for the cabin. I was taken quite aback when I first noticed no flow from the overflow of the water storage tank. I didn’t really understand the spring system, and was going to explore the tank and spring when my excavation contractor arrived (supposedly, this week); but the situation required some immediate action. We were told by the previous contractor that he thought a 500gallon tank was installed in 2003. I knew that considerably less than 500 gallons were left; because I had been using lots of water to wash-down a bunch of furniture and the garage floor. We might be on the verge of having no water at the cabin. I had to take action quickly.

 

I know a little about springs, because my family had one when I was a child. I personally maintained it for a number of years. There were three basic components to this water system that could be problematic. The spring could have moved. Springs sometime find new channels, or can disappear. I noticed many small channels of spring water emerging from several areas around the area I assumed the spring to be. It looked like the spring was still there, and had plenty of flow. There had to be a problem with one of the other two components, the spring dam or the pipe carrying the water from the dam to the tank (approximately 20’ apart). I couldn’t wait for my contractor’s backhoe; I had to excavate by-hand to identify and solve the problem, ASAP.

 

Further investigation located one particularly strong flow of the spring water infiltrating into a ditch running between the road and the water system. I surmised that if I followed that flow, it would lead to the spring source. I excavated for several hours and found the old spring dam and pipe running to the tank. The dam was clearly no longer serviceable. It had been hastily constructed with local materials.  The clays from the surrounding hillside, which were used to pack the breast of the dam, had eroded away leaving the flow was several inches below the pipe. A whole new dam had to be constructed.

 

Our contractor suggested I contact the Armstrong County Conservation District for advice. Dave Rupert at the District was extremely helpful. He had consulted with many farmers who had spring dams, and was intimately familiar with our spring. He, ironically, was on the Board of Directors of The Armstrong County Conservancy when it sold the property to the previous owner, Joe Ackland, approximately 8 years earlier. He suggested that I might face some challenges. He pointed out that the spring was very low relative to the road, making it difficult to make a very deep dam (only a few inches); and that the flow was likely very broad through the roots of an ancient tulip poplar. We talked about using bentonite (aluminum silicate clay) liberally and layers of plastic to facilitate the damming process and to ensure a longer term fix.

 

My first task was to continue to dig-up the old spring to find the highest and strongest source of water possible. As I slowly undermined beneath the root outcroppings of the giant tulip popular, I found the situation was pretty much as Dave had described. The water flow was low and coming from a broad area at the base of this ancient tree, hidden under massive root outcroppings. Clearly, I couldn’t dig much further, and it probably wouldn’t do much good anyway. Furthermore, if I did anything major, I might injure the tree, or worse yet, lose the spring, altogether. It was important that I use the existing fill-pipe in the old dam, because otherwise adjustments would have to be made to the 500 gallon tank about 20 feet away – quite an undertaking, requiring heavy equipment. I wanted to make the existing feed-pipe and tank work, if I was to solve the problem quickly. I decided that no more excavation was prudent, and that rebuilding the old dam with better methods (the old dam did not use betonite or plastic) was the best option.

 

After excavating as far under the roots as possible, I clearly identified the main streams of flow, placed bentonite strategically at the perimeters to narrow the flow into the dam. After several days of trial and error, I realized that capturing 100% of the flow into the spring dam would be very difficult, if not impossible. I eventually surmised that I should be happy with capturing 80% to 90% of the flow for the cabin’s water system. Furthermore, I found that the other 10% to 20% flowed directly under the dam. I was able to simply capture this by creating another small dam with bentonite around the mouth of a 4” pipe and carry it to the culvert area about 20 feet away (I call this the underflow pipe. Note that I capture this water later, if we need it).

 

The breast of the dam is approximately three inches deep and has an outside perimeter about 5’ by 3’. It is constructed with sand, bricks, plastic lumber and clay with a smoothed bottom and sides that creates a pool that completely surrounds the 4” (3600 PSI PVC, perforated) intake pipe that goes to the holding tank. Once the tank fills, the overflow into the ditch matches the flow into the tank.

 

One of the most difficult things to deal with is that the water is constantly running, and it’s cold. With the water constantly running, it seems to go everywhere. It’s hard to be sure you have all avenues of escape covered. You take your chance, and then observe. If there are leaks, you have to go back and redo areas with bentonite or other materials to create a tight seal. Patience is important; even though standing in 50-degree water.

 

Once I was satisfied that the pool bottom and breast were uniform and had effectively encapsulated the whole pipe (sealing around the pipe seemed particularly tenuous, and I tried to use extra bentonite), I covered the bottom of the dam with 4 layers of 8 mil black plastic that lapped over the breast. I then covered the black plastic with a layer of 50 mil butylene rubber roofing material (the butylene acts as a puncture-resisting layer, which added safety as I then filled the dam with sandstone from the area and topped with a mound of river gravel. The edges were heavily sealed with bentonite to prevent movement and provide double safety against leakage. I then covered the mound with a layer of 50 mil PVC landfill cover, which was carefully cut to conform to the hole. This layer of landfill plastic is sloped toward the overflow of the dam (where the under flow pipe is located), and is designed to minimize the flow of surface water into the spring dam. I then covered it with another layer of river gravel – looks like a big turtle. I will now cover a larger area with landfill cover, add a layer of topsoil and mulch the area (maybe put a picnic table on it to ensure no heavy traffic, because it’s next to the road – I was told there use to be a pull-off area where people could get the water)

 

I observed and measured the flow through the tank and from the under flow pipe for about a week, and found that the system was performing consistently. The overflow from the tank dumps into the ditch next to the road, making it is easy to observe water flows or to collect the water samples necessary to test water quality or to measure the quantity of flow. I similarly placed the underflow pipe at a height in the culvert area to facilitate observation and sample collection. I took my first rough measurements on 7/16/08 (using a small beach bucket to collect the water, my stopwatch as a timer and an empty 16 ounce water bottle as a measure). When I took the sample, we were in the midst of a two-week dry spell, but it’s been a fairly rainy spring – I’d say an average year. The flow rates on 7/16/08 were: tank overflow 2 gallons per minute; dam under flow 1 quart per minute. Considering everything, I thought these flow rates indicate that the spring was still strong and consistent. I took another set of readings on 7/19/08 after three more days of no rain and the readings in both pipes were virtually unchanged, using my crude measurement methods.

 

After seeing that the dam seems to be operating as it should, I feel confident in covering the dam area and protecting it from damaging or inappropriate activity.