I've written down the story of building our pond as a "thank you" to the Pond Boss folks who have been willing to share their experiences and wisdom. I've used the Pond Boss forum as a primary research tool during our project, and since I know you guys like pictures I've tried to include several below. I organized our story by construction topic so the pictures aren't necessarily chronological but fit with the topic. Hopefully this outline will be useful to others about to head down this road....The Building of Treehouse PondOur pond journey started in November of 2006 when we closed on our new property. There were no existing buildings so our first project was to see if there was a good pond site. We decided buildings can be built where needed, but ponds are more dependent on the lay of the land. If we were going to have a pond we wanted to site it first. The property is about an hour from our current home so the pond building project would be done "remotely".
In December we talked to the NRCS and got some good information and a confirmation that our soil was good for a pond. The lady from the local office was helpful, but when she brought in the soil specialist from the state office his tone was more bureaucratic. We stopped short of getting their help in design because they wanted to involve more government oversight (like the Army Corps of Engineers) than we thought necessary or advisable. We decided to just look for a good local pond builder.
Choosing a BuilderWe spent some time trying to get recommendations on local pond builders. One name, Tad, came up multiple times and we met with him in January. He had built over 50 ponds and seemed to be easy to work with. We talked to another pond builder but had already made up our minds to hire Tad. His reputation was that he was a good pond builder and that he was honest, and we found him to be both. He has other ventures besides pond building, but you can tell he loves moving dirt and building ponds and he takes pride in his work.
Choosing a SiteWe looked at a couple of different pond sites but agreed that the best site was in a draw on the lower west side of the property. This draw was overgrown with holly and not much use for farming or anything else, but a spring comes out of the hillside on the east end of the draw (upper end) and there are hills all around. We believe there are multiple good house sites on the surrounding ridge. The west end of the draw narrowed between two hills and gave us a good dam site.
Approximate pond location
The NRCS had estimated that we had a 7 acre watershed for the site. They also had tested the soil in the site to make sure it would hold water. The soil specialist said that the closest source for good clay for the dam core was on top of the surrounding ridge to the north of the site.
Dam DesignTad gave us two different estimates on dam height. The lower price was for a 2 acre lake with a 15 foot dam and 12 foot water level at dam. The higher price was a 23 foot dam with slightly less than a 20 foot water level that would give us approximately 2.5 acres. Tad thought the lower height was a better value, but left the decision to us. We wanted a 3 to 1 slope on the water side and a 4 to 1 slope on the back side for mowing. The top would be 12 feet wide so we could drive across it. The clay for the core would be hauled from the borrow site on the adjoining hill top.
We had asked Tad to bulldoze a road and shop site area for us on the south ridge above the pond site. When doing this he asked his operator, Harold, to clear some of the pond site at the lower water height so we could get a better perspective. This was done in late February, 2007, and was very helpful in letting us envision what the pond might look like.
There were three major reasons we decided to go with the higher (water and price) dam:
- The south side of the pond site had a fairly large flat area. From our estimates this would give us a wide portion of the pond at the higher level, but at the lower level would either not be under water or be very shallow water.
- The upper (east) end of the site was a tangled jungle of roots, scrub trees, and other nasty stuff. This would not be a good shoreline and would be better to dig out and cover with water.
- We had been told that we would regret not having the pond as big as possible.
So we told Tad we wanted the higher dam. We discussed some topics I'd learned from reading books/articles and from the Pond Boss site, and I was comfortable that Tad would build us a good pond and work with us on whatever we wanted done.
Getting StartedWe talked about starting the end of March - Tad said that January and February were usually wet for dirt work. However, 2007 was a drought year. It had rained on us the day we met Tad at the property on January 5th, and it didn't really rain again until the summer. Tad was tied up on other projects and didn't get back to our property until the week of the Fourth of July.
The delay was disappointing, but in hindsight it wouldn't have mattered when he started since it was going to take rain to fill it up. During the time we were waiting on Tad we built our
treehouse and worked on our shop. The treehouse took much longer than we thought (because we were working 16+ feet off the ground) so if the pond had gone in quickly we wouldn't have been able to finish it. The treehouse gives our pond a unique feature so we're glad we have it.
Treehouse
On July 7th Tad was ready to work again, but it rained!! He finally got started on July 14th. Tad and his helper cleared and burned for a few hours, then it rained again. During the next week they got most of the trees knocked down and had two large burn piles going for days. We had decided to leave the shore line natural on most of the edge with the trees up to the edge of the water. They cleared and cut the edges so that we won't have much shallow water for weeds.
Dam site after preliminary clearing
From dam site looking toward future pond
Coring the DamOn July 20th Tad cored the dam. We took the family and spent the day watching.
Starting the core trench
Earlier Tad had built a temporary dam to stop the spring from running through the dam area. Tad dug the core about 12 feet wide with his trackhoe. On the sloping sides the core was about 4 foot deep. At the bottom of the core (in the spring channel) he dug down nearly eight feet before he was satisfied that he was on solid dry footing. He dug through different layers of soil, clay, and gravel and I asked him how he knew when he was down far enough. He took us down into the core trench, broke into a seam of dirt at a higher level, and showed us where the spring water was slowly seeping through. I could see what he was telling us, but I was very glad we had hired an expert instead of trying to do it ourselves.
Helpers
Examining the core
Tad showed us where the water would come through if he didn't dig the core deeper
As Tad finished coring a section his workers were moving clay down from the borrow area and spreading thin layers into the core. I asked about compacting the clay and he explained that he typically just used the dozer for the core and spread the layers thin. Above the core he drove his belly scraper pan on the dam material, and when we saw how much weight the pan put on the clay we were convinced. It took most of the day to cut the core and fill the core with good clay. They then opened the temporary dam and let the spring run back across the core until they were ready to put in the pipe.
Filling the core
Looking up the pond site across the core
A Sobering DelayWe didn't hear from Tad for awhile so I called to check with him. I talked to his wife and found out that Tad had suffered a near fatal accident on another job site. While setting some flags on a hill side his 1 ton truck apparently shifted out of gear and rolled down the steep hill toward Tad. His back was to the truck and he didn't hear it because of heavy equipment noise. He felt it hit his leg and thought it was a sheepsfoot roller that was working nearby. He says all he could think of was that the second roller was coming. The truck hit him a glancing blow, breaking his leg/ankle and knocking him out with a concussion. It rolled on down the hill mowing down smaller trees until it hit a large hickory. It was going so fast it bent the entire frame and totaled the truck.
We are very grateful that God spared Tad. He was laid up for a few weeks but is blessed to still be alive. August was spent waiting on Tad to get back on his feet.
DrainpipeWhen Tad got back on his feet (hobbling) they were ready to put in the drainpipe. The drainpipe is approximately 140 feet of 8-inch PVC. It has a gate valve with a pipe handle that we can pull from the surface if we want to drain the pond. We don't plan to pull it unless we need to drain the entire pond - mud and silt would likely keep us from pushing it closed until the pond was empty. If the pond eventually filled with silt/leaves we might not be able to drain via the valve, but in that case we would just try to siphon the water out.
For maintenance (ability to lower the water level) we planned a second drainpipe. This is described later.
Tad and his workers made another temporary dam in the spring channel to allow them to lay the pipe. They laid and glued the pipe sections including the T joint for the 10 inch standpipe. The standpipe is several feet back from the valve so that it is firmly embedded in the front side of the dam.
Gluing the pipe together
They built and installed two seep collars from plywood. We caulked the collar/pipe seams. I asked about whether the wood would rot and Tad explained that packed tightly in the clay without oxygen it will not rot. He said he had tried the PVC collars, but that they were too easy to crack as you covered them and he had stopped using them unless the pond owner insisted. He said that he would use something else if I wanted him to, but that if it was his pond he would do it with the wooden collars. So that's what we went with.
After gluing and setting the pipe they carefully covered and packed the core with clay and started hauling clay for the dam.
Putting in the pipe
Hauling Clay and Moving DirtFor the most part the building of the dam was a long repetitive series of trips to the borrow area with the pan to load with clay (with the help of the big dozer) and return to dump it, in conjunction with spreading the clay in thin layers with the small dozer. I forget how many loads Tad said he hauled but he estimated 4 to 5 thousand yards of clay.
Pan and dozer spreading clay
As part of the hauling they had to clear the borrow area. This had been a brush-covered flat area at the top of a ridge. They first removed the trees and brush with the big dozer and put it in burn piles. Then they pushed the top soil up in piles for spreading later. They exposed a layer of underlying clay that was apparently pretty good material for a dam. By the time they were through cutting clay from this area we had a field larger than a football field. They estimated that they removed 6 feet from the hill top over the entire area.
Examining the new "field" in the borrow area
Loading the pan in the borrow area
Those pans are big :-)
Clearing the trees and brush from the pond area took a while, and the burn piles were going for days. We wanted to keep the site looking natural so we didn't do any big rearrangement of the dirt in the bottom. Tad and crew cleaned up everything well while leaving the tree house intact and working around the spring channel.
More clearing
Main SpillwayThe spillway pipe is 10-inch PVC. The drainpipe is 8 inch through the dam. The valve is a PVC gate valve. I don't have a picture of the valve because Tad installed and closed the valve right before a rain and when we got there next time the valve was under water. There is a PVC pipe with a handle attached to the valve and supported by a post. If we need to drain the pond completely we should be able to pull this handle from a boat.
Picture before pipe was cut off and valve installed
The drain empties into the existing spring channel that drains into our creek.
There will be a trash rack on top of the spillway. This wasn't available when the valve was closed and will now have to be installed from a boat since the water surrounds the pipe.
Secondary DrainWe had Tad install a secondary drain through the dam approximately 4 feet below the projected surface water level. This is 4" PVC. We had three ideas in mind for this drain:
- We intend to use this for irrigation of some garden area below the dam.
- We can use this to lower the pond level up to 4 feet for maintenance, weed control, or construction around the pond.
- Depending on the amount of normal overflow we may later experiment with hydro power generation.
We were there when they installed the pipe. They set it carefully using the transit to check level. They installed one plywood seep collar similar to the ones for the main drainpipe - this pipe will have less pressure than the bottom. Then they covered it carefully with clay and continued building the dam.
Looking through the secondary drain pipe
We used a drain "cage" as a trash rack for the underwater pond end of the pipe. On the outlet side we have a main butterfly valve and then a 4" main drain with a 2" 'Y' off the side. The 2" line will be reduced down to a normal hose bib for irrigation. The main pipe is capped with a screw plug. If we wanted to lower the pond we anticipate that we would close the valve, remove the plug, screw in a coupling, attach a piece of corrugated black drain pipe from the coupling down to the spring channel below, then open the valve.
Butterfly valve for secondary drain
Valve with attached fittings
