Pond Boss Forums POND CONSTRUCTION Building a dam Pipe problems!

We rebuilt our old dam, removed trees/roots, new core, etc. Installed two new 80 foot, 18" PVC pipes with two seep collars each with approx. 22˚ angle through the dam. The pond filled in May, and low and behold, the contractor installed the pipes 8” too high! It is especially frustrating since I made special effort to have a 3-4’ edge depth and lined it with 100 tons of limestone rock!
The contractor’s solution was to cut the lowest pipe to a more acute angle to lower the water level. This brought down the static level about 4 inches. But, now the soil is beginning to erode around the pipe and we still need to lower it 4 more inches. I am considering cutting the pipe again and installing concrete around the pipe to curtail the erosion. Any recommendations or other solutions would be greatly appreciated.
Mark
PS-Does anyone have suggestions to build fish screens around the pipes?

I used about 20 feet of 4 ft. high plastic screening, very similar to snow fence. I got mine from Stoney Creek Equipment Co. in MI Stoney Creek
who have it in 1/2" and 3/4" mesh sizes. I think also gets used for a lot of fish cages.

I put 4 steel "T" posts around our drain box (one at each side a little above the water line, two under water in the middle) and tied the screening to it with insulated copper wire remnants. Sometimes vegeation clogs the screen at the water line, but it just flows through underneath. If the level of the pond rises enough from heavy rain/clogged screen, the water will flow around the ends of the screen. I might lose some fish then, but am willing to risk it under what would amount to emergency overflow conditions.

OK. I'm trying to visualize this. Here is what I understand:

your pipe is at about a 22 degree angle through the dam, and

you need to reduce the pipe height more, and

dirt in the dam is eroding around the pipe - presumably due to the pipe end's proximaty to the dam.

Can you cut the pipe down however much more you need, then put a 22 1/2 degree PVC elbow in it, with an extension to take it further out in the water so dirt won't erode from around it as bad?

If so, it may be possible to run that extension out a ways, plug the end with a flat piece, and then use a drill to cut lots of holes in the section extending out into the water. Depends upon length of the section and the number / size of holes you cut, but you'd restrict the size fish going through at the cost of reducing your outflow rates some. I guess your higher pipe would be the first backup if it were too much restriction... I don't know. Just thoughts.

That's an interesting idea, leave one pipe high and open full bore as the first emergency overflow.

Why not put a 90 deg. elbow on it & extend into deeper water? Then you won't be loosing your most productive water & also won't have to worry about loosing fish.

You mean go ahead and make a legitimate siphon system out of it? Good question... Probably a great idea! Does it freeze in Kansas?

http://www.easywayplastics.com/page/page/1478349.htm

Thanks for the idea of an elbow/extension. If I understand correctly, both of you are saying for me to create a siphoning system. Am I correct in thinking that for a siphoning system to work, the bottom edge of the pipe going through the dam needs to be at my desired water level? If the opening into the new extension pipe is lower than the desired water level, wouldn’t I also need some type of vent or hole at the desired water level? Is there a specific angle of extension elbow necessary and will the approximate 22˚ angle of my existing pipe going through the dam affect the siphoning system? I am concerned about trash build up and it does freeze and thaw frequently in Kansas. I will call PDP to see if they have fittings that would create an airtight seal on my 18” schedule 35 PVC pipe. Does anyone know of another supplier who may carry these fittings?
Mark

bulsprig:

I don’t have a siphon yet so I am not the best one to advise you. The reason I don’t have a siphon is two fold. I haven’t received all the PVC pipe I ordered yet and I haven’t figured out / heard about a good way around the freeze issue.

I think you are correct in thinking that for a siphoning system to work, the bottom edge of the pipe going through the dam needs to be at the desired water level.

I think you are also correct that you also need some type of vent or hole at the desired water level if the opening into the new extension pipe is lower than the desired water level.

I don’t think there a specific angle of extension elbow necessary and your 22˚ angle of my existing pipe going through the dam should not affect the siphoning system. I think the keys are the intake and output level heights.

I don’t think you would have a problem with trash build up.

As stated above, I don’t know a good answer related to the freeze issue.

Jeff