Pond Boss Forums GENERAL QUESTIONS Help HELP PLEASE! - TICKING TIME BOMB? need ideas ASAP

Hello all,


After subscribing for couple years and reading perfect pond(s), in fall of '13 I hired the contractor, etc, etc.

He, against my better judgement, installed a horizontal 15" corrugated drain pipe through the top of the dam and covered it with 6-8" of dirt for my 1.4 acre pond fed by approx 35 acres of runoff.

This past winter/spring of '15 it failed miserably, both my ponds failed actually, on the same day (during the first thaw). The ice had lifted the pipes, water ran underneath and washed out the dam(s).


Fast forward to today, one pond still sits washed out and 4' low. The other was repaired by using a 2x2 concrete catch basin. The top of box was set at water level and one of the side panels of the box was knocked out and roughly 32' of 15" corrugated pipe was cemented into the box to allow water to flow out the bottom of the back side of the dam.

We poured about 1-2 yards of concrete around the 2x2 box where the 15" pipe enters the box and approximately 10' from the box, at the junction of the 12' corrugated pipe and the 20' corrugated pipe, poured a anti-seep collar with approx 2-3 yards of concrete.

NOW...

The lake is filling FAST, and the bottom of that box should be dry, but it is not. There is water seeping in around the area where the 15" pipe is cemented into the 2x2 basin. About maybe a pint or two per minute, for now.

IS THIS A DISASTER WAITING TO HAPPEN?'

Contractor said don't worry (obviously). My thoughts are that it is only a matter of time before the small seep turns into a trickle, turns into a flow, turns into a complete washout and destruction of the pond again.

I have tried hydraulic cement, it worked on the right corner of the box (as you will see in the photo), but the left side began seeping more once i sealed the right side and I was unable to stop the water with the hydraulic cement.

The pond is filling fast, a friend suggested digging it up and putting bentonite around the outside of the box/pipe to seal it up but I'm not sure that is even possible with as wet as the dam is and how fast the pond is rising, soon water will be flowing in from the top of the box because the pond will be full.

Any ideas???

If I'm understanding this correctly, the concrete boxes serve as the drop inlet that loads your drainpipe which goes through the dam. And the water is entering the system on the water side of the dam and exiting through the pipe at the backside of the dam? If that's the case and the leak is where the pipe/box connection was not adequately sealed, I don't think the leak will increase over time. It would have to be eroding concrete or hydraulic cement for the flow to increase.

If this is the situation, the big question then is, does the leak in your system exceed the inflow into your pond (stream, spring, runoff, etc.)? If it exceeds your inflow, the pond will never fill. If not, then I don't think you have a problem.

Vamaz,

You are correct in your understanding!

The concrete box in the picture is the drop inlet and it is leaking at the connection of the drop inlet and outlet pipe that exits backside of dam.

I agree on the flow issue but my inflow from runoff is measure by gallons or tens of gallons per minute and the leak (at least for now) is maybe half a gallon per minute.

My fear is not that the water will erode the cement at the poor connection, but that FREEZE will cause whatever water is leaking to expand the gap that it has found already and the tiny leak becomes a giant leak.

Maybe I am paranoid because ice recently caused me to lose half of the pond at last failure.

Do you think ice could expand that leak?

Or... do you think that ice could cause pressure on that plastic pipe in such a way that it compresses or deforms enough to let even more water run around it?

Maybe I can pour a concrete "hood" over the top of and down along the sides of that exposed pipe?

Here is another view for clarification.

Oh, yeah, the base of the drop-inlet is in the dam, of course. I wouldn't underestimate the power of freeze-thaw-freeze cycles even on concrete. And that water is moving through part of the dam to get to your pipe, so you can bet there will be some erosion there.

I'm pretty sure I'd be draining down that water level so I could get that thing patched for good. And hydraulic cement is good stuff - won't shrink when it dries. I apologize I don't have time to do it right now, but if you do some searching on this site you'll find discussions on using trash pumps or temporary siphon systems to lower water levels.