Pond drain/breach question

[scesnick]

I have posted previously about cleaning out my 3/4 acre pond. it is full of silt. I have thought of many ways to do this but after closer inspection it looks like Im gonna have to get an excavator in and do it the ol fashioned way.
A creek runs beside my pond and about 15 ft lower. The two drains are more like run off pipes. They don't actually drain the pond, they just keep the pond at one depth. These are now leaking by pretty good and or clogged up.

So, the drains need to come out and replaced. and since they are coming out I figured I would just keep digging and breach the pond wall where the drain was to actually drain the pond so i can clean it out. and install a real drain, much lower so i can actually drain the pond if need be and also have a overflow drain as well.

My question is this. How do I go about re-installing the drains or more importantly "Un- Breaching" the pond wall so it doesnt leak? I have heard that the clay would need tamped which makes sense but I have also heard a 'key' should be installed about 30ft long halfway in the pond wall and perpendicular to the drainage ditch. Along with a few anti seep collars. Any other suggestions?

Here is a google map pic of my pond. the drains are at about one o'clock and three o'clock. You can see the pond wall is narrow on that side of the pond. About 30 ft wide or so. Then the pond wall drops off into the creek.

Frostburg, Allegany, Maryland - Google Maps

 

[MarkV]

Stop over at the pondboss forum. A good deal of information there. Pond Boss Magazine: Welcome

MarkV

 

[Fossil Farm]

Site conditions have a big part to play in what can and cannot be
done. You might want to see if the county soil and water conservation
district will take a look at it.
In a new pond construction site, a core trench is installed to cut off seep
water moving underneath the dam. That may be pretty difficult to do
since it is an existing pond without a total rework of the pond. If you
were the one that originally had the pond built, then you would know if
a core trench was originally installed. Anti-seep collars are needed and
there are formulas to figure out how big they have to be based on pipe
size, pipe length, etc. It requires a bit of hand work to tamp clay around
them. A separate pond drain line can be installed if that is needed.
Being right next to a stream makes some of the work a bit more difficult.
Good luck.

 

[charlz]

Maybe using a siphon to drain it/most of it verus a breech? I would hate to breech a perfectly good dam/wall.

Conventional Pond Piping System

 

[scesnick]

Maybe using a siphon to drain it/most of it verus a breech? I would hate to breech a perfectly good dam/wall.

Conventional Pond Piping System

that was my thought too but the two drains that are in there are leaking by. They are concrete and are cracked.

 

[charlz]

that was my thought too but the two drains that are in there are leaking by. They are concrete and are cracked.

Right, my thought was maybe you could use a siphon instead of continuing to dig past the level of the removed drains to drain the pond. This way you keep a lot of the existing integrity of the dam.

 

[scesnick]

Right, my thought was maybe you could use a siphon instead of continuing to dig past the level of the removed drains to drain the pond. This way you keep a lot of the existing integrity of the dam.

I thought about that but i still need to install a new drain that would be capable of of draining the pond in the future if need be.