Water under pond.

[JanaLise]

First, I apologize if this has been addressed before! I’ve been skimming through and searching, and there are many helpful posts on runoff, but they don’t pertain 100% to my situation.

long story short: switched out hard shell for plastic pond liner due to leaks (plan on patching and starting as Pond #2 soon). Had liner all set up, anchored with rocks... fish were happy... and we’ve gotten TORRENTIAL rain here. There IS some runoff which caused the pond liner to slip and it all became a muddy mess. As you can see, the back of the pond still needs to be graded properly and I can figure out how

divert water accordingly.

My issue lies with the water that rises UNDERNEATH the pond. We sit fairly low, and already have issues with water rising (thus the raised Walkway). Any tips on how to keep water from accumulating under the pond? The picture below is sans liner. That is literally all the water that has risen up. The pump is in there because we had to try to drain some out to find the fish that wound up swimming UNDER the liner when it slipped and flooded. Smh. The fish are clean and safe inside but tired of being stalked by the cats. I’d like to get this resolved by this weekend if possible to return the yard to a less disorganized state

TIA!!

 

[j.w]

@JanaLise
Do you have enough liner around the top to make a berm around the whole edge? if so that should keep the runoff out of the pond. If you don't have enough edge liner than I'm not sure what to tell ya.

 

[Mmathis]

Hello and welcome!

There are different ways to address this, but I can only tell you about my situation. We have clay “soil” and a high water table. My 3000 gal pond (in transition so don’t have it any more) suffered from side-slips and wall collapses, and eventually to “water hippos.” That’s what some ponders affectionately call the “water under the liner.” This all happened a little over a year after we finished the pond. I won’t go into the built set-up we used— that’s for a different story — but in the end we built the sides/edges of the pond up about 12” above ground level. That way, the actual water level would never be below ground level, but always slightly above ground level. It has something to do with hydrostatic pressure, but we never had any more water hippos!

 

[poconojoe]

Some people have stuck a piece of PVC pipe down the side between the liner and the ground. Supposedly the water will rise up through the PVC pipe instead of causing a water hippo. The PVC pipe is a path of least resistance. Or I guess, if it is an extreme situation, you could always use an external pump with the intake hose down there between the liner and the ground.

 

[GBBUDD]

Some people have stuck a piece of PVC pipe down the side between the liner and the ground. Supposedly the water will rise up through the PVC pipe instead of causing a water hippo. The PVC pipe is a path of least resistance. Or I guess, if it is an extreme situation, you could always use an external pump with the intake hose down there between the liner and the ground.

Pumps don't pull water they only push.
And if your correct plastic liner is the last material you want to use for a pond Epdm rubber is what I hope your calling plastic

 

[poconojoe]

Pumps don't pull water they only push.
And if your correct plastic liner is the last material you want to use for a pond Epdm rubber is what I hope your calling plastic

Pumps don't pull water? Really? I don't get that, but...ok....
I'm thinking....I've had pumps that had a hose attachment on the inlet side that I used to pull water through a cheapo Tetra skimmer. At least I thought those pumps were pulling.... am I wrong?

So, my pool pump isn't pulling the water? Gravity must be sending it to the pump, then it's pushing it? I don't know...

Wait, that doesn't make sense. So, if you have a flooded basement and you drop in a hose from a pump sitting on ground level, it's not pulling the water?

 

[Lisak1]

@poconojoe - it's confusing, no? I think the pushing comes at the outlet. But I just consider the whole thing MAGIC!

 

[poconojoe]

@poconojoe - it's confusing, no? I think the pushing comes at the outlet. But I just consider the whole thing MAGIC!

Yeah, I'm confused...

 

[GBBUDD]

Thats why you need to prime it pumps the water out the other end is drawn to the pump by siphon

 

[JanaLise]

Pumps don't pull water they only push.
And if your correct plastic liner is the last material you want to use for a pond Epdm rubber is what I hope your calling plastic

Yes, it is. I just didn’t want anyone to get confused from the picture, because the hard shell in the background isn’t what I’m using at the moment. Thank you!

 

[JanaLise]

Some people have stuck a piece of PVC pipe down the side between the liner and the ground. Supposedly the water will rise up through the PVC pipe instead of causing a water hippo. The PVC pipe is a path of least resistance. Or I guess, if it is an extreme situation, you could always use an external pump with the intake hose down there between the liner and the ground.

Thank you for the pipe suggestion! I’ll give that a try today when I rebuild.

 

[JanaLise]

Hello and welcome!

There are different ways to address this, but I can only tell you about my situation. We have clay “soil” and a high water table. My 3000 gal pond (in transition so don’t have it any more) suffered from side-slips and wall collapses, and eventually to “water hippos.” That’s what some ponders affectionately call the “water under the liner.” This all happened a little over a year after we finished the pond. I won’t go into the built set-up we used— that’s for a different story — but in the end we built the sides/edges of the pond up about 12” above ground level. That way, the actual water level would never be below ground level, but always slightly above ground level. It has something to do with hydrostatic pressure, but we never had any more water hippos!

Thank you for responding! I don’t think a raised edge will prevent my hippos since the water underneath will still need to go SOMEWHERE when it accumulates. I might try a combo of the PVC pipe, a trench around the top where it’s highest, and some rocks at the bottom to hold it down?

 

[Mmathis]

Thank you for responding! I don’t think a raised edge will prevent my hippos since the water underneath will still need to go SOMEWHERE when it accumulates. I might try a combo of the PVC pipe, a trench around the top where it’s highest, and some rocks at the bottom to hold it down?

The idea of having the pond level higher than ground level means that the amount of pressure of the water pushing downward, is greater than the pressure of the ground water. The ground water is still there, will always be there.