Pond Boss
Posted By: KRM1985 Contemplating a Sediment Pond - 03/04/19 02:01 PM
My pond is fed from a shallow ditch that winds through my property but originates at the neighboring farmer's field. Probably a 100+ acre field so the amount of runoff that my pond gets is tremendous. The water is always muddier than I would like it to be and i'm certain it's due to the almost constant runoff. After a big rain event it is muddy and in a few days it clears.

Since the water is running through the ditch on my property before it gets to the pond I have several places where I can make a sediment pond. My questions are:

How close should it be to the actual pond? The area I would like to do it is about 100' from the pond but I have the ability if needed to make it farther or closer.

Can I dig a small sediment pond by just using a backhoe to deepen an area of the feeder ditch before it enters the pond?

Does the sediment pond need to be staggered or offset from that feeding ditch to be effective or can it be just a deep hole that is inline?
Posted By: snrub Re: Contemplating a Sediment Pond - 03/04/19 05:09 PM
My best results was to make a 1/10th acre sediment pond next to my main 3 acre pond and a tiny pre-sediment pond ahead of it. The pre-sediment pond is small enough to be cleaned out with a backhoe. It catches the big stuff and makes the bigger sediment pond last longer.

If you can turn the water to slow it, it is better. But multi ponds would help too. my sediment and pre-sediment pond construction

specialty ponds including sediment ponds

rock lining ponds for erosion control

Rock riprap will also help in some situations.
Posted By: KRM1985 Re: Contemplating a Sediment Pond - 03/04/19 06:49 PM
i could definitely make 2 smaller ponds.

There is a lot of grass in the ditch but I was also thinking of maybe putting a load of gravel in the ditch to slow and add some filtering.. not sure if that would be worth while or not...


One concern would be the amount of disturbed soil / clay required to dig the sediment ponds... I would think the new ponds would essentially be a source of sediment to my main pond.. at least until they settled down and washed clean.
Posted By: Quarter Acre Re: Contemplating a Sediment Pond - 03/04/19 07:54 PM
I am in a similar situation, meaning my pond has an excessive watershed and gets muddy from the larger rain events. So, I will be interested in the responses you get. I will add my thoughts with hopes of adding to your thread or at least getting corrected where I could be off base...

The closer to the pond the better, IMO. This leaves less ditch travel between the sediment pond and the fishery which should reduce the water picking up additional sediments. As long as the sediment pond overflow does not cause any erosion problems at the mouth of the fishery, I would think they could be back to back.

My concept of a sediment pond can be compared to a real wide and deep spot in a river. The water hits the wide/deep spot and slows way down allowing the dirt particles to settle out. So. the longer the water stays in the sediment pond the better the results. This leads me to think that the bigger the sediment pond..the better. With an excessive watershed, mine is about 5 to 10 times what it should be, I do not think I could build a big enough sediment pond...my 1/4 acre pond is likely smaller than what the sediment pond should be for my watershed making it a sediment pond all by itself. How big is your pond?

One might argue that if a sediment pond could establish a whirlpool effect that it could drop out more solids, but I will leave that to the fluid dynamic experts. Either way, it probably has marginal benefits compared to "inline". The key is to allow the water to slow down and have time to settle before moving on.

I do have a very small sediment pond right above my pond, kinda. It is what is left from a small old watering hole whose dam has washed out. It really does not allow any appreciable water to build up (12" or so), slow down, and drop out, but what it does do is collect logs which collect sticks which collect leaves which all act as a filter. Ultimately, the hole keeps a fair amount of "stuff" from making it to the main pond (it still lets the muddy water right on through). It dries up in between rains so mosquitoes are not an issue and the box turtles really love rooting through the mostly dry bottom muck in the late spring for bugs and such. Not really a sediment pond, but more of a natural filter.
Posted By: snrub Re: Contemplating a Sediment Pond - 03/04/19 08:56 PM
Originally Posted By: KRM1985
i could definitely make 2 smaller ponds.

There is a lot of grass in the ditch but I was also thinking of maybe putting a load of gravel in the ditch to slow and add some filtering.. not sure if that would be worth while or not...


One concern would be the amount of disturbed soil / clay required to dig the sediment ponds... I would think the new ponds would essentially be a source of sediment to my main pond.. at least until they settled down and washed clean.


I don't think you need to worry so much about building the ponds creating sediment from them. The benefits will far surpass any minor addition the new ponds might temporarily add to the sediment load.

If your pond needs lime (our soil is acidic here) crushed limestone and ag lime are good things to line any ditches going into or between the ponds. Then if you do get erosion in this area, it is moving lime into the pond instead of dirt. In my one acre RES pond I have two field terraces that divert water into the pond. I have lined the bottom of both terraces with ag lime so any erosion where water enters the pond will help the pond with addition of lime.
Posted By: KRM1985 Re: Contemplating a Sediment Pond - 03/05/19 02:41 PM
I agree with Quater Acre on the idea of the sediment pond being a deeper / wider area in a river. That's how mine would probably have to work. I think it would make more sense to first try modifying an area of my feeding ditch. If all else fails I can always push out a larger full blown sediment pond.
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