pond overflow/spillway ideas

[LD1]

Looking for some suggestions as to what others have or have seen. Most all ponds I have seen in my area don't really have an overflow so to speak, but also don't have a lot of fill water coming in either.

Currently, my pond has a 12",culvert with 2 8" culverts for an overflow. I did this cause I need more than a 12, but didn't want to go bigger cause I didn't want to have to build up and over that much higher. The pond is fed with 2 12" culverts and a few 4" tile. The 12's flow full with a good rain. But I am wanting to redo the spillway and get rid of the "hump" over the culverts. So looking for ideas. I also want to be able to drive over it.

Considering the following.

1. Concrete swale. Kinda a shallow u shape. About 4-5' wide and 25' long. But worried about freezing, and not having a great base. My soil all around the pond is thick black waxey muck, that sticks to everything, and never really drys.

2. Considering stone. Not sure what size to get to not wash away. And am afraid it wouldn't support driving over very well due to the muck. And to be thick enough to be firm to drive over, would mean digging deep enough that water would flow through the rocks an cause a lower pond level.

3. Just leave the culverts and live with it.

I appreciate any suggestions. I'll see if I can find a picture of what I am dealing with.

 

[LD1]

 

[TomSeller]

Sure looks good to me. Nice work. WOW ! I would tend to a concrete swale overflow but my ponds are more ground water than flow through.

 

[LD1]

This is definataly a flow through. You can see in the second pic. That was last spring.(the first spring after it was dug). The first pic is how it looks now. But I don't like the hump.

I have read some places online that concrete isn't good for a spillway. Ice and frost heaving, which is a definite concern heren and also erosion and washing out underneath, since I cant really do a suitable gravel base as that would undermine the spillway.

But have also seen several nice looking concrete spillways online too.

I am not opposed to gravel. But what size? I got a load of #57's coming for driveway maintenance. But am afraid its too small and will wash away.

I want whatever is going to last the longest and still be able to drive over with the tractor and mower.

And if I go with rock/stone, is limestone or gravel better?

 

[dave1949]

http://www.factorydirectlandscape.c...category_id=15&option=com_virtuemart&Itemid=2

I would check out geotextiles, filter fabrics. They should keep the muck out of the stone if you build a rocked spillway. I would use 6" to 8" rock, river rock would be nicer looking than crushed limestone. I wouldn't use much gravel if you have a 12" culvert running full, that's a lot of water and maybe enough to move gravel.

You could call a vendor, like above and describe the situation, email a pic whatever, and see what they recommend. Rocked spillways would be my choice over culverts or concrete.

 

[Gary Fowler]

Why not use the same rock that you have around the perimeter? It looks large enough to hold without washing away. You could put down some geotextile fabric first then a couple layers of rock should hold. Use a broken rock with irregular shapes so it locks together rather than round or smooth shapes.

 

[Gary Fowler]

Also you could raise the spill way up so the pond could hold more water. Of course this would need to be done when the pond was a bit low so you wouldn't have to content with any overflow. Remove the culverts and backfill with good clay soil, then rock over the backfill to the elevation that you want to hold water. You could make the water level be almost to the top of your levees. Just make sure the spill way is wide enough to handle ALL the overflow without any going over your unprotected levees.

 

[Gary Fowler]

Here in Arkansas, the AG Extension service recommends (requires it if they participate) a spillway be located on the upper end of the pond. The overflow travels around the levee base by virtue of a swale and is directed to a drainage area, be it creek or canal. They don't allow culverts at all as they say they are impossible to size correctly due to differing amounts of runoff. With the spillway located at the upper (shallow end) and 20 feet wide or so, it will not allow the pond to over flow its levees. I don't know if your pond could accommodate something like that or not.

 

[Western]

My grandfather had a constant pass through pond when I was a kid, it has a concrete spillway with a foot bridge over it and has been solid for 50 years. This is outside Harrison Ark, and plenty of freeze/thaw going on as well. I do believe they poured flat walls into the ground front and back, like a dirt stop/footer. This pond was 5 acres

EDIT: He had a wire mesh wheel that turned with the flow to aid in keeping stoked trout in, actually worked. It was strong enough to drive a small tractor over to mow the bank, he just had some iirc long RR type ties acroos beside the spillway.

 

[oosik]

The outlet to my 5 acre lake is thru a naturally restricted area. It ends up being about 20 feet wide and I've filled the restriction with stone - 6" to 8" and some gravel. There is never a heavy flow so washout is never a problem. The water brings debris to the outlet and it deposits between the stone and further restricts the outlet flow. I more or less control the lake level by the amount of stone and gravel that I place in the outlet. If too much water - from local rain or snow melt - ever raised the lake level it would simply flow over and thru the stone I've placed in the outlet. Thru an entire season the water level will fluctuate about 14 inches. The lake is 80 feet deep and is fed from several springs.

I have never considered creating a bridge like structure at the outlet because there is a 150 yard "moat" between the little 5 acre lake and the big 120 acre lake that the little one flows in to. In the spring, when water in the moat can be up to three feet deep, I only cross it with the ATV. A heavy vehicle, such as my tractor, would most likely sink to unheard of depths.