Pond Boss
Posted By: Don West Dam Erosion - 10/07/02 09:50 PM
I had a two acre pond constructed one year ago and the dam is about 750 feet long.

Within a few hours of finishing the dam it started to rain. We tried to seed the dam with rye grass but it kept washing away.

Now one year later we have a lot of silt in the new pond and severe erosion. Some of the gullies are two feet deep and the top soil we had is not on the bottom of the pond.

We have hired a contractor to repair the erosion but he is not interested or willing to get involved in stopping the erosion from returning.

The sides of the dam are quite steep and and due to a leak (since fixed) the depth of the pond is down to 5 feet from the typical 10 so we have even more of the sloop exposed going into the "rainy season here in East Texas.

I think I know how to repair the erosion but how do I stop it from returning?

Thanks in advance for your advice.
Posted By: Bill Morris Re: Dam Erosion - 10/08/02 10:39 PM
I used unhulled bermuda for quick germination on my dam and around the pond. When moisture is applied I have had it germinate in less than one week. I recently added some to bare spots that are more clay than topsoil so I will see if it comes quickly. I'm not sure what the result will be with the slightly cooler weather we are experiencing these days as well as the shorter days. You may call someone that does the spray application. I have no idea what this might cost but I have seen it hold down erosion in new property developments. It has a mixture of seed, fertilizer and paper (paper holds everything in place). Another idea may be to plant a seed oat on it. my experience with oats is they come up very quickly and they have larger blades than rye. A combination of bermuda and a cool weather seed may me in order this time of year. Good luck with stopping the erosion. If your area is like mine, the rains we've been getting have been steady but not downpours.

BMorris
Posted By: Dave Davidson Re: Dam Erosion - 10/09/02 04:23 PM
Don, I second what Bill says but with a couple of modifications. I believe I would mix rye with the oats. Oats germinate better and quicker but have a tendency to freeze out and die. Also, I get a better volunteer return rate on rye every year. Actually I have had the same erosion problem you are having. I "somewhat" solved it by hauling rocks for rip rap and throwing brush in the gully areas. The problem is that water runs downhill, picks up sand and soil and keeps going. I know one guy who laid hog wire along the dam. Another used the orange plastic fencing. I have seen the orange stuff used along Northern New Mexico roads to stop snow from drifting onto the road. It ought to stop sandy loam. I bought a gasoline powered pump to get my bermuda seed to grow. It made a big difference in the summertime.
Posted By: Bill Morris Re: Dam Erosion - 10/09/02 05:34 PM
Don, Dave is right as far as being able to fill areas with all different types of materials. I have used 40#bags of concrete in some areas where I had bad wash out. I laid them in and let the water harden them then burned the paper off. I have also used scrap bricks from construction sites and the soil catches in the bricks and gradually fills up.

BMorris
Posted By: TROLL Re: Dam Erosion - 10/10/02 01:31 AM
Don , check out the local building supply store for silt fence, it comes in fifty foot rolls, with the stakes. When you install it make sure you trench it in, put in several row in the same ditch, if you can!t f ind silt fence use straw bales, stake the bales in.
Posted By: tim k Re: Dam Erosion - 10/25/02 07:38 PM
on a newly built pond that is fed by runoff (at times with heavy rain can be a VERY heavy runoff) should some type of grate or screening be built over the spillway to prvent fish loss in a heavy overflow? I know in general fish don't swim with the current and would probably stay in the pond but in a super heavy overflow is there still not the possibility of losing fish? Thanks
Posted By: Dave Davidson Re: Dam Erosion - 10/25/02 09:01 PM
Tim, My concern about screen or mesh over a spillway would be that you defeat the purpose of the spillway. Leaves, brush, limbs, and assorted junk will lodge against the screen and back up the water. I lost some small bluegill and fatheads when I got a big rain. However, a year later you wouldn't know it. I would rather lose a couple of fish than a dam.
Posted By: Bob Lusk Re: Dam Erosion - 10/25/02 09:23 PM
Typically, the only fish that leave are the youngest ones, babies that linger near edges and the surface.
Mature fish, especially bass, bluegill and catfish, tend to stay nearest their cover or food supplies. Heavy flow doesn't trigger fish exodus. Lack of food or cover in a lake gives fish a motive to seek greener pastures (literally).
Putting a screen across a spillway has been known to create enough resistance to flow to force water to seek another path, over a dam. I have seen it happen. When water flows over a dam, it can be catastrophic...not only for the dam and lake, but for anything in the way downstream. No screens rising higher than 10 inches lower than the lowest point of a dam.
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