Pond Boss
Posted By: Flame spillway design - 12/01/14 07:17 PM
Ok, I now have water filling the 2 acre pond. I have only a natural dirt spillway right now.I have some time because the pond will need to be at least 12 ft. deep before exiting over the spillway.What are suggestion for covering the spillway area and being able to drive over it with a truck when needed. I do not wish to just put a culvert. I think about 20 feet wide would be good for me. Someone told me pour concrete and others have said just build it out of stacked bags of sakrete. Please help with some ideas. Thanks
Posted By: Pat Williamson Re: spillway design - 12/01/14 07:58 PM
Flame
Got the same situation as you do. I'm going to order a load or two of 2-3" slag and make it 3-6" deep where I can drive over it. In our area nobody uses any other form of overflow system. Or you can cement the bottom an line edges with rock, me I'm just using rock ( slag).



Pat W
Posted By: Flame Re: spillway design - 12/01/14 09:15 PM
Hey Pat, Where is Freestone County? I'm glad you explained slag as rock. Only slag I knew was from my welding days. We are never too old to learn. In my local area we have several "blue rock" quarrys. I can get it delivered and spread for about $300 a dump truck load. We use it to make drive ways out of. I can get it about golfball size. We used to get it about baseball size. Would the larger be better? How about if I put several bags of sackrete down and then dump a load of rock over that to fill in between the bags or do you think rock is all I need?
Posted By: Pat Williamson Re: spillway design - 12/01/14 09:25 PM
Flame

I think you can do whatever you want and it will work, depending how much rain and if it ever fills and how much driving on it you will do. The more driving the more I would put down, making sure not to raise the water level from where your lake guy shot the grade. If you are going to put down 6" then I prob would scoop out the same before adding slag or rock. Slag has a grey - blue look and appears to be like rock ( round irregular but not sharp) and I think it might be cheaper than rock since it is a bi product of steel making


Pat W

Freestone co is near hwy45 north and about 60 miles east of Waco
More or less. I'm near Oakwood
Posted By: george1 Re: spillway design - 12/01/14 10:30 PM
Guys, I think you are playing with fire talkling about a conventional spillway which I believe to be a emergency spillway.
I know Freetstone County soils like the back of my hand as well as East Texas soils.
I have experienced a flash flood on our Freestone County property that washed out a 5 acre neighbor's upstream pond with a conventional spillway. It did considerable erosional damage to our bottomm pasture

Mry son’s property in Delta County has the same soil type and his pond builder installed a spillway siphon system as well as emergency spillway.
I strongly recommend this type system based on my experience,
George

https://www.google.com/search?q=pond+sip...mp;ved=0CEUQsAQ

http://ponddampiping.com/syphon1.html
Posted By: Pat Williamson Re: spillway design - 12/01/14 11:18 PM
George1

While you have a valid point to be made, in our location none of the lakes have anything but a traditional spillway, some being 25 to 30 acres and none have washed out yet. Key word yet. My spillway is prob 30' long and total clay a few inches under the top layer of sand. There are 8 lakes around me and most you can jump over the spillway. My dam base is 225' across and the top is about six feet above the elevation of the spillway. The lake below me doesn't even have a spillway at all.

George did yall get a buck this season?
We got in touch with the game biologist and he is coming out to talk to us about The
Deer management program that you suggested. Thanks for that info also.

Pat W
Posted By: george1 Re: spillway design - 12/01/14 11:51 PM
Pat, you have a valid point - Oakwood area is at a lower elevation than our place and drainage into the Trinity river bottoms - perhaps different soil types. I consider a siphon system an affordable insurance policy.

Only hunting was on opening weekend and no deer taken even though several young 8 pointers observed. Only older "trophy" class bucks are taken by our family members. Late season does on the menu if any permits issued this year -
Good luck with TP&W conservation program.
George
Posted By: esshup Re: spillway design - 12/01/14 11:59 PM
To save yourself some possible headaches in the future, go talk to your counties NRCS agent about where the pond is located at, and how many acres of watershed it has. THAT is the determining factor on how wide a spillway has to be - the speed of the water over the spillway has to be calculated. Too narrow and the speed of the water is fast, and if enough volume of water is there, it'll move softball sized and larger rocks.

The NRCS agent can and will calculate how much water you can see in a 50 and 100 year water event, which is what you have to take into account. I'd hate to have you come back here in 6 years saying "Guys, you know that hurricane that parked over us last week? Well, it washed out the dam and all the fish in the pond are now downstream."

Without knowing all that information, there's no way that I'd make any type of recommendation on what will or won't work. If I were to make a WAG on the spillway size, I'd go with a siphon system, and make it grossly oversize. If the dam is about to be topped, you cannot move enough water fast enough!
Posted By: stickem' Re: spillway design - 12/02/14 12:21 AM
Mr. George1,
My pond has a siphon system that you speak of. It was from the preexisting pond prior to renovation. I figured out that the water line depth of the pond can be manipulated by attaching an upright section of pipe on the discharge side of the dam. With this pipe in place, I can control the water level very accurately. I think this is a very simple and effective design for emergency water level control.
Charlie
Posted By: george1 Re: spillway design - 12/02/14 01:38 AM
Yep, the siphon spollway is a simple and effective system - I just wish I could see it in action more often…! smile





Flushed about every three or so years so far - we need water bad!
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