I have a 1/4 acre stream fed pond. Its average depth is around 5.5 feet and deepest is just over 7 feet. I want to add another foot or so to the dam. What is the best way to do this?

Thanks,
Greg

Welcome to PB! I am absolutely ignorant when it comes to dirt moving, but it seems to me that digging the pond deeper would be preferable, and less risky than raising an already established dam?

Hopefully someone with experience or knowledge in this area will chime in.

Welcome to Pond Boss forum.

I don't know exactly where to start. That is a question that entails hundreds of details to give any sort of decent answer with very little details given.

You need to post some pictures and a LOT more details before anyone can even start to give suggestions. Then they likely can be only that, suggestions and ideas.

A few examples of pertinent details would be:

How big is the watershed or what it the potential water flow? How high is the current dam height over full pool? What kind of current over flow mechanism is in use (ie pipe, earthen spillway, etc.).

Is there suitable dam material available nearby to provide material to add to the dam?

Those are just a few I can think of off hand.

In the most general terms, to raise a dam height it may involve moving as much dirt as composes the original dam. It involves not only raising the height, but also the width to withstand the additional water force pushing on the dam. A new overflow system will need to be installed as well as an emergency overflow.

I'm no expert, just a farmer with some experience with construction equipment. I have raised one dam to about a foot higher than original full pool but it also involved cleaning out completely the old pond. So it was a complete refurbish. I'm also considering raising the dam on another old pond that was refurbished a couple years ago. If I do it, it will be in conjunction with building another pond nearby with plenty of clay/soil from that excavation to supply the needed additional dirt for the dam.

Raising a dam is not a simple process, and on site expert advice from a pond builder will be needed. But with some more details of your situation, at least some good ideas could be provided by other PBF members.

snrub,
The pond is new and basically a small stream that was dug out (105' x100') The dam is about 2 feet over the height of the level of the stream. The stream runs pretty slow in the summer.It is about 8 feet wide and a few inches deep. I would estimate the pond to be about 350,000-400,000 gallons and it took 10 days to fill, in the dry part of summer. In the spring, the stream is about the same width and about a 1 1/2 feet deep and a lot faster. I couldn't guess what the flow would be. The overflow is a spillway over the dam.

I have large amounts of clay and shale for dam material.

I'll try to post some pics later.

thanks,
Greg

I'm not qualified to give advice on such a project, but think I can give some considerations to think about.

My main concern with a pond that has a stream that flows through it would be handling the water flow in a high rainfall event. Everything might be fine for a number of years, then one year comes along with heavy rains and the dam washes out. So one main consideration I would have is making a spillway that can handle the water flow during the worst rain event that could likely happen.

You mentioned the current spillway goes over the dam. If it flows over the portion of the dam that was created with dirt (in other words not around the end of the dam on virgin soil) I would be concerned with erosion that could eventually make the dam fail. You might want to consider a large culvert pipe type overflow big enough to carry normal rain events and an emergency overflow routed around the end of the dam designed in such a way that it would not wash out. Like lined with rip-rap or something along those lines.

If you have a good NRCS agent in your area, he can easily determine the watershed that flows into the pond as well as make estimates of water flow based on historical rainfall data. He can also make a recommendation on the size of pipe overflow needed. NRCS can be a good resource if your project falls within their area of responsibility. Be aware though, if you have dammed up a stream that covers a watershed of significance, it could fall under the jurisdiction of the Corps of Engineers or other government agencies. In which case, might be better to not go down that road.

Thanks for the advice. I'll leave it as is for now.