Pond Boss Forums INTRO Questions & Observations Pond Depth Manipulation

I have an approx 5 acre pond with an earthen damn which flows into a creek then into the river. The pond is approx 25 years old and is only about 4 ft at its deepest point. In the summer it is choked with grasses of varying types. I have added 24 grass carp but not even they can keep up with the growing grasses. I assume this is a depth issue and if the pond was deeper, the grass would not get as much light and be reduced. I am afraid that each year that goes by the dying grasses will only work to make the pond shallower and perpetuate the cycle. I have tried an easy fix of a sandbag wall around the spillway to raise the level but am afraid of water pressure on the earthen dam causing a break.

What is the best fix? Drain the pond and dig it out?? Herbicide the grass?? raise the damn?? Other suggestions or combinations of the above?

If you have a lot of shallow water you will always have at least some grass problems. If you have 5 acres then you are probably about 26 carp shy have of having enough, especially in your case. Draining and starting over is the best way to take control of your pond. It is also the most expensive. Adding to the dam will reduce your water shed(runoff)and it sounds like you already need all the water you can get. If you do not want to inccur the expense of draining you should treat the pond. There are chemicals that will eliminate your grass. You will need to check to see what is legal in your state. I would add more carp and then fertilize as heavy as possible. Make sure you get carp that are 10-12 inches long so that they do not become a meal for existing fish. Get a water analysis done so that you know exactly how to fertilize. We have a shallow pond here in south georgia, about 4 acres. We had a lot of 2-4 foot water. It took us about 2 years to get a handle on our grass problem, as we have a long growing season. We did however get it under control. It has been a great pond.

Here's my thoughts. First, evaluate. Evaluate the dam, the spillway, the watershed and your plant community.
Use this list.
1) You need engineering help.Ask the NRCS (Natural Resources Conservation Service)if they will come inspect your dam, with the goal of raising your water level. They will have some thoughts. If you don't like what they say, enlist the services of a paid engineer and ask the same question. The answer will help decide whether to raise the dam, raise the spillway, or to forego both those options.
2) Evaluate depth of siltation in the bottom of your lake. Get out there in a boat, push a rod into the pond bottom, find soft sediment, push through to hard soils, and measure that depth. Do your checks along the bottom, in an organized fashion, in quadrants. This will give you an idea how much silt sits on bottom, in case you choose to look at draining and removing silt.
3) Evaluate the vegetation community. Identify plant species, percentage coverage of each species. This will give valuable information whether to stock more grass carp, use herbicides, or some other management strategy.
4) Here's the best advice...if you don't quite understand how and why to do the above suggestions, hire a professional pond manager to evaluate for you. It will be worth the fee.

Let me second Bob in saying...hire a professional engineer. It is important that the engineer have a hydraulics and hydrology background. If you hire an engineer that does not specialize in H&H, it will cost you more $$$ because they won't be as efficient.

The H&H engineer will also be able to address the 2nd suggestion Bob mentioned. These are the ways you can cut your costs and do the job right at the same time, the first time. Hire an engineer who is knowledgable about ponds, has good contacts with contractors and can supervise your project to make sure it's done right.

Just my 2 cents.