Pond owners: Plan ahead for dredging

Many ponds are more than 50 years old. Depending on their drainage area, they can accumulate debris, leaves, sediment, yard waste, decaying pond plants, etc.

Eventually the pond will need to be dredged to restore the full use of the pond for the owner. When cattails march out toward the middle of the pond, it is a good indicator it might be time. Dredging a small pond can be done more practically and be less expensive than a larger pond.

A few questions arise if you are going to dredge. Is there adequate access for crawler backhoes, or cranes and even dump trucks and bulldozers? Is there adequate space for stock piling the sediment or mucky stuff?

Will the dredged material need to be hauled away? Did you begin saving up some funds in preparation of the untimely event (Please note here, “Homeowner Association” members, you better start now setting aside a build-up fund for the future event).

How it works

If you plan to dredge your pond or retention basin, the water is usually pumped out first. Then you end up with a small pool of water and fish. This is very appetizing for herons, raccoons and mink.

You might be thinking “gee” now that the bulldozer is here, should I reshape the pond? If you do, please leave the dam alone unless it is leaking or the outlet pipe is bad.

The reason is the dam was hopefully built with a core trench to help seal it up. If you should happen to dig into the dam, be prepared for some additional counter moves to seal it back up.

Most ponds have outlet pipes. In the old days, corrugated metal pipes were used. Today, we have plastic pipes. We have noticed the corrugated metal pipes are showing signs of rusting out. In some cases, to the point of leaking and weakening that part of the dam from water flowing outside and along the pipe called “piping.” You will see backside cave-ins or sloughing of the dam itself.

Ponds versus wetlands

Sometimes, the satellite imagery can not tell the difference between a pond and a wetland. So, when we use the U.S. Fish and Wildlife Service National Wetland Inventory maps here at the office, your pond could show up as a wetland.

You could have some issues as to are you dredging a wetland? Some products are sold that claim to eat up the bottom mucky stuff.

Aerators can be very helpful if they are the bubbler type. However, we don’t think either one can remove sediment accumulations.

Drainage area ponds should be functional for 100-150 years unless too much stuff gets in them or they are not needed any more.

A rule of thumb for a pond to watershed or drainage area is a one-acre pond should have at least four acres of drainage area.

When you have more than that ratio, you could be adding much more stuff to your pond from runoff and it will bring in more unpleasantries the bigger you go.

Flooding myth

We have heard accusations that a pond will cause additional flooding downstream. Actually, we do not agree with this myth because the rainfall or snowmelt that occurred before the pond was there also flowed down the slope and the only difference is now the pond captures it and releases the water through a pipe which is more visual to the eye.

The concentrated flow from the pipe then does look like increased flow onto the downstream neighbor. We have found the pond actually holds back some flow especially in the summer months when pond levels drop anyway.

Medina County was proclaimed the “Pond Capital of Ohio” in 2012 by the Medina County Soil and Water Conservation District Board of Supervisors and the Medina County Commissioners.More than 7,800 ponds of more than an acre in size exist across the county.

Thus, for some of you, dredging is in your future. Check with your local soil and water conservation district for more information and suggestions from their experiences over the years.

About the Author

Jeff is the District Manager for the Medina SWCD since 2006. Before that he was an area representative with the ODNR Division of Soil and Water Conservation through out Northeast Ohio for most of his career. He worked closely with District Boards of Supervisors and staffs on programs and capacity building. More Stories by Jeff Van Loon

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