Creating Ponds and Preventing Pond Pollution
The following material is meant to be used as general guidelines for preventing pond pollution. You should ask the Ohio Department of Natural Resources Division of Wildlife for specific details that are tailored to your land and pond plan.

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Pond Construction
When building a pond you should consider the type of pond you are trying to create (recreational, aesthetic, or agricultural) as well as
the features of your land. The way that you build your
pond can greatly affect the level of pollution in your watershed. Prospective pond owners should obtain technical advice from government agencies for guidance concerning pond design. These agencies offer the necessary experience to recommend the pond size, depth, location, and dam and spillway construction that are best suited to the landowner’s desires and the watershed and soil characteristics.

Ponds can be either embankments or excavated types, depending on the surrounding land forms (see the graphics below). If your site
is flat, then a simple excavation is needed. If the area slopes, you can construct an embankment (dam) across a slope or small watercourse. Embankments across streams and rivers are not recommended due to spillway sizes and overly large watersheds. Embankment-type ponds are a little more complicated, because an outlet pipe and spillway are needed to safely handle the overflow from large storms. Depending on the dam's dimensions, a permit may be required from The Ohio Department of Natural Resources, Division of Water.

A) An excavated pond B) An embankment pond

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Chemicals in the Pond
Ponds often flood during heavy rains causing pond treatment chemicals to enter the stormwater system. Use pond treatments such as copper sulfate or other algal controls sparingly and avoid use altogether during rainy periods. For other material on how chemicals affect stormwater and the alternatives you can use to prevent pollution, visit the Pollutant Alternatives page.

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Conducting Soil Testing
Soils in the watershed have a major influence on how much water reaches your pond because they determine the amount of water that soaks into the ground (infiltration) and the types of plants that grow in the watershed. Concerning the actual site of construction, the soil needs to contain at least 20% clay by weight, at a depth below excavation of three feet, to prevent excess seepage. If porous soils containing sand and gravel underlie a large part of the site, a clay “liner” will need to be brought in and compacted to prevent excess seepage.

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Drainage Area
The pond site needs to be located so that an area of land is located above it that directs water runoff into the pond, keeping it at the designed capacity. This area that drains into the pond is called the watershed. The ratio of watershed to pond area should be between six and thirty acres of drainage per one acre of pond. It is important to consider the land uses of the watershed because it will affect the water quality of the pond. Some factors to consider might include industrial runoff, agricultural pesticides or sedimentation, or failing septic systems. The best land usage for a watershed draining into your pond is forested or non-agricultural grassland.

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Resources
These links will take you to pages outside of the Lawrence County Stormwater Management website.

Ohio Department of Natural Resources Pond Management
Ohio Department of Natural Resources Department of Water
Ohio Department of Natural Resources Division of Wildlife

Graphic by ODNR used with permission