Pond primer: Pond construction homework pays off


CANFIELD, Ohio – It’s a dream of many rural homeowners to build and own a pond for swimming, fishing or boating. But many times, after shelling out thousands of dollars and spending hours to realize that dream, they’re left with dried-up hopes and a hole that won’t fill or hold water.

In other cases, the pond is glazed over with algae and has a bottom lined with slimy green muck – hardly the bucolic setting or the landowner’s aim.

Situations like these have been seen hundreds of times by Kevin Swope, rural technician for the Mahoning County Soil and Water Conservation District, during his 11-year career that includes pond site consultations.

“All it takes is a few hours of homework by the landowner” to help ensure the success of a pond, Swope said.

Nearly 100 people started that homework during a free seminar on pond design and construction, maintenance and fish stocking offered by the Mahoning County Soil and Water Conservation District, extension, and the Division of Wildlife in April. Around the state, similar workshops are being offered by other soil and water conservation districts.

Ahead of the game. Landowners aided by their county’s conservation district can be ahead of the game when it comes to planning a pond.

“Once they’ve done their homework, I can go out and look everything over and get things moving,” Swope said.

The district can also provide landowners soil and topography maps and help identify and head off problems during the consultations.

“A lot of the time we don’t get called out until there’s a problem and it’s too late,” he said.

“One time I went to check on a pond that the owner said he could actually see draining. Poor construction technique and bad site selection played a part, but the big thing was the drain tile laid underneath. It was never cut off.

“But it’s a little hard to put in a trench after the pond is built,” he said.

Failed sites. A number of factors play into building and owning an effective pond and, unfortunately, those factors are often ignored and result in failed swimming and fishing holes, according to Swope.

The most important thing to consider before building a pond is the topography and soil type.

“The first thing to consider is a nice flat site. You don’t want to have to move any more dirt than necessary,” he said.

The region has plenty of open, flat areas suitable for excavated ponds. Land affected by glaciers has high sand and gravel content but still can be made suitable for a pond.

Fill and keep. It’s also important to consider the size of the watershed the pond is in – the number of acres the constructed pond will drain, and how those acres are used. Each surface acre of a pond can handle drainage from six acres of land, but some areas can withstand up to 30 acres of drainage water.

“Downspouts from a house will keep a quarter-acre pond pretty well. If the land above the site is agricultural, you should expect a lot of sediment. If it’s a lot of asphalt, the rainwater is going to come quick,” Swope cautioned.

Sediment is one of the biggest contenders in pond failure, and the biggest pollution factor in Ohio ponds, according to Swope.

More than digging. Because of glacial action, not all soils are the same across the northeastern Ohio and western Pennsylvania region. Differences in soil types, which can be determined by county soil surveys, can affect compaction and make all the difference in the success of a pond. Recommended soils in a pond area should be a mixture of sand, silt and clay.

“I’ve been to hundreds of site evaluations, and find gray clay. For some reason landowners think the coloring means that’s good, but it’s really an indicator of poor drainage,” Swope said.

Swope recommends digging test holes to find what’s below the hardpan, a layer of soil that keeps water from leaking through, and identify where layers change and exist.

“Keep in mind that water flows freely underground, and if there’s a layer that allows water to drain, you’ll need to cut that layer off,” he said, or the pond will never fill.

A picture-perfect pond in the region was built “by the book” but would never fill, according to Swope.

“That thing sat empty or close to it for years before we realized we were only a foot above the bedrock and the water was all draining,” he said, noting the owner opted to pay for southern clay to be hauled in to line the pond so it would fill.

“Even with the greatest planning, something can still go wrong, but planning sure helps,” he said.

Mechanics. Swope also emphasized the need for digging a core trench to eliminate seepage, proper planning and installation of spillways, and proper compaction.

“Bulldozers don’t compact, so make sure you use or hire someone with the right tools,” he said.

Pond owners are also urged to be sure to install a spillway and drain system of pipes to fill and empty the pond. Pipe sizes are determined by watershed capacity, and require complicated engineering to function correctly.

“One of the biggest things is to make sure your contractor is talking the language. If you’re not hearing words like cut-off trench, compaction, or spillway, and they’re not talking about stripping the vegetation and topsoil from the land ahead of time, you should probably start asking some questions,” he said.

“A pond is going to take a while to build, and will cost some money, so make sure it’s done right,” he said.

For more information on pond construction, contact your county SWCD or extension office or the Ohio Division of Wildlife.

(You can contact Andrea Myers at 1-800-837-3419, ext. 22, or by e-mail at amyers@farmanddairy.com.)

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