Released: January 27, 2003

Dry Spell Is Good Time To Remove Pond Sediment

MANHATTAN, Kan. – Drought in the High Plains has made life difficult for farmers and ranchers – even suburban landowners with a few horses, but there’s one way people can use the situation to their advantage.

Low water levels make this an opportune time to remove accumulated sediment from the bottom of ponds, said Kansas State University biological and agricultural engineer Morgan Powell. Removing sediment increases capacity and provides an opportunity to repair areas where they may be leaking.

"It’s puzzling why some ponds leak and others don’t," said Powell, who is a water quality specialist with K-State Research and Extension. He believes that the difference has to do with soil conditions at the time of construction as well as the type of soil predominate in the area.

The typical first step to removing sediment from an existing pond is to pump out all of the water. The landowner should then allow several weeks to let the sediment left in the bottom to dry out.

A pond could also be dredged when it is full of water, but this requires much different equipment that is probably not as available, Powell said.

"It’s possible to have up to 8 feet of sediment, so it’s important to give it enough time to dry," the agricultural engineer said. After drying, the sediment can be removed by a scraper or a bulldozer.

"It’s important to move the sediment far enough away from the pond to ensure that it doesn’t wash back in during wet weather," he said.

Compacting the soil in the bottom and sides helps to form a seal and is critical when a pond is being built or after removing sediment from an existing pond. Compacting involves working the soil while it’s moist.

"Generally, the soil is too dry to get good compaction, so it’s likely you’ll have to add moisture. Sometimes it takes a lot," Powell said. He recommended using a sheepsfoot roller to compact 6- to 8-inch layers to form 1-1/2 to 2 feet of compacted lining for the pond bottom.

Good compaction helps eliminate voids that allow water to run through.

Cleaning sediment out of an existing pond will cost as much or more than building a new pond, so sometimes a choice has to be made, Powell said. If an existing pond is in the best possible place and there are no other good sites on the property, the best option may be to drain the pond and remove the sediment. If, however, there are several good sites in addition to where the original pond was built, it’s likely to be more cost effective to build a new pond.

"Ideally you’d want to build the new pond below the existing pond. That way, the old one serves as a wetland to catch sediment before it washes into the new one," he said.

For more information about pond construction, Powell recommends Agriculture Handbook 590 – "Ponds – Planning, Design, and Construction," a publication distributed by the U.S. Department of Agriculture’s Natural Resource Conservation Service.

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K-State Research and Extension is a short name for the Kansas State University Agricultural Experiment Station and Cooperative Extension Service, a program designed to generate and distribute useful knowledge for the well-being of Kansans. Supported by county, state, federal and private funds, the program has county Extension offices, experiment fields, area Extension offices and regional research centers statewide. Its headquarters is on the K-State campus, Manhattan.

Story by:
Mary Lou Peter, Communications Specialist
mlpeter@oznet.ksu.edu
K-State Research& Extension News