Pond Slope Stabilization Methods

Pond

• Ponds can be naturally created or constructed by human beings to produce pollutant removal from a construction area and allow storm water runoff to occur. The area around a pond is often graded to allow rain water and rain events to run off into a pond that is positioned away from groundwater supplies to avoid the transfer of pollutants into groundwater. The location and construction of ponds is controlled by state and local government construction codes -- for example, in Idaho a pond must be located at least 20 feet from a source of groundwater to avoid contamination.

Vegetation

• The long-term stabilization of a slope around a pond is completed with the addition of vegetation; for example, seeds and seedlings are planted on a slope to reduce the impacts of erosion. Grasses are often used to hold an embankment in place, which grow best when placed in the native soils of the region of the pond. Where native soils are not used, adequately compacted fill soils should be used that are free of loose surface soils, roots and organic debris. Grasses can be placed on a pond slope as either seeds or sod to provide stabilization. Vegetation should be planted on a pond slope at the first practical opportunity to stabilize the slope as soon as possible.

Control

• The control and stabilization of a pond slope while vegetation is becoming established in the soil the use of an erosion control blanket (ECB) or flexible growth medium (FGM). These materials can be manufactured from geotextiles that can remain in position for between 12 and 24 months depending on the growth rate of vegetation on the pond slope. ECBs and FGMs are used to hold newly planted seeds and seedlings in place and provides protection from erosion caused by rainfall and heavy rain events.

Design

• To ensure the proper design of a pond and the slopes around it each pond should be designed by a geotechnical civil engineer, the Idaho Department of Environmental Quality reports. Civil engineer designs are required under some state regulations for pond slopes 6 feet in height and taller. Designs should include the estimation of two-year and 10-year water levels in the pond, along with adequate inlet and outlet pipes.