About Retention Ponds
General Information Performance Data Water Quality Treatment Process Design


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Design

The retention pond tested at the UNHSC is comprised of a sedimentation forebay and a larger basin sized to hold a resident pool of water. It was installed below the water table to maintain a permanent pool of water, and in clay soils, which effectively act as a lining for the system. Side slopes were stabilized with grass, and spillways with stone and geotextile.

Improved designs, not used here, would include stabilization of wetland perimeter with stone and fabric. This perimeter was the location of failure for the pond. In this area, vegetation could not establish and soils were prone to erosion.

In general, these ponds can be designed either above or below the groundwater table. Ponds are commonly designed for both aesthetic and habitat function.

The system is designed to treat the water quality volume. Typically, channel protection volumes (CP_V) are conveyed through the system within 24 to 48 hours.

During conveyance protection volume (Q_p) rain events, stormwater is conveyed through the system, and bypasses the water quality treatment process.