The project involved the expansion of the existing Nelson County Courthouse and parking area. The new expansion generated the need for a 30% phosphorus reduction to meet stormwater quality regulations. The site topography and limited size left minimal workable space for best management practices (BMP) to address the stormwater quality and quantity.

Wiley|Wilson designed a bio-retention filter as the BMP to meet the stormwater quality needs of the site. Utilizing bio-retention provided high treatment efficiency while maintaining a small footprint. The landscaping requirements of the bio-retention filter gave it an aesthetically pleasing appearance, which was important due to the filter’s visibility at the judicial facility. In addition to providing water quality treatment the bio-filter also acts as a detention basin to provide attenuation of the peak flow. A final key element of the bio-retention filter is that it is easily maintained without specialized training or equipment.