The City of Williamsburg and James City County are cooperatively participating in the construction of a demonstration project at the Williamsburg / James City County Courthouse along Monticello Avenue. This work is supported in part by a Chesapeake Small Watershed grant awarded by the National Fish and Wildlife Foundation.

This project consists of converting an existing landscaped and low-lying stormwater conveyance channel situated in the front lawn of the Williamsburg/James City County Courthouse into a stormwater Best Management Practice (BMP) bioretention basin.

The bioretention basin will provide additional water quality treatment to reduce non-point source pollution from existing stormwater runoff at the Courthouse site and from future offsite development areas situated to the east of the site. The purpose of the project is to demonstrate planning, design and construction of a bioretention basin, consistent with the Chesapeake Bay Preservation programs of the City and County, the County’s Powhatan Creek Watershed Management Plan and Better Site Design and Low Impact Development principles generally encouraged by the Chesapeake Bay Local Assistance Department and the Virginia Department of Conservation and Recreation.

The project will demonstrate how existing stormwater drainage features can be effectively retrofitted and blended into the functional landscape of a site to provide a water quality benefit and serve as an attractive feature, even at highly visible locations.

The project area is situated within identified Subwatershed 208 and Catchment 208-103-1 of the Powhatan Creek Watershed Management Plan. Specific stormwater strategies for this subwatershed and catchment include use of Special Stormwater Criteria for Stream Protection Areas, providing stormwater water quality treatment onsite, providing recharge with BMPs that allows for infiltration and filtering and use of more hydrologically sensitive stormwater management in the New Town area.

Conversion of the existing landscaped area into a bioretention basin will result in no new increase of impervious cover or runoff. It will provide an additional water quality benefit and will not result in a substantial increase in the existing water surface elevation at the existing inlet. No impacts are anticipated to existing utilities, the existing Courthouse building or to Monticello Avenue or it’s associated stormwater conveyance system. The bioretention basin will ultimately provide water quality treatment for approximately 2 acres of impervious cover within a 5.3-acre drainage area.