HD11 - Evaluation of Environmental Concerns in the Upper Reaches of Buchanan Creek

Executive Summary:

Item 366 H in the 2018 – 2020 Biennium Budget provided funding to the Department of Environmental Quality (DEQ) for an evaluation of environmental concerns in the upper reaches of Buchanan Creek, a tributary of the Western Branch of the Lynnhaven River (2018 Special Session 1 Va. Acts Ch. 2). The budget language specifically stated that the study should address: 1) adequacy of the channel, 2) evaluation of shoreline deterioration, and 3) potential contamination from the former Birchwood Gardens private sewage treatment facility.

In September 2018, DEQ contracted with the Virginia Institute of Marine Science (VIMS) to conduct this study. VIMS worked on the project, in consultation with DEQ, through July 2019. To address the items included in the budget language, VIMS reviewed historical water quality data and stream assessments, surveyed the stream channel to evaluate the current channel depth and bank morphology, completed channel coring to characterize surficial sediment types and thicknesses, and conducted water quality monitoring at six locations, including three sites on Buchanan Creek, and one site each on Thalia Creek, Wolfsnare Creek, and the Western Branch of the Lynnhaven River.

The final report is attached, and includes the following major findings:

• The Buchanan Creek channel “has reached a state of geomorphological equilibrium and functions well in providing a conduit for stormwater flow, but is not suitable for much of its length for use by watercraft. Alterations of channel morphology may diminish water quality and contribute to bank instability. From a physical, chemical, and biological perspective the results of this study show that the channel is adequate."

• Historical data reviews show “the shorelines along the whole of Buchanan Creek to be relatively stable." VIMS does provide options for enhancing appropriate sections of Buchanan Creek with living shorelines, but concludes that “[t]he results of this study provide strong evidence that the shoreline deterioration is of little concern."

• The modeling and analyses from the study “provide evidence that any sewage treatment plant residues under Birchwood Malibu Park lands have minimal relative contributions to Buchanan Creek pollutant loads".

DEQ has reviewed the report and concurs with the technical findings presented. Regarding the possible management options presented in the report, please note that the findings or options contained in the report do not constitute approval of any project or eliminate the need to follow local, state and federal regulatory and permitting processes. This includes, for example, any local requirements pertaining to tree removal in the riparian zone to ensure compliance with the Chesapeake Bay Preservation Area Designation and Management Regulations (9VAC25-830).