Virginia Administrative Code
Title 9 - ENVIRONMENT
Agency 25 - STATE WATER CONTROL BOARD
Chapter 875 - VIRGINIA EROSION AND STORMWATER MANAGEMENT REGULATION
Part V - Criteria and Requirements for Regulated Land-Disturbing Activities
Article 4 - Water Quantity and Water Quality Technical Criteria for Grandfathered Projects and Time Limits of Applicability Projects
Section 9VAC25-875-710 - Stream channel erosion

A. Properties and receiving waterways downstream of any land-disturbing activity shall be protected from erosion and damage due to changes in runoff rate of flow and hydrologic characteristics, including changes in volume, velocity, frequency, duration, and peak flow rate of stormwater runoff in accordance with the minimum design standards set out in this section.

B. The VESMP authority or department as the VSMP authority shall require compliance with subdivision 19 of 9VAC25-875-560.

C. The locality's VESMP authority may determine that some watersheds or receiving stream systems require enhanced criteria in order to address the increased frequency of bankfull flow conditions (top of bank) brought on by land-disturbing activities or where more stringent requirements are necessary to address total maximum daily load requirements or to protect exceptional waters. Therefore, in lieu of the reduction of the two-year post-developed peak rate of runoff as required in subsection B of this section, the land development project being considered shall provide 24-hour extended detention of the runoff generated by the one-year, 24-hour duration storm.

D. In addition to subsections B and C of this section, a locality's VESMP authority by local ordinance may in accordance with § 62.1-44.15:33 of the Code of Virginia, or the board by state regulation may adopt more stringent channel analysis criteria or design standards to ensure that the natural level of channel erosion, to the maximum extent practicable, will not increase due to the land-disturbing activities. These criteria may include the following: