Section 97. 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, but not limited to, 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 VSMP authority shall require compliance with subdivision 19 of 9VAC25-840-40 of the Erosion and Sediment Control Regulations, promulgated pursuant to the Erosion and Sediment Control Law.

C. The locality's VSMP 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 postdeveloped 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 VSMP 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, but are not limited to, the following:

1. Criteria and procedures for channel analysis and classification.

2. Procedures for channel data collection.

3. Criteria and procedures for the determination of the magnitude and frequency of natural sediment transport loads.

4. Criteria for the selection of proposed natural or manmade channel linings.

Historical Notes

Former 4VAC50-60-97 derived from Volume 27, Issue 26, eff. September 13, 2011; amended, Virginia Register Volume 29, Issue 04, eff. November 21, 2012; amended and renumbered, Virginia Register Volume 30, Issue 02, eff. October 23, 2013.

Statutory Authority

§§ 62.1-44.15:25 and 62.1-44.15:28 of the Code of Virginia.