The hydrologic cycle describes the continuous movement of water above, on, or below the land surface. Water on the surface is found locally in lakes, streams, and wetlands. Accumulation of snow and ice can also be considered surface waters. Below the surface, ground water and moisture within soils represent processes within the cycle. Precipitation, the predominant source of freshwater, exists above the ground in the atmosphere. With development of lands, interruptions to the hydrologic cycle create issues of increased volume and velocity of runoff within the watershed. Surfaces such as parking lots, roadways, and buildings (known as impervious surfaces) that do not allow water to penetrate or be absorbed creates flows of storm water that are conveyed to the storm sewer systems and ultimately to the downstream waterways. Increases in volumes associated with development accumulate downstream and present the potential for localized flooding and stream degradation.
To address adverse affects downstream, the Town of Blacksburg enforces a comprehensive stormwater management ordinance (PDF) through the development review process. The ordinance addresses potential flooding with peak flow reduction requirements and water quality through treatment of the first flush of runoff from impervious areas, which has been shown to carry the highest concentration of pollutant loads. Pollutant loads can be considered the "gunk" that gathers on impervious areas during dry periods, such as oil on parking lots. With the first half-inch of runoff, these pollutant loads are directed to a best management practice (BMP) that is designed to treat this runoff so that the conveyance of these pollutants to downstream channels is minimized. Pollutants that are transported downstream as a result of runoff from the land surface are considered as non-point source pollution, as opposed to point source pollution that can be identified to be released from a single, localized source.
The Town of Blacksburg is taking a proactive approach for addressing issues related to storm water management so as to protect the public health, properties, and downstream waterways from adverse affects that can result from stormwater runoff. A stormwater task force has been assembled for examination of a number of stormwater management issues such as regional storm water management and low impact development. The Town maintains a small municipal separate storm systems (MS4) permit that involves implementation of a Program Plan that includes number of programs and activities to reduce point and non-point pollution into the local storm sewer systems. The Town also participates as a member of the Total Maximum Daily Load (TMDL) Implementation Plan for Stroubles Creek which is intended to develop and implement strategies that limit pollutant loadings to the creek.
For information, please contact 540-961-1124 or email lhixon@blacksburg.gov.
Supplemental Documentation to the Stormwater Ordinance:
Compliance Information for the VSMP Permit:
The Department of Conservation and Recreation (DCR) has requested localities inform developers and contractors of the statewide requirement of obtaining the VSMP permit for land disturbing activities greater than 1 acre and meeting the VSMP regulations. Please visit the DCR website below for permit information.
http://www.dcr.virginia.gov/soil_&_water/vsmp.shtml
MS4 Permit and TMDL Program Information
MS4 Current Permit Cycle Annual Reports:
National Flood Insurance Program
The Town of Blacksburg is a participant in the National Flood Insurance Program which enables residents to purchase flood insurance as a financial protection against flood losses. FEMA provides communities with Flood Insurance Rate Maps (FIRM) that are used to identify flood hazards and assess flood risks. High risk flood zones (A and AE), also called special flood hazard areas, are subject to development restrictions based on the National Flood Insurance Program and the Town of Blacksburg's Floodplain Overlay District.