MCM 5: Post-Construction Stormwater Management
Stormwater Management Facilities (SMFs) reduce pollutants and/or flow through various methods involving natural and constructed water features, some of which are listed below. Virginia Tech has installed approximately 65 SMFs that treat approximately 450 acres.
Detention Ponds are basins in which outlets have been designed to reduce discharge rates or in some cases, to detain stormwater for a set time to allow particles and associated pollutants to settle out. Detention ponds provide water quantity control. Extended and Enhanced Extended Detention Ponds provide water quality control in addition to water quantity control.
Extended Detention Ponds (including Enhanced Extended Detention Ponds) are designed to receive and detain stormwater runoff for a prolonged period. This is achieved using an outlet device that regulates the flow out of the basin at a rate which reduces peak runoff rates, reduces flooding, and provides moderate pollutant removal. Extended and Enhanced Extended Detention Ponds provide water quality control in addition to water quantity control. Refer to the Virginia DEQ Stormwater Design Specification No. 15 for more information.
Retention Ponds are ponds that have a permanent pool of water throughout the year. These ponds treat incoming stormwater runoff by allowing particles to settle and allow biological uptake and microbial activity to take up nutrients. Refer to the Virginia DEQ Stormwater Specification No. 14 for more information.
Bioretention (including Basins and Filters) enhances the quality of stormwater runoff through the processes of absorption, filtration, volatilization, ion exchange, microbial activity, and decomposition prior to exfiltration into the surrounding soil mass (Basins) or prior to entering the underdrain system (Filters). Refer to the Virginia DEQ Stormwater Design Specification No. 9 for more information.
Vegetated Roofs are an excellent way to reduce the amount of water and pollutants that are normally associated with roof water runoff. Refer to the Virginia DEQ Stormwater Design Specification No.5 for more information
Native Meadows play an important role in the stormwater master plan at Virginia Tech. These native grasses enhance groundwater recharge and protect the streams they surround. There are nearly a dozen native meadow sites around campus.
Green Parking, when used in the right combination, can dramatically reduce impervious cover and reduce the amount of stormwater runoff.
Manufactured (Proprietary) SMFs are prefabricated stormwater treatment structures utilizing settling, filtration, absorptive/absorptive materials, vortex separation, vegetative components, and/or other appropriate technology to remove pollutants from stormwater runoff.
For additional information regarding design specifications and removal efficiencies for all stormwater management facilities, visit the Virginia DEQ Stormwater BMP Clearinghouse website.