Virginia DEQ
Home MenuPractice 16: Hydrodynamic Devices
DEQ has approved certain hydrodynamic devices for use in meeting the total phosphorus (TP) water quality requirements of the Virginia Stormwater Management Program (VSMP) regulation.
DEQ Evaluations
The devices listed here have been approved by DEQ in accordance with in accordance with § 62.1-44.15:28 of the Code of Virginia and 9VAC25-870-65 D of the Virginia Stormwater Management Program (VSMP) Regulation.
For each approved manufactured treatment device (MTD), the following information is provided:
- DEQ approval letter
- Web link to view specifications and other product information
- Vendor contact information
- Information reviewed by DEQ.
Sizing Information
To obtain the water quality credit assigned to a manufactured treatment device (MTD), the device must be properly sized. The MTD vendor and design professional are responsible for properly sizing a specific device for a given project.
DEQ recommends that designers and reviewers contact the MTD vendor for specific information regarding the type and size of device needed for each specific project.
To determine the MTD size needed for a project:
- Calculate the treatment volume to the device (TvBMP). The calculated TvBMP can be obtained from the Virginia Runoff Reduction Method (VRRM) spreadsheets.
- Calculate the peak discharge of the obtained treatment volume (qpTv). DEQ’s preferred method to calculate the peak discharge for a BMP drainage area is described here.
- Work with the MTD vendor to ensure that the obtained peak discharge to the device (qpTv) is less than or equal to the maximum treatment flow rate (MTFR) of the device (qpTv < MTFR).