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Stormwater Management Pond Quick Reference Guide

QUICK REFERENCE GUIDE

Stormwater Management Ponds
Fairfax County, Virginia

KEY POINTS

  • All dry stormwater management ponds are designed to retain stormwater temporarily and drain within two to three three days after the rain stops.
  • The county maintainsmaintains over 1,000 dry ponds; an additional 400-500 dry ponds are privately maintained by the property owners.
  • The majority of wet ponds (between 200-300) are privately maintained by the property owners; only a few (less than 10) are maintained by the county. See below for maintenance contact information.
  • State and federal laws require that stormwater be controlled to prevent flooding and reduce pollutants. Stormwater management ponds are constructed to address these impacts of development.
  • A dry pond with a shallow wetland marsh provides better treatment of polluted stormwater and poses less of a mosquito problem than a dry pond with lawn grass because of natural controls such as the fish, frogs, and dragonflies associated with a wetland marsh ecosystem.
  • Mosquito larvae require a minimum of 7-10 days in standing water or other suitable breeding environments to produce mosquitoes.
  • The county has an inspection and treatment program for mosquito control through the Fairfax County Health Department (703-246-2300, TTY 703-591-6435).

DEFINITIONS

  • Wet Pond: A wet detention pond has a permanent pool of water ( wet pond photo ).
  • Dry Pond: A dry detention pond temporarily fills with water during a storm and retains it for up to 48 to 72 hours, but is dry most of the time ( dry pond photo ).
  • Flood Control Pond: A flood control pond is a dry pond that stores stormwater run-off and then releases it slowly over a one to two hour period. It performs very little pollution treatment.
  • Pollution Treatment Pond/Best Management Practice (BMP): A dry BMP is a dry pond that treats stormwater by retaining the water for 48 to 72 hours, allowing sediments and other pollutants to settle. All wet ponds are BMPs.
  • Shallow Wetland Marsh: A shallow wetland marsh is a dry pond with 6- to 18-inch deep pools of water planted with a variety of wetland grasses, flowers, shrubs, and trees.

COUNTY CONTACTS