Stormwater Runoff

Vegetation Management

Many SMFs rely on vegetation to filter sediment from stormwater before it reaches the SMF, prevent erosion of the banks and the bottom of the facility, and to take up and metabolize nutrients and other pollutants. Turf grass is the most common groundcover - although many SMFs use woody vegetation (rain gardens) and wetland plants (wet ponds) to increase pollutant removal. The following is a quick reference of ways to help your vegetation stay healthy.

Mowing. Most grass is hardiest if it is maintained as an upland meadow, cut no shorter than 6 to 8 inches. If a more manicured look is desired, special attention to the health of the turf is needed. Grass should never be cut below 4 inches. Grass on embankments should be cut at least twice during both growing seasons and once during the summer.
Pest and Weed Control. To reduce the amount of pollutants reaching the SMF, avoid over-fertilization and excess pesticide use. Your local Virginia Cooperative Extension office can provide additional information.
Removing Sediment Build-Up. Because vegetation surrounding a SMF is designed to trap sediment, it is likely to become laden with sediment and bare spots may emerge. Bare areas should be vigorously raked, backfilled if needed, and covered with top soil. Disturbed areas should be seeded (a tall fescue grass seed is recommended) and mulched. Excess material should be taken off-site and can be used as a mulch or soil supplement. If the soil becomes compacted, it will require aeration.
Unwanted Vegetation. Some vegetation is destructive to a SMF. Keeping dam and bottom areas free of deep-rooted vegetation (trees and bushes) is critical because roots can destabilize the structure. Consistent mowing and monitoring will control any unwanted vegetation
No Mow Zones. For wet ponds, an unmowed vegetated buffer around the perimeter of the facility (exclusive of the dam embankment) may be established to filter pollutants from adjacent properties and to help prevent shoreline erosion. Activities that have the potential to damage vegetation or compact the soil should be avoided. What may seem like a harmless activity (sports activities, inappropriate landscaping, etc.) could take years off the life of your facility. Before altering vegetation in a SMF, contact Albemarle County's Stormwater Manager, Repp Glaettli for guidance and a list of approved plants.