Erosion and Sediment Control
Erosion and Sediment Control on Construction Sites
What is erosion?
Soil erosion is the process of detachment and transportation of soil materials by water, wind, ice and gravity. Henrico County’s Erosion and Sediment Control Program deals with erosion resulting from (water) raindrop impact on un-stabilized soil, primarily during the development process.
Erosion does occur naturally without requiring human action. This type of erosion is called “geologic” erosion, and according to the Virginia Department of Conservation and Recreation, produces about 30 percent of the total sediment load generated in the United States. Soil erosion resulting from people’s use of land, called “accelerated” erosion, accounts for the remaining 70 percent. Surface mining, forestry, agriculture and construction are the major land use activities that cause “accelerated” erosion.
Henrico’s erosion and sediment control program focuses primarily on construction activities. Erosion resulting from these activities can be 200 times greater than the amount of erosion generated from cropland and 2,000 times greater than that naturally occurring in woodlands.
Why is erosion and sediment a problem?
When natural landscape is converted to build houses, subdivisions, shopping centers, and roads, sediment results from erosion of disturbed soil. Sediment from construction sites is a major contributor to water pollution, flooding, stream channel damage, decreased groundwater storage, slope failures, damage to adjacent and/or downstream properties, as well as causes of project delays and increased project costs when these problem issues need to be addressed.
Successful minimization of these impacts can be achieved more cost effectively and efficiently by preserving the existing vegetation and minimizing the amount of land disturbed at one time on a site. However, when this is not practical or possible, installation of erosion and sediment control (ESC) measures such as silt fence, construction entrances, sediment basins, and especially temporary and permanent seeding is necessary to prevent soil movement/loss in the first place, enhance project aesthetics, reduce complaints, and most importantly, eliminate appreciable damage to off-site receiving channels, property and natural resources.
What activities are considered land disturbing?
Land-disturbing activity in Henrico County is defined as any clearing (including removal of trees), grading, excavating, transporting or filling of land or any other activity that removes vegetation, root mat or topsoil that may result in soil erosion from water or wind and the movement of sediments. In Henrico County, land-disturbing activities equal to or exceeding 2,500 square feet in area require an approved erosion and sediment control plan.
However, the following 13 activities are specifically exempt from the definition and the erosion and sediment control plan requirements:
- Disturbed land areas of less than 2,500 square feet in size;
- Minor land-disturbing activities and individual home landscaping, repairs and maintenance work;
- Individual service connections;
- Installation, maintenance or repair of underground public utility lines when such activity is confined to an existing hard surfaced road, street or sidewalk;
- Septic tank lines or drainage fields unless included in an overall plan for land-disturbing activity relating to construction of the building to be served by the septic tank system;
- Surface or deep mining;
- Exploration or drilling for oil and gas including the well site, roads, feeder lines and off-site disposal areas;
- Tilling, planting or harvesting of agricultural, horticultural or forest crops, or livestock feedlot operations; including a specific list of engineering operations;
- Repair or rebuilding of the tracks, right-of-way, bridges, communication facilities and other related structures, and facilities of a railroad company;
- Agricultural engineering operations including but not limited to the construction of terraces, terrace outlets, check dams, desilting basins, dikes, ponds not required to comply with the provisions of the Virginia Dam Safety Act, ditches, strip-cropping, lister furrowing, contour cultivating, contour furrowing, land drainage and land irrigation;
- Installation of fence, sign, telephone, electric, or other kinds of posts or poles;
- Shore erosion control projects on tidal waters when the projects are approved by local wetlands boards, the Marine Resources Commission or the U. S. Army Corps of Engineers; and
- Emergency work to protect life, limb or property, and emergency repairs.
If you are uncertain as to whether or not a specific activity is regulated, contact John Mulligan, Senior Environmental Inspector at (804) 727-8328.