Erosion Prevention and Sediment Control
Above Images Courtesy of Rogue Valley Sewer Services.
Types of Erosion
- Raindrop erosion (splash) – Raindrop erosion occurs when rain disperses and mobilizes soil particles on contact.
- Sheet erosion - Sheet and rill erosion occur when rain drops and surface flows cause shallow stripping of soil.
- Rill erosion - Rill erosion occurs when surface flows become concentrated and begin to erode the surface.
- Gully erosion - Gully erosion occurs when concentrated flows cause sharp sided entrenched channels deeper than 0.5 meters.
- Stream bank (channel) erosion - Stream bank erosion occurs when streams begin cutting deeper and wider channels as a consequence of increased peak flows or the removal of local protecting vegetation.
Selected definitions adapted from DPI 2005
Impacts of Erosion
Problems resulting from erosion and sedimentation include:
- polluting lakes, wetlands, creeks, and rivers (dirt is a pollutant).
- loss of system capacity and damage to infrastructure leads to flooding and costly system repairs.
- aquatic habitat loss - sediment covers fish habitat and can smother eggs.
- loss of valuable soil (e.g., topsoil).
Human Influences on Erosion
Soil erosion is a natural process that averages 0.2 tons per acre annually. Humans greatly accelerate the process! The loss rate is accelerated to:
- 0.5 tons per acre for managed forests.
- 1.5 to 20 tons per acre for pasture and cultivated lands.
- 150 to 200 tons per acre for unprotected construction sites.
What Can Be Done?
- Develop and implement erosion prevention and sediment control programs (muncipalities).
- Develop and implement erosion control plans for construction activities (Example).
- Incorporate best management practices (e.g., rain gardens, swales, planter boxes) to reduce the amount of water running off your property (homeowners).
- Schedule construction and ground disturbing activities for the dry season or to avoid heavy rain.
- Retain native trees and brush cover on the site. Use native trees in landscaping.
- Cover bare soil before it rains. Use mulch, erosion control blankets, and other materials.
- Protect storm drains. Example.
- Learn more about erosion prevention and sediment control measures.
Regional Stormwater Management
- Bear Creek Watershed (Ashland, Talent, Phoenix, Medford, Central Point, Rogue Valley Sewer Services, and Jackson County).
- Rogue Basin (Grants Pass, Shady Cove, Eagle Point, Cave Junction, Rogue River, Gold Hill, Butte Falls, Gold Beach, Jackson County, Josephine County, and Curry County).