Extra erosion control measures are required starting in October

News Article

The rainy season is coming. For seven months, greater care must be taken to ensure dirt and sediments don't leave construction sites that involve ground-disturbing activity.

From Oct. 1 through April 30, an on-site erosion and sediment control manager must conduct and document regular inspections at least weekly. Additionally, inspections must occur within 24 hours of rain events exceeding one-half inch of rain measured within a 24-hour period by the nearest active rain gauge reported on the City of Portland HYDRA Rainfall Network.

Also from October through April, all denuded sites must be provided with temporary or permanent soil stabilization as soon as practicable and no more than two days after ground-disturbing activity occurs. Sports fields or playgrounds surrounded by vegetative cover or permanently installed curbing are exempt from this requirement.

Ground-disturbing activity is also prohibited between Oct. 1 and April 30 in environmental zones within the Balch Creek and Forest Park subdistricts of the Northwest Hills plan district.

Why erosion control is important

Erosion control is important for maintaining water quality and nutrients in soil. It is also important for protecting nearby streams and the fish and wildlife that inhabit them.

Sediments from disturbed soils can move onto neighboring properties and streets and into sewer systems and other bodies of water. Excessive sediment is a pollutant and damages the functions of both sewer systems and natural watersheds.

The Federal Clean Water Act requires state and local governments to minimize the potential for soil discharges and runoff to pollute nearby waters. Oregon law prohibits the discharge or placement of wastes into waters of the state and the discharge of waste that causes violations of water quality standards.

The Oregon Department of Environmental Quality grants the City of Portland a National Pollution Discharge Elimination System (NPDES) Municipal Separate Storm Sewer System (MS4) permit. The City must comply with all conditions of this permit and take measures to reduce pollutants in stormwater runoff from construction activity.

Where to find more information

For questions about erosion control requirements, or to report a possible violation, please visit the City of Portland's Erosion Control web pageor call the Erosion Control Hotline at 503-823-0900.