Construction stormwater best management practice – Drainage Ditch Projects
Contents
Drainage Ditch Projects
Use this guidance to determine whether a NPDES/SDS construction stormwater permit is needed for your drainage ditch project. To protect water quality, this permit requires best management practices (BMPs) for erosion prevention and sediment control. Using these types of BMPs will prevent sediment from entering surface waters during drainage ditch projects.
Background
Construction activities including clearing, grading, and excavating that will disturb one or more acres of land, or that are part of a common plan of development or sale that will disturb one or more acres of land, requires coverage under a NPDES/SDS construction stormwater permit.
However, construction activity does not include land disturbance of less than five acres for the purpose of “routine maintenance” that is performed to maintain the original line and grade, hydraulic capacity, and original purpose of the facility.
What is routine maintenance?
Examples of routine maintenance practices to maintain the original line and grade, hydraulic capacity, and original purpose of a drainage ditch may include:
- Routine removal of sediment
- Removal of isolated obstructions, such as beaver dams, trees or accumulated debris
- Routine repair of isolated erosion problems along ditch banks
What types of drainage ditch projects do not require a permit?
A public or private ditch clean out project can qualify as routine maintenance and not require NPDES/SDS construction stormwater permit coverage if you determine that all of the following apply to your project:
- The project will disturb less than five acres of land as part of the routine maintenance activity; and
- Clean out of a ditch will return the affected reach to the original line and grade, hydraulic capacity, and original purpose of the ditch; and
- Maintenance of the ditch is in compliance with state and federal wetland regulations, including the MN Wetland Conservation Act, and Section
404 of the Clean Water Act, as applicable; and
- Appropriate BMPs are used for erosion prevention and sediment control to avoid transport of sediment and associated contaminants that would violate water
quality standards downstream from the project area during maintenance and restabilization of the drainage ditch.
Because vegetation is key to erosion control in drainage ditches, routine maintenance should minimize the removal of desirable vegetation to the extent practical and should include prompt reestablishment of temporary and permanent cover on all soils exposed by maintenance operation (For example, daily seeding of appropriate temporary vegetation where grading is complete and establishment of permanent vegetation as soon as practical).
Projects located near outstanding resource value waters or impaired waters may require additional protections. For more information, contact the MPCA office located near you.
What types of drainage ditch projects are not routine maintenance and require a permit?
Drainage ditch repair or maintenance projects that will disturb equal to or greater than five acres of land are not considered routine maintenance and require NPDES/SDS construction stormwater permit coverage. A permit is also required for a public or private ditch project if:
- The project is to establish a new drainage ditch and will disturb one or more acres of land; or
- The project involves improvement of an existing drainage ditch and will disturb one or more acres of land; or
- The project involves repair by re-sloping of an existing drainage ditch and will disturb one or more acres of land.
Application materials
To get an application form and find more information about applying for permit coverage, visit the MPCA construction stormwater Web site at: www.pca.state.mn.us/water/stormwater/stormwaterc.html
More information=
General information:
Please call the Stormwater Hotline at 651-757-2119 or toll-free at 800-657-3804.
Technical information:
Your county Soil and Water Conservation District office can answer many questions about construction site erosion and sediment control practices. For further information, consult:
- Stormwater Compliance Assistance Tool Kit for Small Construction Operators, MPCA, www.pca.state.mn.us/publications/wq-strm2-09.pdf
- Protecting Water Quality in Urban Areas Manual, MPCA, www.pca.state.mn.us/water/pubs/swbmpmanual.html
- Stormwater Management for Construction Activities, U.S. EPA, http://cfpub1.epa.gov/npdes/stormwater/const.cfm (Go to Publications, then to Policy and Guidance Documents)
- Summary Guidance, U.S. EPA, www.epa.gov/npdes/pubs/owm0307.pdf