Development activity can remove soil cover and increase the site’s susceptibility to erosion. This erosion, and the pollutants that can come from construction debris, can have an adverse impact on adjoining properties, the public storm drainage system and the health of our local streams. With the proper use of erosion prevention and sediment control (EPSC) measures, movement of pollutants and soil off of the site can be prevented and minimized
All development related activity within WES service districts is required to provide erosion prevention and sediment control (EPSC) measures as applicable. Sites which disturb 800 square feet or more are required to obtain Erosion Prevention and Sediment Control permit from WES. Also, all development activity within Clackamas County which disturbs 1-acre or greater is required to obtain a Department of Environmental Quality (DEQ) 1200-C Construction Stormwater (Erosion Control) Permit or a 1200-CN Permit.
Types of Erosion Prevention and Sediment Control Permits
Depending on the location, type and size of the development project, different EPSC permits and plans may be needed. The table below is a guide to help determine what is required. Following the table are descriptions of each of the permit types
|Disturbance Area||Permit Type(s) Needed|
|Gladstone, Rivergrove, and WES service districts: SWMACC & CCSD#1
(excluding Happy Valley)
|800 sq. ft. to less than 1 acre of disturbance (thru all phases)||
|1 acre to less than 5 of disturbance
(thru all phases)
|5 acres or more of disturbance
(thru all phases)
|All other areas in Clackamas County|
|1 acre or more of disturbance
(thru all phases)
(Check with DEQ)
WES Erosion Prevention and Sediment Control Permit
WES EPSC Permit is required if the development activity disturbs 800-sq. ft. or more. In order to obtain a WES EPSC Permit, please complete the WES EPSC Permit Application and plans as specified in the application. Typically this permit is issued for residential construction and small commercial/industrial additions and improvements.
Erosion Control 1200-CN Permit
For those sites that are 1 acre to less than 5 acres of disturbance and are located inside of Gladstone, Rivergrove, SWMACC or CCSD#1 (excluding the City of Happy Valley), a Department of Environmental Quality (DEQ) 1200-CN Construction Stormwater (Erosion Control) Permit will be issued by WES along with the WES EPSC permit. To obtain a 1200-CN permit the applicants must submit the required WES EPSC Permit application and 1200-CN template style erosion control plans to WES for review and approval. Click on You can download the WES EPSC Application or 1200-CN Templates to download from our website. Typically the 1200-CN permit is issued for small subdivisions, partitions, multi-family, commercial and industrial projects.
Erosion Control 1200-C Permit
For those sites that are 5 acres or more of disturbance within CCSD#1, SWMACC or Gladstone, or are 1 acre or more of disturbance outside of CCSD#1, SWMACC or Gladstone, a Department of Environmental Quality (DEQ) 1200-C Construction Stormwater (Erosion Control) Permit is required. To obtain a 1200-C permit the applicant must submit the required 1200-C application and template style erosion control plans to DEQ for review and approval. The DEQ 1200-C Templates are available from DEQ's 1200-C Construction Stormwater General Permit webpage. Typically the 1200-C permit is issued for large subdivisions, multi-family, commercial and industrial projects.
Erosion Control Resources
Erosion Prevention and Sediment Control Planning and Design Manual
The purpose of the Erosion Prevention and Sediment Control Planning and Design Manual is to provide a comprehensive and detailed approach towards controlling erosion on construction sites. It includes information regarding materials and installation practices. This manual was created in partnership with the cities of Gladstone, Happy Valley, Lake Oswego, Milwaukie, Oregon City, West Linn, Wilsonville and Oak Lodge Sanitary District and Clean Water Services.
Erosion Prevention and Sediment Control Training
Training in proper selection, installation and maintenance of EPSC measures is available from private sources. While WES does not approve or recommend any private training companies, the banner at the top of this page has training opportunities that WES has been notified of.
Erosion Control Inspections
An Initial Erosion Control inspection is required as part of the construction of a single family home, and shall be completed and approved prior to the contractor pouring the foundation or footings. All non-single family projects such as a commercial, industrial or multi-family shall have the Initial inspection completed and approved prior to any soil disturbance except for the installation of erosion control devices. Permittees must call WES to schedule the Initial Inspection. Monitoring inspections will occur periodically throughout the construction. A Final Erosion Control inspection must be requested by the permittee once the site has been permanently stabilized.
- Single Family Residences
To schedule a single family Initial or Final erosion control inspection use your building permit number and call Clackamas County automated inspection request line at 503-742-4720. Use code 201 for Initial Erosion Control inspections and 297 for Erosion Control Final inspections.
- Commercial and Other
To schedule an Initial or Final erosion control inspection for commercial, multi-family or industrial project call the WES main office number at 503-742-4567 and request to talk with a Development representative.