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Erosion Control / Surface Water Management Permit

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OLWS issues Erosion Control/Surface water Management Permits within its jurisdictional area for sites up to five (5) acres in size. All construction activities affecting areas 500 square feet or greater within OLWS shall obtain an Erosion Control/Surface Water Management Permit. Also, if 1000 square feet or more of new impervious area (roof and/or concrete/asphalt) then a stormwater plan is required as well. Construction activities affecting areas 250 square feet or greater within the undisturbed buffer, sensitive areas, or riparian areas must also obtain an Erosion Control/ Surface Water Management Permit. An Erosion Control/Surface Water Management Permit is also required to discharge to the Districts surface water system.

To calculate the “construction area” (also called a soil “disturbance area”), calculate the square footage of the structure(s) plus peripheral work areas such as foundation forms and backfill spoil areas, equipment pathway (from road or driveway to work area), or any other clearing or vegetation removal.

Likely Construction Scenarios Requiring An Erosion Control Permit

  • Accessory dwelling unit or accessory structure
  • Single family dwelling addition/expansion
  • Single family dwelling new construction
  • Commercial development or redevelopment
  • Grading or clearing
  • Grind and overlay existing asphalt
  • Other site development work

Distinctions

  1. Up to one acre in disturbance area, an “erosion control small lot” permit is required by OLWS.
     
  2. Between one (1) and five (5) acres of disturbance area, a 1200CN permit is required by OLWS.
     
  3. For sites with greater than five (5) acres of disturbed area, a 1200C permit is required from Oregon DEQ.

Review Time

OLWS review time is approximately two (2) weeks. OLWS highly suggests to apply for permit(s) the same week as Clackamas County or other building or development-related permits. OLWS also highly suggests to assure the initial permit application contains all the items listed on the respective permit page(s). If the application is incomplete, additional review time is needed.

What do I need to submit? 
  1. Complete an online permit application on Accela: https://aca.accela.com/OLWSD/ 
    Note: For instructions on how to set up and complete the application, click here.
     
  2. Create and upload an Erosion Control Plan to Accela. This document is uploaded electronically into the Accela permit system. Follow the steps below.
     
  3. The Erosion Control Plan must include the following: The site plan or plot plan used for the Clackamas County building permit can be used as a base. Download the Oregon DEQ example erosion plan and associated manual here. This is relevant to Erosion Control Small Lot (ESCL) permits. Use illustrations from Figure 4 on Page 6 of the Oregon Department of Environmental Quality's best management practices showing best management practices (PDF format; 300dpi minimum). Download an example plan here. This type of plan is appropriate to the following: Single family dwellings including additions, accessory dwelling units, garages, carports, decks, swimming pools and other Erosion Control Small Lot (ESCL) permits for sites between 500 square feet of disturbance and 1 acre of disturbance.
     
  4. For Erosion Control Small Lot (ESCL) permits, the base map/plan can be the "plot" plan used for Clackamas County's building permit. The two examples show the level of detail and type of plan that is expected to be submitted.
     
  5. OLWS primary erosion control interest in ESCP permits are the following: Functionally, retain exposed soil on site and prevent soil trespass (typically from rain events, but also wind) and track-out from equipment tires; Perimeter control such as erosion control fence; Construction entrance to prevent “track-out”; Concrete wash-out area designated on-site so it is not washed out in the public storm sewer system (diluted concrete harms salmon directly); “Spoils” or excavated soil piles being protected/covered; 
     
  6. The Erosion Control Plan should also include the following: Contour lines with elevations to show slope - simple additions or improvements to existing structures may use arrows to show direction of slope only if vertical grade dimensions are indicated;Storage site for excavated materials (soil stockpiles); Location of erosion control Best Management Practices: (e.g. silt fences, catch basin protection, stockpile covering, vegetative filter strip);Concrete washout. Select from three potential methods: straw bales, wood planks, or describe some other method. Drainage during construction - show drainage pattern/direction with an arrow; Drainage after construction - show drainage pattern/direction with an arrow.  Indicate gutter rain drains on proposed structure and proposed rain drain outlet method. Examples include the following: soakage trench, detention system, weep hole to curb or storm system, etc. Essentially, show where the gutter/downspout water is released;Site restoration - permanent landscaping for disturbance area. This should be described in the narrative. It could be on the plan as a plan note;Identify any adjacent or on-site open spaces, natural resources or features such as streams, wetlands and associated buffers. Contact Clackamas County to determine buffer dimensions;Identify and describe any historic localized flooding or surface water runoff issues. This can be described in the narrative.All relevant standard details. For example, if a construction entrance is proposed, attach Detail Drawing 224 from the erosion and sediment control detail drawings, click here.
     
  7. Compose an Erosion Control Narrative; reference example completed erosion control narrative below;If you think any of these items are not relevant to your project, please describe this in the narrative;
     
  8. If prompted, review comments on your plan by logging in and following these instructions.
     
  9. Pay fees at the online Accela portal: https://aca.accela.com/OLWSD/ 
     
  10. Following permit approval, schedule an erosion control inspection through your Accela account; See Attachment Below for Inspection Request Instructions.
Resources 

If you have questions, contact the Development Review Specialist at (503) 654-7765 or email permits@olws.org.

 

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