Erosion control inspections are required prior ground disturbing activity. Please provide plans, permit card and post address on-site. More information on Erosion Control Manual.
Temporary Erosion Control Measures (Inspection Code #200)
- There are several kinds of pre-construction erosion control measures
- Work site perimeter protection
- Install sediment fencing or construction fencing to keep mud and debris from washing off-site
(Note: Trench in and backfill silt fence. Provide silt fence or straw wattles around toe of stockpiles.)
- Sidewalk where it is below grade will trap sediments in run-off
- Use a gravel construction entrance
- Inlet protection such as catch basins or bio bags are good protection against run-off
- Cover earth stockpiles with weighted plastic checking regularly for movement and erosion of stockpile
- Contain construction wastes by covering them in a different location on-site or removing them from construction site
- Do not wash away accumulated mud. Instead, scrape or sweep it manually or with a vacuum sweeper.
- Continually maintain construction site to prevent any lapse in the temporary measures in place
Permanent Erosion Control Measures (Inspection Code #210)
Before issuance of a final approval on all residential or commercial construction sites, certain permanent erosion control measures must be inspected and approved. Provide approved plans, permit card and post address on-site. In order to prepare for your erosion control inspections (code 210) it is important to supply and demonstrate the following:
- Plant required trees and landscaping.
- Exposed soil must be stabilized. Acceptable ways to accomplish this are mulch, compost, bark dust, gravel or sod. Straw is not an acceptable material for permanent erosion control.
- Rain gutters and downspouts must be installed
- In seeded areas, grass or vegetation must cover at least 90 percent of exposed bare soil
- Ditches must be lined with rock. You may use gravel to slow velocity of water and filter run-off.
- All paved surfaces must be clean
- Remove stormdrain inlet protection and temporary erosion control measures when permanent erosion control is installed and site clean-up is completed
Other conditions may apply at your site that are not listed here. Please contact Site Development Staff at (503) 823-6892 for further information.
Permanent Erosion and Sediment Control on sloping sites (Inspection Code #210)
Drainage systems on sloping sites are needed to prevent erosion or remove sub-surface water from wet and steep slopes and should be installed and functional prior to installation of soil stabilization measures.
- Retaining walls are typically required for slopes exceeding a finished grade of 2 horizontal: 1 vertical. Approved plans must show all retaining walls that require a permit. Permits are required for retaining walls over four feet in height measured from the bottom of the footing to the top of the wall.
- Benching and terracing examples are tiered planters and vegetated cribwalls.
- Ground surface stabilization in highly erosive or unstable soils on sloping sites may require extra measures involving soil retaining systems such as retaining walls and bioengineering measures such as live stakes and brush mattresses. Erosion control blankets and netting can be installed permanently. Upon inspection, erosion blankets may use mulch or landscape plantings to hold soil in place.