1. 1 Structural Control Practices ©2002 Dr. Bradley C Paul

2. 2 Structural Control Practices  Storm water conveyance (ditches or channels) –line ditches to prevent sediment –actually size the ditch for the run off expected - don’t just go out for a digging party its easier to do it right the first time than retrofit  Use conveyances to keep process waters away from and separate from storm water

3. 3 Structural Controls  Use Diversion Dikes to block storm waters out of process areas –larger areas may require something more simple like ditches and berms  Build up industrial areas above the grade of surrounding ground –Use paving to funnel process waters to receiving points –Check for cracks to prevent discharges to groundwater

4. 4 More Structural Controls  Pave over spill areas and surround with containment barriers  Use Drip Pans for Minor Spills –Create structural depressions to channel spills to discrete areas for easy clean up with sorbants  Build covering structures for materials

5. 5 Erosion Prevention Programs  Try to maintain lines of vegetation even when disturbance is necessary –Vegetation spreads back easier from established strips –Established strips help to break run-off and erosion –Use increase planning needed to work around to reduce confinements that can cause spills and other problems

6. 6 More Erosion Prevention  Leave buffers around sensitive or problem areas –leave buffer zones around wetlands –put buffer zones around parking lots so that run-off can infiltrate before it goes some place  Stabilize stream banks so that erosion is reduced  Put down mulching matting and netting on erosion prone areas

7. 7 Still More on Erosion  Establish temporary seeding with fast growing species to stabilize soil  Resort to chemical stabilization –vinyls, rubbers, asphaultic materials to hold what can’t be vegetated be aware this can promote rapid run-off make sure your stabilizer is not a contaminant  Use grids of dikes and swells to break the speed of run-off

8. 8 Erosion Controls  Use pipe slope drains to collect and run water down sensitive slopes that could be eroded by run-off from other areas  Install Filter and Silt Fences  Can use staked straw bales as barriers  Use gravel or stone filter berms (since the material is a best management practice it usually can’t be a contaminant when used this way)

9. 9 Erosion Control  Higher gravel barrier that creates small water impoundment is a check dam –These can settle sediment out of water  Build inlet protection for storm water drains –These will have to be regularly inspected

10. 10 Use Sediment Basins  Often serve areas over 5 acres in size  Regular structure or mini-dam requires special features –dewatering outlet above sediment line has a finite sediment storage capacity before clean out is required capacity may be sized using Universal Soil Loss Equation –emergency overflow rip-raped discharge that spreads over an area –has set free board requirements –May need fences to handle liability problems with dumb kids drowning

11. 11 Infiltration Promotion  Many erosion control practices automatically promote infiltration of uncontacted waters  Porous pavements  Vegetation strips and grass swales  Infiltration Trenches –gravel filled trench to take water down may have to check hydrologic balance issues

12. 12 Finishing Out the Program  When all else fails consider water treatment  After the plan is developed use operating history and review of results to fine tune and repair busts in your plan