Storm Water Management and Erosion/Sediment Control

1. Storm Water Management and Erosion/Sediment Control • Storm water management reduces quantity, and improves quality, of runoff in the watershed • Site based approach reduces long term costs to community

2. Why Storm Water Management and Erosion/Sediment Control? • Required by EPA Phase II! • Protect health, safety and welfare • Reduce flood impacts • Reduce impacts to property • Reduce pollution in streams, rivers and Lake Erie

3. Low Impact Development • Low impact development works at individual sites to reduce surface flows, filter storm water, and disperse storage areas • Many solutions are lower cost than engineered approaches

4. Stormwater Topics • Water Quality • Water Quantity • Stream and Ditch Restoration and Management • Low Impact Development • Developed vs. Developing Communities

5. The Basics – Concepts: Water Quantity • Runoff: amount of precipitation and infiltration • Travel time: slope, flow depth/length, and roughness • Peak Discharge: Runoff, Travel Time, Watershed Size, Development Location, Timing of Rainfall, Storage Effect • Time of Concentration: Time from farthest reach to output point

6. Water Quantity ctd. • Impervious Surface: surface with minimal infiltration

7. Water Quantity ctd. • Bank Storage: storage and release within stream or ditch bank • Connection to floodplain is best • Flat subwatersheds are more sensitive to stormwater increases than those with terrain

8. Recommended Practices:Water Quantity Increase Infiltration, Reduce Speed, and Increase Storage (increase travel time) (mimic pre-development conditions): • Reduce impervious surface, increase perviousness • Improve storage and release on-site • Increase roughness • Decentralize/reduce concentration of flow • Take advantage of bank storage • Connect stream to floodplain

9. The Basics – Concepts:Water Quality • Sediments: construction runoff, soil disturbance, stream erosion • Nutrients: fertilizers, septic/animal wastes • Bacteria: sewer overflows, septic/animal wastes • Debris: dumping, sewer overflows • Hazardous wastes: poor storage, poor separation, inappropriate use of materials

10. Water Quality ctd. • BOD – Biological Oxygen Demand • Nutrients in water ABSORB oxygen as they break down • Aquatic life suffers

11. Recommended Practices:Water Quality • Minimize soil disturbance • Minimize water quantity increases in streams and ditches • Filter and settle out sediments and contaminants • Vegetate stream and ditch corridors • Improve storage and separation of materials • Maintain septic systems • Prevent illicit discharges and dumping

12. Stream/Floodplain Restoration • Habitat: vegetation, temperature, hydrology, water quality • Stream hydrology: meanders, pools, riffles, floodplain • Engineering: stream section, relationship to flow patterns of drainage area, floodplain Oxbow River and Stream Restoration

14. Agricultural Ditch Enhancement • Approximate stream morphology: 2-stage or hybrid section • Minimize “maintenance” • Vegetate

17. Stormwater Management BMPs • Require Stormwater Pollution Prevention Plans on development sites • Require developers to control the volume, rate, and quality of stormwater coming off sites • Require good quality installation, and use of low-maintenance facilities • Decentralize stormwater collection and conveyance • Minimize stream crossings • Retain and restore natural stream function • Enhance function of existing agricultural ditches

18. Roles in Storm Water Regulation • Ohio EPA: Water quality: If disturbing > 1 acre, EPA requires SWPPP • Local government must address water quantity issues • SWCDs and watershed groups may be involved in erosion/sediment control, storm water management plan reviews

19. Low Impact Development (LID) • Rain Garden • Vegetated filter strip

20. LID • Bioretention filters/strips • Catch basin insert

21. LID • Disconnect downspouts • Eliminate curb/gutter

22. LID • Pervious pavements

23. LID • Natural drainage basins (wet ponds with natural edge)

24. LID • Green roofs

25. Examples of LID Projects in Ohio • Ladue Trails, Geauga County: Bio-retention • Nottingham Woods, Geauga Co.: rain gardens • Sunset Ridge, Geauga: filter strip • Best Buy, Lorain: sand filter • Dollar General Store, Lorain: dry swales • Deer Valley, Lucas County: bio-retention

26. Advice for Developed Communities • Update and implement codes for low impact site design options (conservation development, compact development, riparian setbacks) • Update and implement codes for innovative stormwater techniques (LID, restore stream section, two-stage ditch section, bioretention, grass swales, rain gardens, etc) • Require provisions for management/maintenance • Improve control of illicit discharges

27. Advice for Developing Communities • Plan and map priority conservation areas, priority development areas, riparian and floodplain protection corridors • Implement codes for innovative site design • Implement codes for innovative stormwater management • Require management provisions

28. Stormwater Management Regulations: Two Types • Construction Runoff Control (AKA Erosion/Sediment Control): Water Quality – Requires SWPPP • Post-Construction Control: Water Quality AND Quantity – managed through SWPPP and SWMP

29. Erosion/Sediment Control: How it works • Requires preparation of a storm water pollution prevention plan (SWP3), or Abbreviated SWP3 • Establishes standards and preferred methods for control of sediment

30. Erosion/Sed Control: Methods • Nonstructural : site design and avoidance of disturbance in the first place • Stabilization: Covering/seeding disturbed areas • Runoff control: Diverting runoff from disturbed areas (swales, dikes, berms, etc.) • Sediment control measures: collecting sediment and keeping it on site (silt fences, settling ponds, storm sewer inlet protection)

31. Post-Construction Stormwater Management : How It Works • Requires Comprehensive Stormwater Management Plan for activities disturbing soil • Sets standards for volume, rate and quality of runoff from completed project • Sets standards for preferred methods and facilities

32. Post-Construction Stormwater Management: Methods • Structural practices acceptable to Ohio EPA: wet retention, dry retention, etc. • Nonstructural: site design, conservation development, minimizing disturbance, riparian/wetland setbacks • Low impact development practices: rain gardens, grassy swales, etc.

33. Both Types: Administrative Issues • Both types must be addressed – together or separate • Standards and practices must meet minimum OEPA standards • Should require compliance with State/Federal Regulations • Must require provisions for maintenance of facilities during and after construction

34. Administrative Issues continued • Who will have responsibility for plan review and inspection? • Who will have responsibility for long-term maintenance of facilities? • How will long term monitoring be handled? • Erosion/Sed Control - Must have authority to stop work immediately • Must have provisions for enforcement • Penalties – most are a misdemeanor

35. Recommended Review Process • Conceptual Plan Stage (“Sketch Plan”) -Pre-application meeting -Sketch Plan Submitted -Review on-site: riparian/wetland delineation 2) Preliminary Plan Stage -Preliminary Plan -determine applicability of state/federal regulations • Preliminary Improvement Plan Stage -Construction drawings -submit crossing, riparian setback, slope stabilization, stormwater etc plans (as required by regulation) -all permits/approvals in process (required) for final approval • Final Plat -record all easements, setbacks, agreements as required by regulation