A Project of the Napa County Resource Conservation District

1. Implementing Sediment and Pathogen TMDLs in the North Bay: Napa River WatershedLeigh Sharp, Executive DirectorNapa County Resource Conservation DistrictNovember 4, 2012 A Project of the Napa County Resource Conservation District in collaboration with North Bay Watershed Association and San Francisco Estuary Partnership with funding from the US EPA San Francisco Bay Water Quality Improvement Fund

2. Napa River TMDL Information • Listed for sediment, nutrients, pathogens • TMDLs adopted for sediment and pathogens • Sources of sediment • Channel incision & bank erosion, roads, gullies, and sheet erosion • associated with vineyards, grazing, rural lands, parks and open space, and public works • Sources of pathogens • On-site sewage disposal systems, sanitary sewer systems, municipal runoff, grazing lands, confined animal facilities

3. Major Project Tasks Implement Sediment TMDL in Napa River Watershed • Conduct outreach • Complete rural road assessments • Implement road improvements in Heath Canyon watershed Implement Pathogen TMDL in Napa River Watershed • Conduct outreach and education to land managers with confined animal facilities • Implement identified projects to manage runoff & erosion Coordinate with other NBWA partners Watershed Monitoring • Sediment and fisheries related monitoring

4. Humboldt County Accomplishments to Date: Road Treatments Roads influence the hydrology of a watershed • Poorly constructed and maintained roads concentrate runoff, increase erosion, and potentially deliver sediments to streams • Studies demonstrate that up to half of all anthropogenic sediment entering streams comes from road-related erosion

5. Excess sedimentation and increased runoff impairs stream function • May: • Pollute water supplies • Increase potential for flooding • Accelerate stream bank erosion and trigger landslides • Erode or harm riparian vegetation

6. Excess sedimentation impairs aquatic habitat • Suffocates fish eggs in spawning beds • Loss of aquatic habitat

7. Nothing in nature mimics a road……but roads are necessary Our goal is to treat roads with practices that are safe for travel and most mimic nature China

9. Sediment delivery from road-related erosion can be episodic or chronic • EPISODIC sediment delivery • Sediment delivery is episodic when it occurs as soils fail in response to storm events or other triggers. The delivery from a site may occur once, or in pulses over an indeterminate time period. Stream crossing washouts, road-related landslides, and gullying can produce episodic sediment delivery. • CHRONIC sediment delivery • Sediment delivery from road surfaces and cutbanks is chronic because it occurs continuously during rainfall events that produce surface runoff

10. Episodic sediment delivery results from poorly designed stream crossing Road surface Culvert Road fill Natural stream grade

11. Aggraded sediments above inlets can cause crossings to wash out Napa County

12. Channel scours below outlet Napa County: treated by RCD in 2009

13. Stream crossing fails and produces episodic sediment delivery Napa County: treated by RCD in 2009

14. Low impact design for a culverted stream crossing on a non-fish bearing stream Road surface (4% outslope) Trash rack Road fill (2:1 slope) Culvert Natural stream grade

15. Fail-safe features impede plugging of culverts and prevent sediment delivery if crossing floods Napa County: treatments in 2010

16. Examples from Heath Canyon Worktreated in 2011 Old culvert inlet New inlet set at grade

17. Examples from Heath Canyon treatments Old culvert outlet New outlet set in at base of fill

18. Old culvert outlet New outlet set in at base of fill New inlet set at grade

19. Armored fill crossings may be sufficient on seasonal-use roads

20. Sediment delivery from road-related erosion can be episodic or chronic • EPISODIC sediment delivery • Sediment delivery is episodic when it occurs as soils fail in response to storm events or other triggers. The delivery from a site may occur once, or in pulses over an indeterminate time period. Stream crossing washouts, road-related landslides, and gullying can produce episodic sediment delivery. • CHRONIC sediment delivery • Sediment delivery from road surfaces and cutbanks is chronic because it occurs continuously during rainfall events that produce surface runoff

21. Fine sediments are generated as vehicles mechanically break down the road surface

22. This is what happens to that powdery dust when it rains Napa County

23. Physical features show surface lowering over time Exposed culvert Napa County: treated by RCD in 2011

24. Shape of road surface can concentrate flow and promote erosion Berm Napa County: treated by RCD in 2009 Runoff Before

25. Low impact road surface design disperses flow across the landscape Rolling dip • Ditch • removed • Berm • removed Runoff Outsloping Napa County: treated by RCD in 2009 After

26. Examples from Heath Canyon Work treated in 2011 Rolling Dips Runoff Runoff Road runoff from side road treated separately, runoff dispersed via rolling dips (away from gully and stream) Road runoff from both roads delivering to a gully and a stream

27. Runoff Before

28. Rolling Dip Runoff After

29. Preliminary Numbers • 6,144 yd3 of sediment delivery to waterways avoided • 4.71 miles of road treated • 32 stream crossings upgraded • 83 rolling dips installed Napa County: No treatment needed

30. Use the right tool for the job Napa County: RCD treatments 2009-2011

31. Plan for cultural resources too Napa County: RCD Treatments 2011

32. Additional Funding Partners • California Department of Fish and Game • Napa County (Measure A) • California Department of Conservation • Private Landowner Napa County: treatment by RCD in 2010

33. Next Steps…… • Complete additional road assessments • Work with rural landowners with confined animals • Develop more QAPPs