1. NORTH TRUNK SEWER REPLACEMENT PROJECT
A City of Santa Rosa Utilities Department CIP Project

2. Four Part Presentation
Project Need and History
Overview of Project Alternatives
Answers to Key Questions
Summary of Environmental Issues

3. Environmental Setting

4. Environmental Setting

5. Environmental Setting

6. Environmental Setting

7. Need for Project Service area: 700+ parcels Parker Hill Chanate

8. Need for Project
The existing sewer is almost 50 years old and is exposed within Paulin Creek

9. Need for Project

10. Need for Project

11. Need for Project

12. History of Project 1956 - sewer constructed
leak discovered and repaired
1998, project included with private development proposals
Open Space District purchased property
2003 – liner installed in exposed section of pipe

13. Project Alternatives Alternative 1 – existing alignment, deeper
Alternative 2 – modified alignment
Alternative 3 – additional modification to 2.
Alternative 4.1 – version of historically ‘ruled out’ alternative. Now preferred.

14. Alternatives

15. Typical arched culvert – alternatives 1, 2, & 3

16. Key Questions Why is the trench so deep for alternative 4.1?
Why is the access road necessary?
How much will it cost?

17. Key Questions
Why is the trench so deep for alternative 4.1?

18. Key Questions
Why is the trench so deep for alternative 4.1?

19. Key Questions
Why is the access road necessary?

20. Vac Truck Size

21. Key Questions How much will it cost?
Alternatives 1, 2, or 3 – Approximately $400k
Alternative 4.1 – Approximately $900k

22. Environmental Issues
The Project was reviewed in accordance with the California Environmental Quality Act (CEQA).
All impacts have been reduced to a less-than-significant level – Mitigated Negative Declaration prepared
Most impacts minimized through selection of Preferred Project.

23. Environmental Impacts
Aesthetics
Biological Resources
Geology & Seismicity
Hazards
Hydrology
Land Use
Noise
Traffic & Circulation

24. Aesthetics
Impacts:
Maintenance Access Road
Sewer Manholes/Aprons
Retaining Wall
Staging Area
Mitigation: Soil and Seed or decomposed granite over aggregate road base; color added to asphalt and wall; revegetation

25. Maintenance Access Road Extending up from Chanate Road

26. Location of the Retaining Wall

27. Retaining Wall

28. Biological Resources Impacts:
Removal of 8 trees (4 heritage trees)
Disturbance in staging area
Mitigation: Arborist on site; hand-digging near root zones; tree replacement per Santa Rosa Tree Ordinance; revegetation of staging area

29. Geology and Seismicity
Impacts:
Potential erosion from excavation of sewer trench
Proximity to the Rodgers Creek Fault
Mitigation: Construction during the dry season; best management practices for stock-piling of soils; use of flexible connections.

30. Hazards
Impacts:
Beneficial impact of removing active sewer from the creek;
some hazards related to excavation of deep trenches.
Mitigation: Emergency Response Plan in place prior to construction; excavation conducted in accordance with OSHA requirements.

31. Hydrology and Water Quality
Impacts:
Potential for sedimentation of Paulin Creek
Potential for encountering high ground water levels.
Mitigation: Construction during the dry season; placement of silt fencing around staging area and active construction zones; pump groundwater to active sewer.

32. Land Use
Impacts:
No substantial changes in use of the project site.
Project generally consistent with General Plan policies and creek setback.
Mitigation: New easement would be required for the change in alignment.

33. Placement of the sewer line outside of the creek setback area

34. Land Use

35. Noise
Impacts: typical construction noise during the construction period; some noise and vibration.
Mitigation: Limits on construction hours; equipment properly out-fitted.

36. Traffic and Circulation
Impact: Truck traffic during the construction period—staging of equipment and removal of soils.
Mitigation: On-site flagger; neighbors notified of project construction period.

37. Access on to Narrow Roadway

38. Mitigation Monitoring Program
A Mitigation Monitoring Program – ensure implementation of mitigation measures.
An Environmental Monitor would be part of the construction team to ensure protection of resources on the site.

39. Questions…? Topics Covered Project Need and History
Overview of Project Alternatives
Answers to Key Questions
Summary of Environmental Issues