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

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

Environmental Setting

Environmental Setting

Environmental Setting

Environmental Setting

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

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

Need for Project

Need for Project

Need for Project

History of Project 1956 - sewer constructed 1996 - leak discovered and repaired 1998, 2000 - project included with private development proposals 2002 - Open Space District purchased property 2003 – liner installed in exposed section of pipe

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.

Alternatives

Typical arched culvert – alternatives 1, 2, & 3

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

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

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

Key Questions Why is the access road necessary?

Vac Truck Size

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

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.

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

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

Maintenance Access Road Extending up from Chanate Road

Location of the Retaining Wall

Retaining Wall

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

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.

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.

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.

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.

Placement of the sewer line outside of the creek setback area

Land Use

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

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.

Access on to Narrow Roadway

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.

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