City of St Helena Upper York Creek Ecosystem Restoration Project April 28, 2015 St. Helena City Council Meeting

Background

1900 – Dam constructed 1930’s - Ceased use as a water source 1965 to 1992 – Four incidents of accidental, catastrophic release of sediment resulting in fish mortality July 28, 1992 – Accidental sediment discharge during maintenance results in complaint filed with Napa County District Attorney

Background March 2002 – City formally abandons right to divert water from York Creek into Upper York Creek Reservoir 2004 – Downstream diversion to Lower York Creek Reservoir removed February 2006 – Agreement with NOAA to pay $70,000, and $70 per day the dam is in place after December 1, 2009 September 19, 2006 – Notice of Preparation of Draft EIR

Background October 18, 2006 – Initial public comment period closed and no comments received April 19, 2007 – City noticed for additional comments through June 4, No comments received. May 31, No comments received. City noticed for additional comments through July 25, 2007 July 26, 2007 – One comment received. City sent to residents on Bieber Road and extended public comment period to August 29, 2007

Background August 30, 2007 – City noticed for additional comments through October 15, October 2007 – Public comment period extended to November 14, 2007, due to request from State Water Board September 2006 to October 2007 – Four public meetings were held August 2010 – Agreement with NOAA to remove the dam and establish fish passage. Beginning October 31, 2012, City will pay NOAA $70 per day that dam is in place.

Project Scope Modify dam to allow fish passage Remove accumulated sediment Maintain stability of Spring Mountain Road

Project Alternatives Full Removal Small Notch Alternative (preferred alternative) Fish Ladder

Project Alternatives

Project Scope Small Notch Alternative DAM EMBANKMENT

Project Scope Small Notch Alternative EXIST. GROUND (DAM) PROPOSED GROUND

Project Scope Current funding: Funding SourceAmount SFWQIF$ 987,876 Proposition 84 IRWMP $ 800,000 City Bond Funds$ 3,016,349 Unidentified$ 1,695,775 Total Project Cost$ 6,500,000

Project Impacts Significant and Unavoidable (4) 1.Aesthetics – Placement of soil at Lower Reservoir may result in a change in the water surface area as viewed from above a)Mitigation – Plant native vegetation 2.Cultural Resources – Dam is considered eligible for listing in the National Register of Historic Places and California Register of Historic Resources. a)Mitigation – Provide graphic and written documentation of the dam’s significance on the City’s website and displayed in a City building.

Project Impacts Significant and Unavoidable (4) 3.Hydrology & Hydraulics – Sediment aggradation in Lower York Creek may increase the frequency and severity of flooding a)Mitigation – implement a channel monitoring program, causative factors analysis, and program to improve channel capacity and promote sediment transport. 4.Noise – Temporary increase due to construction activities a)Mitigation – Work during daylight hours and efficiently schedule activities to minimize hours of noise

Action Open a public hearing for comment Certify the Environmental Impact Report Adopt CEQA Findings and Statement of Overriding Considerations Adopt Mitigation Monitoring and Reporting Plan Authorize staff to proceed with securing final funding and development of Project design and construction bidding documents

Future Identify and apply for grant funding to secure funding for current shortfall Prepare final design documents