Upper York Creek Ecosystem Restoration Project

Upper York Creek Ecosystem Restoration and Aquatic Habitat Enhancement Project

The Project involved the partial removal of the Upper York Creek Dam with the overarching goal of restoring fish passage and habitat connectivity for steelhead trout (Oncorhynchus mykiss), reducing potential for future downstream degradation through low-flow fine sediment releases and their associated fish kills, and allowed for the restoration of approximately three acres of degraded riparian and aquatic habitat surrounding the dam and reservoir, including restoration of roughly two acres of native riparian forest.

Additional project elements for habitat restoration were developed through consultation with the National Marine Fisheries Service, the United States Department of Fish and Wildlife, and the California Department of Fish and Wildlife. Other refinements to the project objectives came through the Section 404 permitting process with the Army Corp of Engineers and the terms of the Section 401 Water Quality Certification through the San Francisco Regional Water Quality Control Board.

Specific Project Objectives

  • Improved fish passage and habitat connectivity. The project provided upstream passage to 1.7 miles of spawning and rearing habitat for steelhead and habitat connectivity for both anadromous and resident fish and for other aquatic and riparian species.
  • Reduced future downstream habitat degradation and fish kills. The project works to prevent potentially detrimental sediment releases during summer low-flow conditions that have caused fish and aquatic organism kills in the past. It provides a permanent solution to prevent short-term aquatic habitat impairment associated with possible dam breach/failure. (View the Upper York Creek Dam Removal)
  • Habitat restoration. The project restored approximately three acres of degraded riparian and aquatic habitat in the existing upper dam and reservoir area. Restoration of natural sediment transport processes occurred through the project site, with potential habitat improvement occurring in the downstream reaches of York Creek and the Napa River. Areas of the project site disturbed during construction activities were revegetated with a palette of multistory native plants. A diversity of habitats for aquatic, riparian, and terrestrial animals were enhanced.

The Notice of Preparation (NOP) for the Draft EIR, which initiated the environmental review process for the Project, was distributed to responsible agencies, interested parties, and the public on September 19, 2006. The 30-day Draft EIR scoping comment period initiated by the NOP was from September 19, 2006, to October 18, 2006. The Draft EIR was subsequently prepared and circulated for public review from April 19, 2007, to November 14, 2007. The initial public review period was set to close on June 4, 2007. In order to obtain more public participation, the City extended the public comment period four times to November 14, 2007. The Final EIR was then prepared, which includes a summary of the Draft EIR, a response to comments received during this extended Draft EIR public review period, as well as minor technical revisions and appendices prepared and added to address the comments. 

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