Prisoners Harbor Coastal Wetland Restoration Project
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Channel Islands National Park National Park Service U.S. Department of the Interior Prisoners Harbor Coastal Wetland Restoration Project Final Environmental Impact Statement February 2010 Channel Islands National Park 1901 Spinnaker Drive Ventura, California 93001 This entire publication is available in PDF format at: http://www.nps.gov/chis/parkmgmt/planning.htm Front cover photo: Mouth of Cañada del Puerto creek, Prisoners Harbor, Channel Islands National Park (Power, 2006) Citation: National Park Service. 2010. Prisoners Harbor Coastal Wetland Restoration Plan. Channel Islands National Park, Ventura, CA. PRISONERS HARBOR COASTAL WETLAND RESTORATION PLAN FINAL ENVIRONMENTAL IMPACT STATEMENT Channel Islands National Park Santa Cruz Island, Santa Barbara County, California February, 2010 ABSTRACT This Final Environmental Impact Statement (FEIS) was prepared in accordance with the Department of Interior National Environmental Policy Act (NEPA), the National Park Service NEPA guidelines (DO-12), and the California Environmental Quality Act (CEQA). This document has been prepared because actions proposed as part of this Final EIS may be a major federal action significantly affecting the quality of the human environment. The National Park Service (NPS) proposes to restore a functional, self-sustaining ecosystem at a coastal wetland site known as Prisoners Harbor and a 40-acre associated stream corridor in the lower Cañada del Puerto Creek on Santa Cruz Island. The project seeks to: (1) recreate a more natural topography and hydrology by reconnecting the Cañada del Puerto stream with its floodplain and removing non-native eucalyptus trees and other vegetation which have proliferated in the lower drainage; (2) increase biological diversity and productivity by removing fill and restoring the historic wetland; (3) provide an enhanced visitor experience by installing viewing benches and additional interpretive displays; and (4) protect significant cultural and historic resources. The Preferred Alternative, Alternative B, would restore 3.1 acres of palustrine wetlands and deepwater habitat, remove all of the cattle corrals and relocate the scale house to its pre-1960s location, remove eucalyptus, control invasive species, construct a barrier to protect archaeological resources, and improve the visitor experience. In addition, a portion of the berm would be removed, thereby reconnecting the creek to its floodplain. Two additional alternatives are analyzed in this EIS: Alternative A (No Action) would not conduct any wetlands or riparian restoration activities; Alternative C would restore only 2.1 acres of wetlands, and leave two of the historic cattle corrals in place. For each alternative action, the Park analyzed the potential environmental impacts that would likely occur, divided into the following categories: Hydrologic Function, Wetlands and Floodplains, Water Quality, Wildlife, Vegetation, Archeological Resources, Historic Resources, and Visitor Experience. Alternative B is the Park’s Preferred Alternative, and the Environmentally Preferred Alternative. It would produce the most ecological benefits by enabling more improvements to water quality, stream shading, flood attenuation, and groundwater exchange. It would remove a resource that contributes to the eligibility of the Ranching District to the National Register-eligible Santa Cruz Island Ranching District, but the District would remain eligible. Impacts to the visitor experience from the loss of the corrals would be partially mitigated by documentation and displays of these features at the Park Visitor Center. As a delegated EIS the official responsible for final approval is the Regional Director, Pacific West Region. Thereafter, the Superintendent, Channel Islands National Park, would be responsible for implementation of the approved project and subsequent monitoring activities. Abstract - i Final Environmental Impact Statement Channel Islands National Park, Ventura, California PRISONERS HARBOR COASTAL WETLAND RESTORATION PLAN SUMMARY OF THE FINAL ENVIRONMENTAL IMPACT STATEMENT Introduction Santa Cruz Island is the largest of the Channel Islands off the coast of Southern California. It is home to a variety of wildlife including a significant number of plants and animals found nowhere else in the world, making Santa Cruz Island a bastion of biological diversity. Ninety percent of the island is listed in the National Register of Historic Places (NRHP) for its archeological significance and the island’s ranching resources have been determined eligible for the National Register of Historic Places. Channel Islands National Park was established to protect and restore these nationally significant resources. The National Park Service (NPS) proposes to restore a functional, self-sustaining ecosystem at a former 9-acre backbarrier coastal wetland site known as Prisoners Harbor and a 40-acre associated stream corridor in the lower Cañada del Puerto Creek on Santa Cruz Island. The proposed project area has been altered during the past 150 years by filling of the wetland; planting or accidental introduction of non-native vegetation such as eucalyptus, stone pines, and kikuyu grass, and construction of a berm, buildings, roads and corrals. The project seeks to: (1) recreate a more natural topography and hydrology by reconnecting the Cañada del Puerto stream with its floodplain and removing non- native eucalyptus trees and other vegetation which have proliferated in the lower drainage; (2) increase biological diversity and productivity by removing fill and restoring the historic wetland; (3) provide an enhanced visitor experience by installing viewing benches and additional interpretive displays; and (4) protect significant cultural and historic resources. The proposed project area supports three types of wetlands: Marine, Palustrine, and Riverine wetlands. Before they were degraded, these wetlands most likely included open water habitat, marsh wetlands dominated by short perennial herbaceous plants, marsh wetlands dominated by cattail and tule, seasonally dry creek bed and associated riparian forest, non-vegetated lagoon habitat, non-riparian willow scrub habitat, and transitional zones between these habitats. Greater diversity and interzonation of wetland habitats at the site would have supported greater diversity and abundance of native flora and fauna. In addition, the greater pre-historic wetland extent provided greater capacity and diversity of physical ecosystem services for biota. At Prisoners Harbor these would have included nutrient retention and cycling and organic soil development. Summary - i Prisoners Harbor Coastal Wetland Restoration Plan Final Environmental Impact Statement Description of the Alternatives The following screening criteria were used to develop and evaluate alternatives for consideration: Achievement of Project Goals and Objectives Hydrologic connection of the creek to the floodplain Groundwater levels and wetland restoration feasibility Area of wetland to be restored and the associated wetland ecosystem values Protection of archeological features Balanced use of mixed resources in the project area Visitor experience Protection and maintenance of the pier and road access The Preferred Alternative, Alternative B, would remove all of the cattle corrals and restore 3.1 acres of palustrine wetlands and deepwater habitat, relocate the scale house to its pre-1960s location, remove eucalyptus, control invasive species, construct a protective barrier around a portion of the archeological site, and improve the visitor experience. In addition, a portion of the berm would be removed, thereby reconnecting the creek to its floodplain. Alternative C differs from B in that it would remove six of the eight cattle corrals and restore 2.1 acres of palustrine wetlands and deepwater habitat, without relocating the scale house. It would also remove eucalyptus, control invasive species, construct a protective barrier around a portion of the archeological site, and improve the visitor experience. In addition, a portion of the berm would be removed, thereby reconnecting the creek to its floodplain. Activities proposed for the Prisoners Harbor restoration include: • Preparing the wetlands restoration area--The Park would start by aggressively targeting, removing, and disposing of known non-native invasive plants on the restoration area – such as kikuyu grass, fennel, and eucalyptus – using appropriate techniques. These removal and disposal techniques may include hand pulling, hand- or machine-excavation, chain sawing, burning, chipping, and/or application of herbicide. • Corral removal-- Under the supervision of park cultural resource specialists and after consultation with the State Historic Preservation Office, the scale house would be partially dismantled, lifted off its current foundation, stabilized on its new foundation in its pre-1960’s location, and reassembled (Alternative B only). The corrals would be dismantled along with other posts, troughs, and old concrete foundations. Alternative B includes dismantling all eight corrals; Alternative C would include dismantling six. • Partial Berm and Fill Removal—The Park would remove approximately 250 feet of the low berm that severed the hydraulic connection between lower Cañada del Puerto and its floodplain, excavate sand and rock fill to restore a portion of the buried wetlands, and then replant the restoration area with native wetland species. Summary - ii Prisoners Harbor Coastal Wetland Restoration Plan Final Environmental