Final Public Notice HMGP 4308-303-035 Bethel Island, Contra Costa County, CA

FINAL PUBLIC NOTICE: Bethel Island Municipal Improvement District Drainage Pump Facility Project, Contra Costa County | HMGP 4308-303-035

The U.S. Department of Homeland Security’s Federal Emergency Management Agency (FEMA) proposes to provide federal financial assistance under the Hazard Mitigation Grant Program to the Bethel Island Municipal Improvement District, (sub-applicant) in Contra Costa County, California, to rehabilitate the existing ditch system along the Taylor Road drainage from Bethel Island Road to Canal Road (proposed action). Pursuant to Executive Order 11988 (Floodplain Management), Executive Order 11990 (Protection of Wetlands), and FEMA’s implementing regulations at Title 44 of the Code of Federal Regulations Part 9, FEMA hereby provides interested parties with a notice of its final decision and an explanation of the alternatives that were considered.

The overall purpose of the proposed action is to mitigate the flood risk to Bethel Island in Contra Costa County, California. The project will rehabilitate the existing ditch system along the Taylor Road drainage in western Bethel Island, from Canal Road to Bethel Island Road (38.034133, -121.670356 to 38.013146, -121.641080). The Taylor Road drainage is a system of earthen trapezoidal channels, corrugated metal culverts, and concrete box culverts that accepts stormwater runoff from eastern Bethel Island and conveys it to a series of pump stations for discharge into the surround system of sloughs. Elements of the ditch system that would be subject to rehabilitation include drainage outlets and culverts and rehabilitation and elevation of the existing Secondary Pump Station. Equipment that may be needed for the project includes pole saws and chain saws for vegetation clearing; excavators and mini front loaders for debris and sediment removal; excavators for culvert ditch reconstruction; and a flatbed truck and crane truck for pump installation. Existing roads and easements will be used to access all construction areas.

The project area is depicted on the FEMA Flood Insurance Rate Map (FIRM), Number 06013C0170G, effective 03/21/2017. The FIRM shows the proposed action lies within Special Flood Hazard Area Zone AE with an elevation of 9 feet, an area that has a 1-percent probability of flooding every year and where predicted floodwater elevations have been established, and within a Regulatory Floodway. The U.S. Fish and Wildlife Service National Wetlands Inventory Map shows the project is located within proximity to a wetland area. The wetlands identified are Riverine habitat (R1UBV) and Other (Pf).

Maps of the project area and its location inside the floodplain and wetlands are available for public inspection. Parties interested in receiving a copy of either map should contact the FEMA Region IX Environmental Officer using contact information provided in this notice.

Five alternatives to the proposed action were considered: Alternative 1: No Action; Alternative 2: Expansion of the Main Pump Station; Alternative 3: Rehabilitation of the Secondary Pump Station; Alternative 4: Construct a New Pump Station; and Alternative 5: Construct a New Retention Basin. Alternative 1 would result in no action being taken to mitigate flood hazards. This Alternative is not recommended because the risk of flood hazards, including damage to property and people, would remain. Alternative 2 includes replacing the failing drainage pipe, adding another pump and discharge pipe, and raising the pump station at or above the 100-year water level elevation. This Alternative is not recommended because it does not address the flooding issues on the lower side of Taylor Road near Bethel Island Road. Therefore, Alternative 2 is not feasible. Alternative 3 would consist of improving the aging pump system currently in place and elevating the pump station at or above the 100-year flood elevation. This Alternative is not recommended because it does not address the flooding issues on the upper side of Taylor Road near Canal Road and the main pump station. Therefore, Alternative 3 is not feasible. Alternative 4 includes constructing a third pumping facility for backup in case the main and secondary facilities become inoperable. This Alternative is not recommended because it would require BIMID to acquire property to construct a new pump station and would not resolve the flooding along Taylor Road. Therefore, Alternative 4 is not feasible. Alternative 5 includes constructing a retention basin on Bethel Island that would manage peak flows during high water events and would be able to control the timing of discharge to adjacent waterways. This Alternative is not recommended because it does not address the flooding issues identified in the drainage study. Therefore, Alternative 5 is not feasible. FEMA has determined that the proposed project is the only practicable alternative available; therefore, the proposed action must be taken at this location for the tank to serve its designed purpose.

The proposed action would have no significant adverse impact on the floodplain and wetlands and would benefit the area by minimizing the impact of floods on human health, safety, or welfare, and results in an increase to the useful life of a structure or facility. Contra Costa County has declared that the proposed action conforms to local floodplain standards, and would be responsible for the management, construction, and maintenance of the proposed action.

Additional information about FEMA’s proposed action may be requested by writing the FEMA Region IX Environmental Officer at FEMA, 1111 Broadway, Suite 1200, Oakland, California 94607, or fema-rix-ehp-documents@fema.dhs.gov. All requests should be received no later than 15 days after publication of this notice. No action will be taken before this date.