Public Notice – Hunters Raw Water Pump Station Mitigation

FINAL PUBLIC NOTICE

 

HUNTER RAW WATER PUMP STATION MITIGATION (PHASE 2)

CALAVERAS COUNTY, CALIFORNIA

HMGP 4431-028-06

 

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 (HMGP) to Calaveras County Water District (Subapplicant) in Calaveras County, California, to increase the reliability of raw water delivery to Hunter’s Water Treatment Plant by upgrading/modernizing the pumping equipment and controls at Hunter Reservoir (proposed action). Pursuant to Executive Order 11988 (Floodplain Management), Executive Order 11990 (Wetlands Management), 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 purpose of the proposed action is to reduce the risk of infrastructure malfunction resulting from mudslides and protect the potable water supply for customers along the Ebbetts Pass Corridor. The proposed action consists of the following: 1) improving and replacing identified pump house equipment (i.e., some pipes and valves within and extending from the pump house); 2) replacing the existing three raw water intake pumps within the pump house with three new modern pumps and relocate the pump controls to the masonry mechanical building along the shoreline of Hunter Reservoir and near Mill Creek; 3) rehabilitating the existing masonry mechanical building along the shoreline (upland area) with new pump controls, doors, roof, electrical service, lighting, ventilation, and communications equipment; 4) replacing the existing 12-inch diameter water pipe (approximately 750 feet long of trenching) between the mechanical building and the surge tank with a larger 16-inch diameter water pipe, which would require trenching within and immediately abutting the Hunter Dam Road right-of-way to remove the existing pipe.

The project area is depicted on the FEMA Flood Insurance Rate Map (FIRM), Map Number 06009C0475E, effective date December 17, 2010. The FIRM shows that the proposed action lies within Zone A, an area that has a 1-percent probability of flooding every year and where predicted floodwater elevations have not been established. The U.S. Fish and Wildlife Service National Wetlands Inventory map shows riverine habitat within the project area.

A map of the project area and its location within the floodplain is available for public inspection. Parties interested in receiving a copy of the map should contact the FEMA Region 9 Environmental Officer using contact information provided in this notice.

Two alternatives to the proposed action were considered: Alternative 1: No Action Alternative; and Alternative 2: Floating Submersible Intake Valves. No action would be taken under Alternative 1 and the water pump station, intake pumps, and water piping at Hunter Reservoir would not be repaired or upgraded. This Alternative is not recommended because it would leave Calaveras County Water District at risk for water supply disruption during natural disaster situations. Alternative 2 included the installation of floating intake valves between the reservoir and the pump house to remove the valves from the reservoir bed, which would reduce sedimentation clogging. This Alternative is not recommended due to reservoir being too shallow to accommodate flooding intake valves. FEMA has determined that the proposed project is the only practicable alternative available; therefore, the proposed action must be in the floodplain. The proposed action would have no significant adverse impact on the floodplain and would benefit the area by improving water flow capacity, protecting infrastructure, and enhancing system reliability and resilience. Therefore, measures to minimize impacts on the floodplain are not necessary. The Calaveras County Water District 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.

Mill Creek is a perennial stream and considered riverine habitat, located immediately downstream from Hunter Reservoir, and is within the defined project area. No heavy equipment is anticipated to be needed within Mill Creek and no work below the ordinary high-water mark of Mill Creek is anticipated. Best management practices (BMPs) would be used to capture debris and prevent sediment from entering waterways. These BMPs would include silt fence or straw waddle around the perimeter of the disturbed soil areas. This would ensure the project would not affect the water quality in Hunter Reservoir or the perennial stream/riverine habitat below the reservoir.

Additional information about FEMA’s proposed action may be requested by writing the FEMA Region 9 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.