FM-5284-AZ Initial Notice

INITIAL PUBLIC NOTICE: Lower Spruce Wash Channel Resiliency, Coconino County, Arizona │ HMGP-5284-01-02

The U.S. Department of Homeland Security’s Federal Emergency Management Agency (FEMA) intends to provide federal financial assistance under the Hazard Mitigation Grant Program to the City of Flagstaff in Coconino County, Arizona, for flood mitigation improvements. The proposed actions would mitigate impacts from flood hazards by grading the channel bank slopes of Spruce Avenue Wash to increase channel capacity and reduce erosion potential, adding channel grade control structures to protect utility and trail crossings, and creating stream energy dissipation devices to slow flood flows. Pursuant to Executive Order 11988 (Floodplain 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 intent to carry out an action affecting a floodplain.

The purpose of the proposed action is to reduce flood hazards. The proposed action consists of 1) sloping the channel banks back with an excavator working from the top of the bank; 2) constructing three rock cross vane weirs to protect utility and trail crossings and help maintain the desired width to depth ratio; 3) installing natural rock structures to correct channel dimensions and energy gradients created by road and trail crossings; 4) installing brush revetments  at five areas and toe rock  at two areas along channel curves to reduce erosion;  and 6) revegetating slope banks with native grasses and shrubs.

The project area is in the 100-year floodplain as depicted on the FEMA Flood Insurance Rate Map (FIRM) Numbers 04005C6828G, effective date September 3, 2010. The FIRM shows that the project area lies within Zone AE, 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.

Additional information about FEMA’s proposed action, including maps showing the potential impacts on floodplains, may be obtained 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, or calling (510) 627-7027. All requests should be received within 15 days after publication of this notice.