Watershed Plan and Environmental Assessment: Flood Management and Water Quality Improvement
Cottonwood, ID

Planning & Funding Assistance. The NRCS has funded $600,000 for the City of Cottonwood to develop an Environmental Assessment and Watershed Plan, and intends to provide over $17M in additional funds through the PL-566 watershed program.  The Cottonwood Creek Flood Management project is structured to satisfy two funding objectives to address flooding and improve water quality within Cottonwood Creek Watershed.

Design Solutions. The Project will mitigate ongoing flooding in the City’s downtown business district that continues to damage numerous business and emergency facilities including the City Fire Station.  The project will implement flood damage reduction measures by removing a failing culvert that is used as a diversion for Cottonwood Creek and installation of new conveyance piping.  Detention basins are being reviewed to manage peak flows and optimize the size of conveyance piping to move floodwaters through the City.

Hydraulics & Water Quality. Improvements in watershed water quality will be attained by addressing toxic levels of ammonia currently discharged to Cottonwood Creek.  The proposed project includes a new storage & reuse reservoir to store treated effluent and land apply during the growing season.  Watershed water quality objectives will be satisfied through the elimination of stream discharge. The storage and reuse reservoir will store treated effluent water for a land application system to serve farmland with added benefit of enhanced production.