West Desert Hot Springs, CA
PACE developed the Master Drainage Plan for a 47 square mile portion of Palm Springs and Desert Hot Springs within Coachella Valley, which previously did not have formalized Master Drainage Plans. The formalized drainage plan identifies regional solutions and ensures necessary implementation of the required flood control facilities associated with the many development areas in order to mitigate the flood hazards. A comprehensive GIS watershed mapping database was developed as a key planning tool and included all of the watershed characteristics and drainage facility planning constraints. The planning effort had to address many limiting physical and regulatory constraints in the plan formulation that included environmental as well as the flood hazards and fluvial characteristics of the alluvial fan. The flood control/drainage facility Master Plan work program could be divided between the planning efforts for two general categories of drainage systems that include the (1) regional flood control facilities, and (2) local subregional drainage facilities. The general steps of the planning process involved (1) baseline engineering analysis of the existing conditions, (2) constraint identification, (3) alternatives plan formulation, (4) engineering analysis of the alternatives and facility sizing, (5) alternatives feasibility screening and selection analysis, and (6) refined engineering analysis of the recommended facility. The team developed a range of conceptual regional flood alternatives and applied a sophisticated alternative screening process to numerically rank and select regional flood control solutions. A drainage facility implementation program was developed through a prioritization analysis and the resulting master plan document that serves as a comprehensive watershed planning guidance document. The plan resulted in 50 miles of storm drain pipes, 10.6 miles of levee systems, 9 stormwater flood control detention basins and 37 major storm drain systems.
Riverside County Flood Control and Water Conservation District