8th Street Drain Improvement

Desert Hot Springs, CA


PACE prepared the engineering design for the improvement of a critical storm drain facility located in the upper portion of the Desert Hot Springs watershed. Despite its location in one of the driest deserts in North America, the City of Desert Hot Springs, CA, is subject to occasional intense flooding, and portions of the City were constructed without adequate flood protection. The watershed extends 3,700 feet within 8th Street, and the proposed facilities range in size from 72-inch to 42-inch pipe diameters with multiple storm drain laterals on connecting streets. The storm drain is designed to convey and intercept the 100-year discharge to prevent flooding on 8th Street and the downstream locations within the City.


The system design had to address numerous complexities due to its need to intercept distributed surface flood flows on an urbanized alluvial fan with difficult physical constraints, including interference by multiple utilities, limited slope, and limited corridor width. PACE prepared a Technical Engineering Basis of Design Report with the hydrologic and hydraulic engineering analyses. Street capacity calculations, catch basin sizing, analysis of alternative alignments, and water surface pressure gradient (WSPG) were used to develop the water surface profile model. PACE provided construction drawings and an engineer’s estimate in compliance with policies set forth by the Riverside County Flood Control and Water Conservation District.


Key Features:

  • Complex urban hydrology
  • Two-dimensional hydraulic analysis
  • Urban drainage design
  • Local street flooding analysis
  • Plans, specifications, and estimates (PS&Es)
  • Detailed utility research / conflicts
  • Traffic control

Riverside County Flood Control & Water Conservation

Flood Control Systems, Stormwater Management / Flood Control