• Flood frequency and peak flow analysis
• Hydraulic and fluvial geomorphic assessments
• Grading and construction plans and specifications preparations
• Regulatory permitting support
• Field Constructions supervision

Clearwater Hydrology (CH) analyzed the causes of hydraulic failure of a portion of the previous stream restoration designed and overseen by Dave Rosgen of Wildland Hydrology Consultants in Alvarado Park, a unit of the East Bay Regional Parks system. The January 1997 flood, with an estimated recurrence interval of 50-100 years for this area of the East Bay, caused channel adjustments through a steep step-pool reach that lead to the failure of a historic bank retaining wall segment. CH conducted a fluvial geomorphological assessment for the encompassing 600-ft. sub-reach of Wildcat Creek and prepared a revised channel restoration design for the reach. CH also supervised its implementation in the summer of 1997. Due to the emergency nature of the work, a rapid turnaround time was requested by the client.

CH completed the restoration hydraulic/geomorphic analysis and design, assisted in permit acquisition, and supervised construction of the project within a period of six months. Construction was accomplished in a narrow time line and accommodated two concurrent construction projects within the same channel reach, one for bridge repair and one for landslide/slope stabilization. A delay in planned subsurface drainage stabilization of an adjoining north bank landslide resulted in a 1.5 ft. southerly shift in the bank position during the following winter. The north bank native material revetment shifted en masse and retained its overall stability. Through its 11th year, the project retains its overall geomorphic stability and riparian regeneration is well advanced along the project reach.

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