• Site topographic surveying
• Reservoir design flood and hydraulic assessment
• Water Rights Permit evaluation and reporting
• Hydraulic and geomorphic analysis and design
• Ecohydrologic functions assessment
• Regulatory agency permitting support
• Engineering plan and specifications preparation
• Field construction supervision and post-construction monitoring

Clearwater Hydrology assisted the Bar X Ranch with the preparation of a Long Term Erosion Control and Mitigation Plan in conjunction with remediation of severe dam outlet channel erosion and permit compliance efforts. The channel erosion immediately downstream of the concrete dam spillway occurred following dam and reservoir construction in 2004. Clearwater Hydrology conducted an existing (post-erosion) condition topographic survey which served as the baseline mapping for the restoration design. Hydraulic modeling software was used to determine design flow depths and channel shear stresses. The upper reach of the project included the spillway outlet channel and an adjoining transition reach to the channel not disturbed during reservoir construction. Design of the upper channel segment featured step-pool and rapid-pool morphologies with a structural emphasis to convey the high-energy, clear water spillway discharges. The skeleton of the constructed cascade consisted of boulder weirs and pools, with transitional bed gradients of 7.4% and 3.5% (rapid-pool sub-reach).

The lower reach included the restoration of a channel segment highly destabilized from cattle activity, and the filling of a non-permitted stock pond. The pond was originally constructed off-stream, but the erosive spillway flows that occurred during the first year following dam and spillway construction (designed by others) had caused channel migration which resulted in a capture of the pond. Willow walls were selected as the major component of the lower reach restoration to provide sufficient erosion protection around the bends of the ribbon-like design channel, and to minimize the disturbance to the upper portion of this reach, which maintained in-channel wetland plants in spite of the cattle grazing in these pasture lands. CH worked closely with the project biologist to design a restoration that would resist erosive flows from the reservoir, while providing some habitat value (i.e. the upper reach) and restore the historic fluvial system and ecology through the area formerly used as grazing pasture (i.e. the lower reach). Permit support was supplied as needed to correct the permit violations that occurred during the original dam and reservoir spillway construction. CH prepared engineering construction plans and specifications and supervised the construction of all aspects of the project, including the construction of the willow walls. Construction was completed in the fall of 2007.

Additional consulting services for the Trust regarding permitted reservoir site evaluation and impact assessment are currently underway.

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