Author(s): K. J. Christison; L. Lee; B. M. Chilibeck
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Keywords: No Keywords
Abstract: The Concrete V-Baffle Drop Structure (CVBDS) was conceptually designed as an replacement for a horizontal multiple step control structure for Stevens Creek, immediately upstream from the Highway 85 crossing near the end of Central Avenue in the city of Mountain View, California. Although the previous horizontal step structure was ideal for measuring discharge and water levels at an established gage station, the steps imposed a barrier for migratory steelhead trout and other native species. The CVBDS concept was considered acceptable for upstream migrating fish as it reduced the drop associated with horizontal steps and provided corridors of slower velocity along the channel banks. Also, the CVBDS was capable of maintaining water levels for discharge measurements at the existing gage. Analyses were performed for the CVBDS in a 1:18 scale physical hydraulic model for the Santa Clara Valley Water District (SCVWD). The model included a 150 m (500 ft) long reach of Stevens Creek extending approximately 25 m (80 ft) upstream from the SCVWD's Stream Gage Station 35, and 15 m (50 ft) beyond the downstream control weir located between the Highway85 bridge piers. Key objectives of the study were to develop a rating curve for the CVBDS and evaluate its performance in terms of fish passage during typical fish migration flow conditions.
Year: 2009