Weiss Associates

Key Project Elements:

  • Multidisciplinary project team to meet client objectives
  • Channel geomorphology analysis
  • Sedimentation and erosion control measures

Channel Geomorphology Study

Alameda County, California

The historic Niles and Sunol Dams were part of the City and County of San Francisco's water transmission system in the early 1900s. Weiss Associates conducted a channel geomorphology study for the removal of these dams to improve fish passage and to address public safety concerns at both dam sites.

The study evaluated whether allowing sediments stored behind both dams to naturally erode and transport downstream is a feasible alternative to excavating and end-hauling sediment. The scope of the study covered possible issues related to channel geomorphology and stability that would be created by the proposed project design. The project team conducted hydraulic modeling to evaluate the project design and assess whether it would lead to negative impacts on the channel geomorphology, such as significant scouring, bank erosion, reduction in natural lateral migration patterns of the channel, undercutting of remaining structure, any subsequent changes to the fluvial processes on Alameda Creek. The project team provided conclusions and recommendations on the initial design and identified other suitable alternatives.

Weiss Associates' services included evaluating fish passage, historic resources, channel geomorphology, and public safety concerns; hydraulic modeling of the fate and transport of sediment stored behind the dams; proposing an adaptive management plan for the partial removal of the dams; and, recommending dam removal alternatives to meet key geomorphology and fish passage issues.

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