For the purpose of evaluating the flow capacities of San Francisquito Creek and the major bridges on the creek, the US Army Corps of Engineers retained Noble Engineers to develop a one-dimensional HEC-RAS model of the creek. The modeled reach is from the mouth of the creek to approximately one mile upstream of Highway 280, with a total length of approximately 55,000 feet. This hydraulic model can further be used to assess future flood conditions, delineate floodplains, and assist in the development of alternatives for improved capacity and regional flood reduction.
After calibrating and verifying the HEC-RAS model using three historic flood events, the model was used to simulate another four historic flood events that caused flooding of the creek. The existing flow capacities of the creek and bridges were evaluated based on the model simulations for a series of flow discharges. A sensitivity analysis was also conducted to test how the Manning’s roughness coefficient impacts the predicted flow capacities. The calibrated hydraulic model will seve as an important tool in the development of the remainder of the San Francisquito Creek Flood Damage Reduction and Ecosystem Restoration feasibility study.
The San Francisquito Creek Hydraulic Study is posted below. In addition to the written report, there are figures posted below that depict stream profiles during selected storm events.
