cbec is developing a current conditions digital elevation model (DEM) and HEC-RAS two-dimensional (2D) hydrodynamic model of the lower American River for the Sacramento Water Forum and the Sacramento Area Flood Control Agency (SAFCA). The DEM and 2D model will help facilitate future habitat restoration projects, flood impact analyses, and levee and bank erosion analyses.

To develop the current conditions DEM, cbec contracted Quantum Spatial to fly topobathymetric LiDAR (green and near-infrared sensors) while cbec collected single-beam sonar data in the deep pools. This effort will produce a high-resolution meter-scale DEM that will aid in the 2D modeling effort. In addition, the DEM will enable future work to understand topographic change and sediment budgets within LAR and support habitat restoration planning.

cbec is calibrating and validating two hydrodynamic models, an ecological flow model and a flood flow model. The ecological model will apply to flows ranging from 500 to 20,000 cfs. The flood model will apply to flows ranging from 20,000 to 160,000 cfs and will support geomorphic and flood impact analyses. In addition to client involvement, the flood model has been developed with input from MBK Engineers, Northwest Hydraulic Consultants, California Department of Water Resources, US Army Corps of Engineers, and the Lower American River Bank Protection Working Group.

This project is ongoing. For an in depth summary of our progress so far, click here.