Climate Change Modeling
Kamman Hydrology and Engineering California, USA
Rachel Kamman www.khe-inc.com
Dates of Performance:
Status of Project:
As part of the Watershed Restoration Planning and Design study for Novato Creek Watershed Hydraulics in Marin County, CA, USA, DSI supported Kamman Hydrology and Engineering (KHE) to develop a high resolution curvilinear orthogonal grid and model of the Novato Creek upstream of Hwy 37, including basins/floodplain, and masks to represent the levee system, with multiple weir/overflow sections to simulate level overtopping. This was combined with this a coarser domain wide model of the Novato Creek below Hwy 37 and above the tidal mud flats on San Pablo Bay. After calibrating this 2-D EFDC unsteady tidal hydraulics base case model, the next phase of the project saw DSI modeling and analyzing a suite of three practical and self-mitigating alternatives to the flood management system within Novato Creek and its tributaries. Phase III project goals included maintaining and improving the existing level of flood protection, reducing dredging costs and associated impacts, improving the efficiency of flood control operations and maintenance, utilizing and supporting natural processes, and adapting to climate change. KHE and DSI collaborated in application of the previously developed numerical models to complete the study. DSI provided model development and modeling analysis in the configuration and application of the model and performed simulations using the alternatives models, to analyze changes in tidal hydraulics and boundary shear stress. The final alternative modeling integrated changes in inflow boundary conditions to combine creek and bay land alternatives to support an integrated assessment of changes in watershed and bayland hydraulics. Evaluation of project alternatives was based on a comparison with existing conditions as described in prior phases of work, factoring in changes in local flood risks to existing community infrastructure at the project location, upstream and downstream; changes in spring tide inundation frequency and associated ecological regimes during low flow conditions; changes in hydraulic/sediment transport capacity and sediment aggradation/erosion within the area of influence of the alternative. Conclusions regarding predicted trends in sedimentation (aggradation and erosion) were based on comparative analysis between Existing Conditions and Alternatives. DSI also undertook development of EFDC_DSI and EFDC_Explorer to meet the unique needs of this project.