California Sea Grant College Program

This dissertation addresses the role that dynamic flow characteristics play in shaping the potential for significant ecosystem benefits from floodplain restoration. Mediterranean-climate river systems present challenges for restoring healthy floodplains because of the inter and intra-annual variability in stream flow, which has been dramatically reduced in an effort to control flooding and to provide a more consistent year-round water supply for human use. Habitat restoration efforts require that this reduced stream flow be altered in order to recover more naturally dynamic flow patterns and reconnect floodplains. This thesis defines and takes advantage of an eco-hydrology modeling framework to reveal how the ecological returns of different hydrologic alterations or restoration scenarios—including changes to the physical landscape and flow dynamics—influence habitat connectivity for freshwater biota. A method for quantifying benefits of expanding floodplain connectivity can highlight actions that might simultaneously reduce flood risk and restore ecological functions, such as supporting fish habitat benefits, food web productivity, and riparian vegetation establishment.