Restoration With Reference: Rediscovering Cerrito Creek in Blake Garden

This investigation focuses on potential improvements to the Blake Garden section of Cerrito Creek for both ecological and social reasons. Cerrito Creek runs through an urbanized watershed from the East Bay Hills to San Francisco Bay. Garden staff recently cleared nonnative invasive Himalayan blackberry (Rubus discolor) from several sections of the streambank, leaving it barren. We identified bank erosion and incision resulting from recent clearing and upstream urbanization as two issues to be addressed. The garden staff identified creek visibility and accessibility as their main concerns. To assess existing creek conditions and restoration objectives we completed longitudinal and cross sectional surveys, measured discharge from an on-site spring, and conducted interviews. We calculated creek discharge using the rational method, measured the surface area of two rooftops to estimate stormwater runoff, and measured discharge from a natural spring in the garden. Based on our assessment, we developed a creek restoration plan that addresses the hydrologic issues we identified, concurrently with those set by the garden staff. Our short-term recommendations include: jute netting and stream-bank plantings to stabilize the banks, constructing a step pool to reduce energy and provide an aesthetic water feature, and installing rain and stream gauges. Long-term recommendations include: geotextile reinforcement and regrading steep banks to improve access and safety, replacing downstream check dams with step pools, removing concrete (substituting alternative stabilization measures), reducing stormwater runoff onsite, and water harvesting from the natural spring. Future studies should monitor the rate of incision, evaluate the effectiveness of restoration measures, and assume an adaptive management approach