Post-Project Appraisal for the Winter Creek Restoration Redwood Grove, UC Botanical Gardens at Berkeley
In fall 2009, the UC Botanical Gardens completed a restoration project on Winter Creek, a tributary to Strawberry Creek. The creek is located in the Redwood Grove on the north side of Centennial Drive, opposite the main gardens. The project was completed in response to severe erosion caused by a pipe culvert that carried runoff from the Lawrence Berkeley Laboratory (LBL) and other development in Strawberry Canyon. For this term project we conducted a post-project appraisal of the Winter Creek restoration to determine whether the restoration achieved its objectives. We obtained relevant project information from the project proponents via interviews and email communication. On three days in October and November 2010, we conducted cross sections, longitudinal profiles, and vegetation surveys. In order to learn more about the Winter Creek watershed upstream of our project site, we conducted a hydrological analysis. Although we only received draft pre-project data, our results show that the cross sections and longitudinal profile have not changed significantly over the first winter since the project construction was completed. Furthermore, we did not detect any significant erosion within the project site. These results are not surprising due to the substantial rock armoring that was utilized in this restoration plan. The planting plan we received from the project partners was preliminary and the UC Botanic Gardens negotiated changes in order to balance the restoration effort with its educational goals to teach visitors about California’s redwood ecosystems in this part of the Botanical Gardens. Our vegetation assessment was inconclusive. Our survey revealed that some species of plants, such as California azalea (Rhododendron occidentalis), were experiencing low survival at the project site. Other species, such as alumroot and wild ginger are annual species, which could not be observed in November. In conclusion, as of its first winter after installation, this project has been successful in reducing erosion and bank failure on Winter Creek in the Redwood Grove. As development continues upstream of the project site with the LBL’s continued expansion, additional runoff may cause additional erosion problems in the future. We would recommend that the UC Botanical Gardens and Campus Capital Projects continue on-going monitoring as well as work with LBL to mitigate its stormwater runoff through the implementation of low-impact design, such as bioswales, retention basins, and flow-through planters.