The Chorro Flats Floodplain Reconnection project in Morro Bay, California is referred to as a successful restoration project because of the thorough planning process and consideration of geomorphic processes in the project design. The Chorro Flats project was part of a suite of projects in the Chorro Creek watershed intended to reduce the sediment load into Morro Bay, a highly productive estuary threatened by an increased rate of infill. In this paper, we present a post-project appraisal one decade after construction. We evaluate the project through several research questions that examine floodplain reconnection, sediment capture, geomorphic changes, and post-project monitoring. Due to a convergence of fortuitous factors and thorough planning, the project achieved sediment capture through floodplain reconnection. In addition, the project achieved its secondary goals to develop in-stream habitat and a healthy riparian zone. We found that monitoring efforts were difficult to replicate, and that continued monitoring of the project is essential to evaluate the lifespan of the project and potential downstream impacts.

While the problem of sedimentation slowly filling dams and reservoirs is innate to the structures, it is especially significant in Mediterranean climates that rely on reservoir storage to mitigate out-of-phase water availability and demand. Reservoirs and their impounding structures have significant impacts on in-stream and riparian ecosystems. Several preventative and mitigation measures have been designed by engineers to limit sediment accumulation and the ecological impacts of reservoirs. Dam removal has been documented to have significant environmental benefits for restoration of aquatic ecosystems and native fisheries but may also lead to eroded floodplains, impaired downstream habitat and loss of flood control capacity. The European Water Framework Directive (WFD) establishes goals and guidance designating “heavily modified water bodies” and achieving “good ecological potential,” but definitions of these terms are not clearly defined. In addition, sediment management is not explicitly addressed in WFD guidance, thus contributing to limited guidance on how reservoir sedimentation should be managed in Mediterranean climates. As a European Union member state and a Mediterranean-climate country, surface water and reservoir management in Portugal is undergoing several changes through actions to achieve WFD goals. We examine how WFD management guidance for reservoirs and their ecological status is currently being considered throughout Europe and in Portugal specifically.