This November 2016 report is titled “A Delta Renewed: A Guide to Science-Based Ecological Restoration in the Sacramento-San Joaquin Delta.”
It documents the Delta Landscapes Project of the SFEI-ASC’s Resilient Landscapes Program, and was prepared for the California Department of Fish and Wildlife and Ecosystem Restoration Program by the San Francisco Estuary Institute at the Aquatic Science Center in Richmond, California.
The Sacramento-San Joaquin Delta is an extremely complex landscape system that supports extensive cities, varied agriculture, recreational opportunities, commercial fisheries, and a huge water management apparatus, delivering water statewide for human enterprises. It also contains remnants of a vast system of marshes and waterways that historically supported a large and highly diverse endemic biota.
Multiple pressures from the growth in the human population of California are continuing to change the Delta ecosystem, leading to a decline in its ability to support the diversity of human benefits that it once provided. It is clear that we must proactively address this dilemma and devise ways to rehabilitate populations of native species and essential ecological functions of this remarkable landscape. If this is not addressed now, we confidently predict that the Delta will continue to change to a much less desirable state.
The Delta was altered over many decades; thus, reversing the decline of native plants and animals has proven difficult. Recovering native species that are adapted to historical habitat types and processes will require a new approach that emphasizes landscape repair processes at appropriate scales in space and time. These investments require large spaces that are bounded by natural features—channels, wetlands and uplands—not levees and roads.
We worry that reconnecting only small properties on subsided land bounded by levees will produce uncertain recovery regimes, limited ecosystem value, and social problems. A long view of landscape rehabilitation also affords flexibility for land acquisition, management of tidal energy, integration with human uses, and interim co-benefits from carbon sequestration, recreation, and terrestrial species conservation.
At this time the Delta is profoundly changed, perhaps irreversibly, by modified flow patterns, degraded water quality, alien species, land subsidence, and simplified, over-connected waterways. Robust policies that address some of these problems (flows, quality, alien species) could improve conditions quickly. However, reconciling competing values may render those measures only marginally effective. Recovering landscape forms, habitat types, and processes that favor native species is a more complex and longer-term undertaking. Land acquisition for restoration and environmental permitting are particularly challenging. Political pressures and policy timelines to complete projects quickly often run counter to the culture of risk-averse permitting agencies.
The purpose of the Aquatic Science Center is the promotion and delivery of science support functions and information management for governmental and non-governmental organizations with roles in water quality protection, policy development, and assessment.