Delta Landscapes Executive Summary

The Sacramento-San Joaquin Delta supplies freshwater to a large portion of California’s cities and agriculture, supports an agricultural economy and culture, and is home to native wildlife found nowhere else in the world. This complex region is hampered by many environmental challenges, including an over-allocated water supply, invasive species, water quality problems, novel ecosystems that no longer support desired functions, aging infrastructure, and a complex management structure. Beyond these challenges, sea level rise, other impacts from climate change, and earthquakes pose significant risks to Delta ecosystems, agriculture and water supply. There is general consensus that ecosystem restoration and planning for future resilience needs to take place, within the context of the Delta’s unique culture and economy.

Imagining a healthy Delta ecosystem in the future and taking bold, concrete steps toward that future requires an understanding and vision of what that healthy ecosystem could look like. For a place as extensive, unique, and modified as the Delta, critical knowledge can be acquired through the study of the past, investigating the Delta as it existed just prior to the substantial human modifications of the past two centuries. Though the Delta is irrevocably altered, its history is still relevant. Underlying geologic and hydrologic processes still influence the landscape. Native species adapted to live in the historical ecosystems, so restoring functional landscapes that reflect historical patterns can increase the success of restoration efforts. 

The Delta Landscapes project investigates the historical ecosystems of the Delta and how they have been modified in the current landscape in order to produce a holistic, aspirational approach to restoration of desired ecological functions. The project goes beyond immediate planning horizons and mandated protection of particular species to explore how restoration of large-scale processes of sediment and water could drive a broad suite of ecological benefits. Restoration or emulation of such processes requires large areas and long time scales. The Delta Landscapes project produced three reports, summarized here, that speak to the past, present, and potential future Delta. The final report, A Delta Renewed, provides a framework for how individual projects planned in the near-term can contribute to a coherent, long-term vision of improving ecosystem function across the Delta. The purpose of this planning framework is to foster more effective and economical restoration of desired functions in a smaller footprint, because each project is contributing to improving a larger system, than could be achieved by projects planned in isolation that each focus on more narrow, varied benefits. The project is purposefully conceived to address only ecological benefits, in the context of a working agricultural landscape with critical water-supply and cultural considerations. The reports can contribute to discussions where social and economic benefits are also evaluated in planning the future Delta landscape. A Delta Renewed User Guide was developed to help different audiences access the information in this report and apply it effectively. 

This research was conducted at the request of the California Department of Fish and Game (CDFG) and the Ecosystem Restoration Program (ERP).