Comparing Futures for the Sacramento - San Joaquin Delta

10. Charting the Future for a Changing Delta

10 CHARTING THE FUTURE FOR A CHANGING DELTA Once a landscape has been established, its origins are repressed from memory. It takes on the appearance of an “object” which has been there, outside us, from the start. karatani kojin (1993), Origins of Japanese Literature To be successful, natural resources management must be able to adapt to changing conditions. This book has looked at the long-term management of California’s Sacramento–San Joaquin Delta, which faces inevitable changes in landscape, economy, and ecology, driven by sea-level rise, climate change,earthquakes,land subsidence,and biological invasions. Management objectives for this region have also been changing over time, as a consequence of long-term shifts in the societal values placed on the Delta’s ecosystem and the species that depend on it to thrive. Now we summarize our conclusions regarding the Delta’s changing landscape, the potential for improving the Delta’s ecosystem,the alternatives for managing water exports from the Delta,and the regulatory and governance challenges that lie ahead. Each of these issues must be addressed as part of a proactive management strategy for the new Delta. THE CHANGING DELTA LANDSCAPE Fundamental changes are inevitable for the Delta. “Restoring the Delta” is an unrealistic and perhaps meaningless notion given the historical changes that have occurred in the Delta and the immutable forces that will operate on it for decades to come. The Delta of the future will have fewer islands and more open water. 169 Increasing Risks of Island Failures Sea-level rise, earthquakes, continued land subsidence, and higher winter flood flows will increase the frequency of Delta island failures and the costs of preventing and recovering from failures. Under today’s risk conditions, most of the Delta’s subsided islands have at least a 90 percent chance of failing some time in the next 50 years. These drivers of change, including an escalating threat of earthquakes and sea-level rise of approximately one foot by 2050 and 3 feet by 2100, will significantly increase this likelihood of failure. High Costs of Prevention and Recovery Maintaining all Delta islands is not cost-effective. Reducing the frequency of island flooding in the Delta would cost many billions of dollars. From a water supply perspective, only the western Delta islands might be essential for keeping salinity away from export pumps in the southern Delta (before significant sea-level rise brings salinity farther into the Delta in any event). Continued investment in many islands in the northern,southern , and eastern Delta can be supported by the economic value of on-island activities and infrastructure such as roads and rail lines. But for nearly 20 subsided Delta islands, there is no compelling economic basis for state investments in levee upgrades or in repairing and restoring the islands after failure. Inevitable Shift to More OpenWater Given the magnitude of projected change during this century, it is unreasonable to assume that the current levee network will be maintained indefinitely at increasing costs and diminishing benefit. These costs,coupled with increasing risk factors, ensure that the Delta landscape of the future will be significantly different from the Delta of the past. Within the next 50 years, the Delta very likely will contain large areas of open water left after islands have flooded. Water quality will be substantially degraded for water export purposes,and perhaps improved for desirable fish species. A Need for Readiness California is unprepared for the changes that will occur in the Delta. Current institutions, regulations, infrastructure, and expectations for the Delta are built around maintaining the Delta in an unsustainable and charting the future for a chang ing de lta 170 deteriorating condition. It is time to prepare for a very different Delta, with a different ecosystem and different water supply and land use capabilities . With timely,purposeful action,there is some choice in what the Delta will become. California will need institutions with sufficient authority, finance , focus, and leadership to accomplish this transition successfully. FISH AND THE DELTA ECOSYSTEM Promising opportunities lie ahead for improving conditions for desirable fish and wildlife in the Delta. For fish, there is bound to be improvement in aquatic habitat as more is created by island flooding. Changes in water operations and habitat management can improve conditions not only for fish but also for other wildlife, especially waterfowl. Benefits of Island Flooding In recent years the Delta ecosystem has...