Images of flooding New Orleans – literally the destruction of a major American city and loss of much of its population – have increased awareness of flood risk in the US. In California, the Sacramento-San Joaquin Delta has been much in the news recently, as the fragility of its levees (long understood by experts, but only recently appreciated by the public) has attracted the governor’s attention, leading him to propose massive re-investment. But even with higher, heavier levees, will the Delta be safe from flooding? Given the unique characteristics of the Delta, does it make sense in the long run for us to build houses below sea level there? Or could alternative scenarios that preserve open-space and infrastructure values provide more benefit and less risk to the San Francisco-Sacramento-Stockton metropolitan region of the future?
In hopes that this fresh experience created a ‘teachable moment,’ the Department of Landscape Architecture and the College of Environmental Design held a two-day symposium, ReEnvisioning the Delta, to consider the implications of the Delta’s ongoing urbanization and to explore alternative futures for the region. The symposium featured presentations on the physical characteristics and unique functions of the Delta, emphasizing its key role for infrastructure, agriculture, and open space within the San Francisco-Sacramento-Stockton metropolis, and on the dynamics of urbanization in the Delta and the surrounding region.
Urbanizing lands below sea level in the Delta strikes many as manifestly unwise and dangerous. Nonetheless, it is occurring now, at a rapid rate. Hans Johnson presented population data showing that the Delta is the fastest growing region in California, with population increasing at rates even faster than developing nations. Panel presentations by Carol Whiteside (former mayor of Modesto), Marci Coglianese (former mayor of Rio Vista and member of the Delta Protection Commission), and John Cain (Natural Heritage Institute) explained how escalating housing prices and a pro-growth political environment in local government are creating the enormous pressure to urbanize flood-prone lands. The author of the Delta Protection Act, former State Senator Patrick Johnson, showed how even the Delta Protection Commission established by the Act is not immune from these incentives to sprawling growth.
Bob Twiss presented an overflight of the Delta landscape that showed how these developments are consuming critical lands at the edge of the Delta that may be essential for future ecosystem management. Graduate student research completed for this symposium also projected future urbanization from general plans, proposed development footprints, aerial imagery, and other relevant GIS data layers. This is the first spatially explicit analysis of urbanization below sea level in the Delta and the likely consequences of that urbanization in the event of catastrophic flooding.
And that disaster potential is escalating. UCB Engineering Professor Ray Seed, who has just completed an NSF-funded study of levee failures in New Orleans, argued that the levees in the Delta are extraordinarily vulnerable to an earthquake-induced mass failure (although techniques exist to make them safe through extended public investment). The current 100-year flood protection standard to which the levees are built, meanwhile, leaves a very significant “residual risk” of a larger-than-100-year flood that could be immensely destructive. Tom Philp of the Sacramento Bee moderated panelists Mike Webb (California Building Industry Association), Ron Baldwin, (Director San Joaquin County Emergency Operations), and Tom Zuckerman (University Pacific, former counsel Central Delta Water District) in a discussion of the varying opinions on how to moderate disaster risks and who should be responsible for levee safety and potential liability.
The second day examined potential futures for the Delta, focusing on the Delta not as a set of problems, but as a place with its own unique history and character. As Jane Wolff, author of the Delta Primer, pointed out, it is a place that can be seen in several different ways — as at once an open space, an agricultural region, a wetland habitat, a recreational region, and an economic resource.
Subsequent talks shared the experience of land conservation efforts for each of these types of landscapes. Louise Mozingo argued that the creation of Central Park in New York and the Emerald Necklace in Boston show that recreational open spaces can be formed in advance of urbanization. Phyllis Faber showed that the history of agricultural land conservation in Marin County contains valuable lessons for the situation Delta farmers are facing. Bob Twiss talked about the land-use controls undertaken at Lake Tahoe to protect water quality, another pressing issue for the Delta today. Santa Monica Mountains Conservancy director Joe Edmiston advocated the use of a state-sponsored Conservancy model to protect conservation values in the Delta. Joe Bodovitz recounted the balancing of conservation and development in San Francisco Bay planning, and Pete Rhoads talked about the enormous planning effort underway to restore the Everglades. The Delta bears important similarities to each of these cases. Other panels, including such notables as John King of the San Francisco Chronicle, Margit Aramburu, formerly of the Delta Protection Commission, and Tom Waters of the US Army Corps of Engineers, expounded on some of these similarities and offered suggestions for moving forward in the Delta.
Innovative ideas for preservation of the Delta’s critical infrastructure, agriculture, and open-space access were also presented by Jennifer Brooke on behalf of the graduate students involved in the annual Tommy Church Design Competition. Interdisciplinary student teams developed plans and designs for a Delta park, recognizing its central role in the San Francisco-Sacramento-Stockton metropolis of the future. The jury awarded two first prizes to the teams of “Wet Feet Wanted,” (Elke Grommes, Mei Minohara, and Zachary Rutz), and “Delta Byways,” (Brooke Ray Smith and Stephen Miller).
Between historical precedents and visionary designs for the Delta’s future, there was no shortage of thought-provoking ideas for this critical region of California. What is needed, participants agreed, is better planning data and, more importantly, a widely shared vision for what the Delta should look like in the future. With the urbanization problem now on the political radar screen, planning efforts can now turn to the challenge of creating that vision of a more secure and resilient Delta region.