Jun 12, 2012
The fate of the Sacramento-San Joaquin Delta is a notorious issue in California. As both the source of half of California's water and a sensitive, threatened ecosystem, it's been a bone of contention between environmentalists and industry for decades.
In an attempt to address the problem, Gov. Jerry Brown's administration will unveil a new management and restoration plan later this year. But how can anyone make sense of Delta habitats when the region has been altered by humans on a massive scale for nearly 200 years?
A new interactive website – a collaboration between Stanford's Bill Lane Center for the American West and KQED's QUEST, using research from the San Francisco Estuary Institute – offers non-specialists an intriguing glimpse into the historical Delta. Historical documents and some clever detective work reveal not only the dramatic changes the landscape has undergone since the early 19th century, but also some of the specific impacts that have put the Delta in its current threatened situation.
"Envisioning California's Delta As It Was" draws on a four-year historical ecology study led by Alison Whipple, a former Bill Lane Center intern, and is accompanied by a radio documentary by KQED reporter and Bill Lane Center media fellow Lauren Sommer. The site features dozens of interactive historical maps, highlights from the archival documents and a walk-through of the region's complex past.
"We wanted to craft an interactive guide to the findings and bring the report to a wider audience," said Geoff McGhee, the Lane Center's director for media and communications. "This is an important issue that most people tune out."
In order to reconstruct the habitat as it was in the 1800s, the researchers turned to a number of archival sources, including maps and historical accounts.
Writings from the time show that the Delta was characterized by "incredible richness and heterogeneity," according to Bill Lane Center Executive Director Jon Christensen. The Delta was a patchwork of wetland, grassland and forest, home to large mammals, including bears and beavers, and a famously productive fishery.
A particularly revealing find was the handwritten memoir of a duck hunter who had become lost in what he described as the "impenetrable tule swamp" that then covered the region. He describes a lake "which had the reputation of being the greatest of all the lake and marsh regions of the country for game." Although the lake was later drained, researchers have been able to identify the lake's original location.
After the Gold Rush
The first major ecological changes followed on the heels of the California Gold Rush. Sponsored by a new federal law that encouraged the drainage of "swamp and overflowed" land, the Delta began to undergo a process of "reclamation." Laborers built levees and channels to handle the Delta's frequent flooding. The tules were burned to make way for farmland.
Some of the changes immediately backfired. In order to spare steamboat operators from the Delta's winding tidal channels, a series of straight canals had been cut along major waterways. But without the mazy streams slowing tidal outflow, low tide suddenly resulted in water levels too low for boats.
Other effects were more gradual. Taking advantage of the region's salmon runs, commercial fishing and canning began soon after the Rush. Within 20 years, salmon populations began to drop noticeably. During the 20th century, other fish populations plummeted into endangered status.
New Estuary Institute findings illustrated on the website suggest that the decline is due not only to overfishing and habitat reduction, but to the effects of pumping Delta water on a massive scale. Removing freshwater at a rate of millions of gallons per minute allows saltwater to push farther into the Delta than ever before, altering the wetland ecosystem.
Gov. Jerry Brown's administration is working on a new Bay Delta Conservation Plan. Whatever the plan consists of, the researchers point out that the maps on the site do not constitute a blueprint for habitat restoration.
"But it informs the possibilities, as well as the limitations, of potential efforts," said Christensen.
The Bill Lane Center's primary goal was to spread this ecological research beyond academia. And in that sense, Christensen said, "This was a grand slam. We brought scientists and journalists together in a way that respected the integrity of the science and scholarship."
Jon Christensen, Bill Lane Center for the American West: (650) 759-6534 [email protected]
Max McClure, Stanford News Service: (650) 725-6737, [email protected]
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