Water skiers ply the gray-green river within view of his front porch. A short walk from his home, he can cast off to fish for sturgeon, salmon and striped bass. His two children ran wild exploring the farm fields, private marinas and hideaways of the fertile islands where the Sacramento and San Joaquin rivers twine.
Saathoff's idyllic life may not last forever. By the time his 11-year-old grandson is ready to have children of his own, scientists predict the delta's network of islands will be imperiled by the rising tides and mountain flood waters caused by global climate change.
Some islands sit 25 feet below sea level, kept dry only by an aging network of fragile levees that channel snowmelt from the Sierra and hold back tidal surges from the bay.
Geologists say the 5,000 residents of the nation's lowest inhabited point near a coastline could be forced out, becoming the first climate change refugees in the United States.
"If global warming keeps up, in a few years this will be waterfront property," said Saathoff, 56, a steamfitter who has raised his house onto an iron platform 20 feet above ground. "We'll just be able to drive the boat up and dock right off the porch."
The majority of the U.S. population lives along a coastline. In the next 50 years, rising tides are expected to swallow islands in Chesapeake Bay, drown parts of the Louisiana coast and threaten the New York subway system, recent data from the U.S. Geological Survey shows. But USGS scientists say the coastal effects of global warming may be felt first among the islands of California's Sacramento-San Joaquin Delta. The islands, large land masses that were once part of a freshwater estuary akin to Florida's Everglades, are surrounded by levees. They sit three times lower than much of New Orleans. They are under threat from two very different forces, both related to climate change. Rising sea levels are expected to send more salt water from San Francisco Bay into the delta's upper reaches. At the same time, warming temperatures will make more precipitation fall as rain rather than snow in the Sierra, raising the specter of flood waters rushing down the rivers. Both scenarios could overwhelm a precarious system of levees. If those forces combine, no one is really quite sure how to calculate the risk.
In the late 19th century, land owners hired Chinese laborers to build a network of levees so they could use the fertile peat soil outside the banks of the San Joaquin and Sacramento rivers as farmland. More than 100 years later, scientists say the water pressure on the improvised mounds of rock and clay has increased and will only grow stronger as tides rise by the end of the century. "The delta is a highly vulnerable, high-risk area subject to major hazards," said Jeffress Williams, lead geologist for the Geological Survey on a national study of climate change's effects on coastal regions. "What is that land going to look like with a two-foot rise in sea level?" State water officials have spent years trying to answer that question. Ideas under consideration include flooding some of the islands entirely and paying permanent residents to leave the delta, said Les Harder, deputy director of the California Department of Water Resources. ——— In a state best known for its congested freeways, larger-than-life entertainers and frenetic startup culture, California's delta is something of an anomaly. Life moves slowly along its one-lane roads and winding waterways, where time is marked with seasonal crawdad festivals, inside lazy marina bars and with the annual alfalfa harvest. On Andrus Island, a spit of land upstream from Saathoff's home on Bethel Island, asparagus fields mix with ranch homes. On a recent afternoon, anglers from across the state climbed out of motorboats berthed at the island's B&W Resort to weigh their catch in an annual bass fishing contest. "The delta's the best place in the entire state to catch big fish," said Larry Merlo, 56, of Buttonwillow, near Bakersfield. "We have the mountains and we have the ocean and the rivers, and we have the delta. There's nowhere else like it." The delta's rural character belies its importance to all of California. Its mosaic of waterways forms the heart of the state's water-delivery system. The Sacramento and San Joaquin rivers carry snowmelt from the Sierra Nevada into the delta, where it is rerouted through a system of canals and pumps to 23 million Californians and thousands of acres of crop lands. But climate change experts predict the Sierra snowpack will shrink and melt faster. During the last 40 years, the median date for peak snowmelt runoff has moved two weeks earlier, said Wim Kimmerer, a hydrologist at California State University, San Francisco. Earlier runoff combined with warm spring rains would produce flood waters that could overwhelm the delta's levees, threatening Central Valley communities that have seen an explosion of suburban growth in recent years as well as residents on the delta's islands. "People who buy homes in the delta have a right to assume that someone is making sure they're not going to flood, as did the people of New Orleans," said Barry Nelson, senior policy analyst at the Natural Resources Defense Council. "Right now, no one is doing that."
Last August, the NRDC and several other environmental groups filed a lawsuit in Sacramento County Superior Court claiming that a developer's plan to build 11,000 homes on the Stewart Tract island ignored Department of Water Resources data on climate change. The data showed the levees protecting the subdivision would provide protection only against a 20-year flood, not a 200-year flood, if sea levels rose by one foot. The U.S. Environmental Protection Agency is requiring the Army Corps of Engineers to evaluate the effect climate change has on flood risk generated by the housing development. Last year, river runoff was so high that the state closed Highway 12 leading to Andrus Island for several days. In 2005, a nearby levee broke and the state poured $44 million into stopping the resulting flood. Candy Kelp, who runs B&W's snack bar, said she watched the water lap just feet from her house that time, but kept praying it would subside. "I wasn't worried because I knew the water was going to go back out," she said of last year's flood, wheeling her bicycle along the private levee protecting her home. "It never really floods over the top here. It just sort of trickles." ——— California voters last year passed bond measures to strengthen the delta's levees and improve flood control throughout the state. At least $775 million in bond money will go toward the delta over the next decade, said Harder, of the Department of Water Resources. In the coming months, officials will decide how to spend the money. Among the ideas is a proposal to reroute fresh water from Northern California rivers around the delta through a peripheral canal, a controversial idea that voters previously defeated. Other proposals would raise all highways, bulk up the levees, flood large islands or move residents out of the central delta, Harder said.
"Flooding would be best on some of the islands that tend to gulp more water out of the delta," Harder said. "But that obviously would be expensive, and would have an effect on people. Anybody who would have to move would be compensated." Saathoff and other homeowners already have started preparing. Some have elevated their homes on stilts three stories high, where the structures are buffeted by wind gusts blowing off the water. Saathoff's next-door neighbor on Bethel Island, Jack Sutton, isn't sticking around to see what happens. His son will miss water-skiing, but the family is leaving their home and moving to Colorado. "If there's additional water pressure, I just don't think this system will hold," Sutton said. "We might get some melting snowpacks up in Colorado, too, but at least we'll be at 7,000 feet up in the mountains."
Source : www.mercurynews.com
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