WASHINGTON — Despite the spectacular near failure of Oroville Dam, a linchpin of California’s vast plumbing system, Congress and the state remain focused on building new dams and repairing existing ones.
But they are giving short shrift to cheaper, more environmentally benign alternatives for water storage.
With more rain this week, the state’s water system is under stress. Thousands of miles of earthen levees in the Central Valley are of dubious integrity, their soils weakened by five years of drought. The 440-mile California Aqueduct, built in the 1960s, is buckling in stretches where overuse of groundwater has caused the land to sink more than 2 feet in places.
These are the stresses that climate change is applying to a state water system built in the last century, overdue for hundreds of billions of dollars in repairs and upgrades, and ill equipped for the longer, hotter droughts punctuated by bigger floods that scientists say will intensify.
Yet just downstream from Oroville, one of the state’s oldest, cheapest and simplest flood control devices is performing brilliantly. The Feather River’s raging floodwaters that damaged Oroville’s two spillways and led to the evacuation of 188,000 people have now spread out across a peaceful, shallow lake called the Yolo Bypass, operated by a simple weir, and are now recharging the aquifer. It is attracting birds and brimming with salmon, smelt and other endangered fish.
“What the crisis at Oroville Dam really makes clear is that a system made out of concrete, to rigidly confine and constrain nature, is always going to be brittle,” said Jacob Katz, a senior scientist at Cal Trout, a fisheries conservation group studying the bypass. “People have been so focused on concrete that it’s taken a long time to realize that working with nature rather than against it is much safer and much more profitable.”
California Secretary of Natural Resources John Laird said the state has tallied half a trillion dollars of needed investment for its water system over the next few decades. The state hopes to get help from Congress and the Trump administration, submitting a list of $100 billion in projects that includes dam repairs.
New dams, the foundation of the last century’s water system, look set to receive the bulk of new investment.
“In a changing climate there’s going to be much more rain and less snowpack and more flows, and it’s really going to increase the need for storage,” Laird said. With $2.7 billion in water bond money voters approved in 2014, Laird said there may be enough money “to maybe do one or two additional big ones,” referring to new dams.
Laird said the state must build new water projects in addition to repairing the old. “We’re doing our best to make sure that’s not a choice, because we do have to do both,” he said.
Four large dam projects selected by state and federal officials in 2000 are under serious consideration. The most popular is Sites Reservoir, which would dam a dry valley 60 miles northwest of Sacramento and fill it with water pumped from the Sacramento River. The reservoir would not block a river and could store up to 1.8 million acre-feet of water, slightly more than half the capacity of the Oroville reservoir. Cost estimates range from roughly $4 billion to $6 billion.
In Congress, Rep. David Valadao, R-Hanford (Kings County), said he expects the House to approve his bill to streamline permitting for new dams, aimed at the four projects with Sites being the most heavily favored.
Paul Wenger, president of the California Farm Bureau, has urged officials to “start moving dirt this year” to build Sites Reservoir. “Our system was designed for 18 million people, and we’re double that now with climate change coming on.” More storage would provide more flexibility in the system, he said.
Dams store a lot of water and control floods, but they also have big drawbacks, many of which were poorly understood when the state’s existing structures were built. By blocking rivers, dams are ruinous to fish and other wildlife, and impair the recharge of downstream aquifers. Evaporation losses are high and getting higher as temperatures warm. Dams have limited lifespans and are extremely expensive.
California has more than 1,400 of them, blocking every major river in the state. The most logical sites already have dams, which means new projects will yield little new water. This winter’s storms have thrown a spotlight on the inherent conflict in California’s use of dams both to store water and prevent floods. The more water is stored, the less space is available to handle floodwaters.
Existing dams need hundreds of millions of dollars in work, said Ron Stork, senior policy advocate for Friends of the River, who with other environmentalists in 2005 urged that Oroville’s emergency spillway be reinforced with concrete, a plea that federal and state officials rebuffed.
“As we take a look at what we learned from Oroville, there are going to be other dams that people are going to recognize have the same problem,” Stork said. “We need to review their designs and be prepared to spend lots of money to address design and maintenance deficiencies so that they can be operated with some degree of confidence and safety.”
Stork said the state and irrigation districts are investing in dam repairs, such as a seismic retrofit of the San Luis storage dam in Merced County that is alone estimated to cost $360 million, a figure he said could go much higher.
As well as the Yolo Bypass works, it has become increasingly difficult to find places to allow rivers to spread across their floodplains, said Jeffery Mount, a watershed scientist at the California Public Policy Institute.
“We’ve occupied the real estate,” Mount said. Rivers have been harnessed into tight channels and floodplains filled with farms and cities. “There’s hardly a square inch of the Central Valley that isn’t in some use already,” he said, and farmers often don’t grant flood easements even when they are paid to do so.
There are other alternatives for storing water, primarily underground in the San Joaquin Valley’s vast natural aquifers that are now being permanently damaged by overpumping.
Stanford University researchers have demonstrated that storing water in the ground is much cheaper and has many environmental benefits. Successful groundwater projects like the Kern Water Bank near Bakersfield have been operating for years and provide a model.
A new state law putting limits on the amount of water that can be pumped out of the ground should give such projects a boost by compelling groundwater conservation. But dam projects are moving faster at the California Water Commission, which will start doling out the water bond money next year. Because the groundwater law is so new, the agencies that would push such projects won’t be formed until this summer. Dam projects that have been on the books for decades have a big head start.
“The timing is completely out of sync,” said Juliet Christian Smith, a senior scientist at the Union of Concerned Scientists, an environmental group, who has been watching the commission’s proceedings. Dam proponents, she said, are ready to go, while the groundwater districts are just beginning to organize.
Laird conceded that groundwater projects may not be ready in time to get much water bond funding. “There’s quite a possibility that if there’s ever another water bond, or future investment, you could try to catch some of those groundwater projects,” Laird said.
Smith said the commission also decided to use a median climate change model to determine which water storage projects pass muster, ignoring potential climate extremes, and potentially tilting the scale in favor of dams.
“This is huge infrastructure with long lifespans,” she said. “They chose a median climate scenario, but it’s the extremes where you have things like dam failures. It’s at extremes where you have zero percent water supplies available from the infrastructure.”
Laird argued that “anything that stores water with increasing rain and less snow is a climate change resiliency project.”
Extremes are what California is likely to see more of, said Daniel Swain, a climate scientist at UCLA’s Institute of the Environment and Sustainability and author of the California Weather Blog.
“We’ve swung pretty quickly from the most intense drought to literally the wettest winter we’ve observed in a century,” Swain said. Although California’s climate has always swung between droughts and floods, rising global temperatures are widening those extremes.
Water experts widely agree that projects like the Yolo Bypass and underground storage should be replicated at every opportunity.
“It’s really extraordinary what the Yolo Bypass accomplishes,” Mount said. Yolo Bypass handles water volumes exceeding those of the Mississippi River and “keeps Sacramento from being wiped off the map,” he said. “These are terrific as flood management structures, and they also provide exceptional environmental benefits.”
Peter Gleick, chief scientist at the Pacific Institute think tank, said the wrong lesson to take from Oroville is the need for more big dams.
“The real lesson we ought to learn,” he said, “is we should be more careful about maintaining what we already have and think about the value of nonstructural solutions to our water problems.”
Article by: Carolyn Lochhead
Published: February 21, 2017 by San Francisco Chronicle
Read original here.