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YOLO BYPASS: Quintuple bypass
Davis Enterprise -
February
27,
2005
By Jeff Hudson
It's 40 miles long, nearly 10 miles wide in places, and covers roughly 59,000 acres.
It floods seasonally -- conveying up to 80 percent of the water that comes booming down the Sacramento River, Feather River and other tributaries during a flood. And because all that water is rerouted into the Northern Delta and ultimately Suisun Bay, the city of Sacramento no longer experiences the kind of catastrophic floods that made the state capital soggy in the late 1800s.
But in many ways, this giant flood control project -- a remarkable feat of 1920s-era engineering -- serves to mimic some aspects of the wildlife-rich ancient wetland existing before Californians began building the levees and weirs that created the Yolo Bypass a century ago. The bypass hosts 200 species of birds (some migratory, some year-round), 42 species of fish, beavers, otters and other wildlife. It's an area greatly loved by duck hunters -- it contains a several private duck clubs (some costing tens of thousands of dollars to join) that maintain extensive private wetlands.
It's also an area important to Yolo County agriculture, including a significant portion of the county's rice acreage. (Rice is Yolo County's second-most valuable crop after tomatoes, worth about $40 million a year).
Because the Yolo Bypass floods seasonally, you can't build much there. You can't even plant a dense stand of trees, because it might impede water flow. Flood control remains the top priority.
Consequently, just a handful of people live in the Yolo Bypass. And few of the region's residents, in Davis, West Sacramento, and elsewhere, give the bypass more than a passing thought.
But if you're a Davisite or Woodlander who drives the freeway, it's right there in your face, every time you head into Sacramento. Hundreds of thousands of commuters drive over the bypass each week, on causeways carrying traffic on Interstate 80 (once described by poet Gary Snyder as "the river of cars") and Interstate 5, a few miles to the north.
The Yolo Bypass also is an integral part of a complex flood-control system extending north to Shasta and Oroville dams, and south to San Francisco Bay. And because flood control is related to growth, and the Sacramento region is expected to grow from roughly 1.9 million residents to 3.8 million residents by 2050, the Yolo Bypass becomes connected to growth issues here, and in a host of government entities with stakes in flood control.
The history
To understand the Yolo Bypass, it's important to grasp the way the area looked before, and what was done to create the bypass we know today.
Through the end of the 1800s, much of today's bypass was known as the Yolo Basin.
"The Yolo Basin was one of several basins that paralleled the course of the Sacramento River, and filled up with flood water in winter months. A lot of it was fairly shallow, and it wasn't within levees, so it would expand and recede depending on how much water there was," said Dave Feliz, wildlife manager with the California Department of Fish and Game in the Yolo Bypass Wildlife Area.
"The delta back then was a backwater, and the water would get stuck and get sucked out to the bay tidally."
The basin could take months to drain, so it became a sort of shallow, seasonal inland sea, "often described as one big tule marsh, with tules 10 feet tall," Feliz said. "It was a real barrier to travel."
The Yolo Basin was crossed by narrow roads that were flooded seasonally. People traveling between Sacramento and San Francisco generally made the trip on riverboats, until a raised railroad track was built through the Yolo Basin to connect the two cities.
In the late 1800s and early 1900s, people in different parts of the Yolo Basin began building levees on "sort of a piecemeal basis," Feliz said. By 1917, there were levees running pretty much "from Cache Slough in the south up to the confluence of the Sacramento and Feather rivers."
The Army Corps of Engineers eventually incorporated these elements into a larger scale system known as the Sacramento Flood Control Project. It added weirs that defined the Yolo Bypass and the Sutter Bypass (which picks up water draining out of the Butte Sinks on the south side of the Sutter Buttes, and conveys it to the confluence of the Feather and Sacramento rivers). The Yolo Bypass was created as a means of channeling water around the city of Sacramento and out into the bay -- and moving the water through the region faster than it had moved through the old Yolo Basin. The Sacramento River itself also was lined with levees, creating a narrow channel through which the water flows quickly.
The overall system was expanded when Shasta Dam (on the Sacramento River) was completed in 1943, followed by Oroville Dam (on the Feather River), Bullards Bar Dam (on the Yuba River), and others in the 1960s, further regulating the river flow.
The mechanics
How does the Yolo Bypass work? Several smaller tributaries flow in from the west: the Knight's Landing Ridge Cut, Cache Creek, Willow Slough, plus Putah Creek (which can carry more water than the other three combined).
But the big flows tend to come over Fremont Weir -- a low, concrete barrier at the north end of the Yolo Bypass, close to the confluence of the Sacramento River and the Feather River. When the water reaches an elevation of 33.5 feet, it goes sliding over the Fremont Weir.
"Usually, when the Fremont Weir tops, the Sutter Bypass (to the north) is already flowing. It's a double whammy," Feliz said.
Intuition may suggest most of the water is coming from the Sacramento River as it enters its confluence with the Feather River at the north end of the Yolo Bypass -- but in this case, no. The Feather River, which picks up water from the Yuba and Bear rivers, joins with the Sutter Bypass, for a combined total of more 10 times as much water pouring into the confluence as compared to the Sacramento River at Knights Landing alone.
Once the Fremont Weir starts spilling, the Yolo Bypass fills with water over the course of several days, "depending on how much water is coming over, and what the tides are doing," Feliz said.
The other major Yolo Basin water entryway is the Sacramento Weir, on the Sacramento River north of West Sacramento. Unlike Fremont Weir, the Sacramento Weir has manually operated gates that are opened to let water through.
It's almost a prehistoric kind of system," said Yolo County Supervisor Mike McGowan, "but it works pretty good."
McGowan added, "When the Sacramento River is running at flood -- or near flood -- stage, and the water coming down the American River gets to the confluence, and the Sacramento Weir is opened, part of the Sacramento River actually runs backward several hundred yards, into the Sacramento Weir," and then through the mile-long Sacramento Bypass into the Yolo Bypass.
"It's a pretty spooky thing to watch. The water at the lower level (of the Sacramento River) is flowing downstream, but the water at the higher level is flowing upstream," McGowan said.
While the Yolo Bypass generally floods January through March, it has flooded as early as mid-October (in 1962) and remained flooded as late as June 2 (in 1939). There also are years when the bypass doesn't flood at all -- including a six-year drought during the 1980s. Farmers don't like the early or late flooding -- an early flood can wipe out a crop, a late one can delay planting to the point there might not be enough time for the crop to mature.
But when the weather cooperates, the bypass can produce favorable results in several overlapping ways. Rice cultivation, for instance, goes hand in hand with migrating ducks. "I like to think of it as a win-win situation for flood control, agriculture and the environmental community," said Yolo County Agriculture Commissioner Rick Landon.
Sportsmen have been hunting ducks in the Yolo Bypass for decades. Chris Fulster, owner of Broadway Bait, Rod and Gun in Sacramento, has been hunting there for 60 years. "I started when I was 12 years old. My dad had a 40-acre pond in the bypass, and you had to walk two or three miles to get to it. There were only a few other clubs in the bypass then."
Now, "from the Davis causeway, it's practically duck clubs all the way down to Liberty Island," Fulster said. (Except for the 16,000-acre Yolo Bypass Wildlife Area, which was created with a grass-roots effort in the 1990s. The project drew a visit from then-President Clinton.)
One of the biggest duck clubs is the Glide-In Ranch, which covers 1,200 acres and has 20 members. "We keep 200 to 300 acres flooded, a lot of places do it. A lot of that land is worth more money as duck club than as farmland," Fulster said. And in this way, the duck clubs have re-created some of the wetland from the original Yolo Basin.
Fulster also mentioned the 17,000-acre Conaway Ranch. "Conaway is planted in rice. They also hunt that."
And while Fulster didn't bring it up, the Conaway Ranch is a hot potato. It was purchased last year, reportedly for $60 million, by a group of Sacramento developers, who could be interested in the property's value for its water rights, or as mitigation land. Yolo County is trying to acquire the property through eminent domain. It's only one example of how development interests, government interests, and flood control are all tied up with a big parcel of land in the bypass.
John Eadie, professor of wildlife ecology and waterfowl biology at UC Davis, describes the bypass as "a huge resource" and added rice cultivation in the bypass is "very important for waterfowl."
"The biggest, most daunting issue is the huge growth projected for this area," Eadie said, "It always comes down to water, and the ability to have water for all the needs -- human uses, agriculture, and usually last on the list are the wetlands."
Fish feast
It turns out the Yolo Bypass is also critical for fish. This was not the finding Davis resident Ted Sommer, an environmental specialist with the Department of Water Resources, expected when he and several other researchers began a study of the area in the 1990s. "The project started out with one of the major questions being, 'To what degree is the Yolo Bypass a deathtrap for salmon?' And the answer was 'Au contraire. It's one of the major nursery areas.' "
When the researchers compared fish hatched in the bypass with fish hatched in the Sacramento River, they learned fish from the bypass pass were "growing remarkably faster. The feeding is greater on the floodplain. The bugs some motorists find a nuisance are a great resource for the fish in the bypass." Sommer compared it to Power Bars for the young fish.
Sommer also found fewer fish got stranded in the bypass as it drained than he'd anticipated. In retrospect, he realized he shouldn't have been surprised. "It's not a coincidence, (the engineers) designed it to drain reasonably efficiently." Actually, Sommer would like to see a bit more water in the bypass during winter months, enough to allow more fish passage. But more water might not sit well with the farming interests.
Peter Moyle, professor of wildlife, fish and conservation biology at UC Davis, said the Yolo Bypass "has really become a substitute for a lot of other floodplains we lost (in this part of California). It ends up being very important for fish."
Balancing interests
Managing the land inside the bypass is very much a matter of balancing the interests of sportsmen, wildlife managers, farmers and (increasingly) visiting classes of students who've come to study the area.
In much the same way, the Yolo Bypass is part of a flood-control system including numerous city and county agencies, as well as the state and federal government. Betsy Marchand, Davis resident and former Yolo County supervisor, is the president of the state Board of Reclamation.
"There is a history since 1850 that some of these jurisdictions do their own thing," Marchand said. "But with increasing population and changing climatic conditions, there has to be a way for people to talk together and see what their mutual interests are, and how they can work together to solve problems. This may sound like Miss Goodie Two-Shoes, but it's our fiduciary responsibility to make this system work to the benefit of citizens, and make sure they don't get flooded out. There's a lot of potential for a lot of serious damage if we don't do that."
"Water doesn't know where the county line is, or the city line is," Marchand pointed out. "You can't have good flood management jurisdiction by jurisdiction. The state must also be a player."
As far as the Yolo Bypass is concerned, Marchand said there's built-up sediment needing to be removed around the Fremont Weir, at the north end of the Yolo Bypass. "And the Sacramento Weir is an extremely old facility, a very critical facility. It's a massive hand labor operation. If we want this flood-control system to work property, we will have to have the infrastructure, and it's my responsibility to tell you the Sacramento Weir needs to be modernized."
Marchand added in terms of California's climate, "there does appear to be a warming trend, and that puts more water in the bypass, earlier (than in past decades)."
Keeping up
The flood-control system was designed between 1900 and 1960, based on limited rainfall and river flow records, and on some false assumptions about flood safety. After high water events in 1986 and 1997, the Sacramento Area Flood Control Agency has strengthened levees and pursued plans to raise the level of Folsom Dam on the American River, as well as increase the capacity to quickly release water from Folsom Dam during periods of high runoff from the Sierra. This, in turn, affects the Yolo Bypass, since some American River water can enter the bypass over the Sacramento Weir.
The Yuba County Water Agency is considering similar changes to the New Bullards Bar Dam, on the Yuba River, which likewise feeds into the Yolo Bypass during high water.
"But there is no silver bullet," said Curt Aikens, general manager of the Yuba County Water Agency. "The flood-control system is a complex system, with lots of varying interests from flood control to endangered species, fishing, farming. ... The list goes on and on."
The list, at this point, also would include the new homes being built south of Marysville and Yuba City in the Plumas Lakes area -- an area of former farmland that has flooded in decades past.
"You have all these issues converging in a way where there are more people (living than in the past)" Aikens said. "(Some of these) levees weren't originally built to protect what's there now."
All of which makes the Yolo Bypass, which is at the end of this complex flood system, carrying water from a half-dozen rivers toward the delta, critical.
"It must never lose its flood role," Marchand insisted, "But there is compatibility for wildlife preservation, birding, wetlands preservation and farming, as well as flood management. It's so close to an urban area. I kind of view it as Central Park is to New York, a great area that's a place to recreate, to appreciate nature, a place for children to learn. I think that's the vision we have to have of the Yolo Bypass. It's a multipurpose facility."
Jeff Mount, professor of hydrology at UC Davis, takes a "big picture" view of the Yolo Bypass as something proven to have many more benefits than its designers may have originally realized.
"By accident, the Yolo Bypass turns out to be the single-most important floodplain-restoration site in the entire Central Valley," Mount said. "Its location, shape, and lack of houses make it the ideal place to support the benefits that we receive from floodplains. ... It also provides billions of dollars worth of flood control for Sacramento, makes up the biggest open space element in the region, and enhances groundwater and surface water quality.
"We would be hard-pressed to design something that does a better job of providing multiple economic, aesthetic and ecosystem benefits than this bypass. And to think that our premier 'restoration' project was designed purely as a flood control structure 100 years ago. We could learn from this." #
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