Tim Washburn on the history and future of Sacramento’s flood control system

Tim WashburnOn March 11th, 2013, the California Water Policy Seminar Series at UC Davis Center for Watershed Sciences continued, hosting Tim Washburn, the Director of Planning for the Sacramento Area Flood Control Agency.  Mr. Washburn served as the Agency’s chief counsel from 1990 to 2009 when he was appointed to his current position.  Mr. Washburn gave a lively presentation on the history and development of Sacramento’s flood control system, discussed the Central Valley Flood Protection Plan, and even gave his views on why the Natomas basin isn’t as vulnerable as some might think.

I think it’s important to have a little background to try to understand the problems we’re facing and some of the ideas that we have about how we might address those problems,” began Tim Washburn.

The Sacramento area flood control system is an incredibly vast, complex system that is part of a commonly administered system by the State of California through the Central Valley Flood Protection Board with joint jurisdiction with the Army Corps of Engineers.  The system was built up by local interests, by the state, and then finally by the Army Corps of Engineers, he explained.

Sacramento River Flood Control System - 144dpiIt was not anything self-evident to people who came to the valley in the 19th century that you could have a system on this scale because in those days, nobody really looked to the state government, much less the federal government, for this kind of governmental service,” he said.   “For the early days of the system, primarily in the last half of the 19th century, this was all done by locals and their counties forming drainage and reclamation districts.  It was well characterized in the book, Battling the Inland Sea, where water, particularly flood water, was regarded as a common enemy, and therefore everybody had a right to keep the water away from them and push it anywhere else they wanted it to go.”

From the 1850s into the early 1900s, there was no overall coordination of flood control planning; “it really was every community for themselves.  But, people did recognize that it wasn’t a particular efficient way to manage this problem.”

During this period, four historic settlements were established: Yuba City on the west side of the Feather River; Marysville at the confluence on the Feather and the Yuba River, Sacramento and the east side of the river, and West Sacramento on the west side of the river.  Those settlements “remain today the principle concentrations of urban development in the valley.  They are relatively low elevation and rely on levees for their protection,” he said, noting ”mostly the urban settlements are where they started, they’ve just gotten bigger and have become ever more reliant on this flood control system for protection.”  Other than those four cities, “it’s mostly very large agricultural districts, some of which, like Natomas north of Sacramento and Reclamation District 784 or Plumas Lakes south of Marysville, have now themselves become a focus of subdivision and development in the modern day.”

The notion that the state and possibly the federal government could play a role in building up the system was novel and revolutionary in 20th century California.  It really took the progressive era of the 20th century in the 1900s under the governorship of Hiram Johnson, for the progressives in California to say this is something that needs to be done to foster the economic development of the Sacramento Valley …  it’s not anything that can be done by these competing localities, so therefore it makes sense for the state to step up and begin to take responsibility for organizing, planning and maintaining the system on a large-scale.”

In the upper part of the valley on the Feather and the Sacramento River, it was very hard to keep those flood flows confined to a leveed channel due to the sheer amount of runoff:  “Think about it like your commute time – between 7 and 9 am and 4 to 6 pm, everybody’s on the freeway and there doesn’t seem to be enough lanes.  Now if everyone would just come throughout the day, there’d be no problem, but that’s not the way we live and that’s not the way floods happen,” he said.

Floods are measured in peak discharges, which is typically the volume of 72 hours, and that volume can be quite large; “so the idea of allowing these floods to seek their historic floodplains was a key insight for building up the notion of this more systematically organized and maintained system and that’s what gave rise to the bypass systems, the Sutter Bypass and the Yolo Bypass,” he said.  “The question was who will build and maintain these common areas and who would take responsibility? That’s really where the notion that the state, in the progressive era, felt it appropriate to step up and do that.”

But it didn’t happen quickly or easily, and it took two large floods in 1907 and 1909 to be the final impetus for the state to decide to take action, which occurred initially with the legislature adopting a plan for controlling floods in the Sacramento Valley in 1911, he explained.  The Army Corps was not far behind; the Corps at the time had the mission to plan for and facilitate interstate commerce and navigation, so the Corps came to the Central Valley to help with navigation, Mr. Washburn explained.  The historic communities were living on the river and were dependent on the river for commerce, because the roads through the valley were very poor.  Navigation was hampered by the sediment that had come down from the mountains due to hydraulic mining: “when the miners finished picking up all the easy gold on the stream, they started blasting it off the hillsides and so there was this constant mass of sediment coming out of the mountains and into the system.  In the 1880s, finally the California Supreme Court said enough, it’s a nuisance, you just can’t discharge your mining debris into the system.”

So the Corps was here to figure out how to make the rivers more navigable under their navigation authority.  They were big proponents of building high levees near the river channel so that in flood stage, the floodwaters, as they had learned in the Mississippi, could drive that sediment on down the river and make for better navigation.  They were resistant to the idea of these large bypasses,” he said.  However, after the floods of 1907 and 1909, which were the largest of the day, “everybody got on the same page and said, alright, we need to begin moving in this direction.”

It literally took five decades to build up this system.  In 1957, the Corps turned the system over to the state of California, who accepted responsibility and maintenance of this completed system which is essentially the system we have today, he said.  “There are claims that people envisioned this as early as 1860, so it took a century to have an idea and to get to the reality of its creation,” he said.  “So all of us who are here today who are in the business of ideas have to be a little humble about how long it takes for our society to understand us and implement our wisdom.  It took a long time.”

There are claims that people envisioned [the flood control system] as early as 1860, so it took a century to have an idea and to get to the reality of its creation, so all of us who are here today who are in the business of ideas have to be a little humble about how long it takes for our society to understand us and implement our wisdom.  It took a long time.”

The New Deal brought with it a greatly expanded sense of the federal role in society and the notion of the possibilities of engineering on a scale even greater than this that tended to focus on building dams for water conservation, hydropower, recreation, and all the good things that the society found desirable,” Mr. Washburn said.  “This was integrated water management because you could build these facilities at the right locations on these systems, and they would add a whole new layer of support to the flood control system because the headwater dams could hold back the three-day peak volumes, virtually doubling the capacity of the system,” he said, adding that the dams also stored water for cities and farms and became part of the state’s plumbing system.

Construction of the dams came right after the levee system had been completed.  “It was envisioned to do something more.  This one was really designed with the flood of record in mind.  In other words, we had these big floods in 1907 and 1909, so let’s build a system that can contain those record floods;  that’s basically what the levee system was designed for.”

There was now a much greater concentration of people in those urban centers in Sacramento, Yuba City, and Marysville, “who require perhaps a more protective standard than the flood of record, so the theory of the 1950s and 60s primarily developed by the Corps of Engineers is that we need to provide these concentrated urban areas with protection against the largest flood, the most extreme flood that is reasonably foreseeable given the hydrologic characteristics of the basin,” he said.  “So they developed a methodology, mostly by taking these historic floods and working with them to expand and enlarge them into what they felt to be very extreme floods that could then be controlled by the headwater dams, so that the water arriving with those big floods could be kept within the levee systems below those dams.  That was the design standard that drove Folsom Dam and then later Oroville, which is also worked in tandem with the Bullards Bar Dam on the Yuba River.”  So there was the ‘flood of record’ standard of protection and then the more exacting and demanding ‘standard project flood.’

During the 1970s, the nation began to debate how to address flood damages, which were then tending to happen across the country with a degree of frequency.  The discussion centered on creating a national flood insurance program, but no private insurers were interested:  “Nobody wanted to come in and insure against flood damages because the pool was basically a bunch of exposed people.  There weren’t enough non at-risk places to make it a good bet for private insurance.  So the government basically said okay, we’re going to back the insurance of structures in the floodplains,” he said.

Congress then debated what standards should apply for the structures in the floodplain that they would be standing behind with the insurance.  “We had proponents of the ‘flood of record’, and we had proponents of the ‘standard project flood.’  It was determined that a national program couldn’t be administered on a ‘flood of record’, and the ‘standard project flood’ had similar problems and was seen as too exacting and too expensive.  So they settled on the statistical 1% annual risk of flooding; the 100 year flood would be the flood we would administer the national insurance program on,” he said.  “The Corps of Engineers was given the responsibility to develop the statistical program for how we derive the one in 100 year flood for the communities across the country and they did.  They developed a whole set of procedures for how you calculate these relatively extreme events, and then regulate and manage the system around them.”

The National Flood Insurance Program was set up in 1973, and in 1978, Sacramento, West Sacramento, Sacramento County, the city and others in the valley joined the National Flood Insurance Program.  “And we then confront it.  Well, does the flood protection meet that standard?  And FEMA turned to the Corps of Engineers and said, ‘do these communities meet our 100 year standard?”  And the Corps, contemplating what we’d created with this system and the headwater dams and the rest of what had been done up to that point, said to FEMA, ‘well, we don’t know of any reason why they don’t.’  ‘Okay, that’s good enough,’” said Mr. Washburn.  “So basically all the communities in the valley came into the national flood insurance program in the late 70s with zone designations of B, moderate risks of flooding, or in some cases C, minimal risks of flooding.  And that really permitted the development of the 1970s and 1980s to go forward without any national flood insurance program constraints or complications.”

sacramento-river-flood-control-system1Then came the record flood of 1986, which was the first flood to test the system since the whole system had been built including the headwater dams, and it was the first chance to see how the system would respond.  “While we didn’t have huge catastrophic flooding, we had some flooding, and we had some very distressed levees.  There was some flooding along the south levee of the Yuba River where the levee failed and water went into the towns of Olivehurst and Linda up in Yuba County, …  but Sacramento skimmed by,” he said.

Now to give you a sense of what was happening in the city of Sacramento in 1986, this whole system was really developed by the state and federal government, and local government had very little to do with this flood control system and very little connection to it,” he said.  “Even though we built a city in a levee-protected flood plain, you cannot find any discussion of the challenges, complications or anything else related to developing an urban city in a levee protected floodplain.  If you look at any of the documents from the city in the 70s, 80s, even after we had CEQA in place, there was no analysis of flood risk,” he said.  The local government had put their faith in the state and federal government and accepted that these entities had said that the city was protected.

When the 1986 flood came, here’s the city going ‘Wow, how does it look out there?” The public works director is calling back to the city manager … he’s walking the levee on the east side of Natomas, saying ‘The water’s right up at the top!  What do you want to do?’ ‘I don’t know, keep me posted!’  There was no plan, nothing,” he said.  “If people would have come from another planet, they would have said ‘let me get this straight, you built the city in a deep floodplain protected by levees and you have no idea what to do when a flood comes along?’”  There wasn’t much local awareness because the local governments had felt the state and federal government had everything under control.

During the flood in 1986, levees in the Natomas area and down along the Sacramento River that had been built from the sediment were rather sandy, and when the water was up against them for a long period time as it was in 1986, “they began to seep water through the levees.  In Natomas, the levees had been built with suction dredge machines that sucked the sand up off the bottom of the river and put it into a trench that had been cut along the Sacramento River.  Then they’d take the dirt when they were finished and kind of ‘make a burrito.’”  The levee was saturated and water started going through the levee and it was about to fail,” he explained.  “We came very close in Natomas to losing the levee on the Sacramento River, and the pocket levee was under a fair amount of duress.  We had to make releases from Folsom Dam that were higher than what was considered the safe level of release –  the system was set up to release 115,000 cfs, and we had to release 134,000 cfs … we nearly had levee overtopping and failure.”

So in 1986, my agency [the Sacramento Area Flood Control Agency] was created, as were other local agencies around the valley, and we began to work with the state of California and the Corps of Engineers to evaluate what had just happened here and to formulate plans of improvement,” he said.  The main conclusion was that the sandy embankments in the Natomas, the Pocket area and some other places around the valley needed to be stabilized.  That was basically done by putting cutoff walls through the levee, although not down through the foundation of the levee, but at least through the levee itself to stabilize it so the water couldn’t go through and pull the material out on the other end, he explained.  In some cases, seepage berms were built on the landside and some levees were raised.  And in the case of Sacramento, “build another dam upstream of Folsom at the old Auburn Dam site, but due to the controversy around the multi-purpose Auburn dam, we’ll just make it a flood control dam and decide later whether it will ever hold water permanently.”

There was also general agreement that the 100 year standard, which we’d organized our life around, was really not an adequate standard,” he said.  The notion was that concentrations of people with a high potential for loss of live and extensive property damage needed something more than the minimum 100 year standard.  “But the Corps had become deeply embedded in statistics and had abandoned the old provide protection against the most extreme flood that we might reasonably expect to occur.  They had gone to a more statistical program that said in effect, provide the level of flood protection that provides the optimum economic benefit, so it was more of an economic benefit analysis,” he said.  “In Sacramento, you could generate a fairly high level of benefit because we have a lot of people here, so the national economic development plan was sort of the federal approach for setting standards for federal investment and that well justified building an Auburn Dam.”

My agency and the state of California didn’t agree that national economic development was the way to look at flood control; we are more public safety based, “so we developed the notion of providing a high level of flood protection for urban areas like Sacramento – at least 1 in 200 year flood protection.  That is where this 1 in 200 year thing came from.  It was a pragmatic response from us in the state to try to reach back to that old public safety standard, the ‘standard project flood.’  That flood was typically said to be 1 in 200 to 1 in 500, so that’s the kind of flood protection urban areas ought to have,” he said.  So in 1990, we put forward the notion of providing urban areas with 1 in 200 year flood protection which is now become deeply embedded in the planning of this system for the future.

We accomplished a great deal between 1986 and 1997, when the next large flood came along.  “So in 1997, a flood on the scale of the 1986 flood came along and another response … what do we need to do here? The Corps had worked with the state of California and they developed this comprehensive plan, but it really didn’t go anywhere because the federal government didn’t really have the initiative or the money, and the state government didn’t either, so we had a period where, although everybody was recognizing the need, there was not really a galvanized response after 1997.“

In 1997, there was a levee failure along the east side of the Feather River into the Plumas Lakes area, and that levee failure was thought to have resulted from water going beneath the levee, pushing material beneath the foundation and bringing the material to the surface on the landside of the levee.  This created voids underneath the levee and caused the levee to fail due to underseepage, he said.  “So by 2003, the state and the Army Corps of Engineers became committed to the notion that underseepage is a risk factor in the Sacramento Valley.  It hadn’t been thought to be that in the past,” he said.  “In the past, underseepage was a flood fighting issue.  If a boil came up on the landside of the levee, you came out and formed your sandbags around it and you controlled the boil, but it would be hideously expensive to go and do all the exploration and all the work you need to preempt underseepage.”  After 1997, the risk of underseepage became a risk factor that was evaluated as to whether the levee would meet the federal 100 year test.  “Now the reason that is significant is you look at all these levees here, there is no way in the world that all of those agricultural districts are going to be able to address this risk factor, even analyze it.”

So since 2003, it’s been evolving to a two-tier system, he said.  “Urban areas that can afford to address underseepage are going to have to do so on the pain of falling into the 100 year floodplain and paying very high insurance rates.  However, agricultural areas are not going to be able to do this; they are not going to be able to achieve that higher standard of flood protection and they are now going to have to deal with the fate of how are they going to be regulated within the national flood insurance program.”

The small communities that dot the agricultural landscape … Knights Landing, Clarksburg, Gridley, collections of 200 or 300 homes, well …it’s thought, at least at the state level, maybe we should have a special program for protecting those communities.  Not the whole basin that they live in, but maybe with compartment levees or other structures that might afford some relief for the generally-not-well off people who live in these small communities and who will horribly oppressed if they have to live in a 100-year regulated flood plain with insurance and no building and the rest of it,” he said.

The Central Valley Flood Protection Plan addresses how to move the urban areas to 200 year flood protection including protection from underseepage, how to address rural levees that are not going to meet that standard, and how to address the small communities that dot the rural landscape, he explained.  “And that’s really the essence of that the CVFPP plan says, is that we now have three-tier system, urban area flood protection, protection for these small communities, which is a new idea and we don’t really have any examples of it, and then essentially continue with the protection that the rural areas have historically had with some focus on repairing the most egregious issues and problems they have in their system.”

Another part of the CVFPP was also to think about what could we do to provide more system capacity, such as widening bypass systems that would allow the system to convey higher, more extreme floods safely.  “Those are somewhat controversial and difficult because they don’t always impart protections immediately to the urban area; they make the system as a whole function better, so we’re having a discussion with DWR about how to prioritize between investing in these system improvements and investing in improvements to the urban areas.”

Obviously there are environmental consequences.  “The environment does a lot better with the system improvements because it creates room to recreate historic floodplain habitats as we’ve been doing and discussing in the Yolo Bypass, as could be done in the Sutter Bypass or down on the San Joaquin. … and the environmental interests are very anxious to see the system improvements be given more weight and more investment,” he said.  “In the urban areas, we’re struggling to meet our minimum 100 and 200 year requirements because there are penalties now for not meeting those thresholds.  If you don’t provide 100 year protection to your community, you can be facing very high insurance rates, you face land use restrictions and moratoriums, and if you don’t meet the state’s 200 year standard, you’re going to face similar constraints on economic development in your community.  So it’s very important to the local agencies like me and the communities that we serve to meet those 100 and 200 year targets while we then seek to work with the state to add resiliency and robustness to the system by expanding the common areas and providing for improved reservoir reoperation and other measures that make the system more robust.”

So what you will see in the next 5 to 7 years is a working out of this debate and discussion, primarily between us and the DWR.  … We’ll be discussing what do we do with what’s left of the 2006 bond money.”  The federal government is largely becoming more and more ineffectual given the partisan divide in Congress and the inability of the federal government to really focus its attention on this project and provide adequate funding to the Corps, “so a big part of our planning in this next period is how do we, at the local level and the state, leverage our non-federal resources, adaptively manage our relationship with the Corps of Engineers, and make our way steadily forward.”

Mr. Washburn on Natomas:

Natomas is a 53,000 acre basin located north of downtown Sacramento.  “It was built in 1912 to 1914 by a private company that bought 75% of the acreage in Natomas for $1 an acre.  It was a huge gold dredging company that took its dredging machines, its capital and its experienced labor, and it went in and put the suction dredge to work in the Sacramento River.  There were bucket excavators digging the drainage canals and piling up the levees, and they basically built the Natomas basin and the one just to the north, Reclamation District 1001.  Then they went out to promote it as ‘Hey, come live in Sacramento! You can be a yeoman farmer on 80 acres right near Sacramento!  It’s great!  And you can see advertisements from the period – it was a real estate development.  It turned out people weren’t quite as enamored with farming, so they went to bigger acreages and finally they sold out all their land in the 1950s, but that basin functions in a particular way in relation to the system.”

The Natomas basin is just downstream of the Fremont Weir, so when water comes out of the Sacramento-Feather system and out of the Sutter Bypass, you want it to go over the Fremont Weir and into the Yolo Bypass, he explained.  “The flow split is about 85% into the Yolo Bypass and about 15% into the Sacramento River channel, so it’s always been thought, from a flood planning point of view, that you do not want a levee failure up at that end of the system because that could have the potential to bring all this water into the Sacramento River corridor down by the city of Sacramento.  … It’s always been anticipated that it would be an urbanizing area and that we would build solid stout levees around Natomas because of its particular position within the system.  So the 18 miles that we upgraded were exactly the five miles of the Cross Canal at the upper end, and 13 miles just south of the airport because you cannot afford to suffer a levee failure there.”

There are 24 miles the rest of the way around Natomas, but 18 of those 24 miles are on the east side where we really don’t have the same kind of issues.  In the lower east side, where Dry Creek and Arcade Creek come in and the American River has an influence there; that’s where you could have a problem, but once you get upstream of Dry Creek along that entire east side of Natomas, we’re really not at such great risk.  The idea has been that that’s an area, if properly designed and protected could reasonably sustain development.”

Drive the Garden Highway and you can see the levee that has been built.  “It’s massive.  We did a hydraulic analysis, and we took the 500 year flood centered in the Sacramento-Feather River system, and in our analysis, where it overtopped rural levees which it did by about a foot or two, we allowed those levees to fail and the water to go out, which we think would probably happen.   And when we got all the way down to Natomas, the 500 year flood elevation was 4 feet below the top of the levee we built.  So we’ve built this massive thing at the bottom of the system that has just incidental floodplain storage above it because those are the ag areas that can’t do the underseepage and won’t be able to meet the urban standard.  While not designed to flood, that’s just the system we’ve inherited,” he said.

Therefore, Natomas is in a relatively advantageous position on the Sac-Feather River, and similarly on the American River because on the American River, you’d have to get a large discharge out of Folsom all the way down to the bottom if you’re going to get it into the Natomas Basin … It’s not clear that you could get a massive amount of water down to the bottom to hit Natomas even on the American River.  So while everyone could debate the wisdom because it is a deep basin; – there are 20 foot flood depths if you get the Sac-Feather going in there, not necessarily the American.  If you get the Sac-Feather going in Natomas, you could have very deep depths but we’re kind of working our way to the point that the likelihood of that occurring is becoming less and less.”

On the future of the flood control system:

We are trying to build the most robust possible flood infrastructure. We expect a metropolitan area like Sacramento will become more densely populated over time, growing hopefully more vertically than horizontally, but it will be more densely populated and it will continue to rely on this flood control system for its protection, he said.

We are somewhat hampered in what we can do with the flood control system outside Natomas.  Take, for example, the Pocket Area where the development is right up to the toe of the levee.  You can’t make a 60 foot wide levee in the Pocket Area unless you are willing to take out 300 private parcels there, and buy them out, which I don’t believe the community is quite prepared to do.

So the resiliency that we’re thinking about at this point is that we are improving Folsom Dam so that it can handle much larger floods more efficiently.  We are building up the resilience of the American River channel so it can take higher flows from Folsom Dam safely down through the channel.  And then we are working regionally with West Sacramento and Yolo County to widen the Sacramento Bypass … that is where the discharge of the American River goes, it goes over the Sacramento Weir and Bypass and into the Yolo Bypass.”

As we’re planning for higher flows on the American River, we want to give those flows an opportunity to go out and into the Yolo Bypass, a much wider channel with less at stake on either side of its levees and not go down the Sacramento River channel where it would threaten the levee in the Pocket Area.  So we are planning to make the system more robust and more resilient in that way.”

The largest floods of record, going back all the way to 1862, where we have empirical data on the size of that flood; it is thought that the 1862 flood in the American River was on the order of magnitude of  similar to 1986 and 1997.  So now we have 160 years.  The flood that we are planning for is 50% larger than 1862, 1986, and 1997.  Now, that is a significant increase …

FOR MORE INFORMATION:

  • Click here to watch the video of Tim Washburn’s speech.
  • Click here to visit the Sacramento Area Flood Control Agency online.
  • Click here to read a journal article on flood management by Professor Jay Lund.
  • Click here for a photo essay on Sacramento’s flood control system.
  • Click here to look for posts of the other speakers in the California Water Policy Seminar Series.

 

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2 comments

  • Gary Lewis

    Thank you for this information on the levees. I’m looking for a book on the engineering and how the building was physically completed. I take my Father-in-Law on drives down many of the levee roads and he always marvels and wonders about how they were built. Any suggestions? Thanks, Gary Lewis

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