Floodplain projects open doors to fewer floods and more salmon
A new approach to flood control is taking hold across Puget Sound. Rivers, scientists say, can be contained by setting them free. Conservationists hope this is good news for salmon recovery.
In 2006 and again in 2009, the Puyallup River spilled over its banks near the town of Orting in Pierce County, each time forcing thousands of residents to flee the muddy floodwaters that damaged many of their homes.
It was a pattern all too familiar across Puget Sound. Residents in flood-prone areas have historically risked millions of dollars in property damage, and in some cases even loss of life, from heavy rains and rising rivers.
Then, in 2014, the waters came to Orting again. They came with nearly the same volume, but this time the people remained secure in their homes. A new flood-control restoration project had allowed the flood surge to spread out in a new way, across a wider plain. The result, scientists say, has also been a more natural and salmon-friendly ecosystem.
Floodplains by Design
The Puyallup River is among 17 major river systems in the Puget Sound region where people are putting their heads together to reduce serious flooding problems, improve salmon habitat, support agriculture and often increase recreational opportunities — all at the same time.
Floodplains by Design, a program that encourages community members to work together, has attracted $80 million in state funding to work on 29 projects statewide over the past four years. Prevention of flood damages alone is expected to make up those costs over time, officials say, while the ecological benefits may be even greater.
In the effort to restore the entire Puget Sound ecosystem, the state established a target to restore 15 percent of the degraded floodplains by the year 2020. To that end, a team of experts funded by the Environmental Protection Agency is now working on a Floodplains "Implementation Strategy" to seek out ways to increase the likelihood of success.
History of river constriction
Early farmers in the Puget Sound region often settled in floodplains along the major rivers, where rich soils had built up after centuries of river overflows during heavy rains. To protect their land from flooding during storms, farmers often built levees along the river.
“When you build a levee to confine one section of a river, it shunts the water downstream more quickly, raising the velocity and the height of the river,” said Bob Carey of The Nature Conservancy, which helped conceive the Floodplains by Design program.
Over time, more and more levees were built to control flooding on the major rivers. As more land was cleared upstream, runoff increased and water flows in the rivers became greater still, so the levees were built higher. The water became swifter. Erosion became more pronounced. Habitat for aquatic organisms, including salmon, began to unravel.
Until recently, efforts to restore the ecosystem often worked around the edges of the degraded river channel, a channel confined by levees and dredged to remove an accumulation of sediments that under natural conditions would have spread out across the floodplain.
As experts intensified their efforts to restore Puget Sound, they began to examine the larger functions of river systems, including wetlands and floodplains.
“There was a realization that a lot of great restoration work was going on,” Carey said, “but there were a lot of other things happening that were not consistent with recovery goals.”
People along the rivers — including farmers and valley residents — worried about flooding. Traditional methods of flood control, such as diking and dredging, remained the primary solution. Meanwhile, other folks were becoming dedicated to restoring salmon habitat. They wanted to restore the natural flow of the river.
State funding for flood mitigation was an entirely separate program from the increasing funding for salmon and habitat restoration, said Scott McKinney, floodplain management policy supervisor for the Washington Department of Ecology.
“The flood-hazard world and the restoration world were not coupled to each other,” McKinney said, noting that things began to change when people stepped back and looked at the entire river system from top to bottom.
“When you look around, you begin to find opportunities on the landscape, places where you have a chance to relieve some of the flood hazard and also do salmon restoration,” he said. “You can take a larger flood-management perspective and, to the degree you can, allow the river to do what it wants to do.”
A new approach
In developing Floodplains by Design, the three major partners — The Nature Conservancy and the state's Department of Ecology and Puget Sound Partnership — soon realized that community collaboration was the key to success in developing projects on a much larger scale than ever before.
“There is no standard approach to this,” Carey said, noting that farms, housing developments, roads and topography are unique to each area, and the needs and desires of the community are paramount.
"You have to figure out what the science says about the needs of the ecosystem." —Bob Carey, The Nature Conservancy
“You have to figure out what the science says about the needs of the ecosystem,” he said, “but you need more than those who care just about salmon recovery. It is about bringing in other priorities, such as public safety, and putting them on an equal footing with environmental benefits. Only in that way can you get everyone working together at a meaningful scale.”
Floodplains by Design is flexible enough to allow consideration of all things possible. Removing levees or moving them back from a river are options to reduce flooding and restore habitat. Changing farm practices, moving homes and realigning roads are other options. Restoring the river itself with side channels, wetlands and floodplains also can provide multiple benefits.
“It’s a process,” Carey said. “You start with a vision and from there try to get to more specific goals and develop a project that can achieve those goals.”
The project on the Puyallup River, called the Calistoga Reach project, involved removal of about a mile of existing riverbank levee and construction of 1.5 miles of levee farther back from the river. Large logjams were added for habitat and to protect the new levee.
In addition, about 55 acres of restored habitat were connected to 44 acres of existing habitat. A new ¾-mile-long side channel to the Puyallup River increased floodplain forest habitat and reconnected 46 acres of backwater area, restoring a total of 101 acres of floodplain.
Besides the increased habitat, the $16-million project has proven itself with increased floodwater storage and conveyance, which has significantly reduced the flooding in the area for many years to come.
The Calistoga Reach Project is just one of many examples of floodplain restoration at work in Puget Sound. This year, seven new projects are underway across the region, each with its own challenges. A few dozen miles north of the Puyallup, in King County, people living along the Cedar River faced a familiar problem. A dogleg known as Rainbow Bend was notorious, sending savage floodwaters that also threatened Maple Valley Highway, a major corridor used by more than 50,000 vehicles a day. Also at risk was the Cedar River Trail, a regional hiking corridor.
Helped by county and state funding, the residents of Rainbow Bend were able to move out of harm’s way by relocating elsewhere, and the river was allowed to reclaim a portion of its original floodplain. The highway, trail and other critical infrastructure are now protected from catastrophic failure.
The $4.9-million Lower Cedar River project, an early pilot effort, removed nearly a quarter mile of levee near Rainbow Bend to allow floodwaters to flow across 40 acres of floodplain plus another 18 acres where a mobile home park was removed. Alterations to the flow substantially reduces the risk to the Maple Valley Highway and Cedar River Trail.
Most people in the Rainbow Bend area welcomed the opportunity to move, said Jon Miller, who had lived through two major floods that came into his house after a period of logging and development upstream. “Every time they forecast a pineapple express, the anxiety level rose,” he noted.
Still, despite some dramatic success stories, the established goal of restoring 15 percent of the degraded floodplains in the Puget Sound region “presents a challenge,” states an early draft of the Floodplains Implementation Strategy. That could be an understatement, given that more than 43,000 acres of restoration are needed to meet the goal while 3,851 acres were listed as restored at the end of 2015.
Although the goal seems daunting, Floodplains by Design has accelerated the restoration effort while supporting other goals established by the state, such as improving salmon habitat, protecting sensitive lands from development and improving human health and well-being, according to the report.
One of the top recommendations of the Implementation Strategy is to increase discussions about the true risks of living in a floodplain and the costs of overcoming the natural tendencies of a river. In accommodating future population growth, planners should be acutely aware of the potential consequences before citing new construction within floodplains, the report says.
"We tend to be overconfident in our engineering abilities..." —Bob Carey, The Nature Conservancy
“We, as a society, generally have a poor understanding of the true risks,” Carey said. “We tend to be overconfident in our engineering abilities to address that risk. If we did full cost accounting and really considered the environmental, social and economic costs and benefits, we would often come up with different solutions.”
One of the historic patterns of development in the Puget Sound region is the conversion of farmland to residential development, a pattern that continues in floodplains despite growing efforts to conserve farmland. In addition to lost revenue, conversion of farmland in rural areas carries higher costs for infrastructure. That includes flood protection as well as roads and utilities.
To discourage floodplain development, the report recommends identifying potential “cost subsidies.” They include increased costs paid by society to maintain roads and utilities, provide emergency services and restore conditions after a major flood.
Understanding the risks and costs could lead to a shift in spending from unnecessary levee expansions to buying out homes in flood-prone areas, the report says. Additional spending could be targeted where ecological and social values could be enhanced.
“If these changes are made, in addition to new development paying for infrastructure and emergency services, land in floodplains would not be as desirable for residential and commercial development, existing residents would be encouraged to sell, and existing public infrastructure would not be redeveloped,” the report says.
Album: Rainbow Bend historic flooding
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Another risk often ignored in planning discussions is that of climate change, which is expected to bring more frequent and intense winter storms in the future, thus increasing the frequency of floods. Other factors wrought by climate change include increasing erosion and landslides, contributing to excessive sediment in the rivers.
“The continued development of floodplains within the context of climate change puts residents at further risk,” the report states, adding that experts should study and quantify the economic, political, and social factors that result in floodplain losses.
The report also recommends regional planning at a scale that considers how multiple projects can protect a variety of land uses within a long stretch of a river.
“For agriculture, this may include land base needs, drainage and flood protection assurances, and an ongoing voice in floodplain planning processes,” according to the report.
“For developed areas, strategic plans could include better flood protections for homes, businesses and critical infrastructure,” the report continues.
“Finally, the ecosystem recovery community will likely look to existing salmon recovery plans that identify the most critical areas to restore through levee setback and riparian zone planting for fish.”
Because regional planning accounts for all viewpoints, projects proposed under Floodplains by Design have gained widespread support in the Legislature, Carey said. Addressing public safety and economic values are seen as strong points of the program.
Since the program officially started, state lawmakers have provided more than $80 million over the past two biennial budgets.
So far, state funding is limited to capital projects, including engineering and design, according to McKinney of Ecology. The early stages of planning, including organization and conceptual discussions, are not covered by state grants.
“You have to have stakeholder involvement; everybody gets that, from the legislators to the scientists,” —Scott McKinney, WA Dept of Ecology
“You have to have stakeholder involvement; everybody gets that, from the legislators to the scientists,” McKinney said. “Right now, we are not funding planning, so we rely on local governments to propose multi-year projects.”
The Implementation Strategy recognizes the need for dollars to cover startup planning, as well as mediators or community facilitators able to help people work out their differences.
Phasing of projects is encouraged, McKinney said, but it is important to maintain large-scale thinking to avoid “a patchwork of activities or ‘Frankenstein floodplain,’ as we call it.”
So far, a cost estimate has not been produced for meeting the Vital Signs target of restoring 15 percent of the degraded floodplains in Puget Sound.
But a 2014 study for implementing Floodplains by Design throughout Puget Sound came up with a rough estimate of $3 billion over the next 10 to 20 years. About $2.2 billion of that was associated with reducing flood risks, while $800 million would go for salmon recovery.