Background: to let the water back in

Record flooding in the Midwest of the United States this year, and recent devastation from floods in Pakistan, Australia, and the east coast of the US reminds us that flooding is the number one hazard in the world in terms of loss of life and damages.

Flood control channels in Walnut Creek, CA move the water through and away from the city as quickly as possible. When not carrying floodwaters, this is what is left.

Though well-intended, traditional technical (often called “structural”) flood management strategies like building floodwalls, dams, dikes, and levees that keep the water away have actually  been detrimental to both public safety and to the environment.  As sea levels rise and our climate changes, threats from floods will prove to be even more severe. We therefore are in need of a more sustainable approach to protect life, jobs, and our natural communities–one that lets water the back in.

Safety. As we relied more on levees, we increased the number of people living behind them. Now when the levee fails or a larger flood comes, the consequences will be much worse than were the levee not there in the first place. Further, most residents in the United States and the Netherlands believe they are safe from floods and are unprepared.

New developments behind levees can flood deeply and quickly-- consequences of a major flood can be catastrophic. Photo courtesy of UC Davis Center for Watershed Sciences)

Levees have permitted us to build and live in places where we would not previously have been able to.  What was once under the sea or seasonally inundated by the river is now a farm, a residential development, a busy shopping mall or worse, a school.  As we altered the natural landscape, we altered the course of the water–it no longer flows or drains in the same way that it used to, and much more of it flows into the channels and waterways that before.  In years like 2011, it is much more than our waterways can handle.

Levees also increase the risk to public safety because financially struggling communities in the United States (the number of these is growing) cannot afford to maintain the flood protection and drainage infrastructure that they already have.  In some cases local agencies still permit new development or redevelopment under the auspice that the structures will eventually be upgraded. This leaves residents now more vulnerable than ever.

Environment.  Concrete floodwalls, levees, dikes, and dams have cut off rivers from their floodplains and separated tidal wetlands from the sea. Estuaries and rivers, tidal marshes, and  floodplains once rich in habitat have been reduced to a series of sediment-starved canals and concrete channels, void of native life, with both declining fisheries and human communities whose economies depend on them.

160 years of reclamation in the California Bay-Delta dramatically changed the landscape and the ecosystem. (Photo courtesy of Jeff Mount, UC Davis Center for Watershed Sciences)

When today’s policy makers are faced with critical decisions, the choice is often inaccurately framed in black and white: a choice between public safety, OR the environment… a choice between  public safety OR the economy. Of course neither of these are choices that anyone wants to make, but fortunately, they don’t have to.

Are levees all bad? No. But they are not enough.

A Solution?  There are many new and old techniques for assessing and reducing flood risk to provide multiple benefits: instead of keeping the water away, we can protect our communities and improve our ecosystems– by letting the water back in.

Allowing rivers to spread out protects communities by reducing the high water level during a flood. As a result, giving room to rivers reduces both the chances of a severe flood and the consequences (damages and loss of life) when a large flood occurs. Giving room to rivers also restores floodplain ecosystems and habitat–critical for the natural and human communities that depend on them.

Room for Rivers in Practice: The Netherlands and the United States  After hundreds of years of holding back the sea, the country of Netherlands is experienced and notorious for advanced flood risk management. After 1995, the country implemented a national “Room for the River” strategy to give rivers space to safely spread out during flood times. Similarly, Americans had good foresight in 1933 when the U.S. Corps of Engineers built the Yolo Bypass to releive the flooding that plagued Sacramento, California.  The bypass routed floodwaters away from the urban areas and into less developed lands that now support thriving ecosystems. As recently as May of 2011, the U.S. Army Corps of Engineers intentionally breached a levee, activating a 1928 plan,  (see New Madrid Floodway) to save the town of Cairo, Illinois, along the Mississippi River from flooding.

Biesbosch National Park, Netherlands

Room for the River creates a rich ecological community at at Biesbosch National Park, the Netherlands


The Sacramento River spills high flows over the Fremont Weir into the Yolo Bypass which reduces flooding in Sacramento and provides important ecological benefit (San Francisco Chronicle, 2011)

So, these strategies exist–what’s the problem? 

Alternative strategies like expanding floodways and bypasses face many barriers to implementation that are largely political and economic. Additionally, public and political perceptions of risk may be skewed (into thinking risk of flooding is low or non-existent) and this influences critical decisions as well.  To name a few…

Many leaders in the U.S. and abroad tend to favor a flood risk management approach that solely depends upon levees, as this allows communities to continue to developing in floodplains and to earn sales-tax and commercial revenue from the new development. Our agencies and local governments in the U.S. are willing to fund projects that require lower immediate costs, and they disregard those that may be more expensive initially yet may provide more longer-term benefits.

In the United States, current methods for evaluating such projects do not have a way to appropriately account for ecological and social benefit.  As a result, proposals like these do not score well cost-benefit analysis.

How does one quantify the benefits of healthy rivers with thriving ecosystems, abundant wildlife, and clean water? Similarly, how does one put a dollar value on the losses from Hurricane Katrina, where four out of five businesses have not yet re-opened, and the hurricane (and aftermath) resulted in the largest in-country migration since the Civil War? Not to mention the loss of life.

In the Netherlands and around the world, alternative, multi-benefit projects face similar challenges and that is why in some areas, researchers, NGOs, consultants, and agencies are pushing for more system-wide analysis of flood risk reduction techniques. We must begin to understand these costs and benefits better so we can move toward more sustainable approaches that truly protect our human and natural communities.

Please stay tuned. Posts in the coming months will investigate and address some of these issues as they apply in the Netherlands, the United States, and globally.

About wateraway

Jessica Ludy is an independent researcher with Unesco-IHE, a Water Resources Planner with ARCADIS, and a Fulbright Scholar in Flood Risk Management at Delft Technical University, the Netherlands. She was formerly the Associate Director of Flood Management at American Rivers in Berkeley, California, where she worked to promote sustainable flood management strategies in regional, and state, and federal agencies. Jessica has also been a lecturer and researcher at UC Berkeley in the Department of Landscape Architecture and Environmental Planning. Jessica grew up on the Great Lakes in Michigan, earned a BSc at the University of Vermont in Environmental Science, and an MSc in Environmental Planning from the University of California, Berkeley. This website is not affiliated with the Fulbright commission, ARCADIS, TU-Delft, Unesco-IHE, or American Rivers.
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1 Response to Background: to let the water back in

  1. Pingback: » A Few Good Reads (9/19/11) Hydraulically Inclined

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