7 Reasons Why You Should Care About Floodplains

7 Reasons Why You Should Care About Floodplains

Our connection to water is essential. People love to live near water and to look out on oceans, rivers, and lakes. Waterways provide drinking water, recreation, irrigation, fishing, and transportation that support communities. They are so integral a part of our daily lives it is easy to forget that they can do a lot of damage during storms and floods. In October 2012,  Superstorm Sandy hit the eastern United States, Canada, and the Caribbean, killing 160 people in the US and causing 65 billion dollars’ worth of damage. In New York and New Jersey, some of the hardest hit areas, homes that were thought to be at low flood risk were damaged by the deluge. Closer to home, the Willamette Valley Flood of 1996 cost $500 million and displaced 3,000 people throughout the Pacific Northwest.

What Are Floodplains?

These events highlight the importance of floodplains, land around bodies of water that takes on excess water in times of flood and when managed wisely, can help to reduce the risk of damage when storms or snowmelt overwhelm the banks.  In other words, when Mother Nature gets dramatic, floodplains go to work.

Why Are Floodplains Important?

So why should you care about floodplains? There are many reasons, but we’ve narrowed it to 7:

Water quality is improved in floodplains where vegetative cover prevents soil erosion and acts as a filter for runoff and overbank flows. Photo of New River courtesy of BLM.

Water quality is improved in floodplains where vegetative cover prevents soil erosion and acts as a filter for runoff and overbank flows. Photo of New River courtesy of BLM.

1. Clean water

Rivers carry sediment, nutrients, and other pollutants, especially when they are running high and fast after a storm. A healthy floodplain gives water space to spread out and slow down. This keeps water cleaner, protecting local drinking water, recreation, and aquatic species like fish. Shading of streams by floodplain vegetation also helps to regulate water temperature.

Floodplains are vital to many species like this Chinook Salmon because they provide important habitat during the freshwater phase of the salmon life cycle. Photo Courtesy of Sam Beebe.

Photo Courtesy of Sam Beebe.

2. Habitat

Floodplains are rich and biologically diverse environments that can support an abundance of plants, birds, and other species on land and in the water. For example, Chinook Salmon (pictured to the left) rely on floodplains during the freshwater phase of their life cycle.

When floodplains are intact, flood waters can spread over a large area of flat open land. This reduces flood velocities and provides water storage to reduce flood depths downstream, reducing flood damage risks to downstream communities. Open Space preserved in McMurry Natural Area and Legacy Park along the Poudre River in Fort Collins allowed flood waters to spread out and slow down during a September 2013 storm. Photo courtesy of the City of Fort Collins.

Photo of McMurry Natural Area storing floodwaters after a storm courtesy of the City of Fort Collins.

3. Flood storage

Floodplains take on and store excess water in times of flood, releasing it slowly overland and into groundwater. The flood storage capacity of floodplains means that there is less likelihood that floodwater will end up in your basement. Floodplains do not eliminate all risk of property damage, but when they are managed wisely, they can definitely help.

Floodplains can act as recharge areas for groundwater. Photo courtesy of the COMET Program.

Floodplains can act as recharge areas for groundwater. Photo courtesy of the COMET Program.

4. Groundwater recharge

Rainwater travels deep into the ground of a floodplain to replenish groundwater supply.  Groundwater travels slowly into rivers, lakes, and wetlands, regulating the availability of water during drier periods, when people, plants, and animals need it most.

River channels naturally meander through the floodplain landscape and over time deposits soil-forming material especially during floods. These deposits provide fertile soil for agricultural production. Photo of Willamette River courtesy of Aaron Hockley.

River channels naturally meander through the floodplain landscape and over time deposits soil-forming material especially during floods. These deposits provide fertile soil for agricultural production. Photo of Willamette River courtesy of Aaron Hockley.

5. Food

Floodplains have rich, fertile soils that have made them attractive to farmers for generations. Some level of sustainable agricultural practices are considered to be compatible with managing floodplains to support key floodplain functions.

It is no coincidence that the railroad and road are located along the Columbia River. The flat, rock-free land lends itself readily to transportation development. Photo courtesy of John Russell.

Photo of railroad and road along the Columbia River courtesy of John Russell.

6. Transportation

It’s no coincidence that some of our nation’s largest and most productive transportation centers are located in floodplains. Some rivers and lakes can support shipping and the flat, rock-free land lends itself readily to road and railroad development, and is conveniently located close to agricultural land.

Recreational opportunities are abundant in and around floodplains like this hiking trial along the Umpqua River. Photo Courtesy of BLM.

Recreational opportunities are abundant in and around floodplains like this hiking trial along the Umpqua River. Photo Courtesy of BLM.

7. Culture

Floodplains provide numerous recreational opportunities, including lakes, rivers, hiking trails, and spaces to see thriving wildlife. In addition, the long history of settlement in floodplains as people have been drawn to the fertile land and abundant resources create a shared culture and sense of place in these locations.

Challenges to Smart Floodplain Management

A functioning floodplain is important for the health of the surrounding ecosystem, as well as for the economic and cultural activities that rely on it. A rapidly-changing policy and physical environment, however, makes management of floodplain resources in an effective and integrated way a daunting challenge for many US communities. Flood frequency and severity is expected to increase in much of the US, yet cities face strong pressure to realize the economic and development value of floodplain areas. Litigation on the National Flood Insurance Program, changing municipal stormwater rules, and projected impacts of climate change are all pushing planners to think about increasing resiliency and reducing risk to people and property. Many towns have small or even volunteer planning commissions and limited budgets to navigate this complexity.

A Path Forward

Better information on flood risk from hydrological modeling, and new(ish) approaches such as Low Impact Development strategies and green infrastructure techniques are providing communities with tools to limit flood damage while maintaining valuable floodplain functions. Programs such as The Nature Conservancy’s Floodplains By Design demonstrate how reconnecting rivers to their floodplains is a more effective solution for protecting urban infrastructure than traditional dams, dikes and levees. And mechanisms such as floodplain function mitigation banking and transfer development rights are being explored as ways to increase the flexibility communities need as they balance development and floodplain function.

Where to Next?

At Willamette Partnership, we are starting some exciting work around floodplains, convening a diverse group of stakeholders to develop a vision for smart floodplain management and tools to support its implementation in communities throughout Oregon.  Along with our partners, we recognize that smart floodplain management is good for the environment, and good for the communities that live, depend, and work on floodplains You can find out more about how we are working with stakeholders and communities to meet these challenges here.

Nicole Maness
Nicole is lead for Willamette Partnership’s work on habitat conservation. In this role, she focuses on building the science-based tools to support incentive programs for aquatic and terrestrial habitat and works with policy makers and stakeholders to implement innovative approaches to restoration throughout the Pacific Northwest. Prior to moving to Oregon, Nicole was the executive director of a think tank at the University of British Columbia that dealt with forest land-use policy in BC. She holds a BSc in Environmental Science from McGill University in Montreal, Canada. When not thinking about conservation, Nicole enjoys exploring the backcountry wilderness, playing the piano, and attaining new levels of patience and optimism as she restores her house in Corvallis.

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