Bill Williams River in western Arizona near the California border. This river was one of nine rivers enrolled at the inception of the Sustainable Rivers Project.
Bill Williams River in western Arizona near the California border. © Tana Kappel/TNC


Natural Infrastructure

Effective, Economical and Sustainable Solutions to Meet America’s Needs

Infrastructure policy should include nature-based solutions to support robust economic development, improve the quality of life in communities and sustain America’s lands and waters for future generations.

The need to improve and maintain America’s infrastructure is well recognized. In its 2017 scorecard, the American Society of Civil Engineers gave the state of the nation’s infrastructure a D+ grade. Increasing impacts from extreme weather events, which have caused more than $1 trillion in damages since 1980, make the challenge even greater. Infrastructure failures are becoming all too common, such as the March 2019 flooding along the Missouri River and in north-central states, causing an estimated $10.8 billion in damages, much of it exacerbated by failed levees and dams.

Nature is a smart solution to help meet the nation’s infrastructure needs. It is an effective, economical and sustainable investment that can provide clean and reliable water supplies, improve and maintain harbors and inland waterways and reduce risks from floods, droughts and fires. Investments in natural infrastructure provide multiple economic, environmental and social benefits to communities that need functioning infrastructure and a healthy environment.

For example, people are safer during floods when rivers have more room for floodwaters to disperse and slow down rather than rise, rage and threaten communities. Along coasts, natural features like sand dunes, marshes and reefs reduce wave heights and absorb storm surges.

Natural infrastructure can be used alone or alongside gray infrastructure (like seawalls, dams, levees and water and wastewater systems) to provide cost-effective and sustainable solutions that bring multiple benefits. In addition to helping reduce risk, natural infrastructure can deliver clean water and air, sustain lands that grow food and provide enhanced recreational opportunities and wildlife habitat—all benefiting local economies.

Policy Recommendations 

Ensure consideration of nature and nature-based solutions in infrastructure projects.

Improve community quality of life and save taxpayer dollars by encouraging resilient approaches and ensuring collaboration with local partners when fixing structures subject to repeated failures due to extreme weather disasters.

Establish innovative finance mechanisms that enable and encourage leveraging federal investment with other federal, state, local and private investments.

Promote advanced mitigation to improve project delivery and outcomes by allowing environmental considerations to be incorporated prior to the start of construction.

Natural Infrastructure is Economic and Effective

Coasts. In a 2017 study, The Nature Conservancy (TNC), in partnership with Risk Management Solutions (a global leading risk modeler for the insurance industry), Guy Carpenter & Co. and others showed that coastal wetlands saved more than $625 million in property damages during Hurricane Sandy and reduced annual property losses by nearly 20% in Ocean County, New Jersey.

Rivers. To meet its temperature requirements for water discharges into the Rogue River from its wastewater treatment facility, the city of Medford, Oregon, evaluated one nature-based and two built alternatives. An economic analysis showed that the river restoration—the natural infrastructure option—was three times more cost effective than a built option. The nature-based option also provides additional benefits, such as better wildlife habitat and water quality.

Urban. Thousands of cities throughout the nation are under court order to improve water quality impaired by stormwater overflows. An Environmental Protection Agency analysis documented an avoided capital cost of $120 million by the City of Lancaster, Pennsylvania, stemming from the city’s decision to use a blended gray and natural infrastructure solution to address water quality pollution occurring from stormwater overflows.

Rain gardens installed at Hyattsville Methodist Church to address the 3 million gallons of stormwater the 3-acre parking lot sheds annually.
First United Methodist Church The Hyattsville, Maryland, site is a part of a project that prevents millions of gallons of stormwater from running into an Anacostia River tributary. © TNC

Natural Infrastructure Investments Demonstrate Success

To mitigate stormwater runoff, Washington, D.C., has instituted a first-of-its-kind stormwater retention credit (SRC) market. The market reduces the impact of stormwater runoff, which is the largest-growing source of pollution to the Chesapeake Bay watershed. It allows land-constrained developers to meet a portion of their stormwater retention requirements by purchasing SRCs. SRCs are generated by stormwater retention projects elsewhere in Washington, D.C., including green infrastructure projects.

Investments in green infrastructure for stormwater retention can bring income to landowners and provide a host of valuable co-benefits, including expanded green space, reduced localized flooding, increased flexibility and onsite revenue options for developers and jobs to build and maintain green infrastructure sites. In particular, offsite credit projects create opportunities for infrastructure investments in underserved communities.



Hamilton City, California

Sacramento River water near Hamilton City, California.
Three pelicans Sacramento River water near Hamilton City, California. © Grant Johnson

In partnership with the U.S. Army Corps of Engineers, the California Department of Water Resources and Reclamation District 2140, TNC is championing a $73 million project where, for the first time, the Army Corps designed a multi-benefit project to specifically reduce flood damages and restore critical floodplain habitat on the Sacramento River.

Construction began in spring 2016. When completed, a new 6.8-mile setback levee will reconnect 1,450 acres of floodplain between the levee and the river. Approximately 1,361 acres will be restored to native riparian habitat and significantly reduce flood risk to the city of Hamilton, where evacuations have taken place six times in the past few decades.