A Partnership with the Audubon Society | 2021
Nationwide and across the globe, climate impacts pose increasing problems to communities and ecosystems. As community leaders and local governments work to address these impacts, nature-based solutions can provide cost-effective options that benefit both communities and wildlife. Earth Economics partnered with the National Audubon Society on three case studies involving restoration and protection of wetlands, barrier islands, and other ecosystems for hazard mitigation purposes. These three cases represent diverse communities and geographies across the nation - in Connecticut, North Carolina, and California.
The results of this work have supported the case for conservation of an entire barrier island in North Carolina and informed Audubon’s new natural infrastructure policy platform, Building Resilience with Nature.
East River Marsh
In Connecticut, the 900-acre East River Marsh is a specialized salt marsh habitat for local wildlife, fish, and birds as well as a flooding defense for local communities. Though the Atlantic Coast was once covered with tidal wetlands like this, East River Marsh is a remnant increasingly threatened by sea level rise. As sea level rise changes the geography and characteristics of these marshlands, Audubon Connecticut is seeking to work with property owners and the greater community to protect undeveloped areas and minimize barriers to marsh migration while maximizing ecological and economic benefits for the surrounding community.
To support Audubon’s work and outreach to local communities, Earth Economics conducted an ecosystem services valuation of the East River Marsh, finding the area’s annual benefit to reach approximately $21.5 million. With this annual value, the marsh is expected to deliver $610 million in economic value to the region over the next 80 years.
Clearly, the marsh is a significant asset to the community, providing critical services that build resilience and community well-being. These services will be especially important as the region experiences climate-related changes such as increased temperatures and more frequent, intense storms over the coming decades.
Marin City
Marin City, California in the San Francisco Bay area will soon embark on an upgrade to the capacity and function of a stormwater basin that was historically a tidal wetland. Located in an unincorporated, low-income and multiracial community in an otherwise affluent county, the wetland area is being championed by local residents along with Shore Up Marin City and Audubon California to advance the Marin City Revitalization Project. This wetland design and restoration project would offer the community not just flood management, but a voice in city decision-making, leading to the co-creation of solutions to restore wetland habitat, create public access, and provide recreational amenities to local residents.
Earth Economics supported the Marin City Revitalization Project with an economic analysis of the estimated annual and long-term dollar value of benefits from the proposed design and restoration. Assuming that 1.6 acres around the fringe of the stormwater basin will be restored to quality San Francisco Bay wetland habitat, the project will return nearly $140,000 per year in benefits to the community, with an additional one-time added aesthetic value of roughly $1 million. Over a 35-year period, the total project benefit would reach roughly $4.4 million in today’s dollars, with a $4.40 return for each dollar invested. By any standard, the payoff of revitalization for the community and local wildlife could be substantial.
Lower Cape Fear
North Carolina’s Cape Fear region is a rich ecological area characterized by a variety of coastal plain habitats, from freshwater swamps and bottomland forests to coastal marshes and barrier islands. All of these habitats are significant both for wildlife habitat and the local community.
Audubon North Carolina is advancing multiple resilience projects to protect, restore, and enhance critical ecosystems in this area. Earth Economics stepped in to conduct an economic analysis of the benefits of three projects:
conservation of the 415-acre Lea-Hutaff Island;
expansion of the footprints of Ferry Slip and South Pelican Islands, which will provide critical waterbird habitat and wetland benefits; and
the expansion and re-establishment of oyster reefs at Shellbed and Striking Islands to improve water quality, restore oyster populations, enhance bird habitat, and buffer storm surge.
The analysis concluded that the asset value of these three improvement projects, minus implementation costs, will reach more than $277 million over a 35-year project lifespan. Additionally, the benefit-cost ratio for these projects combined is roughly 4:1, meaning that each dollar invested will return about $4 in benefits. Preservation of Lea-Hutaff Island alone, which has since been slated for conservation, has a benefit-cost ratio of 44:1, meaning that every $1 invested will return $44 in benefits.
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Photo Credit: U.S. Fish and Wildlife Service Northeast Region via Flickr
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