It can be difficult to directly compare natural (or “green”) infrastructure to traditional (“gray”) infrastructure. Practitioners from the U.S. Army Corps of Engineers (USACE) identified “uncertainty and discomfort in planning life cycle management activities” as one of the most significant barriers to natural infrastructure (NI) implementation.
With traditional life cycle analysis, NI projects may seem uncompetitive with traditional infrastructure methods due to a higher initial cost or longer benefits timeline. A team of researchers from USACE and the University of Georgia’s Institute for Resilient Infrastructure Systems (IRIS), collaborating through the Network for Engineering With Nature (N-EWN), have proposed a new framework for the life cycle analysis of infrastructure projects that includes a more detailed view of project benefits and environmental impacts.
“An element that was generally missing from practice, but that is crucial for NI, is the ability to consider dynamism of features over time and the implications for performance, costs, and benefits.” (Kurth et. al., 2024)
The new paper, published in February 2024 in Frontiers in Built Environment, specifically looks at flood risk management (FRM) projects, which are usually analyzed based on how well they minimize damages to infrastructure. The authors challenge this mindset, asserting that only quantifying “tangible consequences,” or visible damages, may not provide a full picture of the economic or social impacts of flooding.
By reviewing existing FRM project planning and alternatives analysis, the authors found that the major issue with applying these frameworks to NI projects: Overly narrow boundaries of project costs and benefits, specifically the ability to consider project features that are dynamic over time and how those features impact performance, prevent analyses from seeing the co-benefits of these projects.
The framework the paper suggests consists of four concepts: Risk management, Cost, Impacts, and Co-benefits. Co-benefits may include added recreational value, habitat creation or restoration, air or water quality support and more. These benefits are often difficult to quantify in traditional analysis models, but can translate to millions of dollars worth of restored ecosystems, prevented risk and added jobs. Additionally, the authors stress the importance of engaging local stakeholders in infrastructure projects “early and often… to ensure that any physical interventions will map onto perceived value to the local communities.”
The paper also discusses three example applications of life cycle management concepts in NI projects: Louisiana’s Coastal Protection and Restoration Authority created a “Coastal Master Plan,” a set of both structural and nonstructural goals to combat coastal land loss and reduce flood risk. Levee removals in the Tillamook RIver, Oregon, allowed for the restoration of salmon habitat while also widening the river’s floodplain to reduce flood impacts and create economic benefits. The authors describe the full life cycle of a shoreline project in the Netherlands, which involved the coupled effect of a vegetated foreshore to dampen waves and an earthen dike to protect against high water levels. These projects highlight the need for analysis of NI projects to assess all aspects of their functionality.
“Although the framework developed in this paper appears simple,” the paper concludes, “in practical application, there are many barriers that exist to its implementation or barriers to the antecedents to using the framework.” This type of multi-level challenge evaluation will continue to be necessary for the implementation of NI measures and projects, and the N-EWN is proud to support the formation of these collaborative efforts.
Check out the full paper here.
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