Conservation to Avoid Projected Development Provides Cost-Effective Flood Damage Reduction in the Coterminous United States.
Abstract
Flooding is the costliest form of natural disaster in the US and ongoing development in floodplains increases exposure and potential damages while compromising habitat and ecosystem services. Incomplete and inaccurate mapping of flood risk zones hinders the ability of floodplain managers and planners to guide development to limit exposure and mitigate flood risk. Additionally, reliance on local floodplain maps inhibits more regional and integrated management of rivers and flood risk. Here, we quantify the opportunity to prevent future flood damages by avoiding development in natural floodplain areas. Using a 30m resolution, continental-scale, two-dimensional, hydrodynamic flood hazard model with complete coverage of the contiguous US (Wing et al., 2017) alongside projections of land-use change from ICLUS (US EPA, 2017), permits us to examine the extent to which future developments may be at risk of flooding. By calculating the average annual loss incurred by these new developments in every remaining year of the century and comparing the total damages to the acquisition cost of the natural land they are projected to be built on (based on land cost data from Withey et al., 2012), we can calculate the benefit-cost ratio with respect to mitigated flood damage. Acquiring the 675,919 km2 of remaining unprotected natural lands in the 100-year floodplain would cost 156 billion yet would avoid 397 billion in potential flood damages to new development by 2050, rising to nearly $593 billion by 2070. Although the costs and benefits vary regionally, in the majority of counties (70%), the benefit of avoiding flood damages associated with projected future development exceeds the cost of acquiring unprotected natural areas in the 100-year floodplain. This is the case for floodplain acquisitions of various size (e.g. 5-year or 500-year floodplain) under a variety of economic assumptions. Conservation of remaining natural floodplains avoids unnecessarily increasing the economic and human costs of flooding, while simultaneously providing increased habitat and ecosystem services.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.H41M2269W
- Keywords:
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- 3354 Precipitation;
- ATMOSPHERIC PROCESSESDE: 1821 Floods;
- HYDROLOGYDE: 1855 Remote sensing;
- HYDROLOGYDE: 4335 Disaster management;
- NATURAL HAZARDS