Sanchez Georgina M, Lawrimore Margaret A, Petrasova Anna, Vogler John B, Collins Elyssa L, Petras Vaclav, Harper Truffaut, Butzler Emma J, Meentemeyer Ross K
Center for Geospatial Analytics, North Carolina State University, Raleigh, North Carolina, United States of America.
Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, North Carolina, United States of America.
PLoS One. 2024 Dec 31;19(12):e0311718. doi: 10.1371/journal.pone.0311718. eCollection 2024.
In the United States, requirements for flood insurance, development restrictions, and federal buyout program eligibility rely on regulatory designation of hazardous zones, i.e., inside or outside the 100-year floodplain. Extensive research has investigated floodplain development patterns across different geographies, times, and scales, yet the impacts, and potential unintended consequences, of floodplain policies beyond their boundaries have not been empirically examined. We posit that the regulatory 100-year floodplain presents a "safe development paradox", whereby attempts to reduce flood risk paradoxically intensifies it by promoting development in and near flood-prone areas. We conducted the first comprehensive national assessment of historical and future development patterns related to the regulatory 100-year floodplain, examining the spatial distribution of developed land within increasingly distant 250-m zones from floodplain boundaries. We found a disproportionate concentration of developed land (24% or 89,080 km2 of developed land by 2019) in zones immediately adjacent to the floodplain, a trend observed at the national, state, and county levels. Nationwide projections suggest that approximately 22% of all anticipated growth from 2020 to 2060 is likely to occur within 250 m from the 100-year floodplain, equivalent to 6,900 km2 of new development (SD = 2,842 km2). Understanding and anticipating the influence of flood management policies on current and future land use decisions is crucial for effective planning and mitigation strategies.
在美国，洪水保险要求、开发限制以及联邦收购计划的资格取决于危险区域的监管指定，即100年一遇洪泛区的内部或外部。大量研究调查了不同地理区域、不同时间和不同尺度下的洪泛区开发模式，但洪泛区政策在其边界之外的影响以及潜在的意外后果尚未得到实证检验。我们认为，监管规定的100年一遇洪泛区存在一种“安全发展悖论”，即试图降低洪水风险的做法，反而通过促进易洪地区及其附近的开发，加剧了洪水风险。我们首次对与监管规定的100年一遇洪泛区相关的历史和未来发展模式进行了全面的全国性评估，研究了距洪泛区边界越来越远的250米区域内已开发土地的空间分布。我们发现，紧邻洪泛区的区域内已开发土地高度集中（到2019年，已开发土地面积达89,080平方公里，占24%），这一趋势在国家、州和县级层面均有体现。全国范围的预测表明，2020年至2060年所有预期增长中，约22%可能发生在距100年一遇洪泛区250米范围内，相当于6,900平方公里的新开发区域（标准差 = 2,842平方公里）。了解并预测洪水管理政策对当前和未来土地利用决策的影响，对于有效的规划和减灾策略至关重要。
