Temporal and spatial evaluation of stormwater engineering standards reveals risks and priorities across the United States
Temporal and spatial evaluation of stormwater engineering standards reveals risks and priorities across the United States
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DOI：
10.1088/1748-9326/aac696
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发表时间：
2018-07-01
影响因子：
6.7
通讯作者：
Samaras, Constantine
中科院分区：
文献类型：
--
作者：
Lopez-Cantu, Tania;Samaras, Constantine
美国的雨水基础设施是根据政府降水频率文件和国家交通部（DOT）平衡风险和成本的指导方针设计的。然而，政府降水文件和国家DOT指南都很少更新，这增加了降水模式随时间变化的地区的风险。本研究回顾了美国48个相邻州和哥伦比亚特区的州交通部设计手册，发现对于类似的道路和基础设施类型，建议的设计回收期标准存在很大差异。美国43个州1961-2000年连续降水记录之间的降水差异在超过90%的研究区域具有统计显著性。这些差异表明，在降水频率文件最新更新之前安装的雨水基础设施可能设计不足，无法适应当前和未来的气候条件。通过比较各州DOT对每种道路和基础设施类型的设计风暴值，得出了每个气候区域的指数，以评估各州要求的相对严格程度。利用这些指数值、观测到的降水频率估计变化以及每个州的设计手册出版日期，本研究确定了需要优先修订其雨水标准的州，以保持最初预期的设计性能。在43个州中，有8个州需要立即修改其雨水标准。此外，这些州应评估现有基础设施是否需要额外的适应能力来管理观测到的降水增加。在2050年的RCP 4.5和RCP 8.5排放情景下，所有州的优先级都增加了。虽然对提高标准的严格程度的基础设施成本与气候变化下未来损害的预期成本进行比较的地方评估仍然是必要的，但一项不后悔的行动是修改雨水标准，将观测到的降水增加纳入其中。
Stormwater infrastructure in the United States is designed using governmental precipitation frequency documents and informed by State Departments of Transportation (DOT) guidelines that balance risks and costs. However, both governmental precipitation documents and State DOT guidelines are updated infrequently, which enhances risks in areas where precipitation patterns have changed over time. This study reviewed State DOT design manuals from the 48 contiguous US states and the District of Columbia and found wide variation in design return period standards recommended for similar roadways and infrastructure types. Precipitation differences between successive US precipitation documents for 43 states over the period of 1961-2000 were found to be statistically significant in more than 90% of the study area. These differences indicate that stormwater infrastructure installed prior to the latest update of precipitation frequency documents could be under-designed for present and future climate conditions. Comparing State DOT design storm values for each roadway and infrastructure type, an index for each climate region was developed to assess the relative stringency of each state's requirements. Using these index values, the observed change in precipitation frequency estimates, and each state's design manual publication date, this research identified the states that need to prioritize revision of their stormwater standards to maintain the originally intended design performance over time. Eight out of 43 states were found to have the highest priority for immediately revising their stormwater standards. In addition, these states should assess whether existing infrastructure requires additional adaptive capacity to manage observed precipitation increases. The priority increased for all states under both the RCP 4.5 and RCP 8.5 emissions scenarios for 2050. While local assessments comparing infrastructure costs of increasing the stringency of standards versus the expected costs of future damages under climate change remain necessary, a no-regret action is revising stormwater standards to incorporate observed precipitation increases.