EAR-PF: Present and future flood mitigation services of wetland infrastructure across scales

暴雨期间的洪水已经成为城市的主要问题。由于路面和屋顶数量的增加，风暴频率的增加，更强烈的风暴，或者城市和气候的这些特征的组合，城市可能会经历这种洪水。在全球许多城市，特别是在美国，极端降雨造成的洪水可能会特别伤害那些已经处于经济压力下的人、种族和少数民族，以及同时属于这两类的人。城市正试图通过改变城市建设方式来减少强风暴造成的洪水威胁。美国和世界各地的许多城市都在考虑建设湿地或包括天然湿地，以便将水安全地从城市中转移出去。然而，这些想法和做法都是新的，城市还需要了解更多关于城市湿地是否以及如何降低洪水风险的问题。此外，随着当地和全球气候的变化，城市不了解湿地是否以及如何很好地防止城市洪水。在本研究中，将对两个拥有丰富湿地的城市（美国俄勒冈州格雷沙姆和智利瓦尔迪维亚Región de los Ríos）进行研究和建模，以了解拥有湿地的城市在当前和未来如何应对风暴。通过收集数据并对湿地降低洪水风险的三种主要方式进行建模——将水储存在地表，允许水渗入地下，以及让植物消耗水——这项研究将呈现内陆城市湿地对洪水风险影响的整体图景。参与这项研究的研究人员将直接与受洪水影响的社区合作，以确定过去洪水风险高的地区，并教育利益相关者了解他们未来的洪水风险。通过与洪水风险管理人员合作，将从这项工作中吸取的经验教训纳入每个城市的洪水风险计划。雨洪，即当降水速率超过自然和工程排水系统的去除速率时发生的洪水，已成为城市的主要问题，因为城市的不透水地表覆盖面积不断增加，强烈风暴反复出现，风暴日益强烈，或这些特征的组合。洪水可能会给城市造成巨大的经济损失，并导致生命损失。在全球许多城市，特别是在美国，洪水泛滥对边缘群体和少数民族造成了不成比例的影响。随着洪水风险和影响的恶化，城市正在寻求新的发展形式，包括恢复或建设湿地，或将所谓的残余湿地纳入城市结构。然而，关于城市内陆湿地是否以及如何降低洪水风险的研究尚不成熟，而且研究通常没有在适当的城市尺度上考察湿地的累积洪水风险降低效果。研究通常也不考察未来气候条件下的洪水风险，而只考察未来2到10年的风险。本研究将美国俄勒冈州Gresham市和智利Valdivia市（Región de los Ríos）的湿地涵蓄、入渗和蒸散对洪水风险的影响扩大到整个城市，这两个城市都具有广泛的湿地覆盖。数据收集将通过持续监测地表储水量和土壤储水量和植物蒸腾的天气性调查来完成。这些数据将用于重建城市湿地在雨水管理模型中的关键水文功能，进而用于估计典型（10年）和更极端（100年）风暴期间雨水管理系统的性能。据预测，到2100年，这种风暴在这些研究城市将变得更加频繁。通过考虑湿地减少雨洪风险的三种主要水文机制——保留、入渗和蒸腾，本研究的结果将呈现内陆城市湿地对雨洪风险影响的整体图景。通过直接与每个城市受洪水影响的社区合作，参与这项研究的研究人员将确定过去洪水风险高的地区，并教育社区了解他们未来的洪水风险。通过与研究城市的洪水风险管理者直接合作，这项工作的突出经验教训将被纳入每个城市的洪水风险计划。此外，这将是为数不多的试图将绿色基础设施（尤其是湿地）的影响扩大到城市规模的研究之一。这将是第一个将绿色基础设施的蒸腾作用扩大到城市规模的研究。这一切都将使用其他研究人员或实践者尚未采用的混合方法来完成。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Flooding during intense storms has become a major concern in cities. Cities may experience this kind of flooding due to increasing amounts of pavement and roofs, an increased frequency of storms, more intense storms, or an assortment of these features of the city and climate. In many cities across the globe, and particularly in the U.S., flooding from extreme rainfall may especially harm people who are already financially stressed, racial and ethnic minorities, and people who fit in both of these categories. Cities are trying to reduce the threat of flooding caused by intense storms by changing how cities are built. Many cities in the U.S. and across the world are considering constructing wetlands or including natural wetlands in order to trap and move water safely away from people in the city. However, these ideas and practices are new, and there is much more that cities need to understand about if and how wetlands in cities can reduce flood risk. Also, cities do not understand whether and how well wetlands might prevent flooding in cities as the local and global climate changes. In this study, two cities with abundant wetlands (Gresham, OR, USA and Valdivia, Región de los Ríos, Chile) will be studied and modeled in order to understand how cities with wetlands respond to storms in the present day and in the future. By collecting data on and modeling three primary ways by which wetlands may reduce flood risk—storing water on the surface, allowing water to seep through the ground, and having plants consume water—this study will present a holistic picture of the impacts of inland urban wetlands on pluvial flood risk. Researchers involved in this study will work directly with communities impacted by flooding to identify areas of high past flood risk and educate stakeholders about their future flood risk. Lessons learned through this work will be incorporated in flood risk plans for each city through engagement with flood risk managers.Pluvial flooding, which is flooding that occurs when rates of precipitation exceed rates of removal by natural and engineered drainage systems, has become a major concern in cities with increasing impermeable surface cover, recurring intense storms, increasingly intense storms, or an assortment of these characteristics. Pluvial flooding may cause substantial monetary damage to cities and lead to loss of life. In many cities across the globe, particularly in the U.S., pluvial flooding disproportionately impacts marginalized groups and racial and ethnic minorities. As pluvial flood risk and impacts worsen, cities are looking to new forms of development that include restoring or constructing wetlands, or incorporating so-called remnant wetlands into the urban fabric. However, whether and how inland wetlands in urban areas can reduce pluvial flood risk is inchoate, and studies normally do not examine the cumulative flood risk reduction effect of wetlands at the appropriate scale: the city. Nor do studies typically examine pluvial flood risk under future climate conditions, instead only examining risk 2 to 10 years into the future. In this study, the effects of wetland storage, infiltration, and evapotranspiration on pluvial flood risk will be scaled-up to the whole city in Gresham, Oregon, USA, and Valdivia, Región de los Ríos, Chile, which both feature extensive wetland coverage. Data collection will be accomplished through continuous monitoring of surface storage and synoptic surveys of soil storage and plant transpiration. These data will serve to reconstruct key hydrologic functions of urban wetlands in a stormwater management model, which will in turn be used to estimate stormwater management system performance during typical (10-year) and more extreme (100-year) storms. Such storms are predicted to become more frequent in these study cities by the year 2100. By considering three primary hydrologic mechanisms by which wetlands may provide pluvial flood risk reduction—retention, infiltration, and transpiration—the results of this study will present a holistic picture of the impacts of inland urban wetlands on pluvial flood risk. By working directly with communities impacted by flooding in each city, researchers involved in this study will identify areas of high past flood risk and educate communities about their future flood risk. By working directly with flood risk managers in the study cities, the salient lessons this work will be incorporated in flood risk plans for each city. Furthermore, this will be one of few studies to attempt to scale up the effects of green infrastructure, particularly wetlands, to the city scale. This will be the first study to scale up transpiration in green infrastructure to the city scale. This will all be accomplished using a mixed methodology that has not yet been pursued by other researchers or practitioners.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.