CAREER: Science and Education for Connecting Urban Irrigation Efficiency to Streamflow in Semi-Arid Cities

半干旱的美国城市在缺水地区发展迅速。环境可持续性的一个主要挑战是通过确保城市、农业和环境共同确保水的安全来帮助半干旱社区蓬勃发展。在相同供水条件下满足日益增长的用水需求的一个成功方案是通过提高效率来减少城市用水量。城市草坪灌溉现在是减少城市用水量的主要目标，因为它主导着许多半干旱城市的年度用水量。通过提高灌溉效率来减少城市用水量可以在缺水的河流流域发挥关键作用，但目前受到径流量减少和地下水流入河流的潜在意外后果的限制。如果我们改造半干旱城市，减少户外用水，城市的溪流会干涸吗？流经半干旱城市的主要河流会变成涓涓细流，从而对生态、娱乐和下游水资源造成破坏吗？缺乏关于城市灌溉如何影响径流的基础科学知识，限制了美国半干旱地区部分地区实施节水城市灌溉系统。这项工作的目的是预测城市灌溉减少对径流的影响，提高城市地区管理稀缺水资源的能力，并最终为繁荣、可持续的半干旱社区的目标做出贡献。该项目将为对水事业感兴趣的少数族裔学生建立一个指导计划，并让这些学生参与实际操作的城市水研究。该项目由水文科学计划和环境可持续发展计划共同资助。减少城市灌溉在实现水资源稀缺的河流流域的水安全和可持续发展方面发挥着关键作用。城市灌溉可以通过智能、高效的灌溉系统或草坪改装成干旱化和不透水的表面来减少。这项工作将量化目前草坪灌溉对小而半干旱的城市流域径流的贡献。这将在美国科罗拉多州丹佛市通过开发和应用一种新的方法来实现，该方法将水同位素作为自来水的示踪剂与自来水供应商的报告相结合，并在实验流域进行监测。然后，利用灌溉小区和地下-地表-地表综合水文模型，研究减少城市灌溉对半干旱地下水补给和地表径流的影响。最后，本工作将评估大流域半干旱城市廊道现有和减少城市灌溉对径流的水文意义。这项研究将与科罗拉多州城市水资源劳动力多样化的教育计划紧密结合。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Semi-arid U.S. cities are growing rapidly in regions where water is scarce. A major challenge for environmental sustainability is to help semi-arid communities thrive by ensuring that cities, agriculture, and the environment are jointly water-secure. One successfully demonstrated option to meet growing water demands with the same water supply is reducing urban water use through efficiency. Urban lawn irrigation is now the primary target for reducing urban water use, as it dominates annual water use in many semi-arid cities. Cutting urban water use through irrigation efficiency could play a critical role in water-scarce river basins, but is presently limited by the potential unintended consequences of streamflow reduction from less runoff and groundwater flowing into streams. If we transform semi-arid cities to use less water outdoors, will urban streams run dry? Will major rivers flowing through semi-arid cities become trickles, with all the associated damage to ecology, recreation, and downstream water availability? The lack of fundamental scientific knowledge on how urban irrigation affects streamflow has limited the implementation of water-efficient urban irrigation systems in some parts of the semi-arid U.S. The purpose of this work is to predict the effects of reduced urban irrigation on streamflow, enhance the capacity of urban areas to manage scarce water resources, and ultimately contribute to the goal of thriving, sustainable semi-arid communities. The project will establish a mentoring program for underrepresented minority students interested in water careers and engage these students in hands-on urban water research. This project is co-funded by the Hydrologic Sciences Program and the Environmental Sustainability Program.Reducing urban irrigation could play a critical role in achieving water security and sustainability in river basins where water is scarce. Urban irrigation may be reduced through smart, efficient irrigation systems or lawn conversion to xeriscaping and impervious surfaces. This work will quantify the present contribution of lawn irrigation to streamflow in small, semi-arid urban watersheds. This will be achieved in the Denver, Colorado, U.S. area by developing and applying a novel method combining water isotopes as a tracer of tap water with water provider reports, and monitoring in experimental watersheds. Then, using irrigation plots and integrated subsurface-surface-land surface hydrologic modeling, this research will determine the effects of reduced urban irrigation on semi-arid groundwater recharge and surface runoff. Lastly, this work will evaluate the hydrologic significance of present and reduced urban irrigation on streamflow in the semi-arid urban corridor of a large river basin. This research will integrate tightly with an education plan to diversify the urban water workforce in Colorado.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.