CAREER: Active Learning Across Interfaces: Controls on Flow Intermittency and Water Age in Temporary Streams

超过三分之一的美国人口依靠临时溪流--并不总是有水流过的渠道--供水。美国最高法院和环境保护局最近都注意到了解这些溪流的重要性，以确保全国范围内的可钓鱼、可游泳和可饮用的水。令人惊讶的是，预测溪流何时何地干涸，以及哪些溪流最有可能从常年流转到干旱期间偶尔干涸，仍然具有挑战性。该项目将通过绘制河流流向的地图，并将这些地图与预期的控制措施联系起来，包括降雨量、融雪、植物用水和地下特征，以解决这一差距。我们会收集水质样本，以测试这些不同的水流管制措施会否影响水质。这些样本还将表明溪水在多长时间前以雨或雪的形式下降，这可能会影响溪流干涸的频率。此外，该项目将对从小学到研究生院的不同群体的学生进行尖端临时溪流科学方面的培训。将开发新的课程，培训大学生在环境领域的方法，并让河流导游与白水爱好者分享临时溪流科学。最后，该项目将与流域管理人员合作，开发对他们管理的临时河流更便宜、更好的科学见解。临时河流？具有间歇性或短暂流动的渠道？为美国三分之一的人口供水，并维持许多水源系统的河流生态健康。需要研究具有流动地表水的渠道--活跃的排水网络--的动态，以及该网络对气候和土地利用变化的敏感性。这项工作考察了对一系列站点的主动排水网络动态的潜在控制，包括多个NSF临界区观测站。该项目将绘制活跃排水网络地图，并建立模型，将降水、蒸散和推断的传输率模式与活跃排水网络联系起来，包括间歇性对水质的潜在影响。中心假设是导水率是水流持久性的主要控制因素，活跃排水网络中的空间变化反映了水力传导性、几何形状和水龄。该项目将通过培训不同的本科生和研究生群体来整合教学和研究，并通过强化环境野外方法课程、指导本科生研究以及与美国爱达荷州麦考尔户外科学学校合作，与K-12学生和河流导游合作，让他们参与实地研究。最后，该项目将通过与当地流域管理人员就有针对性的联合研究和修复工作开展迭代协作，改善区域河流管理成果。

Over 1/3 of the United States' population relies on temporary streams--channels that do not always have water flowing in them--for their water supply. The U.S. Supreme Court and the Environmental Protection Agency have both recently noted the importance of understanding these streams to ensure fishable, swimmable, and drinkable waters throughout the country. Surprisingly, it remains challenging to predict where and when streams will run dry, and which streams will be most likely to shift from flowing year-round to occasionally running dry during droughts. This project will address that gap by mapping where streams are flowing, and linking these maps to expected controls including rainfall, snowmelt, plant water use, and below-ground characteristics. We will collect water samples to test whether these different controls on flow affect water quality. These samples will also indicate how long ago the stream water fell as rain or snow, which may affect how often a stream dries up. In addition, the project will train a diverse group of students from elementary school through graduate school in cutting-edge temporary stream science. New courses will be developed to train college students in environmental field methods and to engage river guides in sharing temporary stream science with whitewater enthusiasts. Finally, the project will work with watershed managers to develop cheaper and better scientific insight into the temporary streams they manage.Temporary streams ?channels with either intermittent or ephemeral flows ? supply water for ~1/3 of the US population and sustain stream ecological health in many headwater systems. Research is needed on the dynamics of channels with flowing surface waters--the active drainage network--and the sensitivity of this network to changes in climate and land use. This work examines potential controls on active drainage network dynamics across a suite of sites, including multiple NSF Critical Zone Observatories. This project will lead to mapped active drainage networks as well as models linking precipitation, evapotranspiration and inferred transmissivity patterns to the active drainage network, including potential effects of intermittency on water quality. The central hypothesis is that transmissivity is the primary control on flow permanence, and that spatial variations in the active drainage network reflect hydraulic conductivity, geometry, and water age. This project will integrate teaching and research by training a diverse undergraduate and graduate student population in temporary stream science, and by engaging them in field research through an intensive environmental field methods course, mentored undergraduate research, and outreach with K-12 students and river guides in collaboration with the U. Idaho McCall Outdoor Science School. Finally, the project will improve regional stream management outcomes through iterative collaboration on targeted joint research and restoration efforts with local watershed managers.