Collaborative Research: Mapping Changes in the Active Stream Channel Network in Mesoscale Watersheds in order to Understand Distinct Signatures in Event Recession Curves

合作研究：绘制中尺度流域活跃河道网络的变化，以了解事件衰退曲线的独特特征

• 批准号: 1417542
• 负责人: David Chandler
• 金额: $ 20.5万
• 依托单位: Syracuse University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2017-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1417542&HistoricalAwards=false
• 关键词: Collaborative; Research; Mapping; Changes; Active

Water flow in watersheds is most often studied by either measuring stream flow at the watershed outlet or by making point measurements in wells within the watershed. Neither is adequate for gaining a complete picture of watershed function because measurements at the outlet can be too broad and point measurements too localized. This project seeks to fill the knowledge gap by mapping the expansion and contraction of active stream channels throughout the watershed and providing insights into which areas of a watershed are or are not contributing flow to the watershed outlet. This will provide new knowledge for better understanding how water, soil, and chemicals move through watersheds and how stream discharge will change, particularly during periods of little precipitation. As an education and outreach effort of this project, the project will develop hands-on learning opportunities for middle and high school science students and help train graduate students. Pairs of observed rates of stream flow decline after rainfall ends (i.e. recession flow) and the concurrent stream flow value have long been used in the hydrologic sciences to infer aquifer properties at the watershed scale. However, new work has shown that spatial variation in stream flow source areas across a catchment may explain recession as well or better than aquifer property and hydraulics. Thus, there is an emerging debate on what really controls recession. Resolving this debate can provide fundamental insights into watershed function. To investigate the controls on recession, this project will install high-density sensor networks at up to six medium-sized watersheds at different locations throughout the U.S. to map changes in the extent of the active stream channel network. Sensor measurements of discharge will be supplemented with visual mapping of the active stream network, thermal imaging of likely groundwater inputs to streams, and soil moisture measurements. The project could have broader implications for predicting discharge in ungauged basins and understanding processes of solutes moving through watersheds.

流域中的水流最常通过测量流域出口处的流流或通过在流域内的井中进行点测量来研究。这两个都不足以获得流域功能的完整图片，因为出口处的测量值太宽，点测量太多了。该项目旨在通过绘制整个流域的主动流渠道的扩展和收缩来填补知识差距，并提供有关哪些分水岭区域是或没有促成流域出口流量的见解。这将提供新的知识，以更好地了解水，土壤和化学物质如何通过流域移动以及溪流排出将如何变化，尤其是在降水量很小的时候。作为该项目的教育和外展工作，该项目将为中学和高中科学专业的学生创造动手学习机会，并帮助培训研究生。降雨结束后观察到的流量率下降（即衰退流动）和并发流量值在水文科学中长期以来一直使用，以在分水岭量表上推断含水层的特性。 但是，新的工作表明，流域的流源区域的空间变化也可以解释经济衰退或比含水层的特性和液压学更好。因此，关于真正控制经济衰退的原因，存在着一场新兴的辩论。解决这一辩论可以提供对流域功能的基本见解。为了调查经济衰退的控制，该项目将在美国各个位置安装高度密度传感器网络，以绘制Active Stream Channel网络范围的变化。传感器测量将补充有效的流网络的可视化映射，可能对溪流的地下水输入的热成像以及土壤水分测量。该项目可能对预测未加州盆地的排放以及理解通过流域移动的溶质的过程具有更广泛的意义。