Dynamic Response of Watershed Subsurface System to Extreme Rainfall Events

流域地下系统对极端降雨事件的动态响应

基本信息

批准号：
1834290
负责人：
Shemin Ge
金额：
$ 33.18万
依托单位：
University of Colorado at Boulder
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-07-01 至 2024-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1834290&HistoricalAwards=false
关键词：
Dynamic Response Watershed Subsurface System

项目摘要

The episodes of torrential rainfall in September 2013 in the Colorado Front Range caused widespread flooding in the area. While floodwater receded within days, data from subsurface suggested substantial changes in groundwater storage long after the flood. This study seeks to understand the changes in groundwater storage in response to extreme rainfall events. Understanding the effects of extreme rainfall events can provide the basis for predicting aggregated effects over longer temporal and larger spatial scales. By assessing the potential for shallow soils and deeper aquifers to serve as natural storages for floodwaters, this study could provide a scientific basis for water managers to assess the excess water stored during extreme rainfall events and timely utilize the resource when it is released back to streams. The project will have a substantial educational element. Graduate students will be directly involved in research. A two-week undergraduate field course will incorporate some in-situ aquifer tests proposed for this study. A groundwater flow computer model will be created for an undergraduate modeling class project. These field and modeling plans will benefit approximately 90 undergraduate students and offer them the opportunity to learn practical skill sets and a real research experience in water sciences. The project plan also includes recruiting and working with students from underrepresented groups through the RESESS program, an NSF supported summer internship program dedicated to increasing the diversity of students entering geosciences. The overall goal of this research is to better understand the dynamic response of watershed-scale subsurface hydrologic systems to extreme rainfall events. The specific research questions are: (1) How much could precipitation infiltrate into the vadose zone during extreme rainfalls? (2) How much does the subsurface water storage change in the event of extreme rainfall? (3) To what temporal and spatial extent could extreme rainfalls impact subsurface systems? The research plan consists of three components. The first is to collect and analyze hydrologic data that will provide information for conceptualizing the system and the parameters for model calibration. The second is to conduct in-situ and laboratory measurements to characterize the hydrologic properties of the vadose zone and the saturated zone. The third is to develop an integrated vadose-zone and saturated-zone flow model to synthesize data, test hypotheses, and address research questions. The Upper Boulder Creek west of Boulder, Colorado, will be utilized as a test bed because of the availability of existing hydrologic data spanning over the pre- and post-extreme precipitation periods. Using a physics-based mass-balance approach, this study offers a quantitative modeling framework that links precipitation, subsurface flow, and stream baseflow at watershed scales, with an emphasis on rigorous modeling of infiltration processes in the vadose zone. This study will shed new light on infiltration into the vadose zone, dynamic changes in subsurface water storage, and the temporal and spatial extent that a watershed subsurface system could be affected under extreme rainfall events. The study site includes varying geology and geography, making the results transferrable to other regions. This study will advance modeling integrated vadose zone and saturated zone flow through utilizing latest modeling capability and taking advantage of data availability. On the basis of its contribution to rigorous modeling infiltration and site transferability, this study is potentially transformative.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.

2013年9月在科罗拉多州阵线范围内，隆起的降雨发生引起了该地区的广泛洪水。尽管洪水在几天之内退缩，但地下的数据表明，洪水很长时间后地下水存储了很大变化。这项研究试图了解地下水存储的变化，以应对极端降雨事件。了解极端降雨事件的影响可以为预测较长的时间和较大空间尺度的综合效应提供基础。通过评估浅层土壤和更深的含水层作为洪水的天然存放物的潜力，这项研究可以为水管理者提供科学的基础，以评估在极端降雨事件中存储的多余水，并在将资源释放回流中时及时利用资源。该项目将具有实质性的教育元素。研究生将直接参与研究。为期两周的本科野外课程将结合本研究提出的一些原位含水层测试。将为本科建模类项目创建地下水流量计算机模型。这些领域和建模计划将使大约90名本科生受益，并为他们提供学习实用技能和水科学研究经验的机会。项目计划还包括通过Resess计划与来自代表性不足的团体的学生招募和合作，NSF支持的暑期实习计划致力于增加进入地球科学的学生的多样性。这项研究的总体目标是更好地了解流域规模的地下水文系统对极端降雨事件的动态响应。具体的研究问题是：（1）在极端降雨期间，降水量渗入vadose区多少？（2）在极端降雨的情况下，地下储能会发生多少变化？（3）极端降雨会影响地下系统的时间和空间范围在什么程度和空间范围内？研究计划由三个组成部分组成。首先是收集和分析水文数据，这些数据将提供用于概念化系统和模型校准参数的信息。第二个是进行原位和实验室测量，以表征vadose区和饱和区的水文特性。第三个是开发一个综合的vadose区和饱和区流量模型来综合数据，检验假设并解决研究问题。科罗拉多州博尔德西部的上比尔德溪将被用作测试床，因为在前后降水期间跨越了现有的水文数据。使用基于物理的质量平衡方法，本研究提供了一个定量的建模框架，该框架在流域尺度上连接降水，地下流量和流碱流，重点是对vadose区域中浸润过程的严格建模。这项研究将为渗透区域渗透到vadose区域，地下储水的动态变化以及在极端降雨事件下可能会影响分水岭地下系统的时间和空间范围。研究地点包括不同的地质和地理，使结果可转移到其他地区。这项研究将通过利用最新的建模能力并利用数据可用性来推动建模综合vadose区和饱和区流量。根据其对严格建模渗透和现场可转移性的贡献，本研究具有可能性的变革性。该奖项反映了NSF的法定任务，并且使用基金会的知识分子优点和更广泛的影响审查标准，被认为值得通过评估来获得支持。