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，科罗拉多州弗兰特山脉 (Colorado Front Range) 发生暴雨，导致该地区发生大面积洪水。虽然洪水在几天内退去，但地下数据表明洪水发生后很久地下水储量发生了巨大变化。本研究旨在了解地下水储存量因极端降雨事件而发生的变化。了解极端降雨事件的影响可以为预测更长时间和更大空间尺度的聚合效应提供基础。通过评估浅层土壤和深层含水层作为洪水天然储存库的潜力，这项研究可以为水资源管理者提供科学依据，以评估极端降雨事件期间储存的多余水量，并在资源释放回溪流时及时利用这些资源。该项目将具有大量的教育元素。研究生将直接参与研究。为期两周的本科生实地课程将纳入本研究提出的一些原位含水层测试。将为本科生建模课程项目创建地下水流计算机模型。这些实地和建模计划将使大约 90 名本科生受益，并为他们提供学习水科学研究实用技能和真实研究经验的机会。该项目计划还包括通过 RESESS 计划招募来自代表性不足群体的学生并与他们合作，RESESS 计划是 NSF 支持的暑期实习计划，致力于增加进入地球科学领域的学生的多样性。这项研究的总体目标是更好地了解流域尺度地下水文系统对极端降雨事件的动态响应。具体研究问题是：（1）极端降雨期间，渗流区的降水量有多少？（2）极端降雨时地下水储量变化有多大？ (3) 极端降雨对地下系统的影响会在多大的时间和空间范围内发生？该研究计划由三个部分组成。第一个是收集和分析水文数据，这些数据将为概念化系统和模型校准参数提供信息。第二是进行现场和实验室测量，以表征包气带和饱和带的水文特性。第三是开发一个集成的渗流区和饱和区流动模型来合成数据、检验假设并解决研究问题。科罗拉多州博尔德以西的上博尔德溪将被用作试验台，因为可以获得极端降水前后期间的现有水文数据。本研究采用基于物理的质量平衡方法，提供了一个定量建模框架，将流域尺度的降水、地下流量和河流基流联系起来，重点是包气区渗透过程的严格建模。这项研究将为渗流带的渗透、地下水储量的动态变化以及流域地下系统在极端降雨事件下可能受到影响的时间和空间范围提供新的线索。该研究地点包括不同的地质和地理，使得研究结果可以转移到其他地区。这项研究将通过利用最新的建模能力和数据可用性来推进集成渗流区和饱和区流的建模。基于其对严格建模渗透和站点可转移性的贡献，这项研究具有潜在的变革性。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。