Collaborative Research: Effects of Hydrologic Processes on In Situ Stress Transients

了解水如何在地貌中流动和储存是水文学研究中最普遍的主题之一，但水循环的重要方面仍然知之甚少。拟议的研究项目将解决目前在表征水循环方面的局限性，并受到两个相关假设的推动：1.水文上重要的水分含量变化足以引起原位应力状态的可测量变化。2.地应力的瞬时变化可以用来估算多个尺度上的水文通量和库容变化。这项研究将发展与地应力变化相关的水文过程的概念和数值方法，以及测量这些变化的仪器和现场技术。将开发新的现场仪器来测量总应力和有效应力的变化，目标分辨率为1pa。南卡罗来纳州克莱姆森附近的一项概念验证现场测试将比较高分辨率应力测量与水分含量和其他过程的瞬时变化。堪萨斯州将进行一项更严格的实地测试，在那里，该方法将用于估计阿肯色河沿岸河岸地带蒸散和其他影响造成的质量变化。包气带和饱和带的孔弹性理论分析将被用来评估含水率变化对应力的影响，以及各种其他潜在的相互竞争的影响，包括气压变化、地下地质、固体潮、地下水开采、区域水平流动、地表蓄水、交通、风、温度等。新的现场方法是水文科学发现的催化剂，拟议的调查的智力优点是它有可能成为发现的催化剂。这项调查将为新的田间技术、理论分析和仪器设备提供科学基础，这些技术、理论分析和仪器将提高表征水文循环关键方面(ET、土壤水分变化、补给、暴雨流等)的能力。为这个项目开发的技术将产生广泛的影响，提供可用于改进的多尺度数据：验证和校准遥感仪器和算法；估计积雪或冰川的融化或积累；评估侵蚀或沉积物沉积的速率；减少噪音和解决构造应变；评估碳储存速率；安排灌溉的方法；了解森林火灾造成的质量变化以及相关问题。

Understanding how water moves and is stored within the landscape is among the most pervasive themes of hydrological research, but important aspects of the water cycle remain poorly known. The proposed research project will address current limitations in characterizing the water cycle and is motivated by two related hypotheses: 1. Hydrologically important changes in water content are sufficient to cause measurable changes in the in situ state of stress. 2. Transient changes of in situ stress can be used to estimate hydrologic fluxes and changes in storage over multiple scales.This investigation will develop conceptual and numerical methods for analyzing hydrologic processes associated with changes of in situ stress as well as instruments and field techniques for measuring these changes. New field instrumentation will be developed to measure total and effective stress changes with a target resolution of 1 Pa. A proof-of-concept field test near Clemson, SC will compare high resolution stress measurements to transient changes in water content and other processes. A more rigorous field test will take place in Kansas, where the method will be used to estimate changes in mass resulting from evapotranspiration and other effects in a riparian zone along the Arkansas River. Theoretical analyses of poroelasticity in the vadose and saturated zones will be used to evaluate how stresses are affected by changes in water content, as well as a variety of other potentially competing effects including barometric pressure change, subsurface geology, earth tides, ground water extraction, regional horizontal flows, surface impoundments, traffic, wind, temperature, etc. New field approaches are catalysts for discovery in hydrologic sciences, and the intellectual merit of the proposed investigation is that it has the potential to be such a catalyst for discovery. The investigation will provide the scientific basis for new field techniques, theoretical analyses and instrumentation that will advance the ability to characterize key aspects of the hydrological cycle (ET, change in soil moisture, recharge, stormflow, etc.) over scales from less than 1 m to greater than 100 m. The techniques developed for this project will have broad impacts by providing multi-scale data that can be used to improve: validation and calibration of remote sensing instruments and algorithms; estimates of melting or accumulation of snow pack or glaciers; assessment of rates of erosion or sediment deposition; reduction of noise and resolution of tectonic strain; assessment of rates of carbon storage; methods for scheduling irrigation; understanding mass changes resulting from forest fires, and related.