CAREER: A Mechanism for Rapid Soil-water Transport

9985345 Torres具有高度非线性保水或电导率功能的土壤可能表现出快速和缓慢的土壤-水平流过程。 我假设，一个接近零的阈值压头分离的非线性非饱和导水率函数的区域，其中常数和导水率和土壤水含量压头）。 我建议，高强度的降雨在土壤上或附近的阈值压力头将产生一个微妙的，但迅速推进的压力波通过土壤剖面。 压力波将导致K值的大幅增加，储存的土-水的释放，以及高孔隙压力的快速发展。 这种“压力波释放机制”可导致有利于流入非毛细管尺寸的孔（大孔）的水势条件。 因此，“压力波释放假说”可以描述的条件下，当土壤大孔隙“开关”。 压力波释放所携带的水和大孔隙流的启动的联合作用可能导致高孔隙压力的快速发展和边坡失稳。 我将进行理论，实验室和现场实验，以调查压力波释放假设及其对水平流和孔隙压力发展率的影响。这里的教育计划直接将实验与观察联系起来，他们为学生创造了一个独特的机会，在现场实验室获得“动手”水文经验。易于使用的仪器和分析将促进本科生研究1）地下径流过程和2）地下路径长度对城市化河岸走廊缓冲能力的影响。 大约20名教师表示支持拟议的研究教育设施;因此，实地水文实验室每年可以成为数千名学生教育的一个组成部分。

9985345TorresSoil with highly non-linear water retention or conductivity functions may exhibit both rapid and slow soil-water advection processes. I hypothesize that a near-zero threshold pressure head separates a non-linear unsaturated hydraulic conductivity function into regions where constant and where hydraulic conductivity and soil-water content pressure head). I propose that high intensity bursts of rainfall upon a soil at or near the threshold pressure head will produce a subtle but rapidly advancing pressure wave through the soil profile. The pressure wave will cause a large increase in K, the release of stored soil-water, and the rapid development of high pore pressures. Such a "pressure wave-release mechanism" may lead to water potential conditions favoring flow into non-capillary sized pores (macropores). Hence, the "pressure wave-release hypothesis" may describe conditions that dictate when soil macropores "switch on". The combined effects of water transported by pressure wave-release and the initiation of macropore flow may lead to the rapid development of high pore pressures and slope instability. I will conduct theoretical, laboratory and field experiments to investigate the pressure wave-release hypothesis and its effect on rates of water advection and pore pressure development.The educational initiatives herein directly link experimentation with observation, and they create a unique opportunity for students to acquire "hand on" hydrology experience in a field laboratory. Easy to use instrumentation and analyses will facilitate undergraduate research on 1) rainfall-runoff processes and 2) subsurface path length effects on buffering capacity of an urbanized riparian corridor. Approximately 20 faculty expressed their support for the proposed research-education facility; consequently, the field hydrology laboratory can become an integral part of thousands of students' education each year.