Understanding the mechanisms controlling colloid transport and deposition in the vadose zone is an important step in protecting our water resources. Colloid transport in unsaturated porous media was studied using X-Ray Microtomography (XMT), which is a non-destructive imaging technique that provides three-dimensional images at a resolution on the order of...
Infiltration of highly concentrated solutions into unsaturated sand is suspected to be affected by the liquid-gas interfacial tension between the resident water and that of the infiltrating solution. The wetting of non-porous solid surfaces by liquids is commonly quantified by contact angle measurements. However, it is well known that wettability...
Non-dilute salt strength solutions occur in many near surface geologic environments. In order to better understand the occurrence and movement of the water and salt, mathematical models for this non-ideal fluid need to be developed. Initial boundary value problems may then be solved to predict behavior for comparison with observations....
This study explores the use of predictive mapping techniques in developing Landtype Association (LTA) maps for use in natural resource management. These maps are produced for the USDA Forest Service on a regional basis at a 1:100,000 scale. The goal of this study is to develop and test a method...
Engineered capillary barriers typically consist of two layers of granular materials designed so that the contrast in sediment hydrologic properties and sloping interface retains infiltrating water in the upper layer. We report here on the results of two bench-top capillary barrier experiments, and associated modeling. These experiments were conducted to...
This study examined the effects of timber harvest and subsoiling on soil physical properties considered important to forest productivity and hydrologic concerns. Ground based mechanical timber harvesting on some soil types can cause soil disturbance including compaction. These effects in turn can influence multiple important soil physical properties that affect...
The wetting of a surface by a liquid is a crucial part of many natural and industrial processes. Despite numerous existing studies, some elements of wetting-dewetting such as contact angle variation are still poorly understood. Knowledge of contact angle behavior during the flow is necessary for modeling fluid displacements in...
Soils have a critical role in global carbon (C) cycling, containing one of the largest fast-cycling carbon stocks on earth. Robust representation of soil organic matter dynamics in Earth System Models is critical for future climate prediction. Current C cycling models assume that all C cycling in non-hydric (i.e. ‘upland’)...
Systems that contain multi-phase flow in porous media are of interest in diverse fields including environmental engineering, hydrogeology, and petroleum engineering etc. One of the main descriptors of multi-phase flow in porous media is the relationship between capillary pressure and fluid saturation. Capillary pressure is inherently a pore-scale variable and...
An understanding of the factors that influence surface erosion from roads is necessary to prevent and mitigate sediment production from forest roads. This study investigated the impacts of log truck traffic and road hydrology on sediment yield from ten forest road segments in the foothills of the Cascade Mountains of...