Three geographic information system GIS -based distributed hydrological models were developed for flood simulation and forecasting in a subbasin of the Yellow River. A grid-and-topography-based distributed hydrological physical model, i.e., the GTOPMODEL model, is described that includes vegetation and root interception, evapotranspiration, and runoff generation via the saturation excess mechan...

Snowmelt in mountainous areas is an important contributor to river water fl ows in the western United States. We developed a distributed model that calculates solar radia on, canopy energy balance, surface energy balance, snow pack dynamics, soil water fl ow, snow–soil–bedrock heat exchange, soil water freezing, and lateral surface and subsurface water fl ow. The model was applied to describe r...

The objective of this research is to quantify the effects of liquid swine manure application on antibiotic and nutrient (N and P) losses via surface runoff and subsurface drainage under a conventional (moldboard plowing) and a conservation (chisel plowing) tillage system. The field experiment is set up at the University of Minnesota Southwest Research and Outreach Center, Lamberton, Minnesota. ...

Pre-emergence herbicide residues were detected in domestic wells sampled near Tracy, CA. This study sought to determine the source of contamination by comparing soil distribution of diuron [N'-(3,4-dichlorophenyl)-N,N-dimethylurea] and hexazinone [3-cyclohexyl-6-(dimethylamino)-1-methyl-1,3,5-triazine-2,4(1H,3H)-dione] in an agricultural field where the soil was a cracking clay to infiltration ...

Traditional land surface models (LSMs) used for numerical weather simulation, climate projection, and as inputs to water management decision support systems, do not treat the LSM lower boundary in a fully process-based fashion. LSMs have evolved from a leaky-bucket approximation to more sophisticated land surface water and energy budget models that typically have a specified bottom layer flux t...

Mineral and organic salts from beef manure contained in precipitation runoff from feedyard pen surfaces can alter the conductivity properties of soil and water receiving it. Typically, holding ponds are constructed to control runoff from concentrated animal feeding operations. The integrity of these holding ponds has come under increased scrutiny since leakage has the potential to affect soil a...

A watershed's water quality is influenced by contaminant-transport pathways unique to each landscape. Accurate information on contaminant-pathways could provide a basis for mitigation through well-targeted approaches. This study determined dynamics of nitrate-N, total P, Escherichia coli, and sediment during a runoff event in Tipton Creek, Iowa. The watershed, under crop and livestock productio...

[1] Hydrograph source components and stream water residence time are fundamental behavioral descriptors of watersheds but, as yet, are poorly represented in most rainfall-runoff models. We present a new time-space accounting scheme (T-SAS) to simulate the pre-event and event water fractions, mean residence time, and spatial source of streamflow at the watershed scale. We use a physically based ...

[1] One of the greatest challenges in the field of hillslope hydrology is conceptualizing and parameterizing the effects of lateral preferential flow. Our current physically based and conceptual models often ignore such behavior. However, for addressing issues of land use change, water quality, and other predictions where flow amount and components of flow are imperative, dominant runoff proces...

Use of anionic polyacrylamide (PAM) to control phosphorus (P) losses from a Chinese purple soil was studied in both a laboratory soil column experiment and a field plot experiment on a steep slope (27%). Treatments in the column study were a control, and PAM mixed uniformly into the soil at rates of 0.02, 0.05, 0.08, 0.10, and 0.20%. We found that PAM had an important inhibitory effect on verti...