Infiltration which occurred in the process of runoff on farmland surface causes the increasing of soil moisture in unsaturated zone. It’s necessary to comprehend the dynamic process during farmland runoff process, analyze the coupling mechanism of water movement and solute transport among surface/subsurface zone. In this paper, a physically-based, spatially-distributed model was built for simul...

Pathways of streamflow were investigated using geochemical tracers in ungauged headwater and higher-order streams in the semi-arid, forested, Valles Caldera, New Mexico. Combining diagnostic tools of mixing models and endmember mixing analysis (EMMA) shows that streamflow at East Fork Jemez River and San Antonio West (both > 120 km2) was controlled by mixing of three endmembers: near-surface ru...

A new domain, the macropore domain describing subsurface storm flow, has been introduced to the Representative Elementary Watershed (REW) approach. The mass balance equations have been reformulated and the closure relations associated with subsurface storm flow have been developed. The model code, REWASH, has been revised accordingly. With the revised REWASH, a rainfall-runoff model has been bu...

Field and laboratory studies have indicated that rock fragments in the topsoil may have a large impact on soil properties, soil quality, hydraulic, hydrological and erosion processes. In most studies, the investigated rock fragments still remain visible at the soil surface and only properties of these visible rock fragments are used for predicting runoff and soil loss. However, there are indica...

Thirteen million [corrected] metric tons of poultry litter are produced annually by poultry producers in the U.S. Poultry litter contains the sex hormones estradiol and testosterone, endocrine disruptors that have been detected in surface waters. The objective of this study was to evaluate the potential impact of poultry litter applications on estradiol and testosterone concentrations in subsur...

Although studies have evaluated the ecotoxicity and fate of trenbolone acetate (TBA) metabolites, namely 17α-trenbolone (17α-TBOH), 17β-trenbolone (17β-TBOH), and trendione (TBO), their environmental transport processes remain poorly characterized with little information available to guide agricultural runoff management. Therefore, we evaluated TBA metabolite transport in representative agricul...

[1] Based on the diffusion equation and Darcy’s law, Criss and Winston (2008b) developed the one-parameter analytical subsurface flow diffusion hydrograph model to represent the theory of rapid displacement of ‘‘old’’ aquifer water and shallow pore water following rainfall events. We developed a two-parameter analytical surface flow diffusion hydrograph model for urban or other basins that gene...

The identification of runoff contributing areas would provide the ideal focal points for water quality monitoring and Best Management Practice (BMP) implementation. The objective of this study was to use a field-scale approach to delineate critical runoff source areas and to determine the runoff mechanisms in a pasture hillslope of the Ozark Highlands in the USA. Three adjacent hillslope plots ...

Excessive use of animal manure on agricultural lands can impact the quality of surface and groundwater resources. A three–year study (1998–2000) was conducted on nine 0.4–ha plots and on six 2.1–m 2 lysimeters to investigate the effect of two nitrogen (N) application rates from laying hen manure and one N application rate from urea ammonium nitrate (UAN) fertilizer on surface and groundwater qu...