Polyether ionophores, monensin, and salinomycin are commonly used as antiparasitic drugs in broiler production and may be present in broiler litter (bird excreta plus bedding material). Long-term application of broiler litter to pastures may lead to ionophore contamination of surface waters. Because polyether ionophores break down at low pH, we hypothesized that decreasing litter pH with an aci...

according to variety of accessible hydrological models, evaluateing the efficiency of models for different management objectives are essential. therefore, models with simple structure and using minimal input that can provide an acceptable result can serve as an effective tool to watershed managers. hence, the objective of this research is to evaluate the relative performances of the lumped conc...

Correlation analysis is popular in erosion- or earth-related studies, however, few studies compare correlations on a basis of statistical testing, which should be conducted to determine the statistical significance of the observed sample difference. This study aims to statistically determine the erosivity index of single storms, which requires comparison of a large number of dependent correlati...

Contamination by bacteria is a leading cause of impairment in U.S. waters, particularly in areas of livestock agriculture. We evaluated the effectiveness of several practices in reducing Escherichia coli levels in runoff from fields receiving liquid dairy (Bos taurus) manure. Runoff trials were conducted on replicated hay and silage corn (Zea mays L.) plots using simulated rainfall. Levels of E...

Multivariate hydrologic frequency analysis has been widely studied using: (1) commonly known joint distributions or copula functions with the assumption of univariate variables being independently identically distributed (I.I.D.) random variables; or (2) directly applying the entropy theory-based framework. However, for the I.I.D. univariate random variable assumption, the univariate variable m...

[1] There is growing interest in the application of ‘‘continuous simulation’’ conceptual rainfall-runoff models for flood frequency estimation as an adjunct to event-based or statistical design methodology. The approach has advantages that stem from the use of models with continuous water balance accounting. Conceptual rainfall-runoff models usually require calibration, which in turn requires g...

This paper introduces and evaluates DryMOD, a dynamic water balance model of the key hydrological process in drylands that is based on free, public-domain datasets. The rainfall model of DryMOD makes optimal use of spatially disaggregated Tropical Rainfall Measuring Mission (TRMM) datasets to simulate hourly rainfall intensities at a spatial resolution of 1-km. Regional-scale applications of th...

Intermittent streamflow is a common occurrence in permeable catchments, especially where there are pumped abstractions to water supply. Many rainfall-runoff models are not formulated so as to represent ephemeral streamflow behaviour or to allow for the possibility of negative recharge arising from groundwater pumping. A groundwater model component is formulated here for use in extending existin...

The "Grain for Green Project" is a country-wide ecological program to converse marginal cropland to forest, which has been implemented in China since 2002. To quantify influence of this significant vegetation change, Guansihe Hydrological (GSH) Model, a validated physically-based distributed hydrological model, was applied to simulate runoff responses to land use change in the Guansihe watershe...

While engineers have been quantifying rainfall-runoff processes since the mid-19th century, it is only in the last decade that artificial neural network models have been applied to the same task. This paper evaluates two neural networks in this context: the popular multilayer perceptron (MLP), and the radial basis function network (RBF). Using six-hourly rainfall-runoff data for the River Yangt...