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Articles 1 - 14 of 14
Full-Text Articles in Engineering
A Review Of Pesticide Fate And Transport Simulation At Watershed Level Using Swat: Current Status And Research Concerns, Ruoyu Wang
Ruoyu Wang
The application of pesticides in agriculture is a widely-used way to alleviate pest stresses. However, it also introduces various environmental concerns due to the offsite movement of pesticide residues towards receiving water bodies. While the application of process-based modeling approaches can provide quantitative information on pesticide exposure, there are nonetheless growing requirements for model development and improvement to better represent various hydrological and physico-chemical conditions at watershed scale, and for better model integration to address environmental, ecological and economic concerns. The Soil and Water Assessment Tool (SWAT) is an ecohydrological model used in over 3,000 published studies, including about 50 …
Nitrate Runoff Contributing From The Agriculturally Intensive San Joaquin River Watershed To Bay-Delta In California, Ruoyu Wang
Ruoyu Wang
Nitrogen loading from agricultural landscapes can trigger a cascade of detrimental e#11;ects on
aquatic ecosystems. Recently, the spread of aquatic weed infestations (Eichhornia crassipes, Egeria densa,
Ludwigia spp., and Onagraceae) in the Sacramento-San Joaquin Delta of northern California has raised
concerns, and nitrogen loading from California’s intensive farming regions is considered as one of
the major contributors. In this study, we employed the Soil andWater Assessment Tool (SWAT) to
simulate nitrogen exports from the agriculturally intensive San Joaquin River watershed to the Delta.
The alternate tile drainage routine in SWAT was tested against monitoring data in the tile-drained area
of …
Environmental Fate And Impact Assessment Of Thiobencarb Application In California Rice Fields Using Ricewq, Ruoyu Wang
Environmental Fate And Impact Assessment Of Thiobencarb Application In California Rice Fields Using Ricewq, Ruoyu Wang
Ruoyu Wang
Thiobencarb is a commonly used herbicide in Northern California rice fields. Released paddy water containing thiobencarb may pose ecological risks to non-targeted organisms. In this research, the Rice Water Quality Model (RICEWQ) is equilibrium tested and then calibrated using monitoring data at field level. Then it is employed to assess the environmental fate and impacts of thiobencarb in the Colusa Basin, and the effects of different management practices on water use and thiobencarb exposures. The model predicted thiobencarb concentrations from rice fields for multiple years throughout the Basin, using input from California Pesticide Use Reporting (PUR) database, and assessed both the …
Modeling Pesticide Fate And Transport At Watershed Scale Using The Soil & Water Assessment Tool: General Applications And Mitigation Strategies, Ruoyu Wang
Ruoyu Wang
Pesticide residue runoff to surface water is of great concern to local stakeholders who seek to preserve or achieve good water quality. The Soil & Water Assessment Tool (SWAT) has been widely used to assess many environmental problems related to water resources and nonpoint-source pollution, including sediment and nutrient loads and pesticides. However, a comprehensive review of existing studies on SWAT-based pesticide modeling is still not available in the literature. Therefore, in this chapter, we present an overview summarizing all previous SWAT applications in studying the fate and transport of pesticides around the world, based on the peer-reviewed literature. We …
Integrating Multimedia Models To Assess Nitrogen Losses From The Mississippi River Basin To The Gulf Of Mexico, Ruoyu Wang
Ruoyu Wang
This study describes and implements an integrated, multimedia, process-based system-level approach to estimating nitrogen (N) fate and transport in large river basins. The modeling system includes the following components: (1) Community Multiscale Air Quality (CMAQ), (2) Weather Research and Forecasting Model (WRF), (3) Environmental Policy Integrated Climate (EPIC), and (4) Soil and Water Assessment Tool (SWAT). The previously developed Fertilizer Emission Scenario Tool for CMAQ (FEST-C), an advanced user interface, integrated EPIC with the WRF model and CMAQ. The FEST-C system, driven by process-based WRF weather simulations, includes atmospheric N additions to agricultural cropland and agricultural cropland contributions to ammonia emissions. This study focuses …
Predication Of The Sources Of Particulate Polycyclic Aromatic Hydrocarbons In China With Distinctive Characteristics Based On Multivariate Analysis, Ruoyu Wang
Ruoyu Wang
Particulate polycyclic aromatic hydrocarbons (PAHs) have the characteristics of high carcinogenicity, degradation resistance, and long-distance transport. It is necessary to determine the critical sources that contribute to PAHs in atmospheric particulatematter (PM), soils, and sediments. In the present study, particulate PAHs were collected from Chinese cooking, biomass combustion, waste incineration, coal combustion, and petroleum combustion in different regions of the Chinese mainland. Through linear regression analysis, the relationships have been investigated between different measurement units, including the mass of particulate PAHs per mass of particle matter, mass of particulate PAHs per volume of …
Assessment Of Optional Sediment Transport Functions Via The Complex Watershed Simulation Model Swat, Ruoyu Wang
Assessment Of Optional Sediment Transport Functions Via The Complex Watershed Simulation Model Swat, Ruoyu Wang
Ruoyu Wang
The Soil andWater Assessment Tool 2012 (SWAT2012) offers four sediment routing methods
as optional alternatives to the default simplified Bagnold method. Previous studies compared only
one of these alternative sediment routing methods with the default method. The proposed study
evaluated the impacts of all four alternative sediment transport methods on sediment predictions:
the modified Bagnold equation, the Kodoatie equation, the Molinas and Wu equation, and the
Yang equation. The Arroyo Colorado Watershed, Texas, USA, was first calibrated for daily flow.
The sediment parameters were then calibrated to monthly sediment loads, using each of the four
sediment routing equations. An automatic …
Combined And Synergistic Effects Of Climate Change And Urbanization On Water Quality In The Wolf Bay Watershed, Southern Alabama, Ruoyu Wang
Ruoyu Wang
This study investigated potential changes in flow, total suspended solid (TSS) and nutrient (nitrogen and phosphorous) loadings under future climate change, land use/cover (LULC) change and combined change scenarios in the Wolf Bay watershed, southern Alabama, USA. Four Global Circulation Models (GCMs) under three Special Report Emission Scenarios (SRES) of greenhouse gas were used to assess the future climate change (2016–2040). Three projected LULC maps (2030) were employed to reflect different extents of urbanization in future. The individual, combined and synergistic impacts of LULC and climate change on water quantity/quality were analyzed by the Soil and Water Assessment Tool (SWAT). …
Biophysical And Hydrological Effects Of Future Climate Change Including Trends In Co2, In The St. Joseph River Watershed, Eastern Corn Belt, Ruoyu Wang
Ruoyu Wang
Future climate change has the potential to significantly impact crop growth, both directly due to CO2 enhancement and indirectly, through temperature and moisture impacts. This work investigates the biophysical and hydrological effects of future climate change, including trends in CO2, in the St. Joseph River watershed, Eastern Corn Belt. In this study, the Soil and Water Assessment Tool (SWAT) was first modified to take dynamic CO2 concentration as input. A regional crop leaf development curve from Landsat TM imagery was also used to adjust model performance in corn leaf area development for the historical period. A multi-objective calibration strategy was …
Estimation Of The Effects Of Climate Variability On Crop Yield In The Midwest Usa, Ruoyu Wang
Estimation Of The Effects Of Climate Variability On Crop Yield In The Midwest Usa, Ruoyu Wang
Ruoyu Wang
Crop yield is strongly affected by climate variability. When applying ecohydrologic models to study climate impacts on crop yield, especially interannual yield responses to climate stresses, the model simulation of plant available soil moisture must be constrained in order to reproduce plant production variation via moisture related bio-climate variables. In this study, the Soil and Water Assessment Tool (SWAT) is used to investigate the relationship between climate variability and crop yield at four sites (Boone, Woodbury, Madison, and Mason) in the Midwestern USA. The model was first calibrated for soil moisture at the plot scale. The calibrated model was then …
Water Quality Effects Of Cellulosic Biofuel Crops Grown On Marginal Land, Ruoyu Wang
Water Quality Effects Of Cellulosic Biofuel Crops Grown On Marginal Land, Ruoyu Wang
Ruoyu Wang
Since Congress' Energy Independence and Security Act of 2007, there has been increasing interest
in the ability to reach the cellulosic renewable fuel goal of 60.5 billion liters. Cellulosic biofuel crops include
sorghum, switchgrass, Miscanthus, woody crops, and crop residue, among others. Because of concern about
food production on existing highly productive agricultural lands, there is an interest regarding biofuel crop
production on marginal lands. Second generation biofuels, such as perennial grasses and woody plants,
provide an alternative to traditional crops; however, their effects on water quality are not well studied when
grown on marginal lands. Because grasses and woody …
Responses Of Hydrological Processes And Water Quality To Land Use/Cover (Lulc) And Climate Change In A Coastal Watershed, Ruoyu Wang
Ruoyu Wang
Land use/cover (LULC) and climate change are two main factors affecting watershed hydrology and, in turn, influencing water quality. In this paper, the potential changes in flow, Total Suspended Solid (TSS) and nutrient (nitrogen and phosphorous) loadings were investigated under climate, LULC and combined change scenarios in the Wolf Bay watershed in coastal Alabama, USA. Four Global Circulation Models (GCMs) under three Special Report Emission Scenarios (SRES) of greenhouse gas were used to demonstrate the future climate change (2016-2040). Three projected LULC maps (2030) were employed to reflect different extents of urbanization in future. The individual, combined and synergistic impacts …
Individual And Combined Effects Of Land Use/Cover And Climate Change On Wolf Bay Watershed Streamflow In Southern Alabama, Ruoyu Wang
Ruoyu Wang
Land use/cover (LULC) and climate change are two main factors affecting watershed hydrology. In this paper, individual and combined impacts of LULC and climate change on hydrologic processes were analysed applying the model Soil and Water Assessment Tool in a coastal Alabama watershed in USA. Temporally and spatially downscaled Global Circulation Model outputs predict a slight increase in precipitation in the study area, which is also projected to experience substantial urban growth in the future. Changes in flow frequency and volume in the 2030s (2016–2040) compared to a baseline period (1984–2008) at daily, monthly and annual time scales were explored. …
Determining Nutrient And Sediment Critical Source Areas With Swat: Effect Of Lumped Calibration, Ruoyu Wang
Determining Nutrient And Sediment Critical Source Areas With Swat: Effect Of Lumped Calibration, Ruoyu Wang
Ruoyu Wang
In many watershed modeling studies, due to limited data, model parameters for flow, sediment, and nutrients are calibrated and validated against observed data only at the watershed outlet. Model parameters are adjusted systematically for the entire watershed to obtain the closest match between the model-simulated and observed data at the watershed outlet (lumped calibration). It is hypothesized that the relative loadings of pollutants and/or sediments contributed by each computational unit are not affected by this calibration procedure. In other words, areas generating relatively higher pollutant loads with an uncalibrated model will still generate relatively higher loads after calibration. This study …