Source of Atrazine and Desethylatrazine in a River, During Base Flow
A budget of atrazine and desethylatrazine loads was computed for a 116-kilometer reach of the Cedar River in Iowa to determine where these compounds enter the river during base-flow conditions....
Water Quality of Shallow Groundwater Reused for Irrigation
Drainage water was collected by subsurface drains and reapplied to half of a drained alfalfa field in Fallon, Nevada, during the 1989 irrigation season. Irrigation district water was applied...
Hydrologic and Geochemical Approaches for Determining Ground-Water Flow Components
Lyman Lake is an irrigation-storage reservoir on the Little Colorado River near St. Johns, Arizona. The main sources of water for the lake are streamflow in the Little Colorado River and...
Interaction of Irrigation Water and Drainage Flow
This study was conducted to evaluate the effect of irrigation management on subsurface drainage flow in an arid irrigated area. The irrigation management and drainage flow were monitored...
Crop Simulation Modeling for On-Farm Irrigation Management
Crop models that estimate crop productivity in response to soil water offer potential for on-farm irrigation management. Useful models must produce accurate estimates of the soil water...
Crop Growth Models in Irrigation Management: Applications and Limitations
Crop growth models can provide helpful input to the complex process of on-farm irrigation decision making. The use of crop models in irrigation management will likely expand due to improved...
Evapotranspiration and Growth Predictions of CERES Maize, Sorghum and Wheat in the Southern High Plains
Daily ET, leaf area index, and dry matter accumulation were predicted using CERES models for maize, sorghum, and winter wheat grown at Bushland, Texas to determine the models'...
Unique Problems in Modeling Irrigation Canals
Irrigation-canal modeling is based on the same unsteady flow equations used for river modeling. However the canal and irrigation environment present several unique simulation problems...
A Coupled Surface-Water and Ground-Water Model
In areas with dynamic and hydraulically well connected ground-water and surface-water systems, it is desirable that stream-aquifer interaction be simulated with models of equal sophistication...
A New Method for Calculating a Mathematical Expression for Streamflow Recession
An empirical method has been devised to calculate the master recession curve, which is a mathematical expression for streamflow recession during times of negligible direct runoff. The...
Time Scales for Surface-Subsurface Flow Modeling
Traditionally, interactive free surface flow and subsurface flow are analyzed separately, using infiltration rate described by an infiltration formula as the common boundary condition....
Estimation of Ground Cover via Spectral Data
Potato ground cover and spectral data were measured in the Columbia Basin during 1990 growing season. Three spectral models were correlated with ground cover; normalized difference, red...
Crop Canopy Models for Estimating Evapotranspiration from Row Planted Field
To evaluate the consumptive use efficiency of irrigated water, it is useful to estimate the soil surface evaporation component separately from the transpiration component. Interception...
Current Investigations of Hawaiian Taro Pondfield Irrigation Systems
Due to the prominence of taro pondfield irrigation water in the State of Hawaii's system of water rights, the heightened attention given to water resource management under...
Efficient Water Use in Irrigated Wheat
Border irrigated wheat is the main crop in arid, semiarid and winter-dry areas in Mexico. In general water use efficiency is low, since border irrigation systems are not well designed...
Description and Evaluation of Program: CARIMA
The CARIMA code simulates unsteady free-surface flow in simple or multiply connected systems of rivers or canals. The simulation uses the Preissmann implicit finite-difference method for...
Surface Water/Groundwater Interaction Studies
Studies were performed on a high elevation (2440 meters or 8000 feet) valley stream system and a high (1980 meters or 6500 feet) cold desert stream system in Wyoming, to analyze the surface...
Multiobjective Decision Theory ? Decision Support Systems with Embedded Simulation Models
The concepts of multiobjective decision making utilizing embedded computer simulation models and dimensionless scoring functions are described in the context of a decision support system...
Stream Water Quality Modeling in Ankara Metropolitan Area
At the time this study was undertaken, untreated wastewaters from Ankara metropolitan area (capital of Turkish Republic) were being discharged directly into Ankara Creek and its tributaries....
Underground Water Conservation Districts: A Case Study in Water Resources Management
Ground water supplies approximately half of the annual water use in the state of Texas. The water law system in the state is extremely complex and non-integrated, making the management...
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