Controlled Versus Conventional Drainage Effects on Water Quality
Fertilized cropland is a nonpoint source of nitrogen and phosphorus which can contribute to nutrient enrichment problems prevalent in many surface water ecosystems. Research has shown...
Effect of Agricultural Drainage on Water Quality in the Great Lakes and Cornbelt States
The soils and the climate of the Great Lakes and Cornbelt states dictate that drainage is required to carry out economically viable farming activities. When drained, the soils are very...
Effects of Agricultural Drainage on Water Quality in the Lower Mississippi Valley and Gulf Coastal Region
Sediment and nutrient (N, P, K) losses were measured from research plots with surface drainage only and from plots with both surface and subsurface drainage for all or part of the decade,...
Effect of Agricultural Drainage on Water Quality in the Northeastern U.S. and Canada
Drainage has been used in the northeastern U.S. since colonial times. It has only been since the 1970s subsurface drains have been installed at a significant rate in Quebec. Drainage in...
Effect of Agricultural Drainage on Water Quality in the Humid Portion of the Pacific Northwest
Agricultural drainage first began in Washington around 1830 and in Oregon around 1840. The first efforts to drain soils for agricultural use began by constructing shallow ditches spaced...
Electro-Osmotic Removal of Nitrates from Soils
Nitrate migration to ground and surface waters is a serious U.S. contamination threat. Electro-osmosis may be a more effective means for soil reclamation than leaching or chemical treatment....
Irrigation Lettuce with Buried Drip, Surface Drip, and Furrow Irrigation: Spatial Variability of Plants, Soil, and Water
Spatial variability of plant growth, soil, and water was investigated for a furrow, surface drip, and subsurface drip irrigation systems. Variability was analyzed by sampling plant weight,...
Irrigating Lettuce with Buried Drip, Surface Drip, and Furrow Irrigation Systems: Overall Performance
Groundwater nitrate contamination is a major concern in the Salinas Valley of California. The source of much of the nitrate appears to be vegetable production in the valley. A field-scale...
An Irrigation Allocation Planning Model
An irrigation allocation model using multiperiod linear programming was developed to recommend canal water allocation among different irrigated fields to maximize net annual benefits for...
Flow Simulation for Surface Irrigation Design
Experience shows that even the most sophisticated and accurate computer models of the surface-irrigation process will not be widely used by design agencies unless they manifest a certain...
Software Engineering for Irrigation and Environmental Applications
Interactive, user-oriented software has been developed to enhance irrigation design, management and planning. Environmental applications were the central focus of several individual components...
Evapotranspiration by Soil Water Balance Using TDR and Neutron Scattering
The soil water balance method of estimating evapotranspiration (ET) has been widely used since it is considerably cheaper than alternative methods such as the use of weighing lysimeters....
Density Fluctuations and Use of the Krypton Hygrometer in Surface Flux Measurements
The magnitude of the of the Webb et al. (1980) density corrections on water vapor fluxes due to the flux of sensible heat is examined in terms of the Bowen ratio. The correction due to...
Hydrological Impacts of a California Water Transfer
Conaway Ranch, located in Yolo County, California, transferred water to the California Emergency Drought Water Bank (Water Bank) in 1991 and 1992. Water for these transfers was generated...
Effect of Choptank Watershed Drainage Project on Stream Temperatures
Between 1974 and 1982, the Soil Conservation Service, U.S.D.A conducted a stream study on the Choptank Watershed in Caroline County, Maryland to monitor the effects of channel construction...
Simulation of Rapid Reservoir Drawdown for Flood Control, Cowlitz Falls Project
The Cowlitz Falls Dam is a run-of-river project, currently under construction on the Cowlitz River in Washington State, 23 Km downstream from the town of Randle. The requirements for reservoir...
The Influence of Slope and Surface Roughness on Trapezoidal Free Overfall Characteristics
The brink depth-discharge relationship for trapezoidal free overfalls was investigated including the effects of slope and roughness. The theoretical relationship is based on the momentum...
Research Needs in Hydraulic Engineering
The information presented herein has barely dented the surface of the needs for hydraulic research, and of the methods required to obtain funding for that research. The responses and reports...
Nonlinear Flow in Embankments
For a large number of water resources projects, the Dupuit-Forchheimer (D-F) assumption is considered a viable design criterion and, consequently, Darcy law is used to determine the locus...
Modeling Ground Water Mounding in a Heterogeneous Unconfined Aquifer
A numerical, potential flow solution for the flow pattern and water table elevation due to recharge in unconfined, heterogeneous aquifers has been developed using boundary, conforming...
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