Journal of Irrigation and Drainage Engineering: Recent submissions
Now showing items 2541-2560 of 3826
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A Paradigm Shift in Irrigation Management
(American Society of Civil Engineers, 2002)In coming decades, irrigated agriculture will be called upon to produce up to two thirds of the increased food supply needed by an expanding world population. But the increasing dependence on irrigation will coincide with ... -
Irrigation Hydrology: Crossing Scales
(American Society of Civil Engineers, 2002)Hydrology is the science concerned with distribution, circulation, and properties of water of the earth and its atmosphere, across the full range of time and space scales. Subject matter ranges widely from chemical and ... -
New Strategy for Optimizing Water Application under Trickle Irrigation
(American Society of Civil Engineers, 2002)The determination of water application parameters for creating an optimal soil moisture profile represents a complex nonlinear optimization problem which renders traditional optimization into a cumbersome procedure. For ... -
Enhanced Subsurface Irrigation Hydrology Model
(American Society of Civil Engineers, 2002)This paper provides a theoretical basis for new features added to the SWMS_3D model of Simunek et al., including spatially varied land use, dynamic root distributions and water uptake, and various fluxes at the soil-atmosphere ... -
Development of Comprehensive Soil Salinity Index
(American Society of Civil Engineers, 2002)Crop yield is a function of many agroclimatic factors. However, excessive wetness, dryness, or soluble salts in the root zone are three important stresses that inhibit crop growth and reduce yield. Stress due to wetness ... -
Pan Evaporation to Reference Evapotranspiration Conversion Methods
(American Society of Civil Engineers, 2002)Reference evapotranspiration -
Discharge Characteristics of Chimney Weir under Free-Flow Conditions
(American Society of Civil Engineers, 2002)The assumption of a constant coefficient of discharge in the linear head-discharge relationship of a chimney weir is reinvestigated. Based on dimensional analysis and subsequent experiments conducted with three different ... -
Coupled Reservoir Operation-Irrigation Scheduling by Dynamic Programming
(American Society of Civil Engineers, 2002)This paper develops a forward dynamic programming (FDP) model to solve the problem of reservoir operation and irrigation scheduling. The typical scenario for application of the model is composed of a system of two reservoirs ... -
Drop and Energy Characteristics of a Rotating Spray-Plate Sprinkler
(American Society of Civil Engineers, 2002)A laboratory investigation was conducted to measure wetted radii and drop sizes and to estimate the energy characteristics of a rotating spray-plate sprinkler. Maximum wetted radii were positively related to increasing ... -
Applications of Drag-Reducing Polymers in Sprinkler Irrigation Systems: Sprinkler Head Performance
(American Society of Civil Engineers, 2002)The study investigates the effects of polymer additives on sprinkler performance. Experiments were carried out on a medium-pressure sprinkler to determine the effect of polymer additives. Two kinds of polymer additives ... -
Monitoring and Modeling Flow and Salt Transport in a Salinity-Threatened Irrigated Valley
(American Society of Civil Engineers, 2002)Saline high water tables pose a growing threat to the world’s productive irrigated land. Much of this land lies along arid alluvial plains, where solutions must now be developed in the context of changing constraints on ... -
Evaluation of Class A Pan Coefficients for Estimating Reference Evapotranspiration in Humid Location
(American Society of Civil Engineers, 2002)Evaporation pans [Class A pan, U.S. Weather Bureau (USWB)] are used extensively throughout the world to measure free-water evaporation and to estimate reference evapotranspiration -
Minimum-Risk Bedding for Flexible Drain Pipes
(American Society of Civil Engineers, 2002)The soil bedding for nonpressurized buried flexible pipes is critical for minimum-risk performance. Lack of adequate bedding reduces the strength of the pipes by a factor of 2 or more. To compensate, pipes must have high ... -
Discussion of “Optimal Design of Parabolic-Bottomed Triangle Canals” by K. Babaeyan-Koopaei, E. M. Valentine, and D. C. Swailes
(American Society of Civil Engineers, 2002) -
Hydraulic Analysis and Optimum Design of Multidiameter Irrigation Laterals
(American Society of Civil Engineers, 2002)A new analytical continuous-uniform outflow approach that takes into account the effect of the number of outlets on the multidiameter lateral hydraulics is presented. The pressure head profile along the multidiameter ... -
Water Table Rise in Sloping Aquifer due to Canal Seepage and Constant Recharge
(American Society of Civil Engineers, 2002)Analytical solutions of the linearized Boussinesq equation and a fully implicit finite-difference numerical solution of the nonlinear Boussinesq equation were obtained to study transient and steady-state water table rise ... -
Numerical Simulation of Water Flow and Solute Transport to Tile Drains
(American Society of Civil Engineers, 2002)When numerical models are used for estimating the water flow and solute transport at field scale, modelers are confronted with the issue of spatial variability of soil hydraulic properties. In this paper, the concept of ... -
Optimum Design of Microirrigation Systems in Sloping Lands
(American Society of Civil Engineers, 2002)When an area to be irrigated has a high slope gradient in the manifold line direction, an option is to use a tapered pipeline to economize on pipe costs and to keep pressure head variations within desired limits. The ... -
2. Numerical Simulations of Water Flow and Solute Transport Applied to Acid Sulfate Soils
(American Society of Civil Engineers, 2002)Field investigations of Rassam et al. in 2001 have highlighted the effects of infiltration, drainage, and evapotranspiration on the dynamics of water flow and solute transport in acid sulfate (AS) soils. In this work, -
Discussion of “Stability and Mobility of Sand-Bed Channels Affected by Seepage” by Achanta Ramakrishna Rao and Nagaraj Sitaram
(American Society of Civil Engineers, 2002)