Now showing items 3181-3200 of 3826

    • Measuring Water in Trapezoidal Canals 

      Zohrab Samani; Henry Magallanez (American Society of Civil Engineers, 1993)
      Laboratory experiments were conducted to evaluate the hydraulic characteristics of a simple portable flume. The flume consists of a pipe installed axially inside a trapezoidal channel with side slopes of 1/1. The ratio of ...
    • Sprinkler Droplet Effects on Infiltration. I: Impact Simulation 

      Wen‐Jaur Chang; David J. Hills (American Society of Civil Engineers, 1993)
      The water infiltration rate during sprinkle irrigation is known to decrease due to the impact effects of water droplets on soil‐surface structure. In this paper, a numerical simulation model that employs full three‐dimensional ...
    • Mathematical Modeling of Saturated‐Unsaturated Flow to Drains 

      Saleem Ahmad; Deepak Kashyap; B. S. Mathur (American Society of Civil Engineers, 1993)
      Two‐dimensional transient flow to ditches or drains in a heterogeneous, anisotropic porous medium is modeled for appropriate initial and boundary conditions using the finite differences method for the entire saturated‐unsaturated ...
    • Long‐Term Quality of Shallow Ground Water at Irrigated Sites 

      G. J. Beke; T. Entz; D. P. Graham (American Society of Civil Engineers, 1993)
      Areal, vertical, and temporal differences in salinity characteristics of shallow, unconfined ground water were related to irrigation, cropping practices, and surficial geology. Nine wells were monitored monthly for a period ...
    • Aquifer Characteristics and Long‐Term Ground‐Water Levels 

      G. J. Beke; T. Entz; D. P. Graham (American Society of Civil Engineers, 1993)
      Water‐table depth, piezometric head, and precipitation were measured at nine sites in southern Alberta over a period of up to 28 years to determine the effect of irrigation on long‐term groundwater levels. Irrigation and ...
    • Saline Drain Water Reuse in Agroforestry Systems 

      K. K. Tanji; F. F. Karajeh (American Society of Civil Engineers, 1993)
      On the west side of California's San Joaquin Valley, researchers are experimenting with agroforestry systems to help solve the agricultural drainage problem. Eucalyptus tree plantations are used to consume the shallow ...
    • Momentum Model of Flow Past Weir 

      Amruthur S. Ramamurthy; Ngoc‐Diep Vo; German Vera (American Society of Civil Engineers, 1992)
      Circular-crested weirs are used for flow measurement and have wide applications in irrigation systems, where they serve as overflow structures. For flow past such a weir, the discharge coefficient was obtained on the basis ...
    • Precision of Evapotranspiration Estimates Using Neutron Probe 

      Osmar A. Carrijo; Richard H. Cuenca (American Society of Civil Engineers, 1992)
      A simple hydrologic balance model based on neutron‐probe measurements of soil moisture content was used to estimate evapotranspiration for alfalfa. The model results indicated large variations in the amount of estimated ...
    • Flow in Trapezoidal Channels 

      W. E. Hart; B. P. Thoreson; S. A. Musil (American Society of Civil Engineers, 1992)
      Four charts are presented for the selection of standard concrete trapezoidal canals. The charts cover Systeòme International (SI)– and English-dimensioned canals. If the channel invert slope and flow are known, a standard ...
    • Side Weir in Triangular Channel 

      Ali Uyumaz (American Society of Civil Engineers, 1992)
      In this study, numerical investigations of flow over side weirs in triangular channels are reported. Numerical models are obtained from energy principles and solved by a finite difference method. The resutls are presented ...
    • Flow Measurement with Rectangular Free Overfall 

      Vito Ferro (American Society of Civil Engineers, 1992)
      Previous experimental works provide different values of the ratio between the end depth and the critical depth. Differences depend on the crosssection shape of the channel, the roughness of the channel, and the characteristics ...
    • Equation for Evaporation Pan to Evapotranspiration Conversions 

      Richard L. Snyder (American Society of Civil Engineers, 1992)
      The evaporation rate from a class "A" evaporation pan located in a site surrounded by low-growing vegetation can be used to estimate potential evapotranspiration for a grass reference. The evaporation rate for pans and the ...
    • Furrow Flow Velocity Effect on Hydraulic Roughness 

      Thomas J. Trout (American Society of Civil Engineers, 1992)
      The hydraulic roughness of irrigation furrows is generally assumed to be uniform throughout a field. However, water flow, which varies along furrows, reduces roughness by breaking down soil aggregates and depositing sediments ...
    • Irrigation Land Management Model 

      Roy A. Steiner; Andrew A. Keller (American Society of Civil Engineers, 1992)
      The Irrigation Land Management (ILM) model was developed as a research tool to simulate the demand and response of a multiple‐field multicrop irrigation system in a variety of environments in order to assist managers in ...
    • Design of Control Algorithm for Operation of Irrigation Canals 

      J. Mohan Reddy; Amadou Dia; Ahmed Oussou (American Society of Civil Engineers, 1992)
      Using a linearized finite‐difference model of open‐channel flow, the canal operation problem was formulated as an optimal‐control problem, and an algorithm for gate opening in the presence of arbitrary external disturbances ...
    • Reuse Simulation in Irrigated River Basin 

      L. K. Smedema; W. Wolters; P. J. Hoogenboom (American Society of Civil Engineers, 1992)
      Irrigation in a river basin generally implies that the drainage water from upstream schemes is reused in the downstream schemes. The processes of water and salt movement in the schemes (over the soil surface, through the ...
    • Probabilistic Design of Open Drainage Channels 

      Said M. Easa (American Society of Civil Engineers, 1992)
      A method for designing open drainage channels that incorporates the uncertainty associated with various design variables is presented. The design involves two random components: runoff (demand) and channel capacity (supply). ...
    • Working Conditions of Sprinkler to Optimize Application of Water 

      José María Tarjuelo Martín‐Benito; Manuel Valiente Gómez; Juan Lozoya Pardo (American Society of Civil Engineers, 1992)
      It is surprising to note the lack of information usually given by manufacturers about their sprinklers, making it very difficult to correctly select a sprinkler and its working conditions when designing a sprinkler irrigation ...