Now showing items 3661-3680 of 3826

    • Soil Moisture Flow in Drainage‐Subirrigation System 

      Tomasz Brandyk; Jan G. Wesseling (American Society of Civil Engineers, 1987)
      This paper presents some results of calculations performed with a numerical model for unsaturated soil moisture flow. It shows the possibility of using different boundary conditions to obtain the daily moisture content of ...
    • Triangular Side Weirs 

      Chandra Prakash Kumar; Santosh Kumar Pathak (American Society of Civil Engineers, 1987)
      Discharge characteristics of sharp and broad‐crested triangular side weirs have been experimentally investigated. Relations between discharge coefficient and main channel Froude number for different apex angles have been ...
    • Predicting Unsaturated Hydraulic Conductivity from Soil Texture 

      Lynne Alexander; R. Wayne Skaggs (American Society of Civil Engineers, 1987)
      A total of 14 methods to predict
    • Effect of Irrigation on Groundwater Quality in California 

      Kenneth D. Schmidt; Irving Sherman (American Society of Civil Engineers, 1987)
      Deep percolation of irrigation return flow is a major source of recharge beneath most irrigated areas in California. Tile drainage, soils, water in the vadose zone, and shallow groundwater have been studied. Nitrate, ...
    • Conjunctive Use in Sevier River System, Utah 

      Carl H. Carpenter (American Society of Civil Engineers, 1987)
      The Sevier Desert and Sanpete Valley are two subbasins within the Sevier River System in south‐central Utah in which groundwater is extensively used in conjunction with surface water for irrigation. The conjunctive use has ...
    • Effects of Sediment‐Laden Flow on Channel Bed Clogging 

      A. B. Cunningham; C. J. Anderson; H. Bouwer (American Society of Civil Engineers, 1987)
      In open channel systems the phenomenon commonly referred to as clogging is caused by settling and straining of suspended sediment as water moves through the channel bed material, as well as by microbial transport, colonization, ...
    • Canal Capacities for Demand Under Surface Irrigation 

      Albert J. Clemmens (American Society of Civil Engineers, 1986)
      Providing water to users on demand usually requires an increase in canal capacity over the same volume of water delivered at a uniform rate. A simulation model was used to develop demand patterns for hypothetical surface ...
    • Sprinkler Irrigation Project Design with Production Functions 

      Richard G. Allen (American Society of Civil Engineers, 1986)
      A linear‐programming (LP) framework with associated design and cost‐estimating procedures is developed to evaluate the economics of deficit irrigation in system design and to optimize the sizing and operation of irrigation ...
    • Effect of Irrigated Agriculture on Groundwater 

      Herman Bouwer (American Society of Civil Engineers, 1987)
      The time it takes for deep percolation water from irrigated fields to reach underlying groundwater increases with decreasing particle size of the vadose zone material and increasing depth to groundwater. For average deep ...
    • Editor's Page 

      Ted Engman (American Society of Civil Engineers, 1987)
    • Simulating Sprinkler Performance in Wind 

      E. D. Vories; R. D. von Bernuth; R. H. Mickelson (American Society of Civil Engineers, 1987)
      The uniformity of irrigation systems is important to efficiency, yield, and economics. Wind strongly affects this uniformity. A method is presented for simulating the operation of a sprinkler system in wind. Equations ...
    • Environmental Impacts of Irrigation Projects 

      Rameshwar D. Verma (American Society of Civil Engineers, 1986)
      With the increasing population of the world, the area of irrigated agriculture will have to be increased in order to provide food and work for the people. Data presented at the World Food Conference held in Rome in 1974 ...
    • A Penman for All Seasons 

      Richard G. Allen (American Society of Civil Engineers, 1986)
      Ten forms of the Penman combination evapotranspiration equation are reviewed and compared with lysimeter estimates at three locations. Aerodynamic and canopy resistance forms by Monteith and Thom and Oliver and an empirical ...
    • Irrigation Effects in Arizona and New Mexico 

      George V. Sabol; Herman Bouwer; Peter J. Wierenga (American Society of Civil Engineers, 1987)
      Irrigated agriculture accounts for about 90% of all water consumption in both Arizona and New Mexico. More than 50% of this water is pumped from groundwater sources. Some portion of the applied irrigation water is returned ...
    • Modified, Trapezoidal Venturi Channel 

      Willi H. Hager (American Society of Civil Engineers, 1986)
      The flow pattern resulting from a circular cone immersed in a rectangular channel is investigated under critical flow conditions. The apparatus may be used for both permanent and mobile discharge evaluation in open channels. ...
    • Mechanisms and Process Parameters of Filter Screens 

      Avner Adin; Giora Alon (American Society of Civil Engineers, 1986)
      The clogging of strainers is a major problem in drip irrigation systems. The specific purpose of this work is to study clogging mechanisms of filter screens caused by water containing mostly organic particulates (algae). ...
    • Predicting EC for Drainage Water Management 

      P.‐S. Tsui; J. C. Guitjens (American Society of Civil Engineers, 1986)
      In 1982, 405 measurements of the subsurface drainage water quality parameter electrical conductivity (EC) in dS/m were collected. The data were obtained from 15 subsurface drains on 9.3 ha (23 acres) of irrigated agricultural ...
    • Practical Land Grading Based on Least Squares 

      Edmar J. Scaloppi; Lyman S. Willardson (American Society of Civil Engineers, 1986)
      Practical methods for land grading design of a plane surface for rectangular and irregularly shaped fields based on a least squares analysis are presented. The least squares procedure leads to a system of three linear ...
    • Groundwater Management Institutions in Kansas 

      John C. Peck (American Society of Civil Engineers, 1986)
      This paper deals with the management of groundwater in Kansas through the statutory mechanism of the groundwater management district (GMD). A description of the location of water in Kansas and of relevant Kansas law is ...