Now showing items 3501-3520 of 3826

    • Solute Movement Through Root‐Soil Environment 

      John C. Tracy; Miguel A. Marin¯o (American Society of Civil Engineers, 1989)
      A methodology is developed for simulating the movement of water and solutes through a root‐soil system, which accounts for the effect of the solute concentration on the extraction of soil water by a transpiring crop's root ...
    • Water Movement in Horizontally Layered Soils 

      Zohrab Samani; Ali Cheraghi; Lyman Willardson (American Society of Civil Engineers, 1989)
      The water movement in layered soils where fine‐textured soil overlays a coarse textured soil has become very important in recent years due to its effect on the movement of pollutants and the distance to which water can ...
    • Particle Filtration for Wastewater Irrigation 

      Avner Adin; Menachem Elimelech (American Society of Civil Engineers, 1989)
      Conventional water filtration methods cannot be generalized for use in direct wastewater filtration for drip (trickle) irrigation systems. Effluents from an oxidation ponds‐reservoir system and from an activated sludge ...
    • What a Layperson Needs to Know About Water Rights 

      Donald J. Finlayson (American Society of Civil Engineers, 1989)
      People who cannot obtain water service from a water utility need to obtain a right to use a surface or ground water supply. The increasing scarcity of uncommitted water supplies makes this a task that can be difficult and ...
    • Stochastic Approximation Applied to Optimal Irrigation and Drainage Planning 

      Timothy K. Gates; Roger J‐B Wets; Mark E. Grismer (American Society of Civil Engineers, 1989)
      Parameter uncertainty in modeling complex hydrologic systems has resulted in development of stochastically based water management models. Optimal solutions to such models, particularly those having parameters with large ...
    • Effect of Dikes and Sulfuric Acid on Cotton Under Effluent Irrigation 

      Gideon Oron; Yoel DeMalach (American Society of Civil Engineers, 1989)
      Extensive efforts are being undertaken to improve effluent use in arid zones with alkaline soils. This type of soil (loess) is mainly found in the southern parts of Israel with a relatively large amount of water loss due ...
    • Verification of Kirkham's Problem of Layered Soil Drainage 

      G. J. Khan; K. N. Shukla; H. S. Chauhan; Sewa Ram (American Society of Civil Engineers, 1989)
      Steady‐state flow with replenishment to horizontal tube drains in a two layered soil has been simulated in a vertical Hele‐Shaw model. Comparison of analytical solution of Toksoz and Kirkham on the simulated flow system ...
    • Three‐Point Method for Estimating Cut and Fill Volumes of Land Grading 

      Said M. Easa (American Society of Civil Engineers, 1989)
      In this paper, a three-point (TP) method for computing cut and fill volumes for triangular and rectangular grids is developed. In comparison to the summation method and the four-point (FP) method, its advantages are: it ...
    • Systems Analysis of Tank Irrigation: II. Delayed Start and Water Deficit 

      Rama Prasad; S. G. Mayya (American Society of Civil Engineers, 1989)
      Tank irrigation systems in the semiarid regions of India are discussed in this paper. To optimize the grain yield of rice, it is essential to start the agricultural operations in the second week of July so that favorable ...
    • Seepage and Contraction Joints in Concrete Canal Linings 

      Jeff Kishel (American Society of Civil Engineers, 1989)
      Contraction joints in concrete canal linings are often provided with waterstops or joint sealants on the assumption that the cost of these provisions will be justified by a corresponding reduction in water lost to seepage ...
    • Systems Analysis of Tank Irrigation: I. Crop Staggering 

      S. G. Mayya; Rama Prasad (American Society of Civil Engineers, 1989)
      The irrigation potential of a tank system, thousands of which are found in South India, depends upon a number of factors other than water availability. These factors are mainly influenced by the agricultural technology ...
    • Research Imperatives for Irrigation Science 

      Brent E. Clothier (American Society of Civil Engineers, 1989)
      Economic and environmental pressure requires efficient use of any water intended for irrigation. Irrigation over the next decade will be assisted in this push for efficiency by the pull of research and technology. Six areas ...
    • Simulation Models of Sequences of Dry and Wet Days 

      J. W. Delleur; T. J. Chang; M. L. Kavvas (American Society of Civil Engineers, 1989)
      A new statistical model has been developed for the simulation of sequences of dry and wet days. The model is based on the discrete autoregressivemoving average (DARMA) family of stochastic processes, which includes the ...
    • Nonlinear Steady State Seepage into Drains 

      Salihu Mustafa; N. A. Rafindadi (American Society of Civil Engineers, 1989)
      Analytical solutions for water table profiles between drains and drain spacing formulas resulting from nonlinear seepage under steady rainfall recharge are presented. Nonlinear seepage conditions are introduced in the ...
    • Use of Stochastic Hydrology in Reservoir Operation 

      D. K. Frevert; M. S. Cowan; W. L. Lane (American Society of Civil Engineers, 1989)
      Intelligent operation of a complex reservoir system requires that the most current mathematical techniques be incorporated into the decision‐making process. One such technique is stochastic hydrology and, in particular, ...
    • Open Channel Flow Through Transverse Floor Outlets 

      A. S. Ramamurthy; Due Minh Tran; L. B. Carballada (American Society of Civil Engineers, 1989)
      The study of subcritical flow through floor outlets or bottom racks in rectangular open channels has direct applications in horizontal trash‐racks of hydro power plants, in curb outlets of streets and in general to divert ...
    • Sloping Crest Crump Weir 

      Robert J. Keller (American Society of Civil Engineers, 1989)
      A hydraulic model study of an existing sloping crest Crump weir is described. Two models of scales 1:10 and 1:3 were tested. At relatively large heads, the structure behaves as one half of a flat‐V Crump weir with the same ...
    • Continuous Distributed Model of Storage Dominated Watershed Runoff 

      Terrance W. Cundy; Richard H. Hawkins (American Society of Civil Engineers, 1989)
      A continuous spatially distributed model of watershed runoff for storage dominated watersheds is presented. The model is consistent with previously reported concepts and mathematics of infiltration activated watersheds. ...