The Nicola Valley, in the dry interior of British Columbia, is an important cattle ranching area. Alfalfa and grass hay are grown to provide winter feed for the cattle, but due to the low annual precipitation (9.5 ins. at Merritt) and high rate of evapotranspiration, irrigation is necessary. Of the licenced water supply, 95 percent is licensed to agricultural use. In this study, which is of the reconnaissance type, current irrigation practices within the area are described, and on the basis of available data and some field measurements, a method is developed from which irrigation and drainage requirements are determined for several typical locations. Seasonal evapotranspiration was estimated from readings obtained from an Ogopogo carborundum block evaporimeter, and for Merritt, Douglas Lake, and Quilchena, seasonal requirements were found to be 26, 19, and 24 acre ins./acre respectively. The leaching or drainage requirement was found to be low in the Nicola Valley. A local maximum value of 8.3 percent was found, but drainage water not exceeding one percent of consumptive use was estimated for an average season. It was considered advisable to add gypsum to irrigation waters in certain cases to prevent sodium alkali soils from developing; the more usual tests indicating sodium hazard gave unsatisfactory results. The concept of efficiency of water use requires some careful definition: it is pointed out that present definitions of water efficiency can be misleading. Conveyance efficiencies were found to be highly variable with seepage values of 8 percent to 96 percent per mile; efficiency of distribution of irrigation water within a field was taken from comparative data. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

A sprinkler irrigation system is typically designed by first choosing the set of operating conditions and the location for the pipe network, and then selecting the optimal pipe sizes for the network so that the system cost is minimized. An efficient optimizing technique would greatly improve this design process. This thesis examines a number of procedures for optimizing pipe sizes in open-ended (tree-like) sprinkler irrigation systems. The Linear Programming Technique was found to be by far the most suitable procedure for solving complex pipe sizing problems. A computer model utilizing a general linear programming routine is presented for optimizing pipe sizes in gravity systems, and pumping systems with both constant-speed and variable-speed power units. A comprehensive discussion is included, describing all input parameters, and the function and operation of each major segment of the model. An example is used to reinforce ideas formulated in the discussion and to illustrate how the model can be implemented. A complete listing of the model, and a copy of both the input data and the output, for the example, are given in the indices. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

The scarcity of water resources is increasing and marginal quantities of water are becoming more important. The need for sound and conservative management of water supply is imperative. Intensified agricultural production, to feed the ever-increasing world population, is requiring more irrigation, which is the heaviest consumptive use of water. It is desirable, therefore, to seek new techniques that can modify the irrigation water supply regime. Such a modification implies the urgent need for the development of an irrigation water supply regime dictated by seasonal hydrologic considerations and agricultural production that is technologically fully controlled on the basis of long-range stochastic considerations. The fact that most observed historical hydrologic data are usually short and may constitute poor representation of the possibilities for long-term planning in irrigation systems management, reinforces the postulation that any meaningful approach to the optimal development and operation of irrigation systems must take full cognizance of hydrological uncertainty. To achieve optimum competence in irrigation systems management under the predominating constraint of hydrological uncertainty, a methodology that first considers the systems operational policies as well as several levels of water consumption is necessary. To be realistic with operating rules one has to consider the stochastic variability in irrigation planning and thus has to consider uncertainty and risk relating to the major decision input information-(hydrologic information); and other considerations other than strictly maximizing expected economic monetary value must be brought into the model formulation. Any meaningful planning in agricultural water utilization has to be man-centered in approach and must provide objective analysis of subjective considerations. The above rationale led to the development of a stochastic Bayesian Decision Theory optimization model, which specifies expected utility as the criterial objective function to maximize, and which could be realistically employed to identify the best decision-criterion and adequate policies for optimal long-term planning, development and operation of irrigation systems with storage under hydrological uncertainty. The model, which is behavioral in approach, is applied to the Nicola Valley Irrigation District located in the dry, semi-arid interior of Brutish Columbia. Two irrigation operational procedures, two decision criteria, and different crop response function are employed in the analysis to identify the best planning policy for astute irrigation systems management in the region. The results obtained from the model indicate that the optimal areas to irrigate under hydrological uncertainty are dependent on the degree of hydrological uncertainty, the systems operating procedure, the crops irrigated and their responses to water, and on the decision criterion and utility function employed. Post-optimal analyses indicate that optimal policies obtained are very sensitive to discretized probability distribution of the uncertain states of nature, crop response function, utility function and decision criterion, and system operating procedure employed. For Nicola Valley Irrigation District the model shows that the practice of irrigating more alfalfa hectarage at a water consumption level that is below the designated maximum water requirement of alfalfa, - Procedure II, is superior to the practice of irrigating less hectarage to maximum consumptive use of crop and maximum water holding capacity of the soil, - Procedure I. It is also shown that the criterion of maximizing total expected utility, EU, is superior to the criterion of maximizing total expected monetary value, EMV, under uncertainty and risk. The model also shows that it is desirable to have some hydrological forecasting device. In the Nicola region for improved output from the model. Thus, the model has considerable promise as a valid tool for optimal long-term irrigation systems management decision-making under hydrological uncertainty. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Nitrogen (N) fertility and irrigation costs are the greatest input expenses required for rice production in Mississippi, therefore N management and irrigation should be conducted in efficiently. Field experiments were conducted at the Delta Research and Extension Center in Stoneville, MS, and the LSU AgCenter in Crowley, LA, to evaluate water and nitrogen management practices. Nitrogen use efficiency and yield were not different for alternate wetting and drying (AWD) systems compared to a traditional continuous flood. Additionally, experiments were conducted to test for differences comparing two experimental designs, randomized complete block (RCB) and split-plot (SP), for N-rate response trials in Mississippi. Rice grain yield response to N-rate was similar for RCB and SP designs, therefore either experimental design would be appropriate for N-response experiments in rice. Increasing efficiency of water and N management practices further improves environmental and economic benefits from rice production in Mississippi.

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This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

Thesis (PhD)--University of South Australia, 2004.

Thesis (Ph. D. - Hydrology and Water Resources)--University of Arizona. / Includes bibliographical references.

Thesis (M.S. - Soils, Water and Engineering)--University of Arizona, 1985. / Bibliography: leaves 119-121.