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Accueil du site → Doctorat → États-Unis → 1990 → A stochastic approach to conjunctive irrigation and drainage systems design

University of Colorado at Boulder (1990)

A stochastic approach to conjunctive irrigation and drainage systems design

Garcia, Luis Alfredo

Titre : A stochastic approach to conjunctive irrigation and drainage systems design

Auteur : Garcia, Luis Alfredo

Université de soutenance : University of Colorado at Boulder

Grade : Doctor of Philosophy (PhD) 1990

Irrigation and drainage systems are closely interrelated. In the past most of the designs of these systems were conducted separately. This approach made the quantification of the impact of an irrigation system on a drainage system, and vice-versa, time consuming, difficult to perform and, at times, impossible. The practice of designing each component separately has generated extensive work in each discipline, but little work has been done which links the two disciplines. During this study a framework for the design of both irrigation and drainage components as a conjunctive system is developed. This framework takes into account the stochastic nature of the inputs. The implementation of the conjunctive irrigation and drainage system is developed for arid/semi-arid areas. The design of agricultural drains is a function of the amount of water the soil receives as deep percolation. In this study, deep percolation from irrigation events and precipitation will be analyzed, taking into consideration the stochastic nature of these inputs. The stochastic behavior of input parameters creates uncertainty in system performance. This uncertainty makes it impossible to forecast, with complete accuracy, the system performance over its design life. However, if performance is acceptable over a wide range of inputs, the system may be considered to be "robust". This work makes two distinct contributions to the field of Irrigation/Drainage Engineering. First, a decision support system for conjunctive design of irrigation and drainage systems is developed. As part of this conjunctive system, a linkage of soil water modeling techniques is achieved, and a method to model stochastic inputs along with the resulting stochastic system performance is developed. A two phase analytical/numerical model of water movement through the soil proves to perform satisfactorily. A graphical user interface to assist in implementing the method and evaluating the results is developed. Second, an analysis is made to examine alternative design criteria under stochastic system performance. Expected value, reliability, robustness and threshold criteria are examined using data from an experimental plot in Egypt. Analysis of the strengths and weaknesses of each criterion is obtained from the case study experiments

Mots clés : Drainage, Applied sciences, Irrigation, Civil engineering, Agricultural engineering

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Page publiée le 28 février 2015, mise à jour le 19 novembre 2018