Author(s): C. Gonzalez-Cebollada; D. Moret-Fernandez
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Keywords: No Keywords
Abstract: The aims of this paper are to analyze theoretically the influence of the longitudinal slope of a surface irrigation field on the uniformity of irrigation and to provide practical tools to design, analyze and manage surface irrigation systems with longitudinal slope. An example is shown where a 20% savings in water is obtained by giving the field the optimum slope. The idea is to generalize Clemmens and Dedrick’s (1982) graphs taking account the existence of field slope. So, Clemmens and Dedrick’s graphs are a particular case of results obtained when field slope is zero. The analysis is based on solving one-dimensional free surface Saint-Venant equations including infiltration, applying the dimensional analysis to reduce the number of variables involved. Saint-Venant equations are solved with the finite differences method, applying the full hydrodynamic model. The result is a set of 64 three-dimensional graphs that show the relationships of field slope, irrigation uniformity and the rest of the involved dimensionless variables, related to infiltration parameters, Manning roughness coefficient, cutoff time, inflow rate and field length and width. The graphs could be useful in practice to determine the optimum slope of the field, inflow rate or length and width of the field, achieving substantial savings of water in surface irrigation.
Year: 2010