Influence of the Spatial Configuration of the Irrigated Zone on the Irrigation Network Layout Design

Abstract

The present work aims at taking us closer to the study of the influence of the spatial configuration of the irrigated zone on the unit cost (€/ha) of a layout irrigation network design. The layout analyzed in this paper is carried out by means of the algorithm, based on the graph theory which eliminates the skill or experience of the designer, thus giving rise to homogeneous results. These layouts are sized using the method of the modified economic series. Then, the irrigated zone is studied by applying spatial analysis techniques and calculating a series of variables that may have some effects on the cost (€/ha) of the network. Finally, we look for the existing relationship between the spatial variables and the cost by using the statistical technique of multiple regression analysis. Variables such as accessibility of supply, location of the network origin, total irrigated area, density of irrigable plots, perimeter, or hydrants spatial point pattern are extremely important in the cost of the network. The statistical model explains more than 99% of the variability found in unit cost. The equation obtained may be very useful before performing a design, in order to find out a suitable location of the network origin, as well as to check if the design of a single network is preferred to the alternative of dividing it into several smaller networks. Moreover, it would also be interesting to verify if the hydrant spatial point pattern as a whole is appropriate.