Regional scale irrigation scheduling using a mathematical model and GIS

A user-friendly software that contributes to the regional scale irrigation scheduling is presented. The software is based on the numerical solution of Richards equation which is integrated into the ArcGIS environment. Irrigation water needs are visualised by the production of coloured maps of the cultivated area. The software is aimed to the managers of the collective irrigation networks to assist them in the efficient distribution of water. In addition to that the software calculates the proper amount of water that must be applied to meet the crop needs. Therefore it offers the ability to the managers to provide specific irrigation advice to the farmers. A requirement of the software is that the study region must be densely sampled in order to be divided into homogeneous crop and soil texture sub-regions. Spatial variability of the soil hydraulic parameters is handled by applying the scaling method to the set of point measurements contained within each sub-region. This paper describes the main theoretical considerations behind this software and compares two irrigation cases: one with real and one with hypothetical data.