An Electronic Decision Support System that Considers Risk and Site-Specificity in the Evaluation of Irrigation Water Quality

Abstract

Abstract Irrigators are increasingly challenged to maintain or even increase production using less water, sometimes of a poorer quality, and often from unconventional sources. This paper describes the main features of a newly developed software-based Decision Support System (DSS), with which to assess the Fitness for Use (FFU) of water for irrigation. Included in the analysis are site-specific factors, several non-traditional water constituents, and an assessment of the risk of negative effects. A simplified soil water balance and chemistry model is used to assess the water balance components of a cropping system and the redistribution of solutes within a soil profile. Simulations generate user-friendly, colour-coded output, that highlights expected effects of water constituents on soil quality, crop yield and quality, and on irrigation equipment. Because the DSS uses mainly internationally accepted cause-effect relationships to assess the effect of water quality constituents, it is envisaged that the DSS will find universal acceptance and application among irrigation users. In addition to assessing the FFU of irrigation water, the DSS also caters for calculating so-called Water Quality Requirements (WQR). WQRs represent the threshold levels of water quality constituents for irrigation at specified levels of acceptability or risk. Knowledge of WQRs will assist water resource managers to set site-specific targets for the maximum levels of water quality constituents that can be tolerated in a water source before impacting negatively on successful irrigation.