Use of SIRMOD as a quasi real time surface irrigation decision support system

© MODSIM 2005 - International Congress on Modelling and Simulation: Advances and Applications for Management and Decision Making, Proceedings. All rights reserved. Surface irrigation currently accounts for 70-80% of irrigation water use in Australia and surface application is by far the dominant irrigation method applied throughout the world. However, water use efficiencies with surface irrigation methods tend to be low. In recent years a number of surface irrigation simulation models for assessing surface irrigation system performance have been developed. One of the most commonly used models SIRMOD, developed by Utah State University, has seen wide use and evaluation throughout the world particularly by researchers and has been shown to offer potential for increasing surface irrigation water use efficiencies. Considerable efforts are now being undertaken to move use of the model from the realm of a research domain to the farmer domain. Maximum benefit from the use of such models will only occur when farmers have the ability to use Decision Support Systems (DSS) such as SIRMOD in a near real time environment i.e. for individual irrigations. An extensive field investigation of the model was undertaken on a range of irrigation layouts and two different soil types commonly found in south eastern Australia. The regression analysis of measured infiltrated volumes showed a strong correlation with modeled results (Figure 1 r2 = 0.9474). The SIRMOD simulation model was found to adequately predict furrow irrigation characteristics on irrigation layouts and soil conditions typically found in the Murrumbidgee Irrigation Area (MIA). Comparisons of infiltrated volumes predicted by SIRMOD with measured infiltrated volumes gave a strong relationship providing confidence that SIRMOD was able to adequately model furrow irrigation systems typically used in the MIA. This paper presents the results from field testing and evaluation of the model directly with irrigation farmers and user experiences with using SIRMOD as a quasi real time decision support tool. Four areas have the potential to dictate the uptake of the SIRMOD model as DSS: 1. Ease of gathering input data for the DSS 2. Platform delivery of the DSS 3. Relating model outputs to end user needs 4. Level of irrigation water availability and the cost:benefit ratio of using the DSS The use of the SIRMOD model as a management tool for improving irrigation efficiencies was found to be a valuable aid. Adoption of the model in use as a DSS has great potential. Future directions in research should focus on providing a streamlined solution which delivers an integrated system and addresses the four points outlined above. This will ensure irrigation farmers harness the benefit of the model.