System dynamics optimisation approach to irrigation demand management

A Elmahdi, H. Malano, T. Etchells, S. Khan

Research output: Book chapter/Published conference paperConference paperpeer-review

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Abstract

Significant problems of water shortage and deteriorating water quality are contributing to a growing water crisis in many countries. This situation requires creative solutions to achieve sustainable resource management. In the Murrumbidgee river basin, irrigation extraction and land clearing have had major impacts on the river environment (DLWC 1995). Irrigation demand has changed the natural flow regime of the
river which has induced significant environmental changes. Increased demands for water have led to reduced river flows and a reversal of the seasonal flow patterns.
Finding ways to meet irrigation demands and also achieve positive environmental and economic outcomes requires the aid of modelling tools to analyse the impact of alternative policy scenarios. These scenarios seek to assess the impact of options for the allocation of limited water resources between agricultural production and the environment.
This paper presents a novel approach for optimizing these objectives by combining system dynamics and constrained linear objective optimisation approaches. The network simulation optimisation model NSOM has been coupled with a linear programming mathematical algorithm that includes the system constraints. The model uses an economic rationale (i.e. a farmer’s economic decision to maximise the gross margin per Megalitre) that involves assessing alternative cropping mixes and selecting the crop mix that maximises the net return and minimises water used.
The optimisation results from this model have been compared with results from a commercial linear programming solver to verify the capabilities of VENSIM™ optimizer. The comparison shows that VENSIM™ optimizer does achieve the same results.
This paper concludes that system dynamic optimisation approach is a useful tool for irrigation companies and catchment managers to evaluate alternative river system management scenarios. In particular, NSOM has the capability to compare the simulation and optimisation dynamic results synchronized in time for each variable involved in the model. In general based on a preliminary analysis, it is shown that selecting the appropriate crop mix could have positive impacts and benefits for irrigation deliveries and environmental flow. Further research is required to test, calibrate the NSOM model with actual data and study multi-objectives optimisation.
Original languageEnglish
Title of host publicationMODSIM 2005 International Congress on Modelling and Simulation
EditorsShahbaz Khan
Place of PublicationMelbourne
PublisherThe Modelling and Simulation Society
Pages196-202
Number of pages7
ISBN (Electronic)0975840010
Publication statusPublished - 2020
EventInternational Congress on Modelling and Simulation (MODSIM) - University of Melbourne, Melbourne, Australia
Duration: 12 Dec 200515 Dec 2005
https://www.mssanz.org.au/documents/newsletters/MSSANZNewsletter_Feb2005.pdf
http://www.mssanz.org.au/modsim05/index.htm

Conference

ConferenceInternational Congress on Modelling and Simulation (MODSIM)
Abbreviated titleAdvances and Applications for Management and Decision Making
Country/TerritoryAustralia
CityMelbourne
Period12/12/0515/12/05
Internet address

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