- Title
- Improving the efficiency of delivering water in Australian river systems: modelling multiple paths
- Creator
- Gilmore, R. L.; Kuczera, G.; Penton, D.; Podger, G.
- Relation
- 18th World IMACS Congress and MODSIM09 International Congress on Modelling and Simulation. The 18th World IMACS Congress and MODSIM09 International Congress on Modelling and Simulation: Proceedings (Cairns, Qld 13-17 July, 2009) p. 225-231
- Relation
- http://www.mssanz.org.au/modsim09/authorsE-G.htm#g
- Publisher
- Modelling and Simulation Society of Australia and New Zealand and International Association for Mathematics and Computers in Simulation
- Resource Type
- conference paper
- Date
- 2009
- Description
- River managers and modellers use long term planning models to inform river operators and planners on how to best operate regulated river systems. Long term planning models simulate the regulated river system using either rules based approaches or linear optimisation techniques. This paper compares these two approaches and examines the potential for objective driven solutions to be used to generate better rules in the Lachlan River System in NSW, Australia. Multiple supply path problems occur when water can be sourced from storages in parallel, storages in series or delivered by parallel distribution paths. Multiple supply path problems are typically complex and difficult to solve. Both rules based models and objective driven (optimisation) models are used to solve multiple supply path problems for long term planning in Australia’s rural catchments. Rules bases models such as the Integrated Quantity and Quality Model (IQQM) and MSM-BigMod have been used to model rural catchments in Queensland (IQQM), NSW (IQQM) and the Murray River (MSM-BidMod). Optimisation models have been used extensively in Australia for urban water supply modelling and in Victoria for rural and urban systems (REALM, (Diment, 1991), and WATHNET). Specific system information on tradeoffs between the two modelling methods (e.g. efficiency, accuracy of complex processes, and runtime) could be obtained relatively easily by modellers if the software allows a choice of approaches or a combination of approaches. Currently rules based long term planning models are typically run on a daily time step while the optimisation models are run on a monthly time step. It is considered important to be able to run models on either a monthly, daily or sub daily time step. There are run time implications for use of optimisation on daily to sub daily time steps. It may be preferable to model only part of the system with optimisation and the rest with a rules based model which is an option for the Lachlan example. This paper focuses on a case study for supply through multiple paths on the Lachlan River System in NSW that is traditionally modelled using a rules based model (IQQM). Implementing an objective driven model decreased the volumes ordered from the multiple supply paths by 55% and reduced shortfalls by 7% of total demand relative to the rules based model. Using the NetLP solution to generate new distribution rules for orders in IQQM reduced the volumes ordered by 13% and reduced shortfalls by 5.4% of total demand relative to the original IQQM. This illustrates the benefit to river operators and planners of having NetLPs in software packages for long term planning models. Objective driven solutions can be used to generate more efficient rules where a rules based model is preferred, however there will still be tradeoffs in efficiency, modelling accuracy of complex processes, and runtime.
- Subject
- multiple supply; water resources; rules; heuristic; optimization; optimisation; Network Linear Program
- Identifier
- http://hdl.handle.net/1959.13/919464
- Identifier
- uon:8875
- Identifier
- ISBN:9780975840078
- Language
- eng
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