- Godoy, Walter, Barton, Andrew, Perera, Bimalka
- Authors: Godoy, Walter , Barton, Andrew , Perera, Bimalka
- Date: 2012
- Type: Text , Conference paper
- Relation: Hydrology and Water Resources Symposium 2012, Sydney ; 19-22 November 2012 published in Proceedings of the 34th Hydrology and Water Resources Symposium p. 1281-1288
- Full Text: false
- Reviewed:
- Description: Competing interests to water have traditionally been addressed through consultative processes often supported by surface water simulation modelling. Whilst such models are highly effective in demonstrating the effect of changes in system operation, the modelling process is limited to finding one solution at a time for a given set of conditions. Moreover, such traditional approaches have been challenged by the need to develop sustainable water management plans which attempt to meet the need of all users by searching for the optimal operating rules. In recent times there has been growing interest in linking optimisation techniques with simulation models in order to build on the strengths of both modelling approaches in the search for optimal solutions. The modelling approach adopted for this study uses the Elitist Non-dominated Sorting Algorithm (NSGA-II) as the optimisation engine and the REource ALlocation Model (REALM) software as the simulation engine. This optimisationsimulation model is applied to the Wimmera-Mallee Water Supply System which is a complex multireservoir system located in Western Victoria (Australia). The aim of this study is to demonstrate the effectiveness of using an optimisation-simulation modelling approach to develop long-term optimal operating rules. A base case scenario representing the current operating regime is used as a reference point to compare the optimal operating rules produced by the modelling procedure. The results show that by changing certain rules within the current operating regime, the reliability of supply of environmental flows can be improved without affecting consumptive users' reliability of supply, in order to achieve globally optimal operating rules. © 2012 Engineers Australia.
- Description: Proceedings of the 34th Hydrology and Water Resources Symposium, HWRS 2012
- Godoy, Walter, Barton, Andrew, Perera, Bimalka
- Authors: Godoy, Walter , Barton, Andrew , Perera, Bimalka
- Date: 2015
- Type: Text , Conference paper
- Relation: 36th Hydrology and Water Resources Symposium : The art and science of water p. 1213-1220
- Full Text: false
- Reviewed:
- Description: Water resources planning processes around the world are increasingly striving to incorporate sustainability principles in order to find optimal solutions to multi-criterial decision-making problems. The availability of sophisticated modelling techniques such as optimisation-simulation (O-S) models provide a proven approach to efficiently and effectively search for optimal solutions using trusted simulation models. However, optimisation problems in water resources planning are seldom represented using three or more objectives; the so called 'many-objective' multi-objective optimisation problems. Limiting problem dimensionality in this way simplifies visualisation of Pareto-optimal solutions, reduces computational effort, and simplifies the evaluation and interpretation of results. The aim of this study is to present a structured procedure for developing optimal operating plans for complex water resources systems using a combined multi-objective optimisation and sustainability assessment approach. The approach is applied to an 18-objective function MOOP which represents four broad categories relating to environmental, social, consumptive, and system-wide interests for water. The Wimmera-Mallee Water Supply System (WMWSS) is a multi-reservoir system located in Western Victoria (Australia) which is operated to meet a range of conflicting interests for water using complex operating rules. An O-S model is presented which uses the Elitist Non-dominated Sorting Algorithm (NSGA-II) as the optimisation engine and the REsource ALlocation Model (REALM) software as the simulation engine. This O-S model is applied to the WMWSS to search and evaluate candidate optimal operating plans over a 118-year period assuming historic hydro-climatic conditions. The resulting optimal operating plans are ranked in terms of their overall sustainability and compared to a known reference point or 'base case operating plan' which represents the status quo in operating rules for the WMWSS case study. The results show that the combined multi-objective optimisation and sustainability assessment approach is able to find optimal operating plans that are more sustainable than the base case operating plan.
- Godoy, Walter, Barton, Andrew, Perera, Bimalka
- Authors: Godoy, Walter , Barton, Andrew , Perera, Bimalka
- Date: 2011
- Type: Text , Conference paper
- Relation: 19th International Congress on Modelling and Simulation, Perth, Australia, 12th-16th December, 2011 pg. 4029-4035
- Full Text: false
- Reviewed:
- Description: The recently completed Wimmera Mallee Pipeline Project (WMPP) provides reticulated water to 36 towns and about 6000 farms across an area of approximately 2 million hectares in Western Victoria (Australia). This new pipeline has replaced an open channel distribution system and has vastly improved efficiencies in the supply of water, with water savings being returned to the environment, existing consumptive use and new development. One of the challenges for managers of these water recovery projects is to determine the most effective or optimal operational strategy to meet the needs of all water users. The study area supplies a subset of the Wimmera Mallee Pipeline and includes two separate river systems, namely the Glenelg River and the MacKenzie River which flow South-ward and North-ward from the Great Dividing Range respectively. Both river systems have their own unique environmental and socio-economic attributes which are indicative of those relating to the broader Wimmera-Mallee Water Supply System. In Victoria, these often conflicting interests to water have traditionally been addressed through a consultative process supported by surface water simulation modelling. Simulation models attempt to represent all the major characteristics of a system and are therefore tailored to examine "what if?" scenarios. Whilst such models are highly effective in demonstrating the effect of changes in system operation, the modelling process is limited to finding one solution at a time for a given set of conditions. Moreover, such traditional approaches have been challenged by the need to develop sustainable water management plans which attempt to meet the need of all users by searching for the optimal operating rules. Optimisation models have also proven to be effective tools but unlike simulation models are characterised by a numeric search technique and are better suited to address "what should be?" questions. However, the lack of popularity in optimisation models has been due to the complexity in their development, computational effort, and subsequently the simplification in problem specification. In recent times there has been growing interest in linking optimisation techniques with simulation models in order to build on the strengths of both modelling approaches in the search for optimal solutions. The general structure of this combined modelling technique provides for an iterative process; simulation outputs are used to quantify the effect of candidate solutions which are in turn passed to the search engine to find optimal solutions. The aim of this study is to develop a generalised procedure for the formulation of multi-objective optimisation problems relating to multi-reservoir systems with complex operating rules. Importantly the procedure has been developed for problems that are intended to be solved using a combined optimisationsimulation modelling technique. For the present study, the procedure will be used to formulate a sample multi-objective problem for the optimisation of operation of the study area. The procedure is applied in case study form, detailing the various components of the problem, both in mathematical terms and also the necessary qualitative information derived from stakeholder participation. The outcomes of this paper demonstrate: • the importance of on-going stakeholder participation in providing higher level qualitative information as part of (a) the problem formulation process in order to explicitly account for all interests to water, and (b) the optimisation process in order to enable decision makers to make the necessary trade-offs between choosing one optimal solution over another; and • the need to systematically identify the relevant system operating rules that control the movement of water within the simulation model
Multi-objective planning and operation of water supply systems subject to climate change
- Perera, Bimalka, Sachindra, Dhanapala, Godoy, Walter, Barton, Andrew, Huang, Fuchun
- Authors: Perera, Bimalka , Sachindra, Dhanapala , Godoy, Walter , Barton, Andrew , Huang, Fuchun
- Date: 2011
- Type: Text , Journal article
- Relation: International Journal of Environmental, Earth Science and Engineering Vol. 5, no. 12 (2011), p. 174-182
- Full Text: false
- Reviewed:
- Description: Abstract—Many water supply systems in Australia are currently undergoing significant reconfiguration due to reductions in long term average rainfall and resulting low inflows to water supply reservoirs since the second half of the 20th century. When water supply systems undergo change, it is necessary to develop new operating rules, which should consider climate, because the climate change is likely to further reduce inflows. In addition, water resource systems are increasingly intended to be operated to meet complex and multiple objectives representing social, economic, environmental and sustainability criteria. This is further complicated by conflicting preferences on these objectives from diverse stakeholders. This paper describes a methodology to develop optimum operating rules for complex multi-reservoir systems undergoing significant change, considering all of the above issues. The methodology is demonstrated using the Grampians water supply system in northwest Victoria, Australia. Initial work conducted on the project is also presented in this paper.
Testing the robustness of optimal operating plans under various future hydro-climatic scenarios
- Godoy, Walter, Barton, Andrew, Wilson, K., Perera, B.
- Authors: Godoy, Walter , Barton, Andrew , Wilson, K. , Perera, B.
- Date: 2018
- Type: Text , Conference paper
- Relation: 2018 Hydrology and Water Resources Symposium: Water and Communities, HWRS 2018 p. 267-283
- Full Text:
- Reviewed:
- Description: A key challenge for water resources planning processes around the world is to develop operating plans that are optimal under a range of hydro-climatic conditions. The consequences of such long term planning decisions can vary in terms of the social, economic, and environmental impacts. Given these potential impacts, it is important that operating plans are tested under a range of hydro-climatic conditions to ensure that they are sufficiently robust to withstand future changes in climate. The aim of this study is to present a procedure for testing the robustness of optimal operating plans for complex water resources systems using a combined multi-objective optimisation and sustainability assessment approach. The approach embeds an optimisation-simulation (O-S) model which is applied to an 18-objective function multi-objective optimisation problem of the Wimmera-Mallee Water Supply System (WMWSS). The WMWSS is a multi-reservoir system located in Western Victoria (Australia) which is operated to meet a range of competing interests for water using complex operating rules. The O-S model is applied to the WMWSS to search for optimal operating plans over a 100-year period into the future assuming two plausible greenhouse gas (GHG) emission levels. The two GHG emission scenarios represent lower and higher ends of the estimated range of projected GHG emissions, providing a wide range of future hydro-climatic conditions. A robustness test is used to evaluate the validity of the most sustainable optimal operating plans under the two GHG emmission scenarios and also those found previously under a historic hydro-climatic sequence. The test results show that the status quo or base case operating plan is optimal but is neither the highest nor the lowest in terms of the level of sustainability that could be achieved in the WMWSS, under historic and the higher GHG emission scenario. Moreover, the results show that the most sustainable optimal operating plans found under the three hydro-climatic scenarios are sufficiently robust to withstand the full range of hydro-climatic conditions considered whereas the base case operating plan is not as robust. The risks involved in the implementation of operating plans which exhibit large deviations from the base case operating plan are discussed. These risks highlight the importance of problem formulation and sensitivity analysis of the optimal operating plans in order to find real world solutions to real world problems. © CURRAN-CONFERENCE. All rights reserved.
- Authors: Godoy, Walter , Barton, Andrew , Wilson, K. , Perera, B.
- Date: 2018
- Type: Text , Conference paper
- Relation: 2018 Hydrology and Water Resources Symposium: Water and Communities, HWRS 2018 p. 267-283
- Full Text:
- Reviewed:
- Description: A key challenge for water resources planning processes around the world is to develop operating plans that are optimal under a range of hydro-climatic conditions. The consequences of such long term planning decisions can vary in terms of the social, economic, and environmental impacts. Given these potential impacts, it is important that operating plans are tested under a range of hydro-climatic conditions to ensure that they are sufficiently robust to withstand future changes in climate. The aim of this study is to present a procedure for testing the robustness of optimal operating plans for complex water resources systems using a combined multi-objective optimisation and sustainability assessment approach. The approach embeds an optimisation-simulation (O-S) model which is applied to an 18-objective function multi-objective optimisation problem of the Wimmera-Mallee Water Supply System (WMWSS). The WMWSS is a multi-reservoir system located in Western Victoria (Australia) which is operated to meet a range of competing interests for water using complex operating rules. The O-S model is applied to the WMWSS to search for optimal operating plans over a 100-year period into the future assuming two plausible greenhouse gas (GHG) emission levels. The two GHG emission scenarios represent lower and higher ends of the estimated range of projected GHG emissions, providing a wide range of future hydro-climatic conditions. A robustness test is used to evaluate the validity of the most sustainable optimal operating plans under the two GHG emmission scenarios and also those found previously under a historic hydro-climatic sequence. The test results show that the status quo or base case operating plan is optimal but is neither the highest nor the lowest in terms of the level of sustainability that could be achieved in the WMWSS, under historic and the higher GHG emission scenario. Moreover, the results show that the most sustainable optimal operating plans found under the three hydro-climatic scenarios are sufficiently robust to withstand the full range of hydro-climatic conditions considered whereas the base case operating plan is not as robust. The risks involved in the implementation of operating plans which exhibit large deviations from the base case operating plan are discussed. These risks highlight the importance of problem formulation and sensitivity analysis of the optimal operating plans in order to find real world solutions to real world problems. © CURRAN-CONFERENCE. All rights reserved.
A weighted sustainability index for selection of optimal operating plans
- Godoy, Walter, Barton, Andrew, Perera, B., Szemis, J.
- Authors: Godoy, Walter , Barton, Andrew , Perera, B. , Szemis, J.
- Date: 2017
- Type: Text , Conference paper
- Relation: 22nd International Congress on Modelling and Simulation: Managing Cumulative Risks through Model-Based Processes, MODSIM 2017 - Held jointly with the 25th National Conference of the Australian Society for Operations Research and the DST Group led Defence Operations Research Symposium, DORS 2017 p. 1378-1384
- Full Text:
- Reviewed:
- Description: The Wimmera Mallee Pipeline Project (WMPP) provides reticulated water to 36 towns and about 6000 farms across an area of approximately 2 million hectares and forms part of the Wimmera-Mallee Water Supply System (WMWSS). The WMWSS is a multi-reservoir system located in Western Victoria (Australia) which is operated to meet a range of conflicting interests for water using complex operating rules. Since completion in 2010, the pipeline has vastly improved efficiencies in the supply of water, with water savings being returned to the environment, existing consumptive use and new development. However, one of the major challenges for managers of these water recovery projects is to determine the most effective or optimal operational strategy to meet the needs of all water users. In Victoria, these often conflicting interests to water have traditionally been addressed through a consultative process supported by surface water simulation modelling. Simulation models attempt to represent all the major characteristics of a system and are suited to examine “what if?” scenarios. Whilst such models are highly effective in demonstrating the effect of changes in system operation, the modelling process is limited to finding one solution at a time for a given set of conditions. Optimisation models have also proven to be effective tools but unlike simulation models are characterised by a numeric search technique and are better suited to address “what should be?” questions. In recent times there has been growing interest in linking optimisation techniques with simulation models in order to build on the strengths of both modelling approaches in the search for optimal solutions. The general structure of this combined modelling technique provides for an iterative process; simulation outputs are used to quantify the effect of candidate solutions which are in turn passed to the search engine to find optimal solutions. The process of selecting the most preferred optimal solution brings together two aspects of multi-objective optimisation, namely; (i) the quantitative characteristics of these solutions relative to other solutions; and (ii) the higher level qualitative information in the form of stakeholders’ preferences. The aim of this study is to incorporate stakeholder preferences into a sustainability index which has been previously used to evaluate and compare optimal operating plans for the WMWSS. In that previous study, Godoy et al. (2015) applied a multi-objective optimisation and sustainability assessment approach to an 18-objective function multi-objective optimisation problem (MOOP) which represented a range of interests for water. For the present study, the same interests are described in terms of three broad categories i.e. strong environmental preferences, strong social preferences, and strong preferences for the needs of consumptive users. A weighted sustainability index is presented which incorporates these preferences in the original sustainability index formulation. This weighted sustainability index is used to select preferred optimal operating plans previously found by the optimisation-simulation modelling. The results showed that the weighted sustainability index provided a simple means to incorporate stakeholders’ preferences into the selection process and inform the decision maker of a stakeholder’s uncertainty about their values and priorities for water. © 2017 Proceedings - 22nd International Congress on Modelling and Simulation, MODSIM 2017. All rights reserved.
- Authors: Godoy, Walter , Barton, Andrew , Perera, B. , Szemis, J.
- Date: 2017
- Type: Text , Conference paper
- Relation: 22nd International Congress on Modelling and Simulation: Managing Cumulative Risks through Model-Based Processes, MODSIM 2017 - Held jointly with the 25th National Conference of the Australian Society for Operations Research and the DST Group led Defence Operations Research Symposium, DORS 2017 p. 1378-1384
- Full Text:
- Reviewed:
- Description: The Wimmera Mallee Pipeline Project (WMPP) provides reticulated water to 36 towns and about 6000 farms across an area of approximately 2 million hectares and forms part of the Wimmera-Mallee Water Supply System (WMWSS). The WMWSS is a multi-reservoir system located in Western Victoria (Australia) which is operated to meet a range of conflicting interests for water using complex operating rules. Since completion in 2010, the pipeline has vastly improved efficiencies in the supply of water, with water savings being returned to the environment, existing consumptive use and new development. However, one of the major challenges for managers of these water recovery projects is to determine the most effective or optimal operational strategy to meet the needs of all water users. In Victoria, these often conflicting interests to water have traditionally been addressed through a consultative process supported by surface water simulation modelling. Simulation models attempt to represent all the major characteristics of a system and are suited to examine “what if?” scenarios. Whilst such models are highly effective in demonstrating the effect of changes in system operation, the modelling process is limited to finding one solution at a time for a given set of conditions. Optimisation models have also proven to be effective tools but unlike simulation models are characterised by a numeric search technique and are better suited to address “what should be?” questions. In recent times there has been growing interest in linking optimisation techniques with simulation models in order to build on the strengths of both modelling approaches in the search for optimal solutions. The general structure of this combined modelling technique provides for an iterative process; simulation outputs are used to quantify the effect of candidate solutions which are in turn passed to the search engine to find optimal solutions. The process of selecting the most preferred optimal solution brings together two aspects of multi-objective optimisation, namely; (i) the quantitative characteristics of these solutions relative to other solutions; and (ii) the higher level qualitative information in the form of stakeholders’ preferences. The aim of this study is to incorporate stakeholder preferences into a sustainability index which has been previously used to evaluate and compare optimal operating plans for the WMWSS. In that previous study, Godoy et al. (2015) applied a multi-objective optimisation and sustainability assessment approach to an 18-objective function multi-objective optimisation problem (MOOP) which represented a range of interests for water. For the present study, the same interests are described in terms of three broad categories i.e. strong environmental preferences, strong social preferences, and strong preferences for the needs of consumptive users. A weighted sustainability index is presented which incorporates these preferences in the original sustainability index formulation. This weighted sustainability index is used to select preferred optimal operating plans previously found by the optimisation-simulation modelling. The results showed that the weighted sustainability index provided a simple means to incorporate stakeholders’ preferences into the selection process and inform the decision maker of a stakeholder’s uncertainty about their values and priorities for water. © 2017 Proceedings - 22nd International Congress on Modelling and Simulation, MODSIM 2017. All rights reserved.
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