Description:
Water distribution systems have a very long and rich history dating back to the third millennium B.C. Advances in water supply and distribution were followed in parallel by discoveries and inventions in other related fields. Therefore, it is the aim of this paper to review both the history of water distribution systems and those related fields in order to present a coherent summary of the complex multi-stranded discipline of water engineering. Related fields reviewed in this paper include devices for raising water and water pumps, water quality and water treatment, hydraulics, network analysis, and optimisation of water distribution systems. The review is brief and concise and allows the reader to quickly gain an understanding of the history and advancements of water distribution systems and analysis. Furthermore, the paper gives details of other existing publications where more information can be found.
Description:
The operation of a water distribution system is a complex task which involves scheduling of pumps, regulating water levels of storages, and providing satisfactory water quality to customers at required flow and pressure. Pump scheduling is one of the most important tasks of the operation of a water distribution system as it represents the major part of its operating costs. In this paper, a novel approach for modeling of pump scheduling to minimize energy consumption by pumps is introduced which uses pump's start/end run times as continuous variables. This is different from other approaches where binary integer variables for each hour are typically used which is considered very impractical from an operational perspective. The problem is formulated as a nonlinear programming problem and a new algorithm is developed for its solution. This algorithm is based on the combination of the grid search with the Hooke-Jeeves pattern search method. The performance of the algorithm is evaluated using literature test problems applying the hydraulic simulation model EPANet.
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
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.
Description:
Abstract Water resource development has played a crucial role in the Grampians, Wimmera and Mallee regions of Australia, with the main source of surface water located in several reservoirs in the Grampians mountain ranges. Historically, water was delivered by gravity through a vast 19 500 km earthen channel system from the reservoirs to the townships and farms. As a result of the severe and protracted drought experienced in the region over the past 13 years and the projected drying climate, there have been fundamental changes made to the management of water in order to better cope with water scarcity. The primary strategic effort to sustainably manage water resources was by removing the unsustainable transport of water via the open channels which resulted in very high losses through seepage and evaporation. This inefficient system has been replaced by a pressurised pipeline, the largest geographical water infrastructure project of its type in Australia, spreading across an area of approximately 20 000 km2. To manage the change in water balance as a result of the pipeline and drying climate, the regions water corporations and environmental agencies have designed a scheme for water allocations intended to sustain local communities, allow for regional development and improve environmental conditions. This paper describes the unique pipeline system recently completed, provides a brief summary of water sharing arrangements and introduces the research program currently underway to optimise the performance of the pipeline system.
Description:
Abstract Water resource development has played a crucial role in the Grampians, Wimmera and Mallee regions of Australia, with the main source of surface water located in several reservoirs in the Grampians mountain ranges. Historically, water was delivered by gravity through a vast 19 500 km earthen channel system from the reservoirs to the townships and farms. As a result of the severe and protracted drought experienced in the region over the past 13 years and the projected drying climate, there have been fundamental changes made to the management of water in order to better cope with water scarcity. The primary strategic effort to sustainably manage water resources was by removing the unsustainable transport of water via the open channels which resulted in very high losses through seepage and evaporation. This inefficient system has been replaced by a pressurised pipeline, the largest geographical water infrastructure project of its type in Australia, spreading across an area of approximately 20 000 km2. To manage the change in water balance as a result of the pipeline and drying climate, the regions water corporations and environmental agencies have designed a scheme for water allocations intended to sustain local communities, allow for regional development and improve environmental conditions. This paper describes the unique pipeline system recently completed, provides a brief summary of water sharing arrangements and introduces the research program currently underway to optimise the performance of the pipeline system.
Description:
Forecasting supply and demand is fundamental to the sustainability of the water system. Demand for urban water seems on an ever-upward trajectory, with use increasing twice as quickly as population throughout the 20th century. However, data from Ballarat, a city in south-eastern Australia, show that despite this conventionally held wisdom, total water usage actually peaked over 30 years ago. While the 1997–2009 ‘Millennium Drought’ had some effect, the decline commenced many years before. Initially, this was due to a reduction in external domestic water use, which correlates well with an increase in water price. However, the effect was found to not be purely economic as the price was not volumetric-based. Internal water use seems more affected by technological advances and regulatory controls. Interestingly, there was no relationship found between rainfall and water demand. The role of price, water-reduction education programmes, water-efficient technology and regulation supports previous research that a multifaceted approach is required when developing demand-reduction policies and strategies. This finding emphasises the importance of understanding the component of consumptive behaviour being targeted, and ensuring that policies being implemented are appropriate for the desired behavioural change.
Description:
The Cressy-Longford Irrigation Scheme delivers irrigation water supply from the outfall of Poatina Tailrace on Tasmania's Central Highlands Hydroelectric Power Scheme, to the agricultural region surrounding the towns of Cressy and Longford in North Eastern Tasmania. The scheme delivers approximately 10 000 ML of water annually to a land district of 10 000 ha. The scheme consists of mostly open, earth lined channels, with sections of concrete lined channel, pipeline, culverts, drop pipes, and siphons or drop siphons where required for hydraulic design purposes or to provide road access and crossings. The system consists of over 100 km of channel and pipe, in a network of 17 distinct channel sections. The full system and its subcomponents have been modelled, using the generally available package, HEC-RAS, to model open channel sections, approximate pipe performance and to model the network operation under various scenarios. The performance of pipe and culvert sections was independently checked using spreadsheet analysis. The objective of the analysis was to determine the maximum capacity of the system in its current state; determine restrictions to the flow of water through the network; and to identify strategies to increase the capacity to deliver water by at least 30 %. The key restraints on the analysis were to ensure that any increased volume of water carried into the network could be safely discharged out of the network to adjoining natural watercourses in the event that irrigation was suddenly stopped and/or water input to the system increased, for example in the event of a sudden rainstorm. It was found that the system was currently underutilised, and that in most cases the culverts were capable of running full, which greatly increased the possible flow rates allowable in the system. Acoustic Doppler Velocimeter measurements in sections of the channel were used to verify modelled flow rates.
Description:
The physical roughness of a surface changes when freshwater biofilms colonize and grow on it and this has significant implications for surfaces enclosing water conveying systems such as pipelines and canals. Plates with surfaces initially artificially roughened with varying grit size were deployed in an open channel system and biofilms were allowed to grow on the exposed surface. The plates were retrieved at intervals in time and their surfaces mapped using close range photogrammetry. For a fine grit surface (0.5-4 mm particles), diatom-dominated biofilms initially grew between the roughness elements; they subsequently developed as a mat to create a physically smoother outer surface than the underlying rough surface. For a coarse grit surface (2-4 mm), biofilms colonized faster; in one instance, larger clumps of biofilm were observed as transverse ripples across the plate.
Description:
Pumping cost constitutes the main part of the overall operating cost of water distribution systems. There are different optimization formulations of the pumping cost minimization problem including those with application of continuous and integer programming approaches. To date mainly various metaheuristics have been applied to solve this problem. However, the comprehensive comparison of those metaheuristics has not been done. Such a comparison is important to identify strengths and weaknesses of different algorithms which reflects on their performance. In this paper, we present a methodology for comparative analysis of widely used metaheuristics for solving the pumping cost minimization problem. This methodology includes the following comparison criteria: (a) the "optimal solution" obtained; (b) the efficiency; and (c) robustness. Algorithms applied are: particle swarm optimization, artificial bee colony and firefly algorithms. These algorithms were applied to one test problem available in the literature. The results obtained demonstrate that the artificial bee colony is the most robust and the firefly is the most efficient and accurate algorithm for this test problem. Funding :ARC