Shiroma Maheepala

Monthly Hydrologic Data Generation by Disaggregation

Abstract Stochastically generated hydrologic data have been used in the past by water worhorities world-wide for long-term planning of water resources development projects. These data are also currently being used in short- and medium-term planning and operation of water resource systems. For valid and realistic results, it is necessary that the generated data sequences preserve all statistical properties of historical data. This paper presents an improved disaggregation method for generation of alternative sequences of monthly hydrologic data. The method is designed explicitly to preserve the over-year monthly serial and cross correlations, in addition to other monthly and annual parameters of the historic sequence. The method is applied to both single-site and multi-site cases, and compared with two other disaggregation models that are used in Australia. The comparison of results shows that the developed method satisfactorily preserves both monthly and annual statistical parameters of the historic data sequences including the over-year monthly correlations.

Adapting to climate change through urban water management: a participatory case study in Indonesia

The benefits of integrated approaches to climate risk and adaptation studies are increasingly recognised. Thus, there is an increasing need for practical examples of such work in the literature. This paper describes a practical application of an integrated framework for climate change impacts on regional surface water resources and the urban water system in the Mamminasata metropolitan region, Indonesia. Two main features of the framework are: the integration of both climate and other physical and social considerations in the assessment; and the high stakeholder involvement before, during and after project implementation. Although the study is concerned with the Mamminasata region, the overall methodology is transferable to any region in Indonesia or internationally. Key outcomes from this study are: (1) creation of information for Mamminasata planners and water resources managers for when, and under what conditions, the water supply may or may not meet the demand; (2) a clear consensus and shared learning of the problems facing the region among cross-institutional stakeholders; and (3) identification of adaptation options for the urban water system and knowledge gaps and strategies for their implementation. Results of stakeholders’ surveys conducted at the mid-point and at the end of the study indicate that these outputs will provide valuable guidance for future planning and management of Mamminasata regional water resources.

Utilising integrated urban water management to assess the viability of decentralised water solutions

Cities worldwide are challenged by a number of urban water issues associated with climate change, population growth and the associated water scarcity, wastewater flows and stormwater run-off. To address these problems decentralised solutions are increasingly being considered by water authorities, and integrated urban water management (IUWM) has emerged as a potential solution to most of these urban water challenges, and as the key to providing solutions incorporating decentralised concepts at a city wide scale. To incorporate decentralised options, there is a need to understand their performance and their impact on a citys total water cycle under alternative water and land management options. This includes changes to flow, nutrient and sediment regimes, energy use, greenhouse gas emissions, and the impacts on rivers, aquifers and estuaries. Application of the IUWM approach to large cities demands revisiting the fundamental role of water system design in sustainable city development. This paper uses the extended urban metabolism model (EUMM) to expand a logical definition for the aims of IUWM, and discusses the role of decentralised systems in IUWM and how IUWM principles can be incorporated into urban water planning.

A technical decision-making framework: stormwater as an alternative supply source

Stormwater harvesting is a relatively new concept which has developed using traditional stormwater management practices as well as water resourcing and holistic water management concepts. While stormwater harvesting systems have been designed and constructed in the past, the planning and design processes have not followed an integrated approach. This paper addresses this issue and describes a decision-making framework (DMF) that determines the most appropriate stormwater harvesting scheme option based primarily on technical feasibility and financial costs with a focus on neighbourhood-scale development. A case study of an existing urban area in the suburb of Sunshine in Melbourne, Australia, was conducted to demonstrate the DMF. Comparison of all stormwater harvesting scheme options determined that while one scheme option was the most effective option in terms of cost, reliability, quantity of stormwater used and end uses met, several other options could also be examined further for detailed analysis.

Including stakeholder input in formulating and solving real-world optimisation problems

Multi-objective evolutionary algorithms (MOEAs) are becoming increasingly popular for solving formal environmental and water resources optimisation problems. In the past, the focus of these studies has generally been on methodological issues related to the optimisation algorithm. However, in recent years, there has been increased recognition of the need to apply these approaches to real-world problems to facilitate the realisation of their full potential. In order to assist with this, a framework for including stakeholder input in real-world optimisation problems is introduced in this paper, including a conceptual framework and a procedure for implementing it. The framework is applied to an urban water supply security study for Adelaide, South Australia. This study highlights the role of stakeholder input at the various stages of the optimisation process, as well as the resulting changes in the formulation, analysis and results. A discussion of the lessons learnt from the case study is also provided. Framework for including stakeholder input in evolutionary algorithm optimisation.Stakeholder input included at all stages of optimisation process.Framework applied to urban water supply security study in Adelaide, South Australia.

Can stormwater harvesting restore pre-development flows in urban catchments in South East Queensland?

Increases in the impervious area due to urbanisation have been shown to have negative impacts on the physical and ecological condition of streams, primarily through increased volume and frequency of runoff. The harvesting and detention of runoff has a potential to decrease this impact. This paper describes the effects of urbanisation on catchment flow and of stormwater harvesting on reducing those adverse impacts on a stream in South East Queensland (SEQ), Australia. A largely undeveloped catchment located southeast of Brisbane city was calibrated and validated using the Stormwater Management Model (SWMM). This model was used to investigate the effect of a range of future increases in urbanisation (represented by impervious area) on stream hydrology as well as the potential of stormwater harvesting to return the catchments to predevelopment flow conditions. Stormwater harvesting was modelled according to flow frequency measures specified in current SEQ development guidelines. These guidelines stipulate the capture of the first 10 mm of runoff from impervious areas of 0-40% and the first 15 mm from impervious areas of 40% or greater for urban developments. We found that increases in the impervious area resulted in increases in the mean, frequency and duration of high flows, and an increase in the mean rate of rise and fall for storm events in the catchment. However, the predevelopment (non-urbanised) flow distribution was very flashy in comparison with all urbanised scenarios; i.e. it had the quickest response to rainfall indicated by a high rate of rise to and fall from peak flow volume, followed by a return to zero flow conditions. Capturing the runoff according to the development guidelines resulted in a reduction in flow towards the flow distribution of a lower impervious area, however this was insufficient to meet predevelopment conditions. This suggests a stronger influence of impervious areas in this catchment on the volume of runoff than flow frequency measures are able to ameliorate.

Examining the Technical Feasibility of Using Stormwater as an Alternative Supply Source within an Existing Urban Area - a Case Study

Abstract Due to pressure on urban water supplies, stormwater has increasingly been considered as a resource. This view provides opportunities to use stormwater within urban areas. However, there is still limited understanding of how a stormwater use scheme can be implemented, particularly in existing urban areas. A decision making framework to investigate the viability of potential stormwater use scheme options was developed. This framework examines the feasibility of stormwater use in urban areas at a cluster or neighbourhood scale. This paper describes how the decision making framework was adapted to a case study in the suburb of Sunshine in Melbourne, Victoria, and demonstrates how this framework can be applied to a residential urban area. Comparison of all stormwater use scheme options determined that, while one scheme option was the most effective option in terms of cost, reliability, quantity of stormwater used and end uses met, several other options could also be examined further for detailed analysis. As the decision making framework is developed further, additional issues such as environmental, social and economic could be examined.

An object-oriented approach to the integrated planning of urban development and utility services

Abstract This paper describes an object-oriented model for the integrated planning and management of land resources and utilities-related services. The model facilitates thorough evaluation of scenarios involving land use, and delivery of utilities such as water, gas, telephone and electricity. It therefore provides a mechanism for generating alternative urban development patterns in search of lower utility costs. Furthermore, this approach presents a platform for evaluating the multitude of management options that address economic, social, environmental and institutional aspects of utilities-related developments within an urban environment.

A Framework for Short-term Operational Planning for Water Grids

Water grids are emerging as a response to water scarcity in many urban areas. These grids are comprised not only of traditional surface and groundwater supplies, but also alternative, climate-independent water sources such as desalination and wastewater recycling, as well as one and two-way pipelines connecting surface-water supplies in different regions. The complexity and heterogeneity of these water supply networks brings new challenges to water management. Water managers need to determine strategies to operate the system in terms of multiple objectives, subject to uncertainty and boundary conditions relating to climate, demand and infrastructure. This paper outlines a framework of methodologies for developing optimal operating plans for short-term planning for water grids, in terms of the objectives of interest.

Identification of Optimal Water Supply Portfolios for a Major City

AbstractIntegrated urban water management (IUWM) considering alternative water supply options is attracting increasing attention from water resources managers due to its efficiency and flexibility ...