Topic 1 – Global approaches to asset management

Chair:  Franz Schulting & Helena Alegre


TVW infrastructure investment planning process – use of forecasting and uncertainty modelling tools

E. Algaard*, P. Campbell*, P. Chadwick** & S. Pochet*, K. Winfield**

* Three Valleys Water, Three Valleys Way, Bushey, WD23 2LG, UK,

** Mott MacDonald, Station Road, Cambridge, CB1 “RS, UK


Abstract Three Valleys Water (TVW) has carried out a pilot study in collaboration with the consultant Mott MacDonald to identify and quantify the areas of uncertainty surrounding the TVW infrastructure investment programme in order to estimate the risk associated with Three Valleys Water investment decisions. The risk based approach includes an assessment of the likelihood of an asset failure and the consequence of that failure, and is based on models and methodologies developed in house using comprehensive data sets. The objectives of the pilot study were (1) to incorporate uncertainty and optimisation into TVW existing models mainly its “Burst Model” and “Investment Model”, (2) to assess the impact of data or model uncertainty on performance targets and cost optimisation at a strategic level and (3) to achieve a bottom up optimisation of pipe renewals, allowing for uncertainty in key parameters such as the burst model predictions and assumed water savings from leakage control activities. Analysis and modelling of the uncertainties identified were carried in Crystal Ball 2000®. The TVW investment model was also transferred into OpQuest®, a global optimisation software that works with Crystal Ball models to find an optimal choice for a given decision variable, constraints and objectives. The decision variable considered was the length of renewal for each year. The objective of the optimisation was to identify the scenario which minimised the mean of the cumulative total capital plus operational expenditure net present value and satisfying a maximum number of constraints such as the requirement for the total renewal length between [2005; 2010] to be lower or equal to a target renewal length or for the number of bursts to be lower than the burst level targeted. The results of the pilot project to integrate uncertainty modelling and option optimisation into TVW infrastructure investment model are very promising. The suite of tools developed represents a significant advance on current practice, enabling TVW to better exploit the risk trade-offs in its decision making and allows a level of certainty to be assigned to investment decisions.

Keywords Monte Carlo analysis; performance indicator; risk; uncertainty modelling; whole life cost model

<Back to Topic 1>


Whole life cost optimisation model for water distribution systems: using modelling optimisation techniques to explore cost effective mains rehabilitation in Kampala City, Uganda

H. Mutikanga*, J. Sseguya** & K. Vairvamoorthy***  

* National Water and Sewerage Corporation, P.O. Box 7053 Kampala, Uganda,
** UNESCO-IHE P.O Box 3015,2601 DA Delft, Nertherlands,

*** UNESCO-IHE P.O Box 3015, 2601 DA Delft, Nertherlands


Abstract As the assets in the ground continue to age, concern is growing about their continuing performance and the risks of future failure. Like most other utilities, water authorities must manage many aging capital assets that are in varying degrees of deterioration; some of which are nearing the end of their useful lives. Rehabilitation and or/ replacement of deteriorating pipe components demands huge sums of money from annual budgets of water utilities worldwide and yet the funds available for rehabilitation of these assets is limited. It is important, therefore that the available funds are used in the most effective manner. In order to ensure that the available funds are used in the most effective manner, it is important that their capital maintenance decisions not only reflect costs borne now but also the likely costs in the future, and how these can be optimised. This paper attempts to address the issue of optimal Whole Life Costing (WLC) rehabilitation and maintenance strategy of water distribution assets using genetic algorithm technique. The whole life cost approach for rehabilitation and maintenance of water distribution systems is aimed to optimise the present value of pipe replacement, repairs and cleaning costs over a defined analysis period while requirements for water standards are fulfilled. The WLC analysis depicts a rehabilitation strategy over a defined analysis period together with the corresponding cost profile. A case study in Kampala City, Uganda demonstrates that the genetic algorithm can assist in planning of rehabilitation of water distribution systems.


Keywords asset management; whole life cost optimisation; mains renewal; water distribution modelling

<Back to Topic 1>


Application of a DPA method for asset management in small water distribution systems

P. Barata*, H. Alegre** & J. Vieira***

* University of Minho, Campus de Gualtar, 4710 - 057 Braga, Portugal,

** National Laboratory of Civil Engineering, Av. Brasil, 101, 1700-066-Lisboa, Portugal,

*** University of Minho, Campus de Gualtar, 4710 - 057 Braga, Portugal,


Abstract This paper describes a decision support algorithm for assisting in establishing infrastructure investment plans of small water systems. It describes the methodology adopted and the key features of the prototype computer application developed. It refers to an academic study that was carried out in collaboration with a Portuguese research centre and a private water supply service provider. A deterioration point assignment (DPA) method was adopted because DPA methods are particularly suitable for application to systems characterized by lack of pertinent information, which is typically the situation in small utilities. The water distribution network of a Portuguese village, Marco de Canaveses, is presented as case study, serving as a basis for discussion and demonstration of model applicability.

Keywords asset management; rehabilitation; water infrastructures; small systems; decision-support tool

<Back to Topic 1>


A novel methodology to prioritize investment proposals

H. Alegre*, D. I. C. Covas**, A. J. Monteiro*** & P. Duarte****

*    LNEC - National Laboratory of Civil Engineering, Av. Brasil, 101, 1700-066 Lisbon, Portugal,

**   Instituto Superior Técnico, Technical University of Lisbon, Av. Rovisco Pais, 1049-001-Lisbon, Portugal,

***   Instituto Superior Técnico, Technical University of Lisbon, Av. Rovisco Pais, 1049-001-Lisbon, Portugal,

**** LNEC - National Laboratory of Civil Engineering, Av. Brasil, 101, 1700-066 Lisbon, Portugal,


Abstract This paper tackles the problem of establishing prioritization of alternative water rehabilitation investment plans. In mature systems, the planning department is often faced with the problem of selecting investment proposals submitted by different departments, all of them contributing to meet the strategic and tactic corporate objectives, but none of them being critical to meet the service or legal requirements in the short term. This was the frame of the applied research project described herein. In this context, a conceptual model and worksheet-based operational prototype were developed and tested, incorporating the key objectives, assessment criteria and performance measures. A whole-of-life risk-based approach was adopted, including direct, indirect and external costs. A Business Risk Exposure (BRE) technique was used to quantify the main technological and operational risks. The investment benefits are assessed subtracting the global costs of each investment scenario from the corresponding costs of the statu quo. Given that this decision support tool should be applicable to assets of different types (e.g., pipes, pumping stations, storage tanks and treatment facilities), sensitivity analyses were carried out in order to identify, for each asset type, the main cost items to be considered, as a minimum set, in simplified applications of the developed model.  Comparisons between alternative investment proposals require that a single period of analysis is adopted. The selection of this period is not obvious when different asset types, each with different expected useful lives, are involved. Sensitivity analyses were carried out in order to get a better insight of this problem. Finally, alternative prioritization criteria were explored, concluding that investment prioritization should be based on a simple ranking of the total direct relative benefits (i.e., total benefits / capital investment); however, indirect benefits should always be taken into consideration in the final decision.

Keywords asset management; water infrastructure; investment; support tool

<Back to Topic 1>


Scheduling renewal of water supply distribution system – a case study in Portugal

A. J. Monteiro*, A. M. Luís**, A. T. Silva***, J. Sereno****, L. Marçal***** & A. B. Franco******

* ENGIDRO Partner, R. Luis Cristino da Silva, LT 248, 2º 98E, 1950-172-Lisboa, Portugal

** Management Planning and Control, EPAL, Av. da Liberdade, 24, 1250-144-Lisboa, Portugal,

*** ENGIDRO Consultant, R. Luis Cristino da Silva, LT 248, 2º 98E, 1950-172-Lisboa, Portugal

**** Distribution Operation Department, EPAL,  Av. da Liberdade, 24, 1250-144-Lisboa, Portugal,

***** New Supplies Department, EPAL, Av. da Liberdade, 24, 1250-144-Lisboa, Portugal,

****** Managing Board Director, EPAL, Av. da Liberdade, 24, 1250-144-Lisboa, Portugal,


Abstract Many water distribution systems are dealing with the problem of aging infrastructures, and maintaining the efficiency levels of their systems has triggered a number of challenges, like the scheduling of the renewal of the water supply infrastructure, along with the definition of the investment priorities. In 2006, a methodology to define the schedule of renewal of the Lisbon water supply distribution system was developed supported on different approaches: one based on the pipe life cycle analysis, and another based on a multi-criteria analysis. The former took into account mainly pipe failure data analysis in Geographic Information System (GIS), described by the following steps: 1) the pipe failure analysis was made by diameter segments (DN<400 mm and DN>=400 mm); 2) a deterioration model for each diameter segment and pipe material was defined; 3) each unit area (DMA) was classified according to their behaviour age; 4) according to the expected behaviour, an evaluation of the pipe whole life cost is made, for different asset life-time periods; 5) renewal decision was based on the use of the residual asset-life time that minimize the total expected costs. An evaluation of the pipe failures externalities in terms of % of the GDP per capita of the clients affected is presented and the results are compared with pipe failure rate benchmark used by the Portuguese regulator. In the multi-criteria analysis, different physical criteria were taken into account, as well as economic criteria: expected asset life time; water supply reliability; importance of the pipe for the operational flexibility; performance; and repair vs. renewal costs..  An application example of multi-criteria analysis, also using GIS tools, is presented. Finally, the results obtained from the application of each methodology are compared and discussed.

Keywords asset management; deterioration model; life cycle analysis; multi-criteria analysis; water infrastructure renewal

<Back to Topic 1>



Topic 2 – Institutional, organisational and research aspects

Chair: Steve Albee


Developing a sustainability management plan for water supply within Sarawak, Malaysia

K.Jones* & D.Cox**

* Cardno (Qld) Pty Ltd, Level 1, 5 Gardner Close, Milton QLD 4064, Australia,

** Cardno (Qld) Pty Ltd, Level 1, 5 Gardner Close, Milton QLD 4064, Australia,


Abstract The Sarawak State Government of Malaysia undertook a major review of water supply services provided within Kuching City and the adjoining districts within the Kuching and Samaraham Divisions of Sarawak during 2005.  Commencing in late 2006, the State Government extended the study to cover all water supply systems within the State.  The review was greatly assisted by technical assessment, leakage studies and development of Strategic Asset Management Plans for the agencies providing potable water supplies throughout the state.  During late 2006 and extending into 2007, the project was extended to the rest of the State.  The Strategic Asset Management Planning process used is based on the Queensland State Guidelines for Total Management Planning.  The Total Management Planning process quantifies all operational and management requirements in providing water services and brings together all matters critical to successful service delivery.  It addresses continuous improvement on a range of fronts.  This ensures that the role of all components for service delivery are addressed and prioritised through looking at the ‘big picture’ rather than reacting mechanically to a range of initiatives, many of which are extremely driven.  Most of all, the Total Management Plan is a working document for management.  It is successful because management see it as being essential for their needs.  It has been developed to improve water utility performance from within, rather than as an externally imposed requirement.  It is to be used as a basis for water reform in Sarawak.

To assist in effective management of its assets, the Sarawak Government required a process that would:

·   Provide a systematic blueprint for future planning and management;

·   Allow a shared corporate knowledge of relevant issues and agreed, integrated strategies to address technical, environmental, managerial and financial issues;

·  Enable the development of agreed strategies for managing the potential risks and liabilities, such as ageing infrastructure and its financial and service level impacts;

·  Provide a logical and defensible basis for making planning and management decisions;

·  Be a core tool for sustainable management and improved service delivery; and

·  Allow continuous improvement in strategic asset management process.

While the planning process contained all the elements of a more traditional asset management approach, the development process placed additional emphasis on customer focussed outcomes, business re-engineering and enhancement of quality management systems.  The Sarawak Government now has a management plan that has identified both the intermediate change management strategies as well as the long-term requirements for meeting service requirements and associated management, operational and investment strategies.

The paper will outline the investigation processes used and how the key recommendations of the initial study is leading to a new structure for the water industry in Sarawak and how the subsequent studies are resulting in improved prioritisation of investment in water supply.

Keywords asset management; business planning; capacity building sustainability; strategic management planning; technical assessment; water

<Back to Topic 2>


Challenges in asset management of the water supply and wastewater infrastructure in the Republic of Bulgaria

V.  Nikolov* & T. Peitchev**

* Assoc. Prof. Dr., President, Bulgarian Water Association, 1 H. Smirnenski Blvd., Sofia 1046, Bulgaria,  

** Prof. Dr. Eng., Vice President, Bulgarian Water Association, 1 H. Smirnenski Blvd., Sofia 1046, Bulgaria,


Abstract  As of 1 January 2007, Bulgaria is a full member of the European Union, with all rights and obligations ensuing from this. By 1989 the Water Supply and Wastewater (WSW) sector (water sector) in Bulgaria was featuring the following characteristics:

·       Public ownership of all infrastructural assets;

·       The operation of the water supply and wastewater systems as well as the water services were performed by one and the same companies;

·       Equal price of water over the country;

·       Large-scale research and technological activities;

·       The large WSW engineering projects were designed by the national design institute Vodokanalproekt;

·       The operation of the WSW systems was performed by two big public companies (operators), who were owners of the assets of the systems:

o      WSW company – for Sofia city;

o      WSW directorate – with 27 branches in all administrative regions.

In May 1989, WSW Directorate was closed and the establishment of municipal and regional WSW companies started, which brought about some negative consequences that are continuing nowadays.

Attempts for drawing up a law on water supply and wastewater are being made in the last years. The sector needs badly such an act.

The aim of the paper is to make critical professional assessment of the historical and current management of the WSW sector, and to recommend variants of an optimal management structure.


Keywords  sewerage; wastewater; water sector management; water supply

<Back to Topic 2>


Models of regional or municipal Public-Private Partnership (PPP) in order to favour the industrialization of the Integrated Water Service in the ATO's of Southern Italy

C. Arena*, M. Genco** & M. R. Mazzola***

* Consulting engineer, Via Libertà 56 - 90143 Palermo (Italy), Tel. +39 (091) 301969,

** Consulting engineer, Via Principe di Villafranca, 33 - 90141 Palermo (Italy), Tel. and fax: +39(0)91323529,

*** Professor of Hydraulic Constructions, Hydraulic Engineering and Environmental Applications Department, DIIAA, University of Palermo, Viale delle Scienze, 90128, Palermo (Italy), Tel: +39(0)9166577228, Fax: +39(0)916657714,


Abstract The paper assesses the critical issues in the industrialization of water services in southern Italy and introduces two PPP models, a regional company for bulk water service and a network company at the scale of the integrated water service (ISW – municipal water distribution, sewerage and wastewater treatment) as a means to overcome them. Within the general framework of the current national legislation providing the transfer via tenders of water service to contractors in charge of operation, maintenance and carrying out the investments to be paid back by tariffs under public regulation and control, critical aspects in the industrialization process of the water services are identified at different levels, starting from the drawbacks of the methodology prescribed for the assessment of the average tariff to the existence of long transients towards the steady-state phase during which contractors are demanded to undertake risks related to the very uncertain environment in which they are to operate, that are perceived as too high in comparison with the possible guarantees. PPP models can represent a way to share risk between public and private and to encourage investors. The two above mentioned PPP models are then introduced and briefly discussed: one at a regional level for the bulk water service and one at the ATO (Ambito Territoriale Ottimale – Optimal Territorial Ambit, an aggregation of municipalities) level for the management of public assets (network company). They can represent suitable operational models to share the risks related to the transition phase while assuring an effective public control and seizing all the opportunities of an industrial management of service without lowering the expected environmental and service quality targets. The simulation of the behaviour of the network companies in two sicilian ATOs shows that the achievement of consumers’ benefit (rate reduction) can be combined with increased operation returns, provided that the public company is able to offer a superior reliability level to the credit system.

Keywords asset management; competition; public-private partnership (PPP); bulk water service; tariffs

<Back to Topic 2>


Public private partnership models for developing water servicing

D. Stephenson* & G. Mokete**

* University of Botswana,

** University of Botswana,


Abstract The necessity for private partnerships in financing water services is discussed. Models are presented to discuss the role of different agencies in development. The extent of investment particularly in developing countries is lamented and ways of speeding the process investigated.

Keywords development; financing; privatization; water supply


<Back to Topic 2>


Asset management and regulation: the Portuguese case

J. M. Baptista*, J. S. Pires** & J. Almeida***

* Chaiman of the Board of Directors, IRAR – Instituto Regulador de Águas e Resíduos (Institute for the Regulation of water and waste services), Centro Empresarial Torres de Lisboa, R. Tomás da Fonseca, Torre G 8º piso, 1600-209 Lisbon, Portugal,

** Member of the Board of Directors, IRAR,

*** Head of Studies and Projects, IRAR,


Abstract The activities of water supply, wastewater treatment and urban solid waste management are public services of a structural nature essential to the general well-being, public health, environmental protection and the collective security of communities and businesses and environmental protection. These services should be governed by the principles of universal access, service continuity and quality, and cost efficiency and pricing equity.

In the absence of regulation, there are no incentives for operators to improve their efficiency and there is a risk of operators’ interests prevailing over those of users, with the risk that users will receive lower quality services at higher prices. Regulation is a mechanism that seeks to reproduce, in monopoly and highly concentrated markets, the efficiency results that would tend to be obtained naturally in competitive markets. It creates, in effect, a “virtual competition market”, inducing the operator to act in the public interest without jeopardising its economic and financial sustainability.

Asset management can be generally defined as the systematic activities, methodologies, supporting systems and practices undertaken by a company to optimise the life-time performance-to-cost ratio of assets. It is a field of interest to all heavily infrastructured industries, and calls for the convergence of multiple disciplines such as economic and financial analyses, engineering, statistics, risk management and information technology. Usually asset management involves the assessment of a system’s condition, strategy and goals definition, decision supporting tools, priority setting, the implementation of required initiatives and practices and the monitoring of results.

The relation between Asset Management and Regulation is manifest as the regulation procedures such as tariff definition carried out by regulators have clear consequences on the way companies manage their assets: the need to keep tariffs low forces companies to achieve optimum performance.

This paper presents IRAR’s view on the relation between the regulation practices and asset management


Keywords Regulation, asset management


<Back to Topic 2>



Topic 2 – Institutional, organisational and research aspects (contd.)

Chair: Chairmaine Quick


Research needs for Strategic Asset Management (SAM)

K. Rohrhofer*, E. Cabrera**, F. Cate***, Th. Derntl****, P. Gortan*****, A. Jovani****** & M. Olšinská*******

*   K. Rohrhofer, OEKOREAL, A-1170 Vienna, Carl Reichert-Gasse 28, Austria,

** E. Cabrera, University Valencia, Institute for Water Technology, ES-46071 Valencia, Camino de Vera   s/n. Apdo.22012, Spain,

*** F. Cate,  INTERIVAL,  A-1170 Vienna, Carl Reichert-Gasse 28, Austria,

****Th. Derntl, G.W.C.C. Regensburg, D-93059 Regensburg, Lappersdorfer Str. 28, Germany,

***** P. Gortan, Austrian Water, A-7540 Guessing, Europa Strasse 1, Austria,

****** A. Jovani, ERRU, Drinking Water & Sewerage Regulatory Entity, Tirana, Blvd. Zogu I Pare, P.57, Ap. 19, Albania,

******* M. Olšinská, BVS  a.s. Bratislavská vodárenská spoločnosť a.s., SK-826 46 Bratislava, Prešovská 48, Slovakia,


Abstract All Water and Wastewater Works in the world, both in “rich” (“developed”) and in “none rich” (“developing”) countries, manage their assets, often “automatically” using a not specified methodology for Asset Management (AM), when using / operating / maintaining their systems. But many of the system operators do not have a “strategy” to “manage” their assets: only few operate and maintain “strategically” according to Strategic Asset Management (SAM), tailor-made for their specific water supply and / or wastewater systems.

It is obvious that for the sustainability / the cost optimization / the efficiency of the assets of water supply and wastewater systems - and the utility as a whole - a clearly specified SAM is of highest importance. Whilst for Benchmarking and Assessment of the Quality of the provided Services worldwide activities - among the utilities / operations / their associations / politicians / funding and financing organisations / NGOs - are “well accepted” / “requested” / “preconditions for contracting”, in many countries in the world, the principles of AM/SAM are not so well-known and seldom “established” / “requested” / “ institutionalized”.

The research needs for Strategic Asset Management (SAM) of Water Supply and Wastewater Disposal Systems were identified during the development of international standards (ISO) and European guidelines for the management of the relevant services, for the use of Performance Indicators (PIs) and for Benchmarking.

The research results will have great value in the context of both global approaches and institutional and organizational aspects for the utilities / operators / financing institutions of water supply and wastewater systems and - finally - for the users / customers.  Therefore, many research institutions are already orientating their efforts from developing and specifying “Benchmarking” towards “SAM” with much greater activity then it was previously in evidence.

The main “dominant” schools for AM/SAM are from Australia, Canada, New Zealand and USA, but also in Europe (e.g. Austria, Germany, Norway, Portugal, The Netherlands, UK) several initiatives started in the direction of developing guidance for AM/SAM, for several infrastructure systems, not only for water supply and wastewater disposal.


Keywords asset management; benchmarking; cost optimization; efficiency; guidelines; standards; strategic asset management; performance indicators; research; sustainability; utility; wastewater disposal; water supply

<Back to Topic 2>


ISO 24500 standards as a support tool to manage assets

E. Cabrera Jr.*, D. Ellison**, D. Olivier***, J.L. Redaud****, K. Rorhofer*****

* Institute for Water Technology. Polytechnic University of Valencia. Camino Vera s/n. 46022. Valencia. Spain,

** Canadian Water and Wastewater Services,

*** Veolia Water,

**** GREIF- CGAER, Ministère de l’agriculture,

***** OEKOREAL, A-1170 Vienna, Carl Reichert-Gasse 28, Austria,


Abstract The publication of the ISO 24500 series of standards may not provide direct tools to improve the management of assets. However, the documents could prove to be a valuable support tool in terms of improving the overall management of water services, and therefore the management of their assets as one of the key areas. This support would materialize in the definition of service levels, an improvement in the communication between the different stakeholders by providing a common vocabulary and a framework to define tasks and responsibilities. Additionally, the standards should help to clearly integrate the management of assets as part of the strategic policy of the services. Finally, the procedures defined in the standards should allow establishing objectives and defining performance measures to determine the success in reaching these objectives.

Keywords standards; performance indicators; asset management

         <Back to Topic 2>

Strategic infrastructure asset management: concepts, ‘schools’ and industry needs

H. Alegre*

* National Laboratory of Civil Engineering, Av. Brasil, 101, 1700-066-Lisboa, Portugal,

Abstract This paper aims at launching the discussion about IWA future role and priorities with regard to strategic asset management of water and wastewater infrastructures. It shows examples of definitions of asset management, demonstrating the existing diversity and the bias in some of the existing approaches; it presents a subjective selection of the main ‘schools’ in infrastructure asset management; it refers the relevant standards and specifications and identifies industry needs, based on the outcome of previous AM meetings and working groups.

Keywords infrastructure asset management; integrated approaches; research and development

          <Back to Topic 2>

Ownership and management of water utility assets in developing countries: case Kenya

E. M. Vinnari*, E. Nyangeri Nyanchaga** & J. J. Hukka***

* Tampere University of Technology, Institute of Environmental Engineering and Biotechnology, PO Box 541, FIN-33101 Tampere, Finland,

** Department of Civil and Construction Engineering, University of Nairobi, Kenya,

*** Tampere University of Technology, Institute of Environmental Engineering and Biotechnology, PO Box 541, FIN-33101 Tampere, Finland,


Abstract Many developing countries are currently facing challenges related to their water and sewerage infrastructure assets. The most notable problems include the expansion of service coverage through greenfield investments and the rehabilitation of deteriorating infrastructure. In some instances there might also exist ambiguity regarding the asset ownership arrangements and entitlements. This paper reports on the first phase of a research project on water sector asset ownership and management in developing countries, more specifically in the case of Kenya. The first phase of the research has concentrated on the legal-institutional aspects of the issue, while the second phase will focus on the practical implementation  and operationalization of the regulations. Kenya was chosen as the case study location as the country has been undergoing an extensive water sector reform since the late 1990s with the ultimate aim of increasing and improving service coverage to achieve the Millennium Development Goals. This objective is to be reached through the decentralization and division of various tasks and duties, including the separation of water and sewerage infrastructure asset holding from water services provision. A document analysis indicates that asset management and investment planning are carefully considered and provided for in the relevant legislation, strategies and other documents. Transferring the ownership of the assets from the government to lower-level bodies, however, is causing complications due to unclear wording and ambiguities in legislation as well as the lack of established practices for asset valuation. Another legal complication relates to the ambiguous legal status of local authority incorporated companies.

Keywords management; ownership; investment planning; assets; developing countries; Kenya; institutional aspects; regulation

           <Back to Topic 2>

 Accountability and performance of two water utilities at the U.S.-Mexico border

I. Aguilar-Benitez* & J. D. Saphores**

* Associate Researcher and Corresponding Author, El Colegio de la Frontera Norte, Técnicos 277 Colonia Tecnológico Monterrey, Nuevo León, México, Member of the Red de Investigadores del Agua en Cuencas del Norte de México (RECUNOR),

** Associate Professor, Civil and Environmental Engineering, Planning, Policy, and Design Department, and Economics Department, University of California, Irvine, 92697, USA,


Abstract This paper contrasts the performance and institutional contexts of two water utilities located in twin cities at the U.S-Mexico border: The Laredo Water Utilities Department (LUWD) in Laredo, Texas and the Comisión Municipal de Agua Potable y Alcantarillado (COMAPA) in Nuevo Laredo, Tamaulipas, Mexico.  We analyze selected performance indicators for these utilities and describe how accountability mechanisms may be associated with the observed outcomes.

Although to different degrees, each water utility exhibits a range of similar performance issues and financial limitations. In both water utilities, we find that hierarchical accountability relationships between policymakers and providers of water services are strong while feedback from customers to policymakers is weak. On one hand, water users lack effective mechanisms to give feedback to policymakers about the provision of water services.  On the other hand, customers are discharged from their responsibilities because of excessively low water rates and the lack of conservation policies.

In summary, there is a clear need for improving the level of operational performance for both water utilities. Hiring technically qualified water officials rather than mere politicians may help, especially in Nuevo Laredo. Requiring periodic performance audits by independent outside firms would improve transparency and the image of these utilities. In addition, we propose that a more direct and closer proximity to customers may help water utilities perform better. Providing clear and understandable information about the delivery of water services may increase trust in public water supplies and boost community support.

Keywords performance indicators; accountability; professionalization

            <Back to Topic 2>


Topic 3 – Target definition and assessment of performance

Chair: Jaime Melo Baptista


Extended period simulation in the estimation of the economic level of reliability for the rehabilitation of water distribution systems

G. de Marinis*, R. Gargano**, Z. Kapelan***, M. S. Morley****, D. Savic***** & C. Tricarico******

* Dipartimento di Meccanica, Strutture e Ambiente e Territorio (DiMSAT), University of Cassino, via Di Biasio, 43, Cassino, Frosinone (Italy),

** Dipartimento di Meccanica, Strutture e Ambiente e Territorio (DiMSAT), University of Cassino, via Di Biasio, 43, Cassino, Frosinone (Italy)

*** Centre for Water Systems, University of Exeter, Harrison Building, North Park Road, Exeter, Devon (UK)

**** Centre for Water Systems, University of Exeter, Harrison Building, North Park Road, Exeter, Devon (UK)

***** Centre for Water Systems, University of Exeter, Harrison Building, North Park Road, Exeter, Devon (UK)

****** Dipartimento di Meccanica, Strutture e Ambiente e Territorio (DiMSAT), University of Cassino, via Di Biasio, 43, Cassino, Frosinone (Italy)


Abstract The estimation of the Economic Level of Reliability (ELR) is based on the consideration that the water required by users, but not supplied to them owing to the structural inadequacy of the Water Distribution System (WDS), can represent a lost revenue for water companies.

de Marinis et al. (2006) formulated and solved a multicriteria optimisation problem, under uncertain demands, for the rehabilitation of WDS to determine the ELR.  The objectives considered were the minimisation of the total rehabilitation cost (sum of the structural cost and the lost revenue cost) and the maximisation of the hydraulic reliability. The latter was defined as being the probability of simultaneously satisfying the minimum pressure constraints at all nodes of the network.  The specific solution of the Pareto Front which corresponds to the minimal total rehabilitation cost is the  ELR.

Because of the computation time required, this analysis has been performed, thus far, on the assumption that the inadequate operating conditions occur only during the peak daily water consumption hours – allowing the use of a single, steady state hydraulic solution in the determination of the ELR.  Such an hypothesis is appropriate if the WDS under consideration is not notably inadequate. A significantly under-performing hydraulic network may, however, demonstrate inadequacy even in periods of low water demand.  As such, the prior analysis represents an underestimation of the true non-revenue water volume since other significant flow demands may occur at times of day other than that of the peak demand.  For this reason, a more realistic representation of the adequacy of the performance of a WDS requires an extended period simulation (EPS) analysis.

This paper describes the application of an extended period simulation to the derivation of the ELR for a network.  The EPS is facilitated through the use of the deEPANET (Distributed Evaluation for EPANET) software (Morley et al., 2006), which significantly shortens the runtimes for optimisation algorithms.  In this instance, the multicriteria optimal rehabilitation problem for WDS, under uncertain demands, has been solved using an EPS covering a 24 hour period. 

Water demands are considered to be uncertain – this uncertainty is modelled by means of a probabilistic approach coupled to the optimisation model.  The appropriate probability density functions and their parameters having been estimated through an experimental study conducted on a real-life WDS.  The deEPANET software has been extended to support stochastic optimisation by devolving the generation of the uncertain demands to the client computers – resulting in an order-of-magnitude reduction in network traffic during operation and, thus, significant improvements in computational performance.

The methodology proposed is applied to a WDS case study and the results obtained are compared with those that merely consider the peak, steady-state condition, demonstrating that the EPS analysis leads to better accuracy in the estimation of the ELR.

Keywords economic level of reliability; extended period simulation; genetic algorithms; multiobjective optimisation; water distribution system rehabilitation

             <Back to Topic 3>

Failure data analysis – a Dutch case study

I.N. Vloerbergh* & E.J.M. Blokker*

* Kiwa Water Research, P.O.Box 1072, 3430 BB Nieuwegein, The Netherlands,, T: 00-31-30 60 69 756


Abstract The underground capital of water utilities is ageing. Deterioration of the water mains causes supply interruptions, pressure loss or decreasing water quality, which in turn leads to increasing costs over time. Invisible for inspection, little is known about the condition of the pipes. As an alternative to expensive monitoring techniques, maintenance and failure data can be used. Statistical analysis of failure data can be used to predict the probability of failure for a (group of) pipe(s). Two interrelated challenges appear in the statistical analysis. The first challenge lies in obtaining failure data of sufficient quantity, quality and level of detail. The second challenge is concerned with the statistical techniques available for and applicable to the failure data at hand. Roughly three types of statistical techniques are distinguished: descriptive statistics, regression analysis and probabilistic predictive methods. In practice, the statistical techniques that can be applied are determined by the available data. To provide insight in the possibilities and limitations of failure and maintenance databases for statistical analysis, the databases of seven Dutch water companies were scrutinized. The datasets varied in accuracy and extensiveness. Descriptive statistics could be applied to all seven. Regression analysis could be applied to the dataset of one water company, but only successfully for asbestos cement pipes. Probabilistic models could not be applied to the provided data, as the data need for this type of statistics appeared to be too exhaustive for the current registration. Statistical analysis of failure data was successfully used to verify several hypotheses, derived from literature, on the relation between pipe characteristics and failure rate.

Keywords asset management; failure data; failure registration; maintenance records; statistical analysis

              <Back to Topic 3>

Evaluation of the pipeline replacement project for drinking water supply system using performance indicators

K. Ishii* & T. Katsumata**

* Engineering General Institute, Japan Water Works Association, 4-8-9, Kudan-Minami, Chiyoda-ku, Tokyo, Japan,

** Engineering General Institute, Japan Water Works Association, 4-8-9, Kudan-Minami, Chiyoda-ku, Tokyo, Japan,


Abstract One of the most urgent challenges in Japan today is replacing the pipelines for the supply of drinking water. This paper attempts to objectively and quantitatively evaluate pipeline replacement projects by using Performance Indicators (PIs). In comparing the charge for supplying drinking water with the level of service, the use of PIs enables us to provide stakeholders with an intelligible explanation of the effects of pipeline replacement projects and also create materials for assessment purposes.

Keywords assessment of performance; evaluation of pipeline replacement project; performance indicator (PI); earthquake-resistant pipeline; cost to water supply; leakage rate

               <Back to Topic 3>

Explanatory factor “Average Network Age index” (NAX) for mains failures and water losses

R. Neunteufel*, R. Perfler*, H. Theuretzbacher-Fritz** & J. Kölbl**

* Institute of Sanitary Engineering and Water Pollution Control, University of Natural Resources and Applied Life Sciences Vienna, Muthgasse 18, A-1190 Vienna, Austria;

** Graz University of Technology, Institute of Urban Water Management and Water Landscape Engineering, Stremayrgasse 10/I, A-8010 Graz, Austria;


Abstract Nowadays various benchmarking studies are aiming to improve the performance in the water supply sectors of many countries. In Austria significant efforts were spent to determine more than twenty factors influencing the results of performance which is not common with a many other projects. Knowing the influencing or explanatory factors enables a better definition of peer groups and so a better assessment whether some PIs of one utility are in a good or in a poor range.

Concerning mains failures and water losses the strongest influencing factor beside the structural parameter “urbanity” was found to be the age of the pipe network. The simple calculation of the average mains age does not consider that different pipe materials have different service lives. The network age index NAX does and so provides an estimation of how much of the expected service life has elapsed by the time. Beside the definition of peer groups the age index NAX can be used as an explanatory factor for several PIs; to estimate the influence of network age on asset related performance indicators; and in long terms as an estimation whether there is enough rehabilitation and renewal done or not. However it is not recommended to directly derive rehabilitation strategies from age index NAX or to use it as a performance indicator but the NAX can give useful hints whether detailed analyses are to be carried out.

This paper describes why and how the age index NAX was developed and how it is calculated. It includes considerations concerning the used reference ages; possible enhancements and further research; the individual composition of the index value of any utility; and possible applications of the index. Finally there are some examples concerning mains failure rates and water losses using the NAX as a grouping parameter in the Austrian benchmarking project.

Keywords age; asset; benchmarking; index, indicator; pipes; network

                <Back to Topic 3>

 Proposal for a methodology to assess the technical performance of urban sewer systems

A. Cardoso*, S. T. Coelho** & J. Matos***

* Laboratório Nacional de Engenharia Civil, Av. do Brasil 101, Portugal,

** Laboratório Nacional de Engenharia Civil, Av. do Brasil 101, Portugal,

*** Instituto Superior Técnico, Av. Rovisco Pais, Portugal,


Abstract Urban sewer systems constitute a significant patrimony in Europe and worldwide. The structural quality and functional efficiency of sewer systems are fundamental to guarantee their good performance. These systems are nowadays facing problems of ageing, malfunctioning and overloading caused by deterioration due to long life times, improper maintenance, population growth or catchment increase. In order to effectively plan the operation, maintenance and rehabilitation of sewer systems it is important to provide methods and tools for wastewater utilities in order to support the technical management of their systems. The importance of performance evaluation has been growing in most services and economic activities in recent years. Decisions must be economically and environmentally sustainable, the customer/consumer must be satisfied by the product or service provided, and legislation becomes ever more stringent and far-reaching. It is increasingly vital for the managers of an organization to know where, how and when changes must be introduced in order to reach a better performance. These decisions must be taken based on all the available relevant information. The objective of the methodology proposed in this paper is to establish, at the engineering level, the use of a performance assessment methodology suitable for the diagnosis, control and selection of solutions for the improvement of technical processes and systems performance. It can be applied to monitoring data or modelling results, in this case both to extended period operational scenarios and to a range of load factors, displaying appropriate dispersion bands (e.g. percentiles). The methodology is objective-oriented, quantitative and constitutes a standardised approach to technical performance assessment of sewerage systems as a useful contribution to the quest for a common language that would facilitate comparisons, prioritization and the setting of service standards. It is based on relevant performance variables or indicators, meaning the quantity which translates the system behaviour or properties from the point of view taken into consideration (e.g. hydraulic or environmental). It can be applied at catchment or system element level, depending on type of available data; performance functions scores the values of the performance variables or indicators against a scale of performance; for the element level assessment a generalising function is defined for extending the element-level calculation across the system, producing zonal or system-wide diagnoses. Through this methodology an overall view of system performance can be achieved facilitating performance comparisons. A case study is presented to illustrate the application.

Keywords performance assessment; urban sewer systems; rehabilitation

                 <Back to Topic 3>


Topic 4 – Cost and benefit valuation

Chair: Jean Philippe Torterot


Assessing the benefits of rehabilitation programs defined with the CARE-W decision support system

P. Le Gauffre*, H. Haidar* & D. Poinard**

* LGCIE, INSA-Lyon, 20 av. Einstein, F-69621 Villeurbanne Cedex. Fr. pascal.le-gauffre

** Veolia Eau, SLA, 67 quai Charles de Gaulle, 69414 Lyon Cedex, France.


Abstract CARE-W_ARP is a multicriteria decision support software prototype for the construction of annual rehabilitation programs of water networks. It was developed within the CARE-W European research project (Computer Aided Rehabilitation of Water networks, 2001-2004). Two main components may be distinguished in ARP: a) a set of criteria was formulated for the purpose of assessing and comparing water mains; criteria related to the various consequences of pipe failures (leaks and bursts) are expressed by using risk concepts; b) a multicriteria ranking procedure was developed, based on the ELECTRE Tri outranking method. This procedure assigns each pipe to one out of six possible priority levels. Within two Ph-D studies, conducted in 2004-2006, CARE-W_ARP was used as a research tool. Full scale experiments and critical analyses were conducted with data on the asset stocks of Reggio Emilia (It) and Lyon (F). These two research studies proposed new developments and provided original results. A new criteria formulation was proposed to assess the efficiency of rehabilitation projects and a second set of criteria was defined for assessing and comparing rehabilitation programs (alternative selections of a subset of pipes within the asset stock). Results of numerical experiments provided an assessment of the efficiency of rehabilitation programs and demonstrated the impacts of the chosen decision criteria.  A comparison between 4 scenarios tested in Lyon shows that a rehabilitation program elaborated with the support of CARE-W_ARP provides higher benefits than other scenarios. An experiment with data from Reggio Emilia provided similar conclusions.

Keywords asset management; efficiency; multicriteria analysis; prioritization; rehabilitation; water network

                  <Back to Topic 4>

Planning maintenance strategies for Italian urban drainage systems applying CARE‑S

R. Ugarelli*, M. Pacchioli* & V. Di Federico*

* D.I.S.T.A.R.T.,Università di Bologna,Via Risorgimento 2, 40123 Bologna, Italy; e-mail:

Abstract Municipalities have the responsibility of protecting property and public health by safely and efficiently collecting, transporting, treating and disposing wastewater. This includes managing treatment plants, pumping stations and physical pipe network. The municipalities have an obligation to ratepayers to manage the assets to provide acceptable standards of service in a cost-effective manner. Asset management demands balancing desired levels of service and asset standards against costs and risk. Models for asset planning and prioritization are required to allow the understanding of the implications of different asset management strategies on the system performance. At the right time each asset needs to be repaired, replaced, rehabilitated or monitored. Decision making for intervention strategies occurs either reactively in response to failures of an asset or proactively to prevent failures from occurring.

CARE‑S project  (Computer Aided Rehabilitation of Sewer and Storm water Networks) developed under the Fifth Framework Program provides utility’s managers with a suite of tools for estimating the system performances to evaluate the level of service achieved, supporting them in individuating system criticality, defining new goals in the most economic manner in the long term analysis.

This paper includes a brief introduction of the main features of the CARE‑S project, followed by the description of the application of CARE‑S to the urban drainage system of the historical center of Reggio Emilia town (Italy), managed by company ENIA s.p.a.. The outcome of this experience teaches on how much strength has still to be addressed to data collection and organization in order to be able to draw conclusions on asset condition, run decision support tools and assess capital maintenance needs.

Keywords CARE‑S; CCTV; maintenance planning; Reggio Emilia; sewer asset

                   <Back to Topic 4>

Asset management in Copenhagen Energy Sewerage Department

J. Elkjær*

* Analyst, Copenhagen Energy Sewerage Department, Orestads Boulevard 35, 2300 Copenhagen S, Denmark,


Abstract As a response to increased environmental and service level requirements and worsening financial conditions CESD implemented Asset Management in 2004 by a strategic life-cycle costing model and optimized planning procedures. As a result of the output of the life-cycle costing model and other Asset Management activities certain strategic asset plans have been changed causing substantial cost savings from a business as well as a social point of view. An optimized strategy has a potential to reduce the net present value of the future total life-cycle costs by app. 30-40 million €.

Keywords asset management; life-cycle costing; strategic asset planning

                    <Back to Topic 4>

Effect of water costs on the optimal renovation period of pipes

R. Cobacho*, E. Cabrera*, E. Cabrera Jr. * & M.A. Pardo *

* Institute for Water Technology. Polytechnic University of Valencia. Camino Vera s/n. 46022. Valencia. Spain,,,,


Abstract The determination of the optimum renovation period for pipes seldom includes the cost of the water loss through leaks. This paper presents a complete cost model, which not only includes such costs, but aims to determine the influence of such costs in the whole problem. To this purpose, a case study has been prepared from figures obtained in Spanish utilities. A sensitivity analysis has been performed and a range of the variation of the optimum renovation period has been established for typical values of water production costs and average network pressure. Additionally, secondary influences have been studied.

Keywords cost analysis; cost of water; pipe renovation

                    <Back to Topic 4>

Implementing an asset management approach to capital investment planning

D. Sklar* & R. West**

* David C. Sklar, Principal Consultant, Red Oak Consulting (A Division of Malcolm Pirnie), 100 Fillmore Street, Suite 200, Denver, CO 80206, USA,, Tel (303) 316-6507, Fax (303) 316-6599

** Rebecca F. West, Director of Technical Services, Spartanburg Water System and Sanitary Sewer District, 172 N. Converse Street, P.O. Box 251, Spartanburg, SC 29304, USA,, Tel (864) 580-5648, Fax (864) 596-4929


Abstract The ultimate goal of an asset management program is to meet defined service levels at an optimum life-cycle cost, while ensuring long term sustainability of public assets.  Many utilities have discovered that fine tuning their capital planning process to integrate asset management concepts and tools can often yield rapid and measurable cost savings and performance improvements.  This presentation will discuss the major components of a business oriented and financially driven CIP (Capital Investment Planning) process focused on effective project prioritization and analysis. 

Critical to an asset management focused CIP is the development of a “business case” approach (see figure 1) to proposed projects, requiring project sponsors to produce a comprehensive summary for each major project.  Business cases typically include information and analysis such as: project description and purpose, assessment of service level impact, identification of major criticality and risk issues, life-cycle cost forecasts, as well as financial analysis including ROI (Return on Investment) and rate impacts.  Business cases must also include an evaluation of other likely project alternatives and scenarios.  

Figure 1 CIP Business Case Outline

 This formal approach enables a thorough review and prioritization process through cross- functional committees to answer questions such as:

·     What is the risk if the project is deferred for another 5 years?

·     How many emergency events have we responded to at this location or asset over the last 3 years?

·     What are the growth projections that this new project is based upon?

·     What are the likely technical alternatives to the one proposed?

·     How does the project align with strategic plan objectives?  

Utilities have found that an integrated, asset management focused capital planning process is effective because it builds business discipline, encourages analysis of options and alternative solutions, documents expected customer and environmental impacts, and ensures alignment with strategic asset management goals.  In addition, this process provides greater transparency and integration with financial and rate analysis by ensuring that funding requirements are identified up front, customer impacts are understood, and stakeholder needs are considered.

Key benefits of a formal and dynamic capital investment planning process include:

·    Improves capital project and investment prioritization through formal business case analysis.

·    Fosters greater understanding of the long-term service level and cost implications of capital investment decisions.

·    Evaluates the financial, social, and environmental impacts of major capital projects.

·  Creates greater understanding of the true life-cycle cost of capital projects by examining project specific return on investment (ROI), net present value (NPV) and other financial measures.

·    Strengthens long-term financial decision making, enables accurate financial projections, and helps to ensure adequate funding and rate structures.

·   Ensures that the overall CIP has tangible objectives linked to both service level and financial goals.

·  Identifies gaps in information required for decision-making such as: performance measures, historical work order and maintenance data, and realistic cost of service statistics.

·   Ensures that engineering, operations, maintenance, and financial perspectives are all considered.

·   Fosters a culture of asset management throughout the organization.

·  Creates improved trust, understanding, and transparency with the public, elected officials, and stakeholders - strengthening the case for required investments and resources.

This presentation will demonstrate the above concepts through an implementation case study presented by Spartanburg Water System and Sanitary Sewer District.  The case study will focus on the following key topics and lessons learned from the implementation of a formal approach to capital planning and prioritization. 

·  Developing cross functional teams and committees to ensure a balanced perspective on capital planning and asset management issues and drive organizational change.

·  Ensuring that major projects follow a formal and defined analysis and review process to ensure that projects chosen deliver maximum business value and are in alignment with asset management goals. 

·   The importance of aligning capital projects with strategic plan goals and objectives.

·   Building an understanding of cost/benefit analysis for capital projects including the financial impact of capital projects on rates.  

·   Defining service level measures and targets that drive capital project prioritization. 

·  Developing a public support program to educate and inform stakeholders of the need and justification for capital and asset management programs including commissioners as well as civic, business, and neighbourhood groups.

Keywords capital planning; CIP; investment planning

                    <Back to Topic 4>

Topic 5 – Target definition and assessment of risks

Chair: Scott Haskins


The role of uncertainty in urban drainage decisions: uncertainty in inspection data and their impact on rehabilitation decisions

J. Dirksen*, A. Goldina**, J.A.E. ten Veldhuis* & F.H.L.R. Clemens*

* Delft University of Technology, P.O. Box 5048, 2600 GA Delft, the Netherlands, corresponding author:

** AG Advies, Warmond, the Netherlands


Abstract Urban drainage managers express significant uncertainty as to their design and operational decisions. The main uncertainties they mentioned in interviews concern: changing policy guidelines, the quality of technical personnel, the reliability of model calculation results and of information on pipe deterioration, mainly derived from video inspections. Pipe rehabilitation is mentioned in most interviews to cover the largest part of the yearly investments, about half of the available urban drainage budget. This  paper focuses on the quality of historical video inspection data for 4 urban drainage catchments situated in 4 different municipalities and the reliability of rehabilitation decisions that are based on these data. The quality of the data is assessed by comparing the inspection results of two subsequent inspections. The number of pipes for which a certain defect is identified at the first inspection, but not at the second inspection and no indication of any rehabilitation or replacement is present, is used as an indication for the quality of the data (Dirksen et al., in print). Only defects related to the structural condition of the sewer pipes are used in this research, since these defects have are very unlikely to ‘disappear’ without any rehabilitation or replacement. The analysis shows that the percentage of defects that ‘disappear’ between the first and the second inspection is 30% on average over all defects related to the structural condition of sewers, for rigid pipes. If the data were of good quality this percentage should be next to 0 for all defects. The high percentage of ‘disappearance’ indicates that the quality of the inspection data is poor. The inspection data quality is insufficient to base rehabilitation decisions on without adding further information. The same applies to the use of inspection data for modelling and prediction of deterioration processes. The analysis also indicates that the data in the sewer database are often incomplete and not up-to-date. Information on repair actions and maintenance activities, that may provide additional information to support rehabilitation decisions, is often lacking from the database. Urban drainage managers often use simple software tools that calculate necessary repair actions and the remaining lifetime of sewers directly from inspection data in the sewer database. The analysis of inspection data of 4 municipalities has shown that the inspection data are inconsistent and so must be the results of models that are based on these data. Great care is required in the use of these models for planning of rehabilitation actions.

Keywords inspection data; pipe rehabilitation; uncertainty; urban drainage

                    <Back to Topic 5>

Hazard identification and risk analysis of water supply systems

L. Tuhovčák* & J. Ručka**

* Brno University of Technology, Institute of Municipal Water Management, Brno, Czech Republic,

** Brno University of Technology, Institute of Municipal Water Management, Brno, Czech Republic,


Abstract The risk analysis represents a modern approach of determining the level of provision of drinking water supplies for the consumers and the safety of the whole drinking water supply system. The authors of this paper present a methodology of risk analysis of drinking water supply systems and they deal with identification of qualitative as well as quantitative risks posted by the individual system components, the evaluation methods and interpretation of results. Problems relating to uncertainty and poor input data are solved by the application of an FMEA/FMECA technique, which is also demonstrated here on a case study concerning a water-supply tank. Some basic facts and first outputs of the national research project “WaterRisk” are presented in the last part of the document.

Keywords drinking water; FMEA/FMECA; hazard; risk analysis; water safety plans; water supply

                     <Back to Topic 5>

Infrastructure strategic management in contingency situations

A. Ribeiro*, H. Lucas**, J. Sousa***, R. Coelho****, M. Viriato***** & S. Dias******

* Águas do Algarve, S.A., Rua Repouso, 10,  800-302 Faro, Portugal,

** Águas do Algarve, S.A., Rua Repouso, 10,  800-302 Faro, Portugal,

*** Águas do Algarve, S.A., Rua Repouso, 10,  800-302 Faro, Portugal,

**** Águas do Algarve, S.A., Rua Repouso, 10,  800-302 Faro, Portugal,

***** Águas do Algarve, S.A., Rua Repouso, 10,  800-302 Faro, Portugal,

****** Águas do Algarve, S.A., Rua Repouso, 10,  800-302 Faro, Portugal,


Abstract Since the year 2000 the Algarve Multimunicipal System has supplied water to approximately one million people in high season. Surface water sources include different dams namely, Odeleite – Beliche, Funcho and Bravura. However a main dam – Odelouca – is still under construction and water scarcity can occur in the region.
In fact, at the end of 2004 a situation of hydric stress occurred leading to the preparation of a partial contingency plan, which covered part of the Algarve region.
In the beginning of 2005 the whole region of Algarve was affected by hydric stress due to the drought registered in the hydrological year 2004/2005 in Portugal and as a result, a Contingency Plan was developed for the whole region. This Contingency Plan foresees the possible re-activation of old municipal boreholes for groundwater extraction, which have been inactive since 2000.
This Plan was activated in 2005, according to the restrictions imposed by the Drought Commission in order to fulfil the region’s water supply.
This Action Plan established measures and investments for the reinforcement of the supply system, until the new dam is built. The Plan ensured greater flexibility and reliability of the system to meet contingency scenarios such as drought and other emergency situations. Alternatives to water supply included the transfer of treated water between the 2 sub-regions of Algarve as well as the establishment of new water sources in the region.
The Plan also included a regional campaign for the efficient use of water by consumers, which was effective in reducing water consumption, in addition to a study on the evolution of water consumption highlighting the measures.

Keyword contingency plan; drought commission; hydric stress; multimunicipal system

                      <Back to Topic 5>

Statistical analysis of recorded failure data in buried water distribution system pipes

Paulo Praça*, Ilídia Pinheiro** & Sérgio T. Coelho***

* LNEC – Natl. Civil Eng. Lab., Av. Brasil, 101, 1700-066 Lisbon Portugal,

** LNEC,

*** LNEC,


Abstract Water distribution pipe failure records are a primary source of information regarding the state of conservation of the buried infrastructure and the way it is operated. Failure can be defined as an event that requires an intervention to recover pipeline and system function. Such events are normally caused by break or collapse of pipes, and through leaks in unions. The functional effect of the physical damage is reflected in water supply interruptions that can last from a few hours to days, as well as pressure fluctuations, and flow availability and water quality changes at the consumers’ tap.

Knowledge on the weakness of the network – the areas, materials or pipe types with the greatest numbers of occurrences, and the probable causes behind them, is a critical type of information for the network manager, who can act in anticipation to try and eliminate or reduce the failures, the associated costs and the drop in the levels of service at the consumers’.

The purpose of this paper is to contribute to a systematic process of information collection on failures in distribution systems, and to the development of tools for the prediction of failure events, based on the corresponding database of historical failures. Two examples of the latter are made available by the proprietary Care-W procedure and software (, particularly through a PhM and a Poisson-based tools used to predict failure rates for classes of explanatory variables chosen by the user in a water distribution system.

The methods proposed here were developed without the need for sophisticated or expensive software, and are made available based on simple MS® Excel® spreadsheets. Pipe failure records are grouped into explanatory classes of variables, and data is tested for fit to the statistical distribution used (Poisson); statistical indicators are used to evaluate if the classes have been well selected.

With the failure rate for each class, and assuming a given Poisson distribution for the failures, it is possible to calculate the failure probability of each individual pipe. A GIS system (ESRI® ArcGIS 9.1®) is used in order to geographically illustrate failure rates and probabilities (Figure 1). Given those, a tool was developed for assessing the functional consequence of failure of each pipe in the network, in terms of pressure and affected demand, using a network model to evaluate each scenario. This tool was developed using ESRI® ArcObjects® and the Epanet simulator library of functions, and is fully integrated in the GIS system. Running the two mechanisms in conjunction, a quantitative measure of the risk of failure for each pipe (risk=probability of failure x consequence) can be mapped out (Figure 2).

This methodology has been tested and used on the distribution system of Lisbon region municipality, with full integration of the data and results on the GIS system. It is found that the insight into the functional effect of the failures, together with the careful exploration of failure rates and probabilities, affords better supported decision-making in both operational and investment terms.



Figure 1 GIS-based mapping of failure rates

Figure 2 GIS-mapping of risk of system failure caused by the individual failure of each single pipe, expressed as a pressure condition (above or below a minimum pressure requirement Pmin)

Keywords Water distribution, pipe failure, statistical analysis, GIS application.


                       <Back to Topic 5>

Rehabilitation of a large sewer: methodology for the Alcântara interceptor sewer

M. C. Almeida*, F. Fernandes**, N. Charneca*** & M.C. David****

* Laboratório Nacional de Engenharia Civil, Av. do Brasil 101, 1700‑066 Lisboa, Portugal,

** Câmara Municipal de Lisboa, DMPO, DOIS – DCMIS, Av. Almirante Reis 65, 1150-011 Lisboa, Portugal,

*** Laboratório Nacional de Engenharia Civil, Av. do Brasil 101, 1700‑066 Lisboa, Portugal,

**** Laboratório Nacional de Engenharia Civil, Av. do Brasil 101, 1700‑066 Lisboa, Portugal,

Abstract Proactive rehabilitation of sewer systems is increasingly relevant for asset managers. Large interceptor sewers pose specific problems since both their failure and their rehabilitation often result in severe economic impacts for the responsible authority. Furthermore, often full inspection using CCTV is not feasible. Thus, a methodology to define a rehabilitation strategy should include a combination of personal inspection with analysis tools for evaluation of the condition throughout the infrastructure. Early detection of critical situations is essential to reduce the overall risk. Factors influencing the structural deterioration of specific situations should be considered. Design conditions, construction quality, sewer material, surface use, external loading conditions, ground disturbances, hydraulic behaviour, maintenance practices, sewage characteristics and age of sewer are factors that have to be considered.

The case of the combined sewer interceptor of the Alcântara catchment provides a good illustration of the problems that managers have to face in these situations. The Alcântara Stream was covered between 1944 and 1967. The resulting interceptor sewer, approximately ten kilometres long, has a large cross section made of non-reinforced concrete. Flow velocities are high, for both dry and wet weather, and urbanisation has been intense all over the catchment area since the sewer construction.  Expected service life of this sewer is reached (over 40-50 years) and structural problems, mostly occurring since 1995, corroborate this accepted design criteria. The infrastructure was apparently performing well but increasing frequency of structural failures, and identification of a number of locations where serious structural deterioration existed, was an alert to the need for rehabilitation of this interceptor sewer.

An integrated approach to rehabilitation was sought but necessarily with efficient use of resources. Localised visual inspections and detailed analysis of past occurrences allowed for an initial categorisation of the main problems in internal and external causes, the first associated with deterioration resulting from continuous functioning of the sewer, the second, resulting from changes in external loading over the years. The established methodology resulted from the combination of knowledge of the main causes of degradation, selected visual inspections and usage of a tailored Geographic Information System (GIS) tool to incorporate capabilities for spatial analysis that were not available at the existing mapping system.

In this paper, the focus is on the relevance of the understanding of the degradation mechanisms to support the definition of rehabilitation and inspection priorities, especially in large sewers.

Keywords combined sewer system; Geographic Information System; large sewer; rehabilitation; risk management

                        <Back to Topic 5>


Topic 6 – Asset data and information systems

Chair: Chris Royce & Cushla Anich


SIROCO, a decision support system for rehabilitation adapted for small and medium size water distribution companies

E. Renaud*, JC. De Massiac**, B. Brémond*** & C. Laplaud****

* Cemagref, 50 avenue de Verdun 33612 CESTAS France,

** G2C Environnement, 13770 VENELLES France,

*** Cemagref, 50 avenue de Verdun 33612 CESTAS France,

**** G2C Environnement, 13770 VENELLES France,


Abstract The SIROCO project (Système Intégré d’aide au Renouvellement Optimisé des COnduites adapté aux petites et moyennes collectivités distributrices d’eau potable) financed by the French Ministry of Research, is the result of a collaboration between Cemagref and G2C Environnement.

In the framework of the European Commission-funded project, Care-W, (Computer Aided Rehabilitation of Water Networks) several tools and methods were developed, tested and then combined into an integrated decision support system for the rehabilitation of water distribution networks. Generally, Care-W was geared towards larger water companies with sufficient data at their disposal.

The aim of the SIROCO project was to create a tool enabling small and medium size water distribution companies to prioritise pipes for rehabilitation. Individually, these companies do not have enough data to obtain reliable results from break prediction models. In order to overcome this problem, an amalgamated database consisting of data from several companies was proposed. In order to standardise and manage the data more effectively, a geographic information system (GIS) developed by G2C Environnement was used.

A consortium of 16 water companies was established. Data defined in the framework of the project were collected and incorporated into the GIS by means of a purpose-designed interface.

Cemagref then tested the principle of using a break prediction model on an amalgamated database. This enabled the feasibility of such a database to be evaluated. The predictions permitted the subsequent prioritisation of pipe rehabilitation candidates.

Cemagref also tested a hydraulic reliability model on several of the water distribution networks. These tests were able to show that hydraulic reliability software can be used with data originating from a GIS, providing certain topological rules are respected.

A decision support system was constructed, based on specifications and constraints of the various water companies. It was designed to create a hierarchy of potential rehabilitation candidates based on pertinent criteria. The multi-criteria approach considers both the impact of failures and the opportunities for rehabilitation. The selection of criteria results from a compromise between these impacts and opportunities and by using the appropriate tools for the data available.

On the basis of this project, G2C Environnement has developed the "SIROCO” software. An interface has been designed to allow the user to import all the necessary information at the beginning. Tools have also been developed to control the data and take into consideration the original topology of the network. An options module allows appropriate parameters and criteria to be chosen for each user. The mutualisation of the database is performed on a server by Cemagref with import and export functionalities being developed for this effect, so that each individual user only has access to his own data. From the data and model results, a separate module allows the multi-criteria analysis to be performed. This determines the ranking of pipes as rehabilitation candidates – information that can be displayed in graphic form on the GIS.

Keywords break prediction; decision support; integrated system; small utilities

                         <Back to Topic 6>

A GIS based approach to assess the vulnerability of water distribution systems

T. Liserra*, R. Ugarelli**, V. Di Federico*** & M. Maglionico****

* T. Liserra  Department DISTART – Bologna University, v.le Risorgimento n°2, Italy,

** R. Ugarelli Department DISTART – Bologna University, v.le Risorgimento n°2, Italy,

*** V. Di Federico Department DISTART – Bologna University, v.le Risorgimento n°2, Italy,

**** M. Maglionico Department DISTART – Bologna University, v.le Risorgimento n°2, Italy,


Abstract It is a fact that water distribution systems in most European cities are reaching the end of their lifetime; pipe breaks and leaks have had a significant increase in the last years, and there is no evident reason for the future trend to be inverted in the short-term horizon. The history of water networks rehabilitation leans on the so called re-active approach: first the failure occurs, then comes the intervention. Efforts are recently being undertaken in order to establish a rational framework for maintenance decision-making in water distribution systems, based on a new logic: a rehabilitation carried out before the problem takes place is to be preferred, thanks to its higher effectiveness and to the troubles it is able to prevent rather than cure (pro-active approach). Nevertheless, the experience demonstrated that availability of data is sometimes the first problem to be addressed and the application of advanced management approaches is sometimes unfeasible because of the lack of a long term monitoring strategy. Information about the asset and the surrounding environment are often available at the municipality archive, but not recorded in a way to be directly applied for maintenance actions planning.

The aim of this study was to develop a simple but feasible model to assess the vulnerability of an Italian water distribution systems suitable with the level of data available: starting from a typical Italian case study, we defined what can be evaluated, analysed or calculated according to what can be obtained from the Utility in terms of data quality and quantity. The selected case study is the drinking water system of Reggio Emilia town located in the northern part of Italy, managed by ENIA S.p.A..

The paper, after an introduction on asset managements practice, states the definition of reliability variable and criticality index applied in order to run a simplify vulnerability model and presents the results achieved in Reggio Emilia up to this stage of development.

Keywords GIS; modelling; water distribution network; vulnerability

                          <Back to Topic 6>

Application of monitoring and information technologies to optimise asset management

A. Pretner*, A. Bettin** & L. Sainz***

* SGI Studio Galli Ingegneria, via della Provvidenza 15, Padova, Italy,

** SGI Studio Galli Ingegneria, via della Provvidenza 15, Padova, Italy,

*** SGI Studio Galli Ingegneria, via della Provvidenza 15, Padova, Italy,

Abstract Water and wastewater operators are requested to optimise the operation of their assets whilst ensuring quality of services to customers and due respect to the environment. Aged infrastructure, deferred maintenance and investment constraints make asset management an arduous task, aggravated by the fact that most assets are hidden underground. The advances in monitoring and information technologies are however simplifying life for water managers as they help to assess system performance and target capital and operational investments in the most effective manner. This document illustrates the experience gained in two European projects focused on the application of asset data and monitoring tools to enhance the efficiency of water and sanitation services. The first is TILDE, a research project funded by the European Commission aimed at facilitating the adoption of best practice for leakage control in water distribution networks. This project has developed and demonstrated a set of data management tools for leakage control in two pilot areas in Italy, one in Cyprus and another one in Norway. TILDE was completed in 2006 and since then the project technologies have been widely disseminated. Their application has been particularly welcome in those countries facing severe water scarcity where the management of leakage can yield greater economic and environmental benefits. The other project is ADRICOSM, started in 2001 and still on-going. The project focuses on implementing integrated wastewater management to minimise the pollution of the Adriatic Sea. Simulation models of the sewer networks and receiving waters have been developed in order to assess the impact of waste and storm water pollution on the rivers and coastal areas. Both projects tackle major technical problems in asset management which if appropriately solved can draw substantial operational, financial and environmental benefits. Our projects have demonstrated how mathematical modelling, monitoring and data management are crucial to optimise data collection and analysis, and enhance knowledge for decision making.

Keywords leakage; simulation; models; monitoring; wastewater

                           <Back to Topic 6>

Global approaches to asset management - an Australian integration of asset management techniques with executive business decision

T.J. Waldron* & A.V.P. Perry**

* Tim Waldron, Chief Executive Officer, Wide Bay Water Corporation, 29-31 Ellengowan Street Urangan, Queensland, Australia,

** Adrian Perry, Principal Systems Analyst, Wide Bay Water Corporation, 29-31 Ellengowan Street Urangan, Queensland, Australia,


Abstract Wide Bay Water Corporation is Australia’s first local government owned Water Corporation that provides water and sewer services to a region of Queensland, and engineering and scientific services throughout Australia.  A direct correlation has been developed by the Corporation which identifies business value benefits and capital deferment through improved asset management.

Effective asset management has proved to require two main components in Australia.  Firstly sound management practices and secondly efficient systems to support them.  Various good management practices have been developed over the years but they all have the goal of achieving the most cost effective running of an asset for the maximum of its life.

Asset Management Systems in Australia however has the goal of supporting and improving the efficiencies of the asset management practices.  This is achieved through the streamlined flow of more accurate and filtered information to those who require it.  This facilitates faster and better decisions affecting planning, operational and administration efficiency gains.

The benchmark drivers that are now an integrated part of the Corporation’s business initially came about through the re-evaluation of hydraulic data for the need to reduce water losses.  The introduction of the International Water Association’s strategies for reducing losses brought about new measuring systems and new benchmarks.  These produced wonderful business outcomes that improved security of supplies, customer service standards, but most importantly extended asset life.

Some traps to look for when implementing asset management systems is in the design of their adaptation to the business processes. Careful thought should be exercised to adapt the system to the process and not the process to the system. As mentioned before in most cases, asset management processes and principles have been developed and refined for an organization over a period of time. It would be detrimental to these proven developed processes if they were changed to shoe horn into a system just for the sake of a lack of planning and design.

 Respectively, consideration should be given to the implementation of any other business support systems to accommodate the business processes of the core business of the organization. What this means is that as well as the core business system being implemented to fit the organization, the other support systems should be implemented to accommodate the respective business support functions with the core business in mind.

Some of the key questions to consider when designing system implementation is:

·       What do we do?

·       How do we do it?

·       What information do we require to make decisions on the above?

·       What is the key link to the information that we require?

·       Where can this information come from?

Thoughtful answers to these questions are integral to the successful implementation of a core or asset management system.

Another consideration in water asset management is to work from the whole to the part. This principle can be found in various disciplines and industries and Wide Bay Water utilizes it in numerous aspects of its business. As an example, water demand management requires the whole picture to be a known factor before it can be broken down to individual consumptions and hence a difference determined, i.e. system losses. As with water demand management, asset management can also improve with knowing where anomalies occur to help determine why. Informed and effective business decisions can then be made. This leads to the added value of relating a spatial aspect to the components (assets).

Asset management and its supporting systems should use the same principle and consider what the whole picture is before it is broken down into its individual components. Once this is done the individual information components can be aggregated to analyze the difference and use this to make business decisions.

Keywords business value; capital deferment; integration; functionality

                            <Back to Topic 6>

Sustainable implementation of network analysis decision-making tools in the operational environment

Sérgio T. Coelho * & Dalia Loureiro**

* LNEC – Natl. Civil Eng. Lab., Av. Brasil, 101, 1700-066 Lisbon Portugal,

** LNEC,


Keywords Water distribution models, implementation, data-intensive tools, decision-making.

Abstract Water distribution network analysis models are the single most influential tool in understanding existing or projected networks, and a precious aid in the assessment of evolution scenarios. As such, they are at the core of the decision-making process in any short-, medium-, or long-term asset management strategy. However, they are still less than well-established in many parts of the world, particularly in the operational and technical management environments.

Figure 1 Information systems within a water utility

Experience shows that it is only possible to fully realise the potential of network models in a water utility when there is an internal structure explicitly devoted to the tasks of building, managing and updating them in a sustainable and efficient manner. Externally developed models, where often not enough attention is paid to capability building and organisational issues, have a much greater chance of being abandoned by the utility, and after relatively short life spans.

Conversely, the assimilation of model-building knowledge by the utility and the establishment of specific, tried-and-tested internal procedures have shown to be a successful formula that spurs a number of parallel innovative advancements in related areas within the utility. The internal development of simulation models is a powerful strategic driver for the process of information integration across the various information systems (IS) in the utility – GIS, customer/billing system, SCADA system, maintenance IS, laboratory IS (LIMS), etc.

Water utilities are massive data generators; such data is, in turn, a precious asset to the organization. Water network models are a prime example of an engineering-oriented application that is very demanding on the quantity, scope and quality of the data it deploys, particularly if correctly and sustainably developed. It so happens that such information is at the very core of the engineering decision-making process, and beyond. The information requirements involved in the well-supported establishment of a network model place demanding questions to the other systems – particularly the GIS, SCADA and billing IS – that inevitably prompt an increase in quality and depth.

It makes sense, therefore, that the development of network modelling within a water utility is approached in a structured and systematic way, in order to ensure the highest possible benefit in terms of the effort and resources invested – both in the generation of the initial solutions and in their maintenance and expansion throughout their lifespan (Figure 2 shows a recommended phased strategy for model development).

The National Initiative for the Development of Simulation Models (INSSAA), a program ran in Portugal between 2003 and 2006 with the objective of promoting the development and use of simulation models by the utilities, explicitly in the operational and technical management tasks, is thought to be a valuable example of the above principles.

Figure 2 Main stages of model development

Based on phased development, training and knowledge-building  strategies, common to the set of 9 participating utilities, the following main components were covered:

·  Human resources – modelling team set-up, mission definition and organisational fit; training in network analysis model development, use and maintenance.

·  Planning, development, and commissioning by the utility teams of fully functional, calibrated models of network sectors, with a strategy for full territorial coverage.

·  Set-up of data and organisational mechanisms and procedures for the integration of the developed tool, its efficient management and its integration with the other IS across the utility.

This paper presents the INSSAA program and its stages of implementation, and focuses on the results obtained, including the core gains; the main data, human and organisational difficulties and hurdles; and the ways found to overcome them. A discussion is undertaken on the global issues involved in the efficient creation and maintenance of engineering-oriented data-intensive tools, for the operational and technical management environments of water supply utilities.



            <Back to Topic 6>


Topic 7 – Engineering developments

Chair: Dana Vanier


Strategic selection of materials for wastewater networks

S. Sægrov*, L. S. Hafskjold**, P. Kristiansen*** and T. Skaug****

* SINTEF Water and Environment, Klæbuveien 153, 7465 Trondheim, Norway,

** SINTEF Water and Environment, Klæbuveien 153, 7465 Trondheim, Norway,

*** Oslo municipality, Herslebs gate 5, 0506, Oslo, Norway,

**** Oslo municipality, Herslebs gate 5, 0506 Oslo, Norway,

Abstract The city of Oslo is rethinking its strategies for selection of materials to the wastewater networks, in particular pipes and manholes. The new strategy is meant to provide a best possible performance and low costs for maintenance and repairs in a 100 years perspective. It includes selection of materials for new constructions and renovation works and evaluation of existing pipe materials used. Their approach is broad, including all aspects that are important to fill the performance goals. i.e. reliable sanitary service, enough capacity to avoid flooding and no pollution to local receiving waters. The strategy comprises the combination of materials and construction practise as well as the relationship between materials and construction practises used and needs for operation and maintenance. This paper brings an outline of criteria for the future management of wastewater network in Oslo, and it concludes that attention on systems for documentation of all steps in the life cycle is a crucial instrument to maintain a sustainable development.

Keywords life cycle assessment; pipe materials; wastewater

                             <Back to Topic 7>

Degradation of lining systems for drinking water networks

S. Sægrov*, A. Bjørgum**, E. Rodum***, M. Haugen****, L. A. Wermskog*****, K. Reksten******, F. Bjørgum*******

* SINTEF Water and Environment, Klæbuveien 153, 7465 Trondheim, Norway,

** SINTEF Water and Environment, Klæbuveien 153, 7465 Trondheim, Norway,

*** SINTEF Water and Environment, Klæbuveien 153, 7465 Trondheim, Norway,

**** SINTEF Water and Environment, Klæbuveien 153, 7465 Trondheim, Norway,

***** Oslo municipality, Herslebs gate 5, 0506, Oslo, Norway,

****** Oslo municipality, Herslebs gate 5, 0506, Oslo, Norway, kjartan

******* Trondheim municipality, Erling Skakkes gate 14, 7004 Trondheim,

Abstract Samples of different lining methods have been collected and analysed in laboratory. The investigation comprises cement mortar lining, epoxy lining, and cured in place renovating methods (CIP). The result demonstrates that modest corrosion has occurred after relining for cement mortar lining. The epoxy based lining has no corrosion although the attachment to the pipe wall is weak. The CIP pipes do not show any sign of degradation.

Keywords drinking water networks; laboratory investigation; lining; renovation

                           <Back to Topic 7>

Planning the upgrading of urban water networks – is there a need for the CARE‑approaches

S. Sægrov*, F. Sjøvold** & L.S. Hafskjold***

*SINTEF Water and Environment, Klæbuveien 153, 7465 Trondheim, Norway,

**SINTEF Water and Environment, Klæbuveien 153, 7465 Trondheim, Norway,

***SINTEF Water and Environment, Klæbuveien 153, 7465 Trondheim, Norway,

Abstract The European Union supported in 2001-2005 two major projects on the upgrading of water networks, CARE‑W (Computer Aided Rehabilitation of Water networks) and CARE‑S (Computer Aided Rehabilitation of Sewer and Storm water networks). They were carried out by large research teams from 10 countries comprising 15 institutes and 20 cities. Complete methods were developed supporting as well rehab strategies (financial planning), tactics (selection of projects) and technology selection. The systems were tested at the end user sites and valuable experiences were gained. CARE‑W and CARE‑S resulted in high-quality manuals and software prototypes. However, no complete commercial structure for selling and developing the systems were developed. This is still a barrier in marketing and applying the CARE systems worldwide. The paper gives a demonstration of the need for rehabilitation of water networks internationally and approaches to reach an improvement. The CARE‑W/S contribution to this is discussed, and user experiences and recent developments described. The paper is completed by a list of recommendations for cities that is approaching a modern urban water network management.

Keywords condition analysis; strategic planning; selection and ranking of projects; selection of renovation technologies; urban water networks

                             <Back to Topic 7>

Sewer asset management: from visual inspection survey to dysfunction indicators

M. Ibrahim*, F. Cherqui*, P. Le Gauffre* & C. Werey**

* LGCIE, INSA-Lyon, 20 av. Einstein, F-69621 Villeurbanne Cedex, France ; Université de Lyon, Lyon, F-69003, France ; Université Lyon 1, Lyon, F-69003, France,

** UMR Cemagref-ENGEES GSP, 1 quai Koch, BP 61039, 67070 Strasbourg Cedex, France,

Abstract Asset management is an increasing concern for wastewater utilities and companies. Criteria are developed for supporting the definition of investigation and rehabilitation programs. Dysfunction indicators contribute to the calculation of criteria, using expert rules. These indicators are mostly based on visual inspections, which provide major information. However, difficulties remain in the translation of visual inspection survey into dysfunction indicators. This article presents a methodological approach aiming to fill this lack. In the framework of the French RERAU program (Rehabilitation of urban sewer networks) a methodological approach has been developed in order to convert visual inspections of sewer segments into four possible condition grades {1, 2, 3, 4}, grade 4 corresponds to the worse condition. Three complementary procedures are thus executed: (a) expert rules based on sequences of observation codes, (b) comparison of single score to threshold and (c) rules based on analysis of segment profiles (scores distribution). An experiment lead in the Bas-Rhin (France) illustrates the different steps of the methodological approach and the applicability of the RERAU methodology on CCTV data. Moreover, confrontation between expert assessment of sewer segments (condition grade) and calculated scores has demonstrated the necessity of considering diagnosis imperfection, which may lead to misclassification in some cases. The algorithm proposed in this article aims to minimize a cost function with costs assigned to false positive diagnosis test (segment classified in worse condition than experts’ opinion) and false negative diagnosis test (segment classified in better condition than experts’ opinion). The algorithm is described in detail and applied to an example. Thus imprecision of assessment is taken into account: the threshold is chosen as to be the most efficient (in term of cost). This approach is generally applicable to numerous domains, when levels of performance need to be defined.

Keywords dysfunction; grade; indicator; misclassification cost; threshold; visual inspection; sewers

                             <Back to Topic 7>

Planning the rehabilitation of the Las Vegas water distribution network using CARE-W

A. Vanrenterghem-Raven *, P. Sampson**, S. Hafskjold*** & J. Rostum****

* PhD; Research Assistant Professor; Polytechnic University; Dept of CE; Metrotech Center 6; Brooklyn, NY 11201;

** Pat Sampson; Las Vegas Valley Water District (LVVWD); 1001 South Valley View Blvd; Las Vegas, Nevada 89153;

*** Sigurd Hafskjold; SINTEF Building and Infrastructure; Water and Environment; Klæbuveien 153 NO-7465 Trondheim; NORWAY;

**** Jon Rostum, Ph.D; SINTEF Building and Infrastructure; Water and Environment; Klæbuveien 153 NO-7465 Trondheim; NORWAY;


Abstract In July 2006, the Las Vegas Valley Water District (the District) awarded a team of researchers led by Polytechnic University, New York, NY, (Poly) and SINTEF, Trondheim, Norway, (the Research Team), a contract in view of implementing an advanced Asset Management program centered on CARE-W (Computer Aided Rehabilitation of Water Networks) for the planning of the rehabilitation of their 3,800 miles of buried pipes. The focus of this project is to provide LVVWD with tools to improve their planning and decision making process, plan and justify for potentially necessary water rate increases based on properly collected and analyzed data. This paper describes:

·       The conditions at LVVWD that led to this effort as well as the objectives pursued

·       The CARE-W-centered tools and program put in place

·       The current advancement of the project as well as future plans

Keywords water networks; asset management; rehabilitation planning program; implementation

                             <Back to Topic 7>

Topic 7 – Engineering developments (water supply)

Chair: Will Williams & Paul Conroy


Self-cleaning networks put to the test

E.J.M. Blokker*, P.G. Schaap* & J.H.G. Vreeburg**

* Kiwa Water Research, Groningenhaven 7, Nieuwegein, the Netherlands,

** Kiwa Water Research, Delft University of Technology


Abstract The Dutch drinking water companies design their water distribution systems according to the so-called New Design Rules, which allow for smaller and more branched distribution systems. Due to higher velocities these design rules hypothetically lead to resuspension and removal of particles and thus to self-cleaning networks. Three distribution networks were selected to test the validity of the new design rules. The first is a conventional (looped) network from 1986. The second network was built in 2002 and is branched but with relatively large diameters (110 and 63 mm). The third one was built in 2004 according to the new design rules: a branched PLUS network (with, at the ends, pipe diameters as small as 40 mm). By means of particle counting, flow measurements and flushing experiments it was proven that the branched PLUS network is self-cleaning, the branched network is partly self-cleaning and in the looped network sediment is building up leading to an increased discoloration risk.

Keywords asset management; self-cleaning networks; distribution network design; water quality

                             <Back to Topic 7 (water supply)>

The impact of pipe segment length on break predictions in water distribution systems

M. Poulton*, Y. Le Gat** & B. Brémond***

* Cemagref, 50 avenue de Verdun 33612 CESTAS France,

** Cemagref, 50 avenue de Verdun 33612 CESTAS France ,

*** Cemagref, 50 avenue de Verdun 33612 CESTAS France,


Abstract Break prediction models are important tools in asset management and rehabilitation planning of water distribution systems. To some extent though, they may depend on the configuration of the network as defined in the company database.  This paper examines the effect of the length of pipe segments on break predictions and proposes methods for eliminating short sections of pipe sandwiched between longer pipes and for concatenating segments of the same (or similar) nature. A study was conducted on a large French network using a set of rules and length threshold values to prepare several different data files.  These data files, containing the pipes' attribute information and associated break histories were used with the statistical model, LEYP, to make break predictions for each segment.  The results were compared using a number of indicators. Ultimately, there would appear to be little benefit in concatenation as the model is likely to become less sensitive and less able to distinguish between risk factors.

Keywords water distribution systems; break prediction; database management; pipe segment length

                             <Back to Topic 7 (water supply)>

Strategies for integrating alternative groundwater sources into the water supply system of the Algarve, Portugal

T.Y. Stigter*, J.P. Monteiro*, L.M. Nunes*, J. Vieira**, M.C. Cunha**, L. Ribeiro*** & H. Lucas****

* FCMA - Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal,,,

** FCTUC - Departamento de Engenharia Civil, Pólo II - Universidade de Coimbra, 3030-290 Coimbra, Portugal,,

*** CVRM/Geo-Systems Centre - Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisboa, Portugal,

**** Águas do Algarve, S.A., Rua do Repouso 10, 8000-302 Faro, Portugal,

Abstract The future availability of drinking water in the Portuguese Algarve region is put at risk by the continuing rise in water demand, the decreasing amount of rainfall and the increasing potential for the occurrence of more-intense or longer-lasting drought periods, related to global climate changes. Moreover, tourism and agriculture, the two main economic activities in the region, rely heavily on the available water resources, particularly during dry periods, posing a threat to the public water supply. Until recently, the multimunicipal public water supply system (MPWSS), created in 2000 and managed by the regional Water Utility Águas do Algarve, was entirely based on surface water provided by large reservoirs. During the extreme drought of 2005 serious consequences of this single-source strategy were felt, when several reservoirs reached their exploration limit, and could not satisfy the water demand.

During that period, the regional water utility realized that in order to guarantee public water supply in the long-term, a strategy based on an integrated water resources management (IWRM) scheme is needed. Therefore, alternative water sources need to be integrated into the MPWSS, the most important one of which is groundwater, the principal source of public supply in the Algarve before the existence of the MPWSS. Currently, a decision-aid model that will promote the IWRM in the region is being developed. In this paper one of the necessary tasks for that model is highlighted, namely a screening selection of groundwater wells with sufficient quantity and quality to allow their integration into the water supply network. The quantitative criteria are based on aquifer properties and well yields. Qualitative criteria are based on the construction of water quality indices that reflect the well’s degree of violation of drinking water standards for a given set of variables. The different variable sets include “toxic variables (i.e. pesticides, trace metals, PAHs)”, “nitrate and chloride”, “iron and manganese” and “microbiological parameters”.

The results indicate that over 40 existing municipal wells, with a total yield of more than 1000 l/s, can be integrated into the MPWSS. An additional 25 wells (600 l/s) will be usable after appropriate disinfection and iron and manganese removal, or mixing with surface water.

Keywords Algarve; groundwater; public water supply; standard violation index

                             <Back to Topic 7 (water supply)>

Technical condition assessment of metallic water supply pipes as part of their rehabilitation planning

H.-C. Sorge*

* Institute for Research in Underground Construction and Pipeline Technologies, FITR Weimar e.V., Georg-Haar-Str. 5, 99427 Weimar, Germany,

Abstract Up to now the technical condition assessment to specify the necessary need for rehabilitation of water supply pipes is oriented on parameters like breakage rates, water losses and the need of costs for replacement rates. In addition, an important parameter is the technical operating life of the supply pipe, affected by the estimate of the development of existing and acceptable breakage rates. However the choice of alternative and less expensive techniques to renovation is not possible by determining of breakage rates. A new basic approach and topic of this paper is the presumption, that besides the expansion of breakage rates technical condition and also the technical operating life of water supply pipes are quantifiable by the remaining load-bearing capacity of these underground pipes. The necessary tool to determine the remaining load-bearing capacity and the actual technical state of a pipe section are technical analyses and a new prognosis procedure, presented in this paper. Through means of the technical analyses on metallic water supply pipes another important parameters will be regarded. From this parameters so called indicators of deterioration are generated. Due to the indicators of deterioration it is possible to determine, to compare and to assess the technical condition of pipe samples from several pipe lines. By assuming of an approximately linear-progressive structural deterioration it is possible to predict the time of first and following water losses (in case of cracks) or the time of total failure (in case of lower deviation of the load bearing capacity). In both case the end of the technical operating life is reached. The technical analyses and prognosis procedure are an option for water utilities to refine and improve the prediction of the technical operating life or remaining operating life of their water supply pipes. Furthermore the technical analyses allowed assessments of the technical conditions without preceded breakages or failures (otherwise necessary to estimate breakage rates). Thus, this method prevents breakages or failures and is a contribution to a sustainable preservation of water main assets. Finally a useful and sustainable investment of financial resources regarding planning of rehabilitations (renewal or renovation) and a high quality of supply in urban water utilities is guaranteed.

Keywords life cycle engineering; assessment methods; maintenance; water main assets

                             <Back to Topic 7 (water supply)>

Strategy for the development of optimized flushing plans

A. Korth*, S. Richardt** & B. Wricke***

*DVGW Water Technology Center Karlsruhe (TZW), Branch Dresden, Germany,

**Sebastian Richardt, DVGW Water Technology Center Karlsruhe (TZW), Branch Dresden, Germany, richardt@tzw‑

***Burkhard Wricke, DVGW Water Technology Center Karlsruhe (TZW), Branch Dresden, Germany, wricke@tzw‑


Abstract One aspect to be considered in asset management are the costs for measures to safeguard the drinking water quality in the network. The main reason for visible quality changes is the mobilisation of loose sediments which leads to customer complaints. To avoid brown water the deposits have to be flushed out of the network before a critical level is reached. The distance of time between the flushing procedures depends on the deposit formation process in the pipes. As the velocity of the deposit accumulation is different, in dependence on the material and hydraulic situation, a strategy was developed at TZW to determine the sediment forming processes as a basis for establishing network-specific flushing plans. An optimized flushing plan offers a minimization of expenditures for the water supplier and an optimization of the cleaning effect. Through this, the water supplier has a clear basis for the calculation of costs for the regular cleaning of the distribution network.

Keywords brown water; drinking water quality; deposits; turbidity measurement

                             <Back to Topic 7 (water supply)>


Topic 7 – Engineering developments (wastewater)

Chair: Sveinung Saegrov


Advances in the modelling and optimisation of sewerage infrastructure investment planning

G. Heywood*, C. Pearman** & J. Lumbers***

* Tynemarch Systems Engineering, Crossways House, 54-60 South Street, Dorking, Surrey, UK,

** Tynemarch Systems Engineering, Crossways House, 54-60 South Street, Dorking, Surrey, UK,

*** Tynemarch Systems Engineering, Crossways House, 54-60 South Street, Dorking, Surrey, UK,

Abstract Sewerage infrastructure assets account for a large proportion of the asset value of UK water companies, and yet in recent years have been subject to relatively low rates of investment. At the 2004 Periodic Review, Ofwat noted that analysis to support capital maintenance plans was weaker for sewerage infrastructure assets than for water infrastructure or non-infrastructure assets.

This paper describes an approach to assessing the investment requirements for sewerage systems that combines a number of technical advances in modelling sewer failures and consequence assessment using primary data at the pipe level, together with derived data from other sources, as well as topographical information.

Models of sewer condition deterioration, collapse rate, blockage rate and flooding and pollution consequences have been developed, and are being used as the basis for the identification of optimal investment requirements to meet defined targets for service to customers.

Deterioration models have been derived from detailed sewer defect data from CCTV surveys, utilising both the density and severity of defects recorded. The deterioration modelling has made use of improved estimates of the dates at which sewers were laid, based on a unique approach to the automated analysis of historical maps.

All models have been developed using data recorded at the pipe level, and may be applied at the pipe, drainage area or cohort groups of sewers as required.

Consequence models make use of topographic variables derived from digital terrain model data. These models identify the point at which water would reach the surface following a blockage or collapse, and the approximate route of overland flow.

Models have been developed and applied for several UK water and sewerage companies. The models developed are being used to identify optimal capital maintenance requirements, including trade-offs with increased or decreased operational activity. Proactive survey results and intervention options are included in the analysis.

Keywords sewerage; deterioration modelling; investment planning

                             <Back to Topic 7 (waterwater)>


Attaining the most sustainable solution in stormwater control in England and Wales

S. Kennedy* & L. Lewis**

* The Management School, The University of Sheffield, 9 Mappin Street, Sheffield, S1 4DT, U.K.,

** The Management School, The University of Sheffield, 9 Mappin Street, Sheffield, S1 4DT, U.K.,


Abstract Conventional Urban Drainage Systems (CUDS) are increasingly recognised to be an inherently unsustainable solution to stormwater control (Gunasekara and Bray, 2005). The approach is proving to have considerable detrimental impacts such as increasing the risk of flooding elsewhere in a catchment and contributing to water quality problems by  transporting, and thus transferring, pollutants quickly from urban areas into watercourses or  groundwater. Conversely, Sustainable Urban Drainage Systems (SUDS) attempt to mimic natural drainage patterns and represent a fresh approach to stormwater control.

This paper recognises SUDS as the most sustainable way to drain new developments and argues that they should be part of strategic asset decision making. Further, if both the capital and operational costs are considered using a whole life costing approach, the latter will often show SUDS as the most cost effective drainage option available to a developer as well as a well-designed scheme adding value to the homes of a residential development. Despite being able to articulate such benefits, the implementation of SUDS by developers is not a widespread practice in England and Wales. However, as SUDS are an increasingly popular approach in mainland Europe and Scotland, this paper investigates the reasons as to why this is the case.

In doing so, the paper compares SUDS implementation in England and Wales, which has had limited success, with that of Scotland, where the use of SUDS is now standard practice (McKissock et al, 2003). Legislation in Scotland has created an understanding between stakeholders and facilitated the uptake of SUDS as developers are sure of adoption of the shared public SUD systems providing predetermined conditions are met. As no such legislation exists in England and Wales who should be taking long-term responsibility for SUDS is not clearly defined. This comparison of SUDS practice amongst UK countries suggests that the regulatory framework in England and Wales is neither facilitating the best management of assets nor the implementation of the most sustainable drainage solution.

This observation notwithstanding, there are many organisations which champion the implementation of SUDS in England and Wales. Thus the paper focuses on the real versus perceived barriers to the use of SUDS and how these might be overcome in the interests of more efficient asset management in the longer term. Many of these barriers relate to the lack of experience of SUDS and a shortage of historical information concerning costs and risk management. This paper suggests these matters can be overcome using a combination of training in SUDS, conferences on sustainable drainage, SUDS networks and site specific feasibility reports, using SUDS experts and written in the language of developers/ local authorities are also advocated to aid the removal of many barriers.

Keywords adoption; barriers; legislation; local authorities; Sustainable Urban Drainage Systems (SUDS)

                             <Back to Topic 7 (waterwater)>

Economic rehabilitation of sewer systems by ground penetration radar investigations

H. Stepkes*, J. Zimmermann**, K. Müller**, M. Siekmann* & J. Pinnekamp*

* Institute of Environmental Engineering, RWTH Aachen University, Mies-van-der-Rohe-Str. 1, 52074 Aachen, Germany;

** Research Institute for Water and Waste Management (FiW e.V.) at the RWTH Aachen University, Mies‑van‑der‑Rohe‑Str. 17, 52056 Aachen, Germany;


Abstract The ground penetrating radar (GPR) is a well known technique for the detection of dislocations, which caused by geological or human made influences. Especially cavities and bedding defects in the area of buried sewers may lead to sudden lowering of above lying built-up areas. Within the scope of a research project carried out by the Institute of Environmental Engineering (ISA) of the RWTH Aachen University, it was studied in which way and how rapidly these cavities develop, caused by damages at the sewers. For early detection of these bedding defects, the GPR process presents itself. The visualization and combination of the information of data measured by GPR was subject of an additional research project of ISA, so that the operators of sewer systems will dispose of an additional tool for assessment of the sewer state, for prioritization of rehabilitation necessities and for the choice of appropriate rehabilitation strategies.

Keywords bedding defects; cavity formation; data management; ground penetrating radar; infiltration; urban drainage

                             <Back to Topic 7 (waterwater)>

Objective condition assessment of sewer systems

K. Müller* & B. Fischer**

* Research Institute for Water and Waste Management at the RWTH Aachen University, Mies-van-der-Rohe-Str. 17, 52074 Aachen, Germany;, Phone: +49 (0) 2 41 - 80 2 6825, Fax: +49 (0) 2 41 - 87 09 24

** RWTH Aachen University, Department of Medical Informatics, Pauwelsstr. 30, 52057 Aachen, Germany,


Abstract Apart from guaranteeing the proper function of sewer systems in day to day operation, sewer system operators also must ensure that the substance of this valuable public asset is preserved for the future. This requires an all-encompassing, periodical or demand-oriented, high-accuracy condition assessment to issue respective maintenance procedures in time. The quality of condition assessment relies on the technical limits set by the TV systems used. Further, the qualification and motivation of the camera operator on the one hand, and the subjective perception on the other hand lead to considerable inaccuracies in condition rating. As a result, neither the classification and evaluation of defects nor the scheduling of repairs can be implemented with the desired degree of accuracy.

The OZEK research project therefore pursues the aim of significantly reducing these system-inherent sources of error. The intention is to improve the condition assessment making it more objective and reliable by digital image processing and classification methods. Extensive test and training condition data has been acquired by Stadtentwässerung Braunschweig, Germany, in its daily routine with the PANORAMO® inspection method. At current, 99.6% sockets and 84.4% connections are detected in 13km of pipe.

Keywords sewer system, condition assessment, inspection, image processing, PANORAMO®                            

<Back to Topic 7 (waterwater)>

Technical management of sewer networks - a simplified decision tool

V. Sousa*, M. Silva**, T. Veigas***, J. Saldanha Matos***, J. Martins**** & A. Teixeira****

* Escola Superior de Tecnologia do Barreiro/IPS, Rua Stinville nº14, Barreiro, Portugal,

** HIDRA - Hidráulica e Ambiente. Lda, Av. Defensores de Chaves nº31 1º Esq, Lisboa, Portugal,

*** Instituto Superior Técnico, Avenida Rovisco Pais, Lisboa, Portugal, or

**** SIMTEJO - Saneamento Integrado dos Municípios do Tejo e Trancão S.A., Av. Defensores de Chaves  45, Lisboa, Portugal, or


Abstract Priority of actions and investments in sewer technical asset management may be based on evaluation of sewer performance with respect to the risk and magnitude of failure. The present paper describes a general expert system developed to support operation and maintenance activities on sewers. At this stage the tool was developed to identify the critical reaches of the system and establish priority in sewer cleaning and inspection operations in order to define cleaning and inspection frequency. It aims to reduce the number of structural and functional failures and, as a result, reduce both emergency repair and preventative costs. The selected approach was based in a “failure oriented forecast” taken in account selected parameters and different data: sewer diameter, slope, material, age and depth. The approach was developed for the technical asset management of the collection network explored by SIMTEJO and applied to the Chelas sewer system, one of the three main sewer systems of Lisbon city, in Portugal.

Keywords cleaning; decision tool; inspection; maintenance; sewer networks; technical asset management

                            <Back to Topic 7 (waterwater)>