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** &
*
** Mott MacDonald,
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
H.
Mutikanga*, J. Sseguya** & K. Vairvamoorthy***
* National
Water and Sewerage Corporation, P.O.
Box 7053 Kampala, Uganda,
harrison.mutikanga@nwsc.co.ug
** UNESCO-IHE P.O Box
3015,2601 DA Delft,
Nertherlands, segyjp@yahoo.co.uk
*** UNESCO-IHE P.O Box 3015, 2601 DA Delft, Nertherlands k.vairavamoothy@unesco-ihe.org
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
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, pedro.miguel.barata@clix.pt
** National Laboratory of Civil
Engineering, Av. Brasil, 101, 1700-066-Lisboa, Portugal, halegre@lnec.pt
*** University of Minho, Campus de Gualtar, 4710 - 057 Braga, Portugal, jvieira@civil.uminho.pt
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
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, didia.covas@civil.ist.utl.pt
*** Instituto Superior
Técnico, Technical University of Lisbon, Av. Rovisco Pais, 1049-001-Lisbon,
Portugal, ajm@civil.ist.utl.pt
**** LNEC - National Laboratory of Civil Engineering, Av. Brasil, 101, 1700-066 Lisbon, Portugal, pduarte@lnec.pt
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
Scheduling
renewal of water supply distribution system – a case study in
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 a.j.monteiro@engidro.pt
** Management Planning and Control, E
*** ENGIDRO Consultant, R. Luis Cristino da Silva,
LT 248, 2º 98E, 1950-172-Lisboa, Portugal engidro@engidro.pt
**** Distribution Operation Department, E
*****
New Supplies Department, E
****** Managing Board Director, EPAL, Av. da Liberdade, 24, 1250-144-Lisboa, Portugal, abfranco@epal.pt
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
Keywords asset management; deterioration model; life cycle analysis; multi-criteria analysis; water infrastructure renewal
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
** Cardno (Qld) Pty Ltd, Level 1, 5
Abstract The Sarawak State Government of Malaysia undertook a major review
of water supply services provided within
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
V. Nikolov* & T. Peitchev**
*
Assoc. Prof. Dr., President, Bulgarian Water Association,
** Prof. Dr. Eng., Vice President, Bulgarian Water Association, 1 H.
Smirnenski Blvd.,
Abstract As of
· 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
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
* Consulting engineer, Via Libertà 56 - 90143
Palermo (Italy), Tel. +39 (091) 301969,
claudioarena1@yahoo.it
** Consulting engineer, Via Principe di Villafranca,
33 - 90141 Palermo (Italy), Tel. and fax: +39(0)91323529,
genco.m@libero.it
*** 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,
mariorosario.mazzola@fastwebnet.it
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
Public private partnership models for developing water servicing
D. Stephenson* & G. Mokete**
*
**
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
Asset management and regulation: the Portuguese case
J. M. Baptista*, J. S. Pires** & J. Almeida***
*
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
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, karl@rohrhofer.at
** E. Cabrera, University Valencia, Institute for Water Technology,
ES-46071 Valencia, Camino de Vera s/n.
Apdo.22012, Spain, qcabrera@gmf.ups.es
*** F. Cate,
INTERIVAL, A-1170 Vienna, Carl
Reichert-Gasse 28, Austria, office@interival.at
****Th. Derntl,
G.W.C.C. Regensburg, D-93059 Regensburg, Lappersdorfer Str. 28, Germany,
otto.kehrer@kehrer-planung.de
*****
P. Gortan,
Austrian Water, A-7540 Guessing, Europa Strasse 1,
******
A.
Jovani, ERRU, Drinking Water & Sewerage Regulatory Entity, Tirana, Blvd.
Zogu I Pare, P.57, Ap. 19, Albania, arjanjovani@yahoo.com
*******
M.
Olšinská, BVS a.s. Bratislavská
vodárenská spoločnosť a.s., SK-826 46 Bratislava, Prešovská 48,
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
Keywords asset
management; benchmarking; cost optimization; efficiency; guidelines; standards;
strategic asset management; performance indicators; research; sustainability;
utility; wastewater disposal; water supply
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.
** Canadian Water and Wastewater Services,
tdellison@cwwa.ca
***
Veolia Water,
dominique.olivier@veoliaeau.fr
**** GREIF- CGAER, Ministère de l’agriculture,
jean-luc.redaud@agriculture.gouv.fr
*****
OEKOREAL,
A-1170 Vienna, Carl Reichert-Gasse 28,
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
Strategic infrastructure asset management: concepts, ‘schools’ and industry needs
H. Alegre*
* National Laboratory of Civil
Engineering, Av. Brasil, 101, 1700-066-Lisboa,
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
Ownership and
management of water utility assets in developing countries: case
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,
eija.vinnari@tut.fi
** Department of Civil and Construction
Engineering,
*** Tampere University of Technology,
Institute of Environmental Engineering and Biotechnology, PO Box 541, FIN-33101
Tampere, Finland, jarmo.hukka@tut.fi
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
Keywords management; ownership; investment planning; assets; developing countries; Kenya; institutional aspects; regulation
I. Aguilar-Benitez* & J. D. Saphores**
* Associate Researcher and Corresponding
Author, El Colegio de
** Associate Professor, Civil and
Environmental Engineering, Planning, Policy, and Design Department, and
Economics Department, University of California, Irvine, 92697, USA,
saphores@uci.edu
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
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
Keywords performance indicators; accountability; professionalization
Topic 3 – Target definition and assessment of performance
Chair: Jaime Melo Baptista
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), demarinis@unicas.it
** Dipartimento di Meccanica, Strutture e Ambiente e Territorio (DiMSAT),
University of Cassino, via Di Biasio, 43, Cassino, Frosinone (Italy) gargano@unicas.it
*** Centre for Water Systems, University of Exeter,
Harrison Building, North Park Road, Exeter, Devon (UK)
Z.Kapelan@exeter.ac.uk
**** Centre for Water Systems, University of Exeter,
Harrison Building, North Park Road, Exeter, Devon (UK)
M.S.Morley@exeter.ac.uk
***** Centre for Water Systems, University of Exeter,
Harrison Building, North Park Road, Exeter, Devon (UK)
D.Savic@exeter.ac.uk
****** Dipartimento di Meccanica, Strutture e Ambiente e Territorio (DiMSAT), University of Cassino, via Di Biasio, 43, Cassino, Frosinone (Italy) c.tricarico@unicas.it
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
Failure data analysis – a Dutch case study
I.N. Vloerbergh*
& E.J.M. Blokker*
* Kiwa Water Research,
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
K. Ishii* & T. Katsumata**
* Engineering General Institute,
Japan Water Works Association,
** Engineering General Institute,
Japan Water Works Association,
Abstract
One of the most urgent challenges in
Keywords assessment of
performance; evaluation of pipeline replacement project; performance indicator
(PI); earthquake-resistant pipeline; cost to water supply; leakage rate
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;
roman.neunteufel@boku.ac.at
** Graz University of Technology, Institute of
Urban Water Management and Water Landscape Engineering, Stremayrgasse 10/I,
A-8010 Graz, Austria; theuretzbacher@sww.tugraz.at
Abstract Nowadays various benchmarking studies are aiming to improve the
performance in the water supply sectors of many countries. In
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
A. Cardoso*,
S. T. Coelho**
& J. Matos***
* Laboratório Nacional de Engenharia Civil, Av.
do Brasil 101, Portugal, macardoso@lnec.pt
**
Laboratório
Nacional de Engenharia Civil, Av. do Brasil 101, Portugal, stcoelho@lnec.pt
*** Instituto Superior Técnico, Av. Rovisco Pais, Portugal, jsm@civil.ist.utl.pt
Abstract Urban sewer systems constitute a significant patrimony in
Keywords performance assessment; urban sewer systems; rehabilitation
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 @insa-lyon.fr
** Veolia Eau, SLA, 67 quai Charles de Gaulle, 69414 Lyon Cedex, France. david.poinard@veoliaeau.fr
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
Keywords asset management; efficiency;
multicriteria
analysis; prioritization; rehabilitation; water network
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: rita.ugarelli@mail.ing.unibo.it
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 (
Keywords CARE‑S; CCTV; maintenance planning; Reggio Emilia; sewer asset
Asset management in Copenhagen Energy Sewerage Department
J. Elkjær*
* Analyst, Copenhagen Energy Sewerage Department,
Orestads Boulevard 35, 2300 Copenhagen S,
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
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.
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
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, dsklar@pirnie.com,
Tel (303) 316-6507, Fax (303) 316-6599
** Rebecca F. West, Director of Technical
Services,
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
·
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
Topic 5 – Target definition and assessment of risks
Chair: Scott Haskins
J. Dirksen*, A. Goldina**, J.A.E. ten
Veldhuis* & F.H.L.R. Clemens*
* Delft University of Technology,
** AG Advies, Warmond, the
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
Hazard identification and risk analysis of water supply systems
L. Tuhovčák* & J. Ručka**
* Brno University of Technology,
** Brno University of Technology,
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
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, a.ribeiro@aguasdoalgarve.pt
**
Águas do Algarve, S.A.,
Rua Repouso, 10, 800-302 Faro, Portugal, h.lucas@aguasdoalgarve.pt
***
Águas do
Algarve, S.A., Rua Repouso, 10, 800-302 Faro, Portugal, j.sousa@aguasdoalgarve.pt
****
Águas do Algarve, S.A., Rua Repouso, 10,
800-302 Faro, Portugal, r.coelho@aguasdoalgarve.pt
*****
Águas do Algarve, S.A., Rua Repouso, 10,
800-302 Faro, Portugal, m.viriato@aguasdoalgarve.pt
******
Águas do Algarve, S.A., Rua Repouso, 10,
800-302 Faro, Portugal, s.dias@aguasdoalgarve.pt
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
In the beginning of 2005 the whole region of
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
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
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, ppraca@lnec.pt
** LNEC, ipinheiro@lnec.pt
*** 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 (http://care-w.unife.it/), 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
|
|
|
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.
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, fernando.fernandes@cm-lisboa.pt
***
Laboratório
Nacional de Engenharia Civil, Av. do Brasil 101, 1700‑066 Lisboa,
Portugal,
ncharneca@lnec.pt
**** Laboratório Nacional de Engenharia Civil, Av. do Brasil 101, 1700‑066
Lisboa, Portugal,
cdavid@lnec.pt
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
Topic 6 – Asset data and information systems
Chair: Chris Royce & Cushla Anich
E. Renaud*, JC. De Massiac**, B. Brémond***
& C. Laplaud****
* Cemagref, 50 avenue de Verdun
33612 CESTAS France, eddy.renaud@cemagref.fr
** G2C Environnement, 13770 VENELLES France,
jc.demassiac@g2c.fr
*** Cemagref, 50 avenue de Verdun 33612 CESTAS
France, bernard.bremond@cemagref.fr
**** G2C Environnement, 13770 VENELLES France, c.laplaud@g2c.fr
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
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,
tonino.liserra@mail.ing.unibo.it
**
R.
Ugarelli Department DISTART – Bologna University, v.le Risorgimento n°2, Italy,
rita.ugarelli@mail.ing.unibo.it
***
V. Di Federico
Department
DISTART – Bologna University, v.le Risorgimento n°2, Italy,
vittorio.difederico@unibo.it
**** M. Maglionico
Department
DISTART – Bologna University, v.le Risorgimento n°2, Italy,
marco.maglionico@unibo.it
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
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
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, augusto.pretner@sgi-spa.it
** SGI Studio Galli Ingegneria, via della
Provvidenza 15, Padova, Italy, alessandro.bettin@sgi-spa.it
*** SGI Studio Galli Ingegneria, via della
Provvidenza 15, Padova, Italy, luz.sainz@sgi-spa.it
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
T.J. Waldron* & A.V.P. Perry**
* Tim Waldron, Chief Executive Officer, Wide Bay Water Corporation, 29-31 Ellengowan Street Urangan, Queensland, Australia, timw@widebaywater.qld.gov.au
**
Adrian
Perry, Principal Systems Analyst, Wide Bay Water Corporation,
Abstract Wide Bay Water Corporation is
Effective asset management has proved to
require two main components in
Asset Management Systems in
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
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.
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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.
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
** SINTEF Water and Environment, Klæbuveien
153, 7465
***
****
Abstract The city of
Keywords life cycle assessment; pipe materials; wastewater
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
** SINTEF Water and Environment, Klæbuveien 153, 7465
*** SINTEF Water and Environment,
Klæbuveien 153, 7465
**** SINTEF Water and Environment,
Klæbuveien 153, 7465
*****
******
*******
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
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
**SINTEF Water and Environment, Klæbuveien 153, 7465
***SINTEF Water and Environment, Klæbuveien 153, 7465
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
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, frederic.cherqui@insa-lyon.fr
** UMR Cemagref-ENGEES GSP, 1 quai Koch,
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 (
Keywords dysfunction; grade; indicator; misclassification cost; threshold; visual inspection; sewers
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; avanraven@poly.edu
**
Pat Sampson;
Las Vegas Valley Water District (LVVWD); 1001 South Valley View Blvd; Las
Vegas, Nevada 89153; Pat.Sampson@lvvwd.com
***
Sigurd
Hafskjold;
****
Jon Rostum,
Ph.D;
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
· 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
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
** Kiwa Water Research,
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
Keywords asset management; self-cleaning networks; distribution network design; water quality
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, matthew.poulton@cemagref.fr
** Cemagref, 50 avenue de Verdun 33612 CESTAS
France , yves.legat@cemagref.fr
*** Cemagref, 50 avenue de Verdun 33612 CESTAS France, bernard.bremond@cemagref.fr
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
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, tstigter@ualg.pt, jpmontei@ualg.pt,
lnunes@ualg.pt
** FCTUC - Departamento de Engenharia Civil, Pólo
II - Universidade de Coimbra, 3030-290 Coimbra, Portugal, jvieira@dec.uc.pt,
mccunha@dec.uc.pt
*** CVRM/Geo-Systems Centre - Instituto Superior
Técnico, Av. Rovisco Pais, 1049-001 Lisboa, Portugal, nlrib@alfa.ist.utl.pt
**** Águas do Algarve, S.A., Rua do Repouso 10,
8000-302 Faro, Portugal, h.lucas@aguasdoalgarve.pt
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
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
H.-C. Sorge*
* Institute for Research in Underground
Construction and Pipeline Technologies, FITR Weimar e.V., Georg-Haar-Str. 5,
99427 Weimar, Germany, christian.sorge@fitr.de
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
Strategy for the development of optimized flushing plans
A. Korth*, S. Richardt** & B. Wricke***
*DVGW
Water Technology Center Karlsruhe (TZW), Branch Dresden, Germany,
korth@tzw-dresden.de
**Sebastian
Richardt, DVGW Water Technology Center Karlsruhe (TZW), Branch Dresden,
Germany, richardt@tzw‑dresden.de
***Burkhard Wricke, DVGW Water Technology Center Karlsruhe (TZW), Branch Dresden, Germany, wricke@tzw‑dresden.de
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
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,
** Tynemarch Systems Engineering, Crossways House,
*** Tynemarch Systems Engineering,
Crossways House,
Abstract
Sewerage infrastructure assets account for a large
proportion of the asset value of
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
Keywords sewerage; deterioration modelling; investment planning
Attaining the most sustainable solution in stormwater control in England and Wales
S. Kennedy* & L. Lewis**
* The
** The
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
In doing so, the paper compares SUDS
implementation in
This observation notwithstanding, there are many organisations which
champion the implementation of SUDS in
Keywords adoption; barriers; legislation; local authorities; Sustainable Urban Drainage Systems (SUDS)
Economic rehabilitation of sewer systems by ground penetration radar investigations
H. Stepkes*,
J. Zimmermann**,
K. Müller**,
M. Siekmann*
& J. Pinnekamp*
*
** Research Institute for Water and
Waste Management (FiW e.V.) at the RWTH Aachen University, Mies‑van‑der‑Rohe‑Str.
17, 52056
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
Keywords bedding defects; cavity formation; data management; ground penetrating radar; infiltration; urban drainage
Objective condition assessment of sewer systems
K. Müller* & B. Fischer**
* Research
Institute for Water and Waste Management at the
**
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
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,
vitor.sousa@estbarreiro.ips.pt
** HIDRA - Hidráulica e Ambiente. Lda, Av. Defensores
de Chaves nº31 1º Esq, Lisboa, Portugal,
marisalsilva@gmail.com
*** Instituto Superior Técnico, Avenida Rovisco Pais,
Lisboa, Portugal,
jsm@ist.utl.pt or
tiago.veigas@gmail.com
**** SIMTEJO - Saneamento Integrado dos Municípios do Tejo e Trancão S.A., Av. Defensores de Chaves 45, Lisboa, Portugal, j.martins@simtejo.adp.pt or a.teixeira@simtejo.adp.pt
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
Keywords
cleaning; decision tool; inspection; maintenance; sewer networks; technical
asset management
