IAHR/IWA Joint Committee on Urban Drainage

IWA/IAHR Joint Committee on Urban Drainage

Next Events

  • Leading Edge Strategic Asset Management (LESAM) - Paphos/Cyprus, April 28-30 2025.

  • Urban Drainage Modelling (UDM), Innsbruck/Austria, September 15-19, 2025, website

  • Sewer Processes and Networks (SPN) - Trondheim/Norway, May 2026

  • NOVATECH - Lyon/France, June 29 - July 3, 2026

  • International Conference on Urban Drainage (ICUD), Ningbo, China, June 2027, website


Urban drainage systems are designed to convey stormwater runoff and sewage flows of magnitudes varying from low dry-weather flows to floods, control fluxes of pollutants resulting from human activities, and contribute to the general well-being of the urban population. Furthermore, such goals should be accomplished within the framework of integrated management of urban waters, with minimal impacts on receiving waters, in a cost-effective way, and under conditions of steadily increasing populations of large cities. In view of these high demands, urban drainage is becoming a key issue in the management of urban water resources.

The main objective of the Joint IAHR/IWA (International Water Association) Committee on Urban Drainage is to promote an ecosystem approach to the planning, design and operation of urban drainage. This objective supports sustainable development of urban areas, protects their natural environment, and requires that hydrologic, hydraulic, water quality and ecological issues of drainage design are properly considered in a cost-effective integrated way. Computer modelling, operational research techniques and expert systems are standard tools for the optimisation of drainage design, operation and their associated costs.

Every urban area has its special characteristics depending on climate, topography, development, engineering practices, institutional and political framework, population and economy. Thus, there are no universal solutions which could be recommended under all circumstances and the state-of-the-art solutions have to be examined and promoted with respect to the specific local conditions and drainage problems. For example, drainage problems in developing countries as well as in the newly established democracies in Eastern Europe need special considerations. These countries are facing great difficulties in dealing with environmental issues under adverse economic conditions, strong competition among various sectors for limited available funds, and the lack of effective institutional arrangements that can resolve these problems.

The Joint Committee organises the triennial International Conferences on Urban Storm Drainage, related workshops and training courses, supports regional or specialty conferences, publishes technical reports and a comprehensive annual newsletter, and initiates research on important issues.

Research Agenda

Rainfall/Runoff Processes and Modelling: The theoretical development of rainfall/runoff models has reached maturity and further progress will be incremental . Current research issues include adaptation of models for use in the realm of hydroinformatics (i.e., in conjunction with special databases), use of radar-measured rainfall data including moving rainstorms, efficient routing of pressurised flow in a computing environment with full graphical support, refinement of flow quality modelling, consideration of management options (storage and treatment facilities), interactive, dynamic control required in real-time control studies, and realistic modelling of sediment transport and flow quality.

Assessment of Stormwater and CSO Quality and Its Impacts: The traditional approach to stormwater and CSO (Combined Sewer Overflow) quality focused on chemical characterisation with successive emphasis on solids, biodegradable matter, nutrients, heavy metals, hydrocarbons, and trace organic contaminants. These chemical protocols often fail to distinguish between toxic and non-toxic contaminants, their bioavailability or the synergistic effects of chemical cocktails. Hence, current research focuses on the assessment of stormwater and CSO quality by ecotoxicity measurements. Further development of methods for the assessment of stormwater and CSO impacts is needed, using such concepts as biotesting, biomonitoring and biological community assessment. Some of these methods can be also used for monitoring impacts of thermal enhancement of urban runoff. The methodology to be developed needs to recognise the time-dependent nature of CSO and stormwater impacts, and the associated acute and cumulative effects.

Role of Sewer Sediment: Sewer sediments cause numerous problems in drainage operation, including loss of hydraulic capacity, concentration and transport of pollutants, septicity accompanied by gas and corrosive acidity production, and a risk of washout into the receiving waters or overloading at the wastewater treatment plant. Furthermore, many treatment or control options applied to CSOs and stormwater result in sediment settling and accumulation (e.g. in stormwater ponds, CSO tanks), and the settled sediment causes problems similar to those caused by sewer sediment, including impacts on water quality in the overlaying water column. Progress has been made in mathematical description of transport of sewer sediment, either as a suspended load, or bedload. Options for sediment control have been developed, and generally include combinations of management practices in urban catchments, including source controls and improved maintenance of streets and catch basins, and in-system improvements. New research should focus on the behaviour of cohesive sediments, and the water quality impact of contaminated sediments. 

Stormwater Management: Best management practices (BMPs) mitigate the impacts caused by progressive urbanisation, including increased discharges and volumes of runoff, and export of pollutants or heat from urban catchments. Although individual BMPs vary due to differences in climate, stormwater characteristics, local conditions, design procedures, and modes of operation and maintenance, international experience with BMPs can be summarised in the following four points: (1) No single BMP offers a universal solution to stormwater pollution; (2) BMPs should be considered as part of the treatment train, which starts in the catchment, continues in the collection system and a series of complementary BMPs, and ends with in-stream measures; (3) The sustainability of BMPs has to be ensured through proper operation, design modifications (where required to meet the original objectives) and maintenance; and, (4) Even though well-designed BMPs provide stormwater quantity and quality control, visual amenities, and wildlife habitat, they must be recognised as wastewater treatment facilities that may impact on wildlife and cause contaminant entry into the food chain. Further research is required on new BMPs (e.g. biotreatment systems), advanced knowledge of BMP performance in a treatment train and under special conditions (sensitive receiving waters, urban redevelopment, cold climate, tropical climate), their sustainability by proper maintenance, and their role in sustainable urban development.

CSO Control: Perhaps the greatest innovation in CSO control is the introduction of the integrated management approach to CSOs, considering the catchment drainage (including the collection system), wastewater treatment plant (WTP) and the receiving waters. In fact, only this integrated approach to pollution control offers a true assessment of the effectiveness of individual system components and a basis for their optimal design. In the analysis of CSO control, several components are considered - source controls, storage (in-line and off-line), treatment (both central and satellite), and in-stream measures. Source controls address both reduced influx of stormwater (e.g. by such BMPs as infiltration) and controls of dry weather flow or solids deposits (storage prior-to storms, reduced pollutant fluxes through regular maintenance etc.). Temporary in-system storage can be created by oversized storage pipes, or off-line by special storage facilities. Recognising that the methodology for CSO control by storage is well developed, the current research focuses on treatment processes for CSOs, including lamellar settling, degritting with a chemical stage for pre-treatment and flotation reactor, chemically aided settling with microsand, and UV disinfection for protection of recreational uses of the receiving waters. 

The complexity of sewer systems, and the dynamics of flow, storage, loads and treatment processes, make it particularly desirable to control the sewerage/treatment/receiving water systems in real time. Real time control (RTC) was found particularly useful in systems with operation problems varying in type, space and time, and with some idle capacity. Further research continues on RTC of quality of wastewater and receiving waters, and reliable hardware. 

Hydroinformatics: Functional, spatial and temporal integration required in comprehensive drainage studies necessitates the use of computer models. The international modelling practice continues to be dominated by a limited number of well-supported and continuously updated modelling packages incorporating some aspects of hydroinformatics and merging environmental modelling with information technology. A wide range of options available in some of these tools allows to address comprehensive drainage/environmental systems, including the collection system, management and control schemes, WTPs and receiving waters. Expert system supports and RTC simulation modules are also available. Further refinement of such tools through new research is desirable. 

New JCUD Working Groups
Contact the working group leaders if you want to find out more:

  • Emerging Contaminants (Lena Mutzner, EAWAG; Kefeng Zhang, University of New South Wales)

  • Large Research Infrastructures (José Anta Alvarez, University of Coruña)

  • Blue-Green Infrastructure (successor of WSUD/SOCOMA groups) (Peter Bach, Ostschweizer Fachhochschule)


At the ICUD 2024 conference the JUCD hands out three awards:

  • The Career Award of the Joint Committe on Urban Drainage (JCUD) has been awarded to:

    Ana Deletić (Australia)

  • The Mid-Career Award of the JCUD has been awarded to:

    Manfred Kleidorfer (Austria)

  • The winner of the Poul Harremoës Award is:

    Travis Dautzer (University of Michigan, USA)

At the tri-annual ICUD conference the JCUD hands out three awards:

Leadership Team
Manfred Kleidorfer

University Innsbruck


Past Chair
David McCarthy

Monash University, EPHM Lab


Jon Hathaway

University of Tennessee

United States of America

Frederick A. Locher

Bechtel Systems and Infrastructure Inc. (Retired)

United States of America

Seith Mugume

Makerere University


John Okedi

University of Cape Town

South Africa

Juan Pablo Rodríguez Sánchez

Universidad de los Andes


Mariacrocetta Sambito

University of Enna “Kore”


Alma Schellart

University of Sheffield

United Kingdom of Great Britain and Northern Ireland

Baiqian Shi

Monash University


Sylvie Spraakman

City of Vancouver



IAHR/IWA Committee on Urban Drainage website




16th International Conference on Urban Drainage (ICUD 2024), 9-14 June 2024, Delft, the Netherlands

12th Urban Drainage Modeling Conference (UDM 2022), Jan 10-12, 2022 in Costa Mesa, California, USA

15th International Conference on Urban Drainage (ICUD 2020), 25-28 October 2021, Melbourne, Australia

14th International Conference on Urban Drainage (ICUD), 10-15 September, 2017, Prague, Czech Republic

13th International Conference on Urban Drainage (ICUD 13), 7-11 September 2014, Sarawak, Malaysia.

12th International Conference on Urban Drainage (ICUD 12), 11-16 September 2011, Porto Alegre/RS - Brazil.

11th International Conference on Urban Drainage (ICUD 11), 31 August - 5 September 2008, Edinburgh International Conference Centre, Scotland. CD-ROM. available from David Blackwood at Aberlay University. Email:

11th International Conference on Urban Drainage Modelling (UDM), 23-26 September 2018, Palermo, Italy.

10th International Conference on Urban Drainage Modelling (UDM), 20-23 September 2015, Mont-Sainte-Anne,Quebec, Canada.

9th International Conference on Urban Drainage Modelling, 4-6 September 2012, Belgrade, Serbia. Contact: Dusan Prodanovic.

8th International Conference on Urban Drainage Modelling and the 2nd International Conference on Rainwater harvesting and Management, 2009, Tokyo, Japan.

UDM’98, 4th Int. Conference on Developments in Urban Drainage Modelling, London, UK, 21-24 September, 1998. 2 vol.s, 850 pages, soft-bound. £60. Dr. D. Butler, Dept. of Civil Engineering, Imperial College of Science, Technology and Medicine, Imperial College Road, London SW7 2BU, United Kingdom. E-mail:

Urban Drainage Modelling – Speciality Symposium, 20-24 May, 2001. Orlando, Florida, USA. in USA: US$ 134, incl. shipping. Outside USA: US$ 180, incl. air shipping. From: ASCE Publishers. Tel: +1 703 295 6252 or E-mail:

7th International conference of Sustainable Techniques and Strategies in Urban Water Management (Novatech) 27 June - 1 July 2010, Lyon, France. Email:

6th International Conference on Sustainable Techniques and Strategies in Urban Water Management (Novatech) 24-28 June 2008, Lyon, France. CD can be ordered at www.novatech.graie.

10th International Conference on Urban Storm Drainage, 21-26 August, 2005, Copenaghen, Denmark. E-mail:

9th International Conference on Urban Storm Drainage, 8-13 September, 2002, Portland, Oregon, USA. Proceedings from: ASCE Publishers. Tel: +1 703 295 6252 or E-mail:

8th International Conference on Urban Storm Drainage, 30 August - 3 September, 1999, Sydney, Australia. Proceedings from IWA Publishing, Alliance House, 12 Caxton Street, London SW1H 0QS, UK. E-mail:

7th International Conference on Urban Storm Drainage, 9-13 September, 1996, Hannover, Germany. Prodeedings from Prof..F. Sieker, 7th ICUSD, Institut für Wasserwirtschaft, Universität Hannover, Appelstrasse 9a, D-30167 Hannover, Germany

6th International Conference on Urban Storm Drainage, September 12-17, 1993, Niagara Falls, Canada. Proceedings from Seapoint Publishing, 2880 Seapoint Drive, Victoria, B.C. V8N 1S8, Canada. Fax +1 604 472 1057.

5th International Conference on Urban Storm Drainage, 23-27 July, 1990, Osaka, Japan. Porceedings: 3 volumes. Prof. T. Sueishi, Secretary General for 5ICUSD, c/o Dept. of Environmental Engineering, Osaka University, 2-1 Yamadaoka. Suita 565, Osaka, Japan. 

Novatech 2016 28 June - 1 July 2016, LyonTech La Doua EcoCampus, France.

5th International Conference on Innovative Technologies in Urban Drainage (Novatech), June 6-10, 2004, Lyon, France. E-mail:

4th International Conference on Innovative Technologies in Urban Storm Drainage – Novatech, 25-27 June, 2001, Lyon, France. Free CD-ROM from Elodie Graie, Group Recherche Rhone-Alpes 

9th International Conference on Sewer Processes and Networks (SPN 9), 27-30 August, 2019, Aalborg, Denmark

22nd European Junior Scientists Workshop "Monitoring Urban Drainage Systems", 18-22 May 2015, Chichilianne, France.

1st International Conference on Urban Drainage and Highway Runoff in Cold Climate, March, 25-27, 2003, Riksgransen, Sweden. Contact: maria.viklander@sb.luth

UNESCO International Symposium on Frontiers in Urban Water Management: Deadlock or Hope, June 18-20, 2001, Marseille, France. Book + CD-ROM free of charge from: Division of Water Sciences, UNESCO, 1 rue Miollis, 75732 Paris Cedex 15, France. Tel: +33 1 4568 4004 / Fax +33 1 4568 5811.

2nd International Conference on Interactions between Sewers, Treatment Plants and Receiving Waters in Urban Areas INTERUBA II, 18-20 June, 2001, Lisbon, Portugal. Proceedings from: INTERUBA II Conference Secretariat, Instituto Superior Tecnico, Av. Rovisco Pais, 1096 Lisboa Codex, Portugal. E-mail:

IMUG 2000, April 12-14, 2000, Prague, Czech Republic. Proceedings US$ 45. Pavlina Nesvadbova, Hydroinform a.s., Na vrsich 5, Prague 10, Czech Republic.

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