IAHR/IWA Joint Committee on Outfall Systems


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Message from the Chair

While the world has seen many changes and faced many challenges in the last few years, the need to safely dispose of wastewater has anything but diminished. Effective sanitation and the conservation of our oceans, rivers and marine resources remain paramount and form two of the key United Nations Sustainable Development Goals.

Despite recent challenges, work has continued internationally to advance the science and technology of all aspects of wastewater discharges from outfalls. Many new outfall systems have also been built or are currently in development making 2023 an exciting year for all practitioners in this field!

So, whether your interest lies in design, construction, diffuser hydraulics, environmental impacts, or outfalls as a whole, we hope you find the content of interest and it encourages you to get involved.

Prof. Majid Mohammadian

Next events

Latest publications


Outfalls, often designed as submerged multiport diffusers are gaining increased acceptance as effective means for the disposal of treated municipal or industrial wastewater, stormwater and combined sewer overflows, cooling water, and brine effluents from desali-nation plants into coastal waters and estuaries. The main objectives of the Committee are to advance the science and technology of all aspects of coastal wastewater discharges from outfalls and their design, and to facilitate communication between the diverse groups of practitioners in the field. The Committee recognizes the considerable potential for integra-ted systems of wastewater treatment and disposal that consider the response of the receiving waters and their natural assimilative capacity. The design and siting of submarine outfalls is a complex task that relies on many disciplines including oceanography, civil and environmental engineering, marine biology, construction, economics, and public relations. These diverse disciplines are rarely brought together in a single group and the strength of the Joint Committee is the linkage of the expertise of IWA, which is more oriented towards wastewater treatment and water quality issues (e.g. bacteria modeling, nutrient transforma-tion, algae growth, sedimentation and flocculation processes), with the expertise of IAHR, which is more oriented towards hydraulics and fluid mechanics (e.g. jets and plumes, stratified flows, coastal flows, mixing and transport processes, physical and numerical mo-deling, wave forcing, pipe scouring, internal manifold hydraulics).

Leadership Team
Majid Mohammadian

University of Ottawa


Vice Chair
Ed Beling



Past Chair
Matthew Wood

HR Wallingford

United Kingdom of Great Britain and Northern Ireland

Ryan Abrey


New Zealand

Alejandro Barrio

Agua y Saneamientos Argentinos S.A. Av. De los Ombúes 209 C1426CKA CABA - Argentina


Mitchell Baum



Hossein Kheirkhah Gildeh

University of Ottawa


Jie Song

East China University of Science and Technology


Riaan Van der Merwe

Khalifa University

South Africa

Eduardo Yassuda

Tetra Tech


Tobias Bleninger

Federal University of Paraná, Brazil


Daniel Botelho

Water Technology Pry Ltd


Philip Roberts

Georgia Institute of Technology

United States of America



Annual reports

Latest events

International Symposium on Outfall Systems 


  • IAHR Webinar on Outfall Systems Design: A Down under Perspective, Feb. 15, 2024 | Video

  • IAHR Short Course on Outfall Discharge Modeling and Analysis. Online. 30 October - 1 November 2023 Recordings Summary

  • IAHR Webinar on Numerical Simulation of Effluent Discharges. 16 May 2023

  • International Conference on Desalination, Environment and Marine Outfall Systems. 13-16 April 2014 | Sultan Qaboos University, Muscat, Oman

  • 7th International Symposium on Environmental Hydraulics. 7-9 January 2014 | Singapore

  • International Symposium on Outfall Systems 2011. 15-18 May 2011 | Mar del Plata, Argentina

  • Advanced Study Institute on Recent Developments in Nearshore Coastal Water Quality Research: Prediction, Hydro-biological Interactions and Management. 14- 19 December 2009 | University of Hong Kong, Hong Kong SAR, China

  • Techonological Advances in the Design and Control of Desalination Discharges into the Sea. 5-6 October 2009 | Valencia, Spain

  • 5th International Conference on Marine Waste Water Discharges and Coastal Environment (MWWD 2008)

  • 4th International Conference on Marine Waste Water Discharges and Environment (MWWD 2006)

  • 31st IAHR World Congress - Water Engineering for the Future - Choices and Challenges. 25-30 September 2005 | Seoul, Korea, including an outfalls workshop

  • XXI Congreso Latinoamericano de Hidráulica. 18-22 October 2004 | Sao Pedro, Brazil, including a Keynote on outfalls

  • 4th International Symposium on Environmental Hydraulics. 15-18 December 2004 | University of Hong Kong, Hong Kong SAR, China

  • Workshop: Submarine Outfalls: Design Considerations and Environmental Performance Monitoring. 1-3 December 2003 | Sao Paulo, Brazil

  • 30th IAHR World Congress. 24-29 August 2003 | Thessaloniki, Greece, including a short course on "Design and Construction of Sea Outfalls"

  • 3rd International Conference on Marine Waste Water Discharges and Environment (MWWD 2004). 27 September-2 October 2004 | Catania, Italy

  • 2nd International Conference on Marine Waste Water Discharges (MWWD 2002)

  • 1st International Conference on Marine Waste Water Discharges (MWWD 2000)

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