Taha Al-Washali

PhD fellow


Taha AL-Washali is a water engineer from Yemen. Currently, he is a PhD fellow in water supply engineering, working on developing tools and methods that enable water utilities manage and minimize losses in water distribution networks, with a particular focus on intermittent supply.
Taha AL-Washali got his bachelor degree in civil engineering from Sana’a University, Yemen, and got his master of science (Excellent) in water resources management from Cologne University, Germany. He joined the water sector from the first day of his bachelor graduation, and becomes more inspired about water by every day goes by. He started in a GIZ project, a project engineer at KFW national project, and later became a general director of the projects department in the national water supply and sanitation authority in Yemen. He worked in many projects for several governmental and international agencies, including GIZ, KFW, USAID, WHO and OXFAM. He also contributed to the Yemeni revised National Water Strategy and Investment Program, and the Yemen Country Profile in the UN-WHO Global Water and Sanitation Assessment Report. In 2014, he joined the academia, the Water and Environment Center in Sana’a University in a project aiming to build the capacity of the center. Since then, his research interests focus on water supply efficiency, including: water loss assessment, modelling and minimisation, pressure management, leakage control, water meter accuracy, and apparent losses. Besides water loss management, interesting research includes real time break-event detection, asset management, and benchmarking (PIs).


Losses in Water Distribution Networks: a Study on the Assessment of Water Loss and its Components and Sub-Components in Developing Countries


AL-Washali, T., Sharma, S., Kennedy, M., AL-Nozaily, F., & Haidera, M. (2019). Monitoring the Non-Revenue Water Performance in Intermittent Supply. Water, 11(6)1220.

AL-Washali, T., Sharma, S., Kennedy, M., AL-Nozaily, F., & Haidera, M. (2019). Modelling the Leakage Rate and Reduction Using Minimum Night Flow Analysis in an Intermittent Supply System. Water, 11(1) 48.

AL-Washali, T., Sharma, S., & Kennedy, M. (2018). Alternative Method for Nonrevenue Water Component Assessment. Water Resources Planning and Management, 144(5),  04018017.

AL-Washali, T., Sharma, S., & Kennedy, M. (2016). Methods of Assessment of Water Losses in Water Supply Systems: a Review. Water Resources Management, 30(14), 4985-5


LinkedIn: https://www.linkedin.com/in/taha-al-washali-2201ab59/

ResearchGate: https://www.researchgate.net/profile/Taha_Al-Washali

Other information


AL-Washali, T., Sharma, S., Kennedy, M., AL-Nozaily F, and Haidera M. (2019). Normalizing Water Loss Level in Intermittent Supplies. IWA 1st Intermittent Supply Confernce. 2019, April 7-9, Kampala, Uganda.

AL-Washali, T., and Noaman A. (2019). The Yemen Experience on Water Harvesting. Nairobi Knowledge and Experience Exchange Symposium, March 4-8, Nairobi, Kenya.

AL-Washali, T., Sharma, S., Kennedy, M., AL-Nozaily F, and Haidera M. (2019). Analysis of the potential of leakage reduction scenarios: Are they dependent on each other?. IWA Water Efficient 2019, January 13-16, Manila, The Philipenese.

AL-Washali, T., Sharma, S., Kennedy, M., Lupoja R. P., Shawagfeh Z., AL-Nozaily F, Haidera M., AL-Koli H. S., and AL-Shaieb R. (2018). Comparative Analysis of Non-Revenue Water Assessment Methods in Three Cases in Developing Countries. IWA Water Loss 2018, May 7-9, Cape Twon, South Africa.

AL-Washali, T., Sharma, S., Kennedy, M., AL-Nozaily F, and Haidera M. (2018). Water Loss Assessment and Monitoring in Intermittent Supplies. International Conference for Sustainable Development of Water and Environment 2018, January 18-19, ChenYang, China.

AL-Washali, T., Sharma, S., and Kennedy, M. (2017). Water Loss Monitoring. German Arab Master Programs Conference 2017, November 2-3, Berlin, Germany.

AL-Washali, T., Sharma, S., and Kennedy, M (2017). Water Loss Assessment in Developing Countries. IHE-Delft PhD Symposium 2017: Climate Extremes and Water Management Challenges, October 2-3, Delft, The Netherlands.Best Presentation Prize.

AL-Washali, T., Sharma, S., Kennedy, M., AL-Nozaily F, and Haidera M. (2017). Does A Lower Non Revenue Water Level Always Mean Better Performance?. IWA Benchmarking Conference 2017, May 15-17, Vienna, Austria.

AL-Washali, T., Sharma, S. Kennedy, M. and Shwagfeh, Z. (2017). Economic Modeling for Prioritizing Leakage Reduction Measures in AL-Zarqa, Jordan. 4th Arab Water Week, 18–23 February, Dead Sea, Jordan.

AL-Washali, T., Sharma, S., and Kennedy, M. (2016). Non-Revenue Water Evaluation in a Complicated Context: The Case of Sana'a Water Supply System. IWA Water Loss 2016 Conference, 31 January – 3 February, Bangloure, India.


Van Steenbergen F., AL-Washali, T. Aklan, M. (2018) & AL-Qubati W. Water Security in Yemen After War and Conflict: Stocktaking Report. Infrastructure and Cities for Economic Development, DFID, UK.

AL-Washali, T., AL-Derwish A., Lerebours A., Carter S., & Farrington M. (2016). WaSH Assessment in Urban Sana’a: Desk Review Report, Scoping Study of Urban WaSH. Oxfam, Yemen.

AL-Washali, T., Sharma, S. & Kennedy, M. (2016). Non-Revenue Water Breakdown in Zarqa Water Supply System. Summary Report, Jordan.

Yemen Profile in: UN-WHO (2014). Investing in Water and Sanitation: Increasing Access, Reducing Inequalities. Global Analysis and Assessment of Sanitation and Drinking Water, World Health Organization, Geneva, Switzerland.


AL-Washali, T. (2017). Damage Assessment of Water Supply in Yemen. Forgotten War Conference, 25 February, Berlin, Germany.

AL-Washali, T. (2017). The Overlooked Yemen: Call for Action, Focus on Water. Yemen The Worries Seminar, 27 January, MetaMeta Research, 's-Hertogenbosch, The Netherlands.

AL-Washali, T. (2016). Research Poster Design. Training Seminar, 25 June, Water and Environment Center, Sana’a University, Yemen

Blogs and Articles:

AL-Washali, T., Steenbergen F., Sharma, S. & Kennedy, M. (2017). Let the crisis not get hold of us: water supply in Yemen. Water Blog in Water Channel.

AL-Washali, T. M. (2015). Challenges, Achievements, and Gaps of WASH Sector in Yemen: Brief Summary of UN-WHO WASH Assessment in Yemen. AL-Miah Magazine. Issue No. 86 Print. Yemen.

Research Summary

There is no water supply system with zero losses. Water loss in water supply systems is a global problem that undermines the sustainability of water services in the cities and water resources in the basins. However water loss monitoring is complicated in developing countries where water losses can’t be assessed accurately and regularly at a component level.  For intermittent water supply, water loss is difficult to be assessed accurately because the level of water loss is influenced significantly by the variation of water production. Besides, assessing water loss components using minimum night flow testing is difficult as several water utilities lack technical capacity and water sufficiency, to ensure the saturation of the ground storage tanks in the network. On the other hand, the high uncertainty of illegal water use estimation influences the accuracy of water loss component assessment through establishing the top –down water audit methodology. Therefore, the objective of this research is to develop methods and approaches for assessment of the water loss and its components and sub-components, addressing the needs of intermittent supplies in a developing country context. To achieve that, the study aims at suggesting normalization approach of water loss level, and developing a new methodology for water loss component assessment. The study also aims to carry out an in-depth analysis of meter accuracy and water thefts, which should improve the water loss component assessment through the top-down water audit methodology. The main output of this study are new process-oriented and cost-effective methodologies and guidance for intermittent supply systems, for water loss normalization, component assessment and modelling.


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