EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Towards improving a national flood early warning system with global ensemble flood predictions and local knowledge; a case study on the Lower Shire Valley in Malawi.

Thirza Teule1, Anaïs Couasnon1, Kostas Bischiniotis1, Julia Blasch1, and Marc van den Homberg2
Thirza Teule et al.
  • 1VU University, Institute for Environmental Studies, Water and Climate Risk, Netherlands (
  • 210 (The Netherlands Red Cross), The Hague, The Netherlands

Flood risk, a function of hazard, exposure, and vulnerability, is increasing globally and has led to more and more disastrous flood events. Previous research has shown that taking early action is much more cost-effective than responding once the flood occurs. Such an anticipatory approach requires flood early warning systems (EWS) that provide ample lead time and that have sufficient spatial resolution. However, in developing countries, often the skill of available forecasts is insufficient to create a more effective triggering mechanism as part of a flood EWS.

This research presents an assessment of two methods to improve an existing flood EWS using a case study of the most flood-prone area of Malawi, i.e. the Lower Shire Valley. First, the forecast skill and trigger levels of the medium-term Global Flood Awareness System (GloFAS) model are determined for four gauge locations to assess how they can improve the national EWS. Secondly, an assessment is done on how the process of integrating flood forecasts based on local knowledge with official forecasts, can help to improve the EWS. This is done by semi-structured interviews at the national level and focus group discussions at the community level. The study shows that GloFAS does not predict absolute discharge values precisely, but can be used to predict floods if the correct trigger levels are set per location. The integration of multiple forecast sources is found to be useful at both national and community levels. An integration process is proposed where village stakeholders should take the leading role by using existing disaster management and civil protection coordination mechanisms. Overall, both methods can contribute to improving the flood EWS and decreasing the flood risk in the Lower Shire Valley in Malawi.

How to cite: Teule, T., Couasnon, A., Bischiniotis, K., Blasch, J., and van den Homberg, M.: Towards improving a national flood early warning system with global ensemble flood predictions and local knowledge; a case study on the Lower Shire Valley in Malawi., EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-507,, 2019

Display materials

Display file

Comments on the display material

AC: Author Comment | CC: Community Comment | Report abuse

Display material version 1 – uploaded on 04 May 2020
  • CC1: Comment on EGU2020-507, Michael Szoenyi, 07 May 2020

    Hello Thirza, sorry, I missed the chat window for your presentation and master thesis, really interesting. I understand you completed data collection before cyclone Idai and Kenneth struck the region. Were you able to revisit or even validate some of your findings based on the 2019 impacts?

    • AC1: Reply to CC1, Thirza Teule, 07 May 2020

      Hi Michael, thank you for your comment. Unfortunately, at the time of the research, we were not able to retrieve the data at the time of cyclones from the government of Malawi. However, it would be very interesting to validate it with the 2019 effects indeed.