Users can get started: Sava Flood Forecasting and Warning System for riparian states in the Sava River drainage area

Published: 9 January 2018

Deltares is working together with Royal HaskoningDHV, Eptisa, the Hydro-Engineering Institute Sarajevo and Mihailo Andjelic to assist five Eastern European countries in the drainage area of the Sava River to implement a forecasting and warning system for droughts and floods. It also collaborates closely with local experts and the national and local authorities. Recently, a new version of the system was delivered.


On 12 and 13 December, 25 operational forecasters (hydro-meteorological organisations from several countries) met up in Ljubljana to examine the first complete version. The US embassies from the five countries donated the hardware (laptops and servers) so they could get started. New features in this almost final version are: the flood maps, data assimilation (links models to measured water levels and drainage) and dealing with uncertainties (like the weather).

Users impressed by the possibilities

The users were very impressed by the possibilities of the system and expressed their enthusiasm about the fact that all of the data and models were now included in one system. Never before has such a transboundary forecasting system been deployed with which so many different countries and authorities are involved. One of the unique elements of the developed system is its thorough recording of how accurate the forecasts were (work is being done on ‘performance indicators’), so the system can be continuously optimised.

Next steps

The next steps are: implementing adjustments based on the initial findings in the coming three months. Then it will be thoroughly tested over six months. In November 2018, the definitive version will finally be ready. Klaas-Jan van Heeringen (project leader of the consortium and hydrologist from Deltares) clarified, “I am especially proud that we have been able to produce a system that works well for everyone in such an internationally diverse context. Naturally, there are still a few challenges to be faced, for example the organisation remaining after our work is done: how do we keep the system alive and who will have which roles and responsibilities.”

Special project

Sava-FFWS (Flood Forecasting and Warning System) is a very special project because there are five countries in the drainage area of the Sava River (97,700 km2): Slovenia, Croatia, Bosnia and Herzegovina, Montenegro and Serbia. Plus, a tiny part of the drainage area lies in Albania. Each country has its own models, monitoring systems, forecasting systems, water authorities and interests. To be effective, an FFWS must bridge these differences and enable collaboration in the field of operational forecasting.