Sava Flood Forecasting Warning System: example of transboundary cooperation on flood forecasting

Published: 31 October 2018

Deltares, along with Royal HaskoningDHV, Eptisa, the Hydro-Engineering Institute Sarajevo and Mihailo Andjelic have been working with five Eastern European countries in the Sava River basin to implement a new flood forecasting and warning system (Sava FFWS). Last week, the final release (2.0) of the system was delivered and implemented through a project closing event in Zagreb.

Disastrous floods in 2014

Between 14 and 20 May 2014 there were disastrous floods in the Sava basin that resulted in 79 casualties and substantial economic damage in Croatia, Bosnia, Herzegovina, and Serbia. Assessments of the total damage in the area range up to 3.8 billion Euros.

Versatile system

Sava FFWS is a versatile forecasting system based on available data and models in five different countries: Slovenia, Croatia, Bosnia and Herzegovina, Montenegro, Serbia and Albania aimed to prevent such big flooding damage as in 2014 by warning ahead of time. For the first time the data and models of all the individual countries have been collected and unlocked in one shared system and, where possible, the connection between meteorological forecast models and hydro models has been established. This makes the Sava FFWS a unique system in the region and an example for the rest of the world when it comes to transboundary cooperation on flood forecasting.


Hanneke Schuurmans (Royal HaskoningDHV): “Configuring the Sava FFWS was a technical challenge. However, the biggest challenge was designing the system in such a way that it would answer to all the stakeholder’s needs. To make sure the system would fulfill everybody’s needs we worked together with all the stakeholders involved. When the system actually answers to their day-to-day practice as well as to capacity building we safeguard ownership. Also we’ll ensure that they will support and continue to use the system in the future, reducing the impact of floods like the one in 2014. “

Mature base for future extensions

Klaas-Jan van Heeringen (team leader of Deltares): “We had to connect all available operational fluvial and meteorological data with the hydrological and hydraulic models. But how do you deal with significant differences between the 19 beneficiary organizations, spread over the 5 riparian countries? There were quite some organizational challenges and differences in experience and culture. By keeping an open communication we managed to overcome these issues and deliver a valuable product. We delivered a mature base for future extensions and developments, such as forecasting for low flows, navigation and usage for hydropower”.

Group picture of all stakeholders / end users during the final workshop in Zagreb last week

Delft-FEWS software

The Sava FFWS combines multiple numerical hydrological and hydraulic models to simulate the expected flows and water levels throughout the Sava river basin. It is built on the Delft-FEWS software, an open data integration software platform for operational water management and forecasting developed by Deltares.