Flood management in Flanders: from 3 steps to 3 layers

By Ann Crabbé and Hannelore Mees

In 2005, the Flemish government presented its first Water Policy Brief, a document outlining the focus points for Flemish water policy in the coming years. In this document, the government put forward the concept of ‘capturing, storing and draining’; a 3-step approach to be implemented by authorities at all levels. The approach imposes water managers, firstly, to capture water at its source, so it could infiltrate the soil. In a second step, redundant water needs to be stored in buffer zones and, finally, to be slowly released.

ann_crabbeStill today, the 3-step approach remains a dominant guideline for Flemish water managers at the different administrative scales. In recent documents, however, Flemish governmental authorities started referring to a new terminology: multi-layer water safety. The concept of multi-layer water safety is based on 3 P’s, which have also been mentioned in the European Flood Risk Directive (2007/60/EC): Prevention, Protection and Preparedness. In its symposium on multi-layer water safety (Antwerp, 17 June 2013), the Flemish Environment Agency questioned the government’s current focus on capturing, storing and draining. According to the organisation, the P of protection can no longer face the risk of flooding on its own and Prevention and Preparedness have to be brought into the scope. In its latest implementation plans (e.g. Action Plan 2011 and Follow-up Reports 2012 & 2013), the Flemish government already seems to have adopted this new approach. Throughout Action Plan 2011, the number of actions on risk prevention and preparation are equal to provisions on flood protection. The formal discourse of the document, however, continues to support the 3-step approach.

The (preliminary version of the) second Water Policy Brief links the current policy practice with a new official discourse. ‘Capturing, storing and draining’ remains the keystone of water quantity management, but has been completed with two additional guidelines: making room for water and minimalizing damage. The first guideline will be met by a number of spatial planning regulations and the possible introduction of servitudes for property owners on water storage (prevention) . Minimizing damage should be achieved through a mixture of measures on prevention, protection and preparedness.

Currently, 7% of the Flemish region (98.500 out of 1.352.225 ha) is located in flood risk areas and 2% of its population lives in these zones. Complete restraint from living in flood risk areas is considered unrealistic as a single strategy for risk prevention. For that reason, the Flemish Environment Agency started a pilot project on water safe building. Main idea is not to restrict all settlements in flood risk zones or to prevent floods in build areas at all cost, but to limit the damage that could be caused by them.

Hannelore_Mees4As a concrete start for the new strategy, the Flemish Environment Agency carried out an integrated flood risk study of the Flemish region (including climate change projections), and inserted these data into 3 cost-benefit analyses: on protection, prevention and preparedness measures (VMM, 2013). The main conclusion of the report is that none of the 3 P’s could be used as a single strategy in flood management. Risk prevention proved to have the greatest benefits but requires a budget 4-6 times higher in comparison to additional protection infrastructure. Within the range of protective measures, only resp. 24% and 73% of all planned flood plain and embankment projects appeared to be cost-efficient. Measures on preparedness (including sand bags) generated very high benefit-cost rates but could obviously not withstand a flood on their own.

As a conclusion, we can state that the Flemish government has explicitly acknowledged the importance of diversifying flood risk management strategies, as is also put forward as a key message of the STAR-FLOOD project. We witness policy initiatives on prevention and preparation to complement protection measures. In the near future, we will make further investigations on the compatibility of the strategies that are implemented on multiple government levels. We will also give special attention to government regulations on the recovery side. As regulating this is a competence of the Belgian national government, it will require specific coordination efforts.


The three step approach: capturing, storing and draining

The three step approach: capturing, storing and draining
Author: Peter Dauvellier, with kind permission to reproduce the illustration