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Brabantse Delta

The Watermolenbeek-Aa of Weerijs-Mark river basins are located in the southern part of the Netherlands and the north-eastern part of Flanders. The region is characterized by a complex network of rivers, dikes, and polders, which are managed to prevent flooding and support agriculture.

© Waterschap Brabantse Delta

The Brabantse Delta encompasses the Upper Mark, Aa or Weerijs, and Watermolenbeek catchments. Spanning over 1400 km², about 1/3 lies in Flanders and 2/3 in the Netherlands. Key waterways include the Watermolenbeek, Aa or Weerijs, and Boven Mark. These streams flow to the Volkerak Zoommeer via the Mark-vliet system.

The Wildertse Beek rises on Kalmthoutse Heath, becoming Kleine Aa in Essen. In the Netherlands, it's the Watermolenbeek, mostly canalized. Water levels are regulated by weirs, notably in Roosendaal. The subsoil is sandy, with agricultural fields and grasslands covering nearly two-thirds of the catchment. Urban areas like Roosendaal split the flow, with discharge measurements at Essen and Gastelsveer.

A little further to the east is the basin of the Aa of Weerijs (confluence of the Kleine and Grote Aa). Originally, the area was a vast swampy area, with less dynamic discharges than nowadays. The area has been heavily drained for agriculture in the 19th century. In addition to grasslands and arable land, the brook valley also has substantial high-quality tree cultivation. Larger centres are Zundert, Rijsbergen and Breda. Discharge and water level measurement are kept at Brecht, Wuustwezel and south of Breda.

Slightly further east, the (Boven-)Mark meanders. This is a typically rainwater-fed lowland stream, which has distinct peaks in discharge and decreases sharply during dry periods. Upstream of Castelré can still be characterised as a naturally meandering stream with flow. Downstream of the mouth of 't Merkske, both the Flemish and Dutch parts of the Upper Mark have been normalised. During normalisation, the stream was deepened and widened and equipped with weirs. This aimed to prevent flooding due to excessive rainfall and optimise water management for agriculture. Much of the catchment has an agricultural function. Discharge and water level measurements are available for Minderhout, Merksplas, Meer, Mark Weir A-E and Weir de Blauwe Kamer.

 

1.450

Square kilometers

40m

Height difference

14%

Urban area

375.000

Buildings

Upcoming research: 

For these river basins, a joint transnational stresstest is under development. With a stresstest, we try to investigate the resilience of the water systems for extreme weather conditions and identify which measures may be considered to become better prepared for these extreme floods and droughts. Read more details about this research in our magazine.

© Waterschap Brabantse Delta

Publications in this basin

Global analysis of impacts from supra-regional flooding in the Brabantse Delta (Dutch)

This study carried out a global analysis of the possible consequences of extremely large-scale precipitation, such as the ‘Limburg rainfall’ in 2021, for the management area of Brabantse Delta regional water authority. This study is a collaboration with the regional water authority and is a follow-up to a 2021 hackathon conducted on a Dutch national scale, in which West Brabant had already been used as a case study area.
Netherlands
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What-if simulation in Flanders with precipitation July 2021 (Dutch)

This report describes what the impact would be if a water bomb such as the one that occurred in July 2021, and caused a lot of damage due to floods in Wallonia, would fall across the whole of Flanders. Two precipitation events are calculated for which hydrological and hydrodynamic calculations were carried out with the model instruments of the Hydraulic Engineering Laboratory. Flood maps were then calculated along the navigable waterways and damage calculations were made (report only in Dutch).

Resilient Waterland - Weerbaar Waterland (Dutch)

Advice of the expert panel on flood protection to the Flemish government. With 'Weerbaar Waterland', the expert panel formulates an adapted strategy for water security in Flanders, with ten coherent actions and a plan of action to implement it as soon as possible.

Advice on droughts Brabant: Zonder water, geen later (Dutch)

Advice to Brabant's (ground)water partners on the structural adjustments that are needed in the (ground)water system, (ground)water management and (ground)water use from an integral and long-term perspective on drought, and what this requires from all parties that have (direct) influence on this.
Netherlands
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Neighboring basins