Detailed view for Geraardsbergen

Concerned RiverDender
TypeObermeyer, air filled
Short Description

Geraardsbergen weir will be located on the Dender River, in Belgium, and is projected to be built in 2016 and 2017.

It is a air-filled Obermeyer dam and it is composed of 2 spans of 7 meters wide and 4.3 meters high for a total length of 14 meters.

Main characteristics
Water Head (m)1.62
Upstream height (m)16.85
Downstream height (m)15.23
Discharge (m/s)1-115
Total length (m)14
Number of spans & dimensions

2 spans of 7 meters each

Weir height (m)4.3
Progress statusFuture construction
Date of completion10/15/2017

Waterwegen en Zeekanaal NV


Waterwegen en Zeekanaal NV

Design group
  • Engie Fabricom
  • Dyrhoff UK (agent for Obermeyer Hydro Incorporation)
  • Technum

Engie Fabricom

Cost estimation3,000,000 euros


PIANC References for this project

In progress


The Dender River is divided into three lines at the location of the weir. Actually, these lines are used for two old weirs (built around 1860) and a lock. Several parts of this site are protected as historic monuments, as well as the landscape, which makes the project complex. Indeed, the new structure has to be built without having an impact on the previous ones.

The project consists in a new Obermeyer weir in the central line and a fish passage in the right line. The lock remains unchanged in the left one.

As the section of the new gate is larger than the one of the old weir, an underground bypass under the old weir will be built.

The new structure will be composed of two spans of 7 meters wide and 4.3 meters high each. The panels will be sustained by air-filled bladders.

All specific parts of that gate (rubber reinforced bladder, hinge, restraining straps and seals) will be provided by Obermeyer Hydro Inc.

The range of regulation is 100%, which means that the dam can be fully inflated or deflated.

Documents to download
  • 107- PReview WG166- Geraardsbergen Weir Dender River.pdf - 107- PReview WG166- Geraardsbergen Weir Dender River.pdf