For the demands of the European Water Framework Directive 2000/60/EC, the Department of Waterways and Public Works launched the programm “Ruimte voor de rivier” (translates as space for our rivers).
This program has 9 variaties to enlarge the capacity of rivers in the Netherlands. Over 30 project started (and in 2021 finisched) to make space for rivers like the Rhine, the Waal (a branch of the Rhine) and the Maas, to remove object, strenghen the dikes and remove sludge.
A problem in the river the Ijssel, between the municipalities of Zwolle and Deventer, is the large curve in the river between Veessen and Wapenveld. The solution is a huge straight trench, as bypass, which is dry during normal capacity of the river. On initiative of the Vallei and Veluwe Waterboard a study started in 2007 to see how to prevent a situation with evacuation of 250.000 people in ’93 and ’95.
With a budget of 187 million Euro’s the capacity of the river Ijssel is enlarged with 10%, and the design and construction is completed by the combination of Van Hattem and Blankevoort (a VolkerWessels company) and Boskalis “combination Ijsselweide”.
Volker Infra Design(a VolkerWessels company) is responsible for the design of the project, with the support of Witterveen+Bos and Lodewijk Baljon engineers, they made the design in phases.
For the construction of the bypass construction was a rerouting of the existing waterways necessary, and with that new levels were decided and a system to drain the bypass after use, and make it ready for agriculture.
From 2015 the construction started from design to construct, and KWT added mechanical engineering to the project for the detail engineering of the civil design works. The contract was for 16 penstocks, 11 tilting weirs, 1 butterfly gate, and 4 hydraulic operated temporary gates.
All product were manufactured in Stainless Steel AISI304:
16 penstocks in the size of 1.500 x 1.250 up to 2.500 x 2.000mm.
11 Tilting weirs in the size of 2.000 x 1.100 up to 8.250 x 2.100mm
1 Butterfly gate of 1.800 x 2.750mm
2 Hydraulic operated temporary gates adjustable from 1.200 – 1.500mm width and 1.500mm high.
2 Hydraulic operated temporary gates adjustable from 2.000 – 3.000mm width and 2.800mm high.
Because details on civil construction had to be designed after the design of the KWT products, like the position of rebar, we had to use a LEAN planning. This requires more input and cooperation than a conventional manufacturing process.