Central Dredging Association

Understanding dredging

Making room for rivers

Major Function
Other Functions
Rhine, Waal, IJssel and Meuse rivers, The Netherlands
Total sediment/soil volume 35 - 40 mln. m3 (including flood plain soils), (excess sediment/soil volume 5 mln. m3)
In Water Reallocation at final location
Present, but acceptable for reuse within the Dutch Soil Directive (criteria: no unacceptable eco¬tox
Mix of gravel, sand, silt and clay, both wet (sediment) and dry (floodplain soil)
Real project scale
Ministry of Infrastructure and the Environment, Rijkswaterstaat
Multiple consutlancies and contractors (on different subprojects), Research institutes: STOWA, KNMI, Deltares, Alterra and universities
Research program
National Water and Climate Knowledge and Innovation Programme (covering topics like ecological impact, climate adaptation, resilience, adaptive delta planning, cyclic rejuvenation, flood probability, etc.)
Deltares (Arjan.Wijdeveld@deltares.nl)
Year start – end
2006 - 2015
Download Case Study

The goal of the Dutch Room for the River Program is to give the river more room to be able to manage higher water levels. For 30 locations measures were taken to give the river space to flood safely. This as an alternative to further increase the height of the dikes. To make this possible, ~ 40 mln. m3 of soils and sediments had to be reallocated.  Most of the soils/sediments could be used within the project, but for some of the sediments an under water storage site (much like a Confined Deposition Facility or CDF) had to be constructed. By using old (or sometimes newly constructed) quarry sites (gravel, sand or clay) these quarry sites could be partially filled.  The end result is an increase in wetland and shallow lake habitat.

Constructing a CDF type of solution (the stored sediments have contamination levels in line with the  soil use specific standards, hence they are not seen as contaminated) in former pit lakes is one example of beneficial sediment use within room for the river. There are more examples. See the provided web links for information on the 30 locations.

Graphical information:

case study room for river // cs_room-for-river.jpg (280 K)

case study room for river reallocation // cs_room-for-river-reallocation.jpg (105 K)