Project - Preliminary investigation of the waterbed at the Brabantse and Sliedrechtse Biesbosch

Preliminary investigation of the waterbed at the Brabantse and Sliedrechtse Biesbosch

Project description

MH Poly has done a preliminary investigation of the waterbed of several locations on the waterways at the Brabantse and Sliedrechtse Biesbosch during the months September till November 2014. This is done in with the combination VolkerInfra/Van Oord (ViVo).

The cause of this preliminary investigation is the maintenance dredged activities at these waterways. Only the areas which are not deep enough according to the nautical minimal depth will be dredged. The main goal of the investigation was to increase the insight in the quality of the to be dredged material. In addition the existence of asbestos in the waterbed is also investigated.

A total of 37 samples areas were taken from the waterways with has a total length of 12,5 km. In accordance with the standards and protocol 370 samples were bored. Field work is done by protocol 2003 and 2018 certified employees. This is done with a small vessel without spud poles. The borings are done with a piston samples. The borings are drilled till the maximum needed depth including 0,2 overdepth. Due to the possible presence of unexploded ordnance the deeper (original) soil could not be disturbed.

For the chemical composition over 50 mixed samples are investigated at the laboratory with the standard C2 package for fresh water. Together with the chemical investigation the sand size and the possible amount of asbestos are investigated.

The preliminary investigation is an acknowledge evidence for the reuse of the dredging material. This investigation is used by the contractor as an input for the sediment transport plan.
- Preliminary investigation in accordance with NEN 5717;
- Preliminary investigation in accordance with NTA 5727;
- Determining of water and investigation type in accordance with NEN 5720 ;
- Preparation and coordination field works;
- Inspection of location for asbestos material in accordance with protocol 2018
- Taking of samples with various methods in accordance with “protocol 2003”;
- Selecting of samples for the dredged area in accordance with NEN 5720;
- Chemical and physical laboratory investigation;
- Testing and reviewing results;
- Report and advising the client in accordance with NEN 5720.