Long before Marine Systems took over the contract for the maintenance of the National Water Measuring Network (LMW), Citadel sensor were used to measure the conductivity and water temperature at measuring locations. The Citadel sensors are located at more than 30 measuring locations, with several sensors at one location which are under the management and maintenance of Marine Systems. Because the sensor are end-of-life, Rijkswaterstaat has decided to switch to a new type of sensor: the NKE Mosens UV sensors.

The NKE sensor has the great advantage that the fouling growth due to the application of UV light is less than the fouling growth when using the Citadel sensor. This would mean that the relevant measurement locations will become more maintenance friendly in the future. Rijkswaterstaat has divided the roll-out of the NKE sensors over several batches to ensure that the roll-out flows smoothly into the next batch.

Prior to the rollout, a design phase took place in which various building blocks for the rollout were developed and tested. These starting points have been laid down in a provisional and final design.

Therefore, the rollout of the NKE sensors involved more that just replacing the sensor. After the design phase, the following changes took place in the realization phase at the locations that had to be converted:

  • Manufacturing and mounting the sensor holder (NKE sensor has different dimensions);
  • Fabricate and assemble custom sensor blocks;
  • Assembling and modifying the drawers and connecting boxes;
  • Assembling and modifying the interface and connection boxes;
  • Implementing the changes in documentation, adjust drawings, adjust working instructions and monitor fouling growth during the first time maintenance.