Helicopter measurements started in the northern Netherlands

Together with the provinces of Fryslân, Groningen, and Drenthe, Waterbedrijf Groningen, Vitens, Wetterskip Fryslân, and the Hunze en Aa's and Noorderzijlvest water boards, we are mapping the subsurface.

From early August until February 2026, a helicopter will fly over parts of Groningen, Fryslân, and Drenthe to map the subsurface. This will help determine where clay layers that protect groundwater are located, and where fresh and salt groundwater can be found.

What's happening? 

A round measuring device approximately 20 meters wide is suspended beneath the helicopter. This instrument emits weak electromagnetic signals, similar to those from a cell phone. These signals measure the subsurface, providing information about the soil layers and groundwater. The measurements are safe for humans, animals, and nature. There is no flying during the breeding season and strict rules apply to nature reserves.

What do you notice about this? 

  • During the day, the helicopter flies at an altitude of approximately 80 meters at a speed of 60 to 80 kilometers per hour.
  • This may cause brief noise disturbance. Animals may be frightened by this.
  • The pilot keeps an eye on the surroundings and takes animals into account;
  • Keep a close eye on animals and take measures if necessary, such as keeping them indoors temporarily.

Planning

The schedule depends on the weather and may change on a daily basis. The current flight schedule can be viewed online: Freshem

Watch the online webinar on YouTube about the FRESHEM-NL project: Webinar Groundwater in focus with helicopter measurements. The FRESHEM-NL project. Province of Fryslân (2025)