Measurements are being made from the air on the distribution of fresh and salt groundwater in Zeeland. This insight is important for implementing sustainable groundwater management, including taking measures to counteract potential salinization. Water Board Scheldestromen, Province of Zeeland, and Evides Water Company are participating in the national project Freshem-NL.
The distribution of fresh and salt groundwater is being mapped again for part of Zeeland. Similar measurements were carried out by a helicopter with a measuring instrument in the shape of a cigar in 2014 and 2015. From August 15, a helicopter will again take to the air, now with a hoop-shaped measuring instrument.
Measurements
For the measurements in Zeeland, about 3,000 flight kilometers are planned. The following areas will be flown over starting August 15:
- Zak van Zuid-Beveland;
- Noord-Beveland;
- Kop van Schouwen;
- Oost-Zeeuws-Vlaanderen (from the line Dow-Sas van Gent);
- A part of the Markiezaat and the nearby Hogerwaardpolder.
Zeelands Importance
The measurement data will be processed into a 3D map of the fresh-salt distribution of the groundwater. This is expected to be available by mid-2027 on this page. A comparison of the new 3D map with that from ten years ago will show whether the underground fresh water reserves have changed.
FRESHEM-NL
The FRESHEM project stands for FREsh Salt groundwater distribution by Helicopter ElectroMagnetic survey. In the project, the electrical resistance of the underground is measured with a measuring instrument that hangs under a helicopter. The technique allows measurements to be made up to a depth of 200 meters below the surface.
FRESHEM was previously applied in Zeeland. The results led to the research being applied throughout the Netherlands. Of the current inventory, 13% is focused on Zeeland territory. The project involves seven provinces, seven water boards, five drinking water companies, and two knowledge institutes working together. The total costs amount to approximately seven million euros, half of which is financed from the national Delta Fund. Rijkswaterstaat is not a partner but does contribute financially.
Scarce Resource
Fresh water is scarce in Zeeland. This is because our province is surrounded by salty seawater and the water in the underground is also primarily salty. The water in Zeeland is almost everywhere too salty to irrigate crops. There are few natural sources, putting the availability of fresh water under pressure. FRESHEM-NL provides important information about existing fresh water bubbles. Based on this, along with groundwater measurements and models, strategies, policies, and measures can be developed to sustainably manage fresh water reserves for the future.
Daily updates are posted on www.freshem.nl, and the flight routes can be seen per day.
