Provincial executives, water authorities, and water companies investigate subsurface composition
Climate change is putting pressure on the availability of fresh water. Longer periods of low precipitation lead to drought and increased demand for fresh water. In addition, rising sea levels are causing groundwater to gradually become saltier. We also refer to this as salinization. To ensure that nature, agriculture, and economic activity suffer as little damage as possible in the long term and that sufficient drinking water remains available, knowledge of the subsurface is of great importance. The provinces of Groningen and Drenthe, the Hunze en Aa’s and Noorderzijlvest water boards, and Waterbedrijf Groningen are therefore conducting research into the subsurface of the province of Groningen and the northern tip of Drenthe.
Project FRESHEM
The current understanding of the subsurface is based on old measurements that were conducted sporadically across the area. As a result, the information is relatively general and insufficient. The Freshem-NL project is therefore conducting a precise survey. FRESHEM stands for FREsh Salt groundwater distribution by Helicopter ElectroMagnetic survey.
Measurements taken by helicopter
During the Freshem-NL project, measurements are being taken using a helicopter. This allows the subsurface to be mapped to metre up to 200 metre . Along the coast, the focus is on the salinity of the shallower groundwater. In the other areas, the focus is on mapping where freshwater is present. All measurements will result in a three-dimensional image of freshwater and saline groundwater in the subsurface and the presence or absence of clay layers.
Future
The knowledge gained from the project is being used to identify potential groundwater extraction areas and assess the availability of freshwater for nature, agriculture, and businesses. In addition, this information helps in implementing targeted measures to mitigate the effects of salinization.
Research in the Netherlands
The project is being carried out in the coastal provinces throughout the Netherlands. Seven provinces, seven water boards, five water utilities, and two research institutes are collaborating on this initiative. The Province of Fryslân is serving as the lead partner. The provinces of Groningen and Drenthe, the Hunze en Aa’s and Noorderzijlvest water boards, and Waterbedrijf Groningen are jointly providing over €500,000. The total cost is approximately €6 million. The Delta Program Freshwater is funding half of this amount. The two research institutes, Deltares and TNO, are carrying out the project.
Lead time
Similar surveys have already been conducted in Zeeland, and those results provide a good indication of the information that will also become available for Groningen and Drenthe. Preparations for the survey are taking place this year. Mapping of the subsurface is expected to begin in 2023, with the first results available in 2024.