Provinces, water boards, and water companies investigate subsurface composition
Climate change is putting pressure on the availability of fresh water. Longer periods with little precipitation lead to drought and greater demand for fresh water. In addition, rising sea levels are causing groundwater to slowly become saltier. This is also known as salinization. To ensure that nature, agriculture, and industry suffer as little damage as possible in the long term and that sufficient drinking water is 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 part of Drenthe.
Project FRESHEM
The current picture of the subsurface is based on old measurements that were carried out in a fragmented manner across the area. As a result, the information is relatively general and insufficient. The Freshem-NL project therefore involves carrying out accurate measurements. FRESHEM stands for FREsh Salt groundwater distribution by Helicopter ElectroMagnetic survey.
Measurements by helicopter
During the implementation of Freshem-NL, measurements are taken using a helicopter. This allows the subsurface to be mapped to a depth of up to 200 meters. Along the coast, the focus is on the salinity of the shallower groundwater. In the other areas, the focus is on mapping where fresh groundwater is present. All measurements result in a three-dimensional image of fresh and salt groundwater in the subsurface and the presence or absence of clay layers.
Future
The knowledge gained from the project will be used to map potential groundwater extraction areas and the availability of fresh water for nature, agriculture, and businesses. In addition, the information will help to take targeted measures to reduce 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 companies, and two knowledge institutes are collaborating on this project. The province of Fryslân is acting as the coordinator. The provinces of Groningen and Drenthe, the Hunze en Aa’s and Noorderzijlvest water authorities, and Waterbedrijf Groningen are jointly providing more than €500,000 in funding. The total costs amount to approximately €6 million. The Delta Program Freshwater is financing half of this amount. The two knowledge institutes, Deltares and TNO, are implementing the project.
Lead time
Similar measurements have already been carried out in Zeeland, and the results provide a good indication of the information that will also become available for Groningen and Drenthe. Preparations for the study are taking place this year. It is expected that mapping of the subsurface will commence in 2023, with the first results becoming available in 2024.