Soil subsidence in the Netherlands greater than expected.
Although we have long suspected that the ground in the Netherlands is subsiding, the first nationwide measurements proving this have now been published. The subsidence is much greater than expected, particularly in the west of the country. This is evident from data on the new Soil Subsidence Map of the Netherlands , which was presented this week by the Netherlands Centre for Geodesy and Geo-information (NCG) on Tuesday, November 20 at Geobuzz in Den Bosch and on Thursday, November 22 during the Veenomeen event in Zaandam.
Bodemdalingskaart.nl Interactive map
A research team led by Prof. Ramon Hanssen (NCG / TU Delft) has incorporated three different types of measurement data into the underlying model: satellite radar, GPS, and gravity measurements. The data were used to create an interactive map on a publicly accessible website: bodemdalingskaart.nl. Because the map shows not only the different soil types in the Netherlands but also the location of oil and gas fields, it clearly illustrates the causes of the observed ground displacement. The map is updated daily with the latest satellite data. This makes it possible, for example, to track whether ground displacement decreases when less gas is extracted in Groningen.
Shallow displacement
The map has enabled researchers for the first time to distinguish between the deeper causes of soil subsidence, such as gas extraction, and the effects in the top few meters. Until now, it was not possible to measure this top layer directly. It turns out that in some places in the Netherlands, this 'shallow' subsidence is even greater than the more well-known, deeper causes. This subsidence is now clearly measurable, particularly in the peat and clay areas in the west of the country. The consequences of the past summer are also noticeable: dozens of houses show cracks and subsidence as a result of the dry weather. Climate change appears to play a significant role in this accelerated subsidence. The relatively warm summers dry out the peat soil, accelerating the subsidence. This process is irreversible: the peat oxidizes, which also means that more CO2 is released into the atmosphere.
According to Prof. Hanssen, the map clearly shows how serious the problem of forced relocations in the Netherlands really is: 'If relocations continue at the current pace, it could mean the end of the typical Dutch landscape with meadows, cows, and windmills, or cause enormous damage to historic city centers.' The PBL (Netherlands Environmental Assessment Agency) (p. 8) estimates that this damage could amount to as much as €22 billion by 2050.
However, the fact that this can now be effectively measured is good news. Water managers can use the measurements to improve their water level management, for example by better predicting periods of drought.
About the map of soil subsidence
The bodemdalingskaart.nl project is an initiative of the Netherlands Centre for Geodesy and Geo-information (NCG), the same organization that initiated the Amsterdam Ordnance Datum (NAP) water level measurements, designed the first continuous GPS network in the Netherlands, and developed the Actual Elevation Model of the Netherlands (AHN). Various universities, knowledge institutes, and companies, including SkyGeo, have contributed to the result. SkyGeo is an expert in radar analysis and monitoring of infrastructure and the Earth's surface.
Breakthrough in the collaboration between SkyGeo and TU Delft
The improvement of satellite radar analyses, which made shallow shifts visible with millimeter precision, was made possible primarily by the processing and integration of the satellite data on the scalable SkyGeo platform. The billions of measurements are partly derived from Sentinel-1 SAR images from the European Space Agency (ESA). Based on these images, SkyGeo has developed countless innovative algorithms. SkyGeo initially invested heavily in the data center and technological breakthroughs that are now front-page news. The shift data is publicly available starting today.
High-resolution radar images
The radar images used for bodemdalingskaart.nl have a low resolution. Furthermore, the data is only available per raster cell, making it unsuitable for general insights. In addition to the freely available low-resolution data, SkyGeo also offers high-resolution data, allowing displacements to be mapped in much greater detail – at the level of individual bridges, roads, and buildings.
Update Land Subsidence Map 2019
In late 2019, SkyGeo released a major update for bodemdalingskaart.nl, featuring the most recent satellite data. We will continue to support this fantastic initiative in the coming years, so feel free to use the map for basic analyses. More detailed information on specific areas is available for a fee.
