Disentangling Subsidence from Shallow Soil Processes and Gas Extraction in a Dutch UNESCO World Heritage Polder with InSAR and Data Assimilation
article
Many deltas and coastal plains are densely populated because of their fertile soils and strategic locations. Yet, these areas face substantial subsidence challenges, as a result of human subsurface activities at multiple depths. Subsidence studies so far focus on the effects of individual causes, limiting the understanding of total subsidence. This is also the case in the Netherlands, with much of its coastal land already below mean sea level. This is primarily the result of centuries of water management. The subsurface in these areas is composed of soft soil, making them highly susceptible to subsidence by shrinkage, oxidation, and compaction. The effects of subsidence are locally aggravated by deeper hydrocarbon extraction. This study centers around the Beemster polder, a UNESCO World Heritage site that exemplifies complex human-induced subsidence originating from multiple depths. We distinguish the contributions of the shallow and deep subsidence causes in a joint model. We quantified the contributions and optimized modeling with data assimilation. The results of the combined effects were optimized for 2015–2022 using InSAR data. Locations with the thickest surficial peat layers exhibit over 5 mm/year subsidence, yet the effect of thick clay beds is also substantial. The expected subsidence related to gas extraction is not expected to exceed 30 mm in the period 2020–2050. Findings from this work deepen our understanding of subsidence dynamics, offering an approach that can be applied to similar subsidence-prone coastal and deltaic regions worldwide, where multiple overlapping factors drive subsidence.
TNO Identifier
1023368
Source
Earth Systems and Environment, pp. Epub 2 Dec.
Pages
Epub 2 Dec