Tenth International Symposium on Land Subsidence papers online

Published: 1 May 2020

Despite the Tenth International Symposium on Land Subsidence (TISOLS) in the Netherlands has been postponed to 17-21 May 2021 due to the Covid-19 virus the TISOLS proceedings have been published.

More than 13 papers with Deltares (co)-authors are published and freely accessible via the Corpernicus website. Land subsidence in coastal areas worldwide is still an under-appreciated problem in many countries despite the high costs. A lack of familiarity with the phenomenon is getting in the way of adequate countermeasures. “Making these conference papers freely accessible is one of our ways to share our research and expertise with other parties to address land subsidence and to help designing counter-measures”, according Gilles Erkens subsidence expert at Deltares and observer of the UNESCO Land Subsidence International Initiative. “There is no ‘one-size-fits-all’ solution, tailored approaches are needed, and sharing best practices and lessons learned helps to formulate the best strategy for each area”.

Deltares TISOLS papers

Deltares contributed with  the following papers:

Monitoring shallow subsidence in cultivated peatlands
Sanneke van Asselen, Gilles Erkens, and Francis de Graaf
Levelling and extensometers are applied to monitor subsidence in a cultivated peatland in Overijssel, The Netherlands, in the period end 2018 to end 2019. Preliminary results show vertical movements in the order of centimeters related to seasonal dynamics (rise in autumn/winter, subsidence in spring/summer) and shorter-term dynamics related to groundwater level fluctuations. Additional data collection is needed to assess long term net subsidence. Download the paper.

Reliability of InSAR satellite monitoring of buildings near inner city quay walls
Arjan A. M. Venmans, Martin op de Kelder, Jarco de Jong, Mandy Korff, and Martijn Houtepen
Amsterdam may need to upgrade 200 km of its quay walls along the historic canals. Upgrading the quay walls could damage the nearby buildings. The rate of vertical deformation of the buildings is used as indicator of potential foundation problems. This paper shows that rates observed in PS-InSAR satellite measurements are in good agreement with traditional levelling measurements. Unlike the levelling measurements, the PS-InSAR measurements provide almost 100 % coverage and have little lead time. Download the paper.

Towards unraveling total subsidence of a mega-delta – the potential of new PS InSAR data for the Mekong delta
Philip S. J. Minderhoud, Ivana Hlavacova, Jan Kolomaznik, and Olaf Neussner
The populous and low-lying Vietnamese Mekong delta is facing accelerating subsidence rates and effective mitigation strategies are urgently needed to save-guard the future sustainability of the delta. This paper gathers results from existing measurements and estimates of subsidence in the Mekong delta and presents new, delta-wide estimates of subsidence based on satelitesatellite measures. We outline a planned approach to advance towards improved quantitation of individual subsidence drivers. Download the paper.

Atlantis, a tool for producing national predictive land subsidence maps of the Netherlands
Huite Bootsma, Henk Kooi, and Gilles Erkens
A tool is presented that allows efficient and largely automated production of predictive land subsidence maps on a national scale in the Netherlands. The tool, based on Python scripts, is named Atlantis and calculates the subsidence induced by phreatic groundwater level management in Holocene soft-soil areas through peat oxidation and consolidation. Process formulation, input datasets and data handling procedures are elucidated. Maps produced with Atlantis will soon be available online. Download the paper.

Modelling subsidence due to Holocene soft-sediment deformation in the Netherlands under dynamic water table conditions
Henk Kooi and Gilles Erkens
Minimizing land subsidence is of increasing importance in urban areas in The Netherlands. Modelling was done to shed light on various measures to control the water table in reducing land subsidence. Calculations were done for conditions that occur in the city of Gouda. Results suggest, amongst others, that measures that can more permanently raise the water table by a small amount are more effective than measures that prevention a large water table drop during an occasional drought. Download the paper.

Creep consolidation in land subsidence modelling; integrating geotechnical and hydrological approaches in a new MODFLOW package (SUB-CR)
Henk Kooi and Gilles Erkens
Creep of soft soils such as clays and peat are important in settlement caused by surface loads. By contrast, creep is not commonly considered in land subsidence driven by groundwater pumping. This is odd, because the subsidence involves the same types of soft soils. A new MODFLOW-2005 land subsidence package is introduced that includes creep. In an application to northern Jakarta it is shown amongst others that creep contributes to subsidence long after drawdown in pumped aquifers has stabilized. Download the paper.

Systematic assessment of damage to buildings due to groundwater lowering-induced subsidence: methodology for large scale application in the Netherlands
Ana Laura Costa, Sien Kok, and Mandy Korff
In the Netherlands, subsidence of peat and clay soils due to (artificial) lowering of the groundwater table and loading of soft soils causes extensive damage. The topic is a major concern to homeowners and public authorities but an integrated risk assessment is currently lacking. In this paper, we propose a modular methodology for the systematic countrywide assessment of two subsidence-related damage mechanisms to buildings. Its application will support private and public decision-making. Download the paper.

Predicting land deformation by integrating InSAR data and cone penetration testing through machine learning techniques
Melika Sajadian, Ana Teixeira, Faraz S. Tehrani, and Mathias Lemmens
Cities developed on compressible soils are susceptible to land deformation. Its spatial and temporal monitoring and analysis are necessary for sustainable development of these cities. Techniques such as remote sensing or predictions based on soil characterization can be used to assess such deformations. The objective of this study is to combine these two using machine learning in an attempt to better predict and understand deformations. Download the paper.

The 6M approach to land subsidence
Gilles Erkens and Esther Stouthamer
For many subsiding coastal areas, solutions to subsidence are readily available, but difficult to implement. To facilitate decision making and implementation of measures to subsidence, a sound and shared knowledge base is required. But how to start creating such a knowledge base? This paper presents a comprehensive, step-by-step approach to address land subsidence, illustrated by best practice examples from around the world. This 6M approach will contribute to lowering the threshold to act. Download the paper.

Cost-benefit analysis of urban subsidence mitigation strategies in Gouda, the Netherlands
Sien Kok and Saskia Hommes-Slag
Subsidence is expected to cause significant damage to infrastructure and building foundations in the Netherlands. As the processes are mostly human-induced, this damage may be prevented. Economic impact assessment can help identify the optimal approach to dealing with subsidence, but experience with this is still limited. We develop a cost-benefit analysis (CBA) of strategies developed in the historic center of Gouda, the Netherlands which was used by the municipality to focus future efforts. Download the paper.

Dutch national scientific research program on land subsidence: Living on soft soils – subsidence and society
Esther Stouthamer, Gilles Erkens, Kim Cohen, Dries Hegger, Peter Driessen, Hans Peter Weikard, Mariet Hefting, Ramon Hanssen, Peter Fokker, Jan van den Akker, Frank Groothuijse, and Marleen van Rijswick
Ongoing subsidence is a complex problem for the Netherlands. Old strategies for coping have limits. In the Dutch National Scientific Research Program on Land Subsidence (2020–2025), we will develop an integrative approach to achieve feasible, legitimate and sustainable solutions for managing the negative societal effects of land subsidence, connecting fundamental research on subsidence processes to socio-economic impact of subsidence and to governance and legal framework design. Download the paper.

Late Holocene differential subsidence and relative sea level rise in the Tabasco Delta Mexico
Kees Nooren, Kim M. Cohen, Jaap H. Nienhuis, and Wim Z. Hoek
Coastal subsidence owing to compaction of Holocene strata affects large delta plains such as the Tabasco delta in southern Mexico (Gulf coast). Collected field-data allows for quantification of differential subsidence over several time windows and reconstruction of relative sea-level rise back to 5000 years ago. Observed differential subsidence of 1–1.5 m is mainly caused by compaction of buried strata in response to the accumulating overburden of the prograding beach-ridge complex. Download the paper

Make a reservation in your agenda for TISOLS 2021

The TISOLS organisation invites you to come to the Netherlands 17-21 May 2021, share your latest research findings, learn about new developments, and meet your peers. Via the TISOLS website  more information will be provided later this year. Everybody who has contributed to the present TISOLS proceedings will have the opportunity to present their work or an update of it. New research and insights may also be presented.

TISOLS is organised under the auspices of the Unesco IHP Land Subsidence International Initiative. This working group has endeavored to improve and disseminate knowledge on land subsidence since the 1970s, through International Symposia on Land Subsidence, collaborative projects and publications.