Deformation monitoring of dam infrastructures via spaceborne MT-InSAR. The case of La Viñuela (Málaga, southern Spain)

Dams require continuous security and monitoring programs, integrated with visual inspection and testing in dam surveillance programs. New approaches for dam monitoring focus on multi-sensor integration, taking into account emerging technologies such as GNSS, optic fiber, TLS, InSAR techniques, GBInSAR, GPR, that can be used as complementary data in dam monitoring, eliciting causes of dam deformation that cannot be assessed with traditional techniques. This paper presents a Multi-temporal InSAR (MT-InSAR) monitoring of La Viñuela dam (Málaga, Spain), a 96 m height earth-fill dam built from 1982 to 1989. The presented MT-InSAR monitoring system comprises three C-band radar (~5,7 cm wavelength) datasets from the European satellites ERS-1/2 (1992-2000), Envisat (2003-2008), and Sentinel-1A/B (2014-2018). ERS-1/2 and Envisat datasets were processed using StaMPS. In the case of Sentinel-1A/B, two different algorithms were applied, SARPROZ and ISCE-SALSIT, allowing the comparison of the estimated LOS velocity pattern. The obtained results confirm that LaViñuela dam is deforming since its construction, as an earth-fill dam. Maximum deformation rates were measured in the initial period (1992-2000), being around -7 mm/yr (LOS direction) on the coronation of the dam. In the period covered by the Envisat dataset (2003-2008), the average deforming pattern was lower, of the order of -4 mm/yr. Sentinel-1A/B monitoring confirms that the deformation is still active in the period 2014-2018 in the central-upper part of the dam, with maximums of velocity reaching -6 mm/yr. SARPROZ and ISCE-SALSIT algorithms provide similar results. It was concluded that MT-InSAR techniques can support the development of new and more effective means of monitoring and analyzing the health of dams complementing actual dam surveillance systems

MT-InSAR and Dam Modeling for the Comprehensive Monitoring of an Earth-Fill Dam: The Case of the Benínar Dam (Almería, Spain)

The Benínar Dam, located in Southeastern Spain, is an earth-fill dam that has experienced filtration issues since its construction in 1985. Despite the installation of various monitoring systems, the data collected are sparse and inadequate for the dam’s lifetime. The present research integrates Multi-Temporal Interferometric Synthetic Aperture Radar (MT-InSAR) and dam modeling to validate the monitoring of this dam, opening the way to enhanced integrated monitoring systems. MT-InSAR was proved to be a reliable and continuous monitoring system for dam deformation, surpassing previously installed systems in terms of precision. MT-InSAR allowed the almost-continuous monitoring of this dam since 1992, combining ERS, Envisat, and Sentinel-1A/B data. Line-of-sight (LOS) velocities of settlement in the crest of the dam evolved from maximums of −6 mm/year (1992–2000), −4 mm/year (2002–2010), and −2 mm/year (2015–2021) with median values of −2.6 and −3.0 mm/year in the first periods (ERS and Envisat) and −1.3 mm/year in the Sentinel 1-A/B period. These results are consistent with the maximum admissible modeled deformation from construction, confirming that settlement was more intense in the dam’s early stages and decreased over time. MT-InSAR was also used to integrate the monitoring of the dam basin, including critical slopes, quarries, and infrastructures, such as roads, tracks, and spillways. This study allows us to conclude that MT-InSAR and dam modeling are important elements for the integrated monitoring systems of embankment dams. This conclusion supports the complete integration of MT-InSAR and 3D modeling into the monitoring systems of embankment dams, as they are a key complement to traditional geotechnical monitoring and can overcome the main limitations of topographical monitoring

POTENTIAL OF SENTINEL-1A FOR NATION-WIDE ROUTINE UPDATES OF ACTIVE LANDSLIDE MAPS

Slope deformation is one of the typical geohazards that causes an extensive economic damage in mountainous regions. As such, they are usually intensively monitored by means of modern expertise commonly by national geological or emergency services. Resulting landslide susceptibility maps, or landslide inventories, offer an overview of areas affected by previously activated landslides as well as slopes known to be unstable currently. Current slope instabilities easily transform into a landslide after various triggering factors, such as an intensive rainfall or a melting snow cover. In these inventories, the majority of the existing landslide-affected slopes are marked as either stable or active, after a continuous investigative work of the experts in geology. In this paper we demonstrate the applicability of Sentinel-1A satellite SAR interferometry (InSAR) to assist by identifying slope movement activity and use the information to update national landslide inventories. This can be done reliably in cases of semi-arid regions or low vegetated slopes. We perform several analyses based on multitemporal InSAR techniques of Sentinel-1A data over selected areas prone to landslides

A new land \u2013 based gravity data set for the Alps and adjacent regions \u2013 the AAGRG at work

A pan-Alpine gravity data map, homogeneous regarding input data sets, applied methods and corrections as well ascommon reference frames, is not available yet. Therefore, all countries around the Alps have agreed to contributewith gravity data and/or gravity data processing techniques to a recompilation of the alpine gravity field in theframe of the AlpArray Gravity Research Group (AAGRG). Also to collaborate with other groups in AlpArray.In the last year group members met two times to set up guidelines for joint processing and homogenizationof existing gravity data sets. Following the results and appointments of the last technical AAGRG meeting inBratislava October 2018, the members of the 9 participating countries decided to present a first data set of theBouguer gravity field in September 2019 on a 2km x 2km or 4km x 4km grid for the public. Other compilationswill follow: maps of Free Air Gravity, regional field and the corresponding residual gravity field. These new datasets will be available to all AlpArray partners for interdisciplinary work and modelling.This new Bouguer anomaly will be station completed with at least 1 point/4 km2 resolution and compiledaccording to the most modern criteria. In general, even though global models like SRTM1 perform well, thepreference was given to local DEMs - if available. Two software packages for topographic corrections on thebase of ellipsoidal heights are available: \u201cTOPOSK\u201d, developed by Slovak colleagues, and the \u201cadaptive masscorrection\u201d from the Kiel group. The results of both methods are being tested and compared. The geophysicalindirect effect and its determination are also taken into account. Special emphasis is put on the lakes in the studyarea. They have a considerable effect on the gravity of stations that lie at their edges (for example, the partiallyvery deep reservoirs in the Alps). In the Ligurian and the Adriatic seas ship data of the Bureau Gravim\ue9triqueIinternational will be used. Although not unproblematic, these data got the preference over satellite data.In the AAGRG, long discussions were centered on the calculation of long-distance effects of topogra-phy/bathymetry and its compensating masses (root). The first compilation of the AA Bouguer anomaly mapwill, however, be prepared WITHOUT taking long-distance effects in account. The group agreed to extendthe correction radius to the Hayford zone O2(167 km). All topographic corrections will be calculated as masscorrections between the physical surface and the ellipsoidal reference. The group further discussed the necessityof a 3D interpolation of the gravity grid values. Although a 3D interpolation would be required from themethodological-theoretical point of view (the problem is the non-identical gravity and height grids), it was decidedto perform a 2D interpolation in the first compilation - the method of Kriging shall be applied. The poster will visualize the mentioned correction effects and illuminate the necessity of a complete revision of the existing land based Alpine gravity data

Monitoring embankment dams from space using satellite radar interferometry: Case studies from RemoDams project

[EN] The monitoring procedures with different geotechnical/structural sensors and classical geodetic techniques including GNSS are the usual practices in most of the dams where these controls are established. Other geomatic techniques such as TLS, GB-SAR and multi-temporal InSAR (MT-InSAR), allow the determination of 3D displacements with the advantage of covering a large number of control points. In particular, MT-InSAR techniques enable the detection of displacements at a very low cost compared to other techniques, and without the need for field work or the installation of special equipment. In addition, they can provide a single source of information on the stability of the dam when monitoring programs are not carried out due to lack of funding, resources or other reasons. These techniques provide measurement uncertainties of the order of 1 mm/year, interpreting time series of interferometric phases of coherent reflectors present in the area, called Persistent Scatterers. In this work, we present the adaptation and application of MT-InSAR techniques to monitor embankment dams, obtaining vertical displacements, characterizing their consolidation rates, and allowing the identification of potential problems surrounding the reservoir that require further field investigation. This study is part of the ReMoDams project, a Spanish research initiative developed for monitoring dam structural stability from space using satellite radar interferometry.ERS-1/2 and Envisat data sets were provided by the European Space Agency (ESA). Sentinel-1A/B data were freely provided by ESA through Copernicus Programme. Data have been processed by DORIS (TUDelft), StaMPS (Andy Hooper), SARPROZ (Copyright (c) 2009-2020 Daniele Perissin), and SNAP (ESA). The satellite orbits are from TUDelft and ESA, as well as from the ESA Quality control Group of Sentinel-1. Research was supported by: (a) ESA Research and Service Support for providing hardware resources employed in this work, (b) ReMoDams project ESP2017-89344-R (AEI/FEDER,UE) from Spanish Ministry of Economy, Industry and Competitiveness, POAIUJA-2021/2022 and CEACTEMA from University of Jaén (Spain), and RNM-282 research group from the Junta de Andalucía (Spain), (c) ERDF through the Operational Programme for Competitiveness and Internationalisation - COMPETE 2020 Programme within project «POCI-01-0145-FEDER-006961», and by National Funds through the FCT – Fundação para a Ciência e a Tecnologia (Portuguese Foundation for Science and Technology) as part of project UID/EEA/50014/2013, (d) The Ministry of Education, Youth and Sports from the National Programme of Sustainability (NPU II) project «IT4Innovations excellence in science - LQ1602» (Czech Republic), and (e) Slovak Grant Agency VEGA under projects No. 2/0100/20Ruiz-Armenteros, A.; Delgado-Blasco, JM.; Bakon, M.; Lamas-Fernández, F.; Marchamalo-Sacristán, M.; Gil-Cruz, AJ.; Gil-Cruz, A.... (2023). Monitoring embankment dams from space using satellite radar interferometry: Case studies from RemoDams project. Editorial Universitat Politècnica de València. 397-404. https://doi.org/10.4995/JISDM2022.2022.1388339740