Measurement of current changes in land levels as input to long‐term planning for flood risk management along the Thames estuary

Bingley, R. M.; Teferle, Felix Norman; Orliac, Etienne; Dodson, Alan; Williams, Simon; Blackman, D.; Baker, T. F.; Riedmann, Michael; Haynes, Mark; Press, N.; Aldiss, Don; Burke, H. C.; Chacksfield, Barrie; Tragheim, D. G.; Tarrant, Owen; Tanner, Steve; Reeder, Tim; Lavery, Sarah; Meadowcroft, IC; Surendran, S.; Goudie, J.; Richardson, D. P.

doi:10.1111/j.1753-318x.2008.00018.x

Cited by 7 publications

(14 citation statements)

References 6 publications

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“…This area encompassed a network of three CGPS (continuously-measured GPS) and 12 EGPS (episodically-measured GPS) stations, established in 1997. A total of 60 descending ERS and ENVISAT SAR scenes (Track 51, Frame 2565) spanning nearly nine years (March 1997 to December 2005) were processed by Nigel Press Associates Ltd., to generate a dataset of about 950,000 PS points (Bingley et al, 2007;Bingley et al, 2008).…”

Section: Determinations Of Changes In Land Level and Vertical Ground mentioning

confidence: 99%

“…This exercise enabled the calculation of a 'shift' factor of -0.66 mm a -1 to convert the line-of-sight velocity given for the PS points with respect to the reference scatterer, to AG/GPS-aligned PSI estimates of vertical ground velocity. This 'shift' was applied to each of the 950,000 PS points individually (Bingley et al, 2007;Bingley et al, 2008).…”

Section: Ag Gps and Psi Combinationmentioning

confidence: 99%

“…4 and Table 1), significantly increase the range and rate of this value. Combining the regional average vertical ground velocity estimates with determinations of rates of sea-level rise shows that there has been a 1.8 to 3.2 mm a -1 rise in sea level with respect to the land along the Thames Estuary and River Thames over the past few decades / past century (Bingley et al, 2008).…”

Section: Ephemeral Movements or Long Term Patterns?mentioning

confidence: 99%

“…A study to determine rates of change in land level and in relative sea level around the UK was undertaken from March 1997 to December 2005 (Bingley et al, 2007;Bingley et al, 2008). This project determined the average 'background' rate of sea-level change in British coastal waters, decoupled from changes in land level, i.e.…”

Section: Introductionmentioning

confidence: 99%

“…On a regional scale, the project also used serial measurements from GPS, but in addition it included the determination of ground velocity for about 950,000 points using PSI (persistent scatterer interferometry) techniques. The PSI data were corrected using the AG/GPS determinations to provide a measure of absolute ground motion, relative to the geoid (Bingley et al, 2008). This paper presents a geological interpretation of the AG/GPS-aligned PSI land level change data, demonstrating (A) that the PSI data is non-random, and so is a valuable tool for assessing patterns of modern ground movement, especially when aligned with measures of absolute ground movement, (B) local and regional patterns of ground movement and (C) probable mechanisms controlling those movement patterns.…”

Section: Introductionmentioning

confidence: 99%

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Geological interpretation of current subsidence and uplift in the London area, UK, as shown by high precision satellite-based surveying

Aldiss

Burke

Chacksfield

et al. 2014

Proceedings of the Geologists' Association

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Long term planning for flood risk management in coastal areas requires timely and reliable information on changes in land and sea levels. A high resolution map of current changes in land levels in the London and Thames estuary area has been generated by satellite-based persistent scatterer interferometry (PSI), aligned to absolute gravity (AG) and global positioning system (GPS) measurements. This map has been qualitatively validated by geological interpretation, which demonstrates a variety of controlling influences on the rates of land level change, ranging from near-surface to deep-seated mechanisms and from less than a decade to more than 100,000 years' duration.During the period 1997 to 2005, most of the region around the Thames estuary subsided between 0.9 and 1.5 mm a -1 on average, with subsidence of thick Holocene deposits being as fast as 2.1 mm a -1 . By contrast, parts of west and north London on the Midlands Microcraton subsided by less than 0.7 mm a -1 , and in places appear to have risen by about 0.3 mm a -1 . These rates of subsidence are close to values determined previously by studies of Quaternary sequences, but the combined GPS, AG and PSI land level change data demonstrate a new level of local geological control that was not previously resolvable.

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Section: Determinations Of Changes In Land Level and Vertical Ground mentioning

confidence: 99%

Section: Ag Gps and Psi Combinationmentioning

confidence: 99%

Section: Ephemeral Movements or Long Term Patterns?mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Geological interpretation of current subsidence and uplift in the London area, UK, as shown by high precision satellite-based surveying

Aldiss

Burke

Chacksfield

et al. 2014

Proceedings of the Geologists' Association

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Sea‐level scenarios for evaluating coastal impacts

Nicholls

Hanson

Lowe

et al. 2013

WIREs Climate Change

170

145

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Global-mean sea-level rise will drive impacts and adaptation needs around the world's coasts over the 21st century and beyond. A key element in assessing these issues is the development of scenarios (or plausible futures) of local relative sea-level rise to support impact assessment and adaptation planning. This requires combining a number of different but uncertain components of sea level which can be linked to climatic and non-climatic (i.e., uplift/subsidence of coastal land) factors. A major concern remains about the possibility of significant contributions from the major Greenland and Antarctic ice sheets and this must be factored into the assessments, despite the uncertainty. This paper reviews the different mechanisms which contribute to sea-level change and considers a methodology for combining the available data to create relative (or local) sea-level rise scenarios suitable for impact and adaptation assessments across a range of sophistication of analysis. The methods that are developed are pragmatic and consider the different needs of impact assessment, adaptation planning, and long-term decision making. This includes the requirements of strategic decision makers who rightly focus on low probability but high consequence changes and their consequences. Hence plausible high end sea-level rise scenarios beyond the conventional Intergovernmental Panel on Climate Change (IPCC) range and which take into account evidence beyond that from the current generation of climate models are developed and their application discussed. Continued review and development of sea-level scenarios is recommended, starting with assimilating the insights of the forthcoming IPCC AR5 assessment.

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Natural and Anthropogenic Geohazards in Greater London Observed from Geological and ERS-1/2 and ENVISAT Persistent Scatterers Ground Motion Data: Results from the EC FP7-SPACE PanGeo Project

Cigna

Jordan

Bateson

et al. 2014

Pure Appl. Geophys.

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Abstract-We combine geological data and ground motion estimates from satellite ERS-1/2 and ENVISAT persistent scatterer interferometry (PSI) to delineate areas of observed natural and anthropogenic geohazards in the administrative area of Greater London (United Kingdom). This analysis was performed within the framework of the EC FP7-SPACE PanGeo project, and by conforming to the interpretation and geohazard mapping methodology extensively described in the Production Manual (cf. http://www. pangeoproject.eu). We discuss the results of the generation of the PanGeo digital geohazard mapping product for Greater London, and analyse the potential of PSI, geological data and the PanGeo methodology to identify areas of observed geohazards. Based on the analysis of PSI ground motion data sets for the years 1992-2000 and 2002-2010 and geology field campaigns, we identify 25 geohazard polygons, covering a total of *650 km 2 . These include not only natural processes such as compaction of deposits on the River Thames flood plain and slope instability, but also anthropogenic instability due to groundwater management and changes in the Chalk aquifer, recent engineering works such as those for the Jubilee Line Extension project and electricity tunnelling in proximity to the River Thames, and the presence of made ground. In many instances, natural and anthropogenic observed geohazards overlap, therefore indicating interaction of different processes over the same areas. In terms of ground area covered, the dominant geohazard is anthropogenic land subsidence caused by groundwater abstraction for a total of *300 km 2 , followed by natural compression of River Thames sediments over *105 km 2 . Observed ground motions along the satellite line-of-sight are as high as ?29.5 and -25.3 mm/year, and indicate a combination of land surface processes comprising ground subsidence and uplift, as well as downslope movements. Across the areas of observed geohazards, urban land cover types from the Copernicus (formerly GMES) EEA European Urban Atlas, e.g., continuous and discontinuous urban fabric and industrial units, show the highest average velocities away from the satellite sensor, and the smallest standard deviations (*0.7-1.0 mm/year). More rural land cover types such as agricultural, semi-natural and green areas reveal the highest spatial variability (up to *4.4 mm/year), thus suggesting greater heterogeneity of observed motion rates within these land cover types. Areas of observed motion in the PSI data for which a geological interpretation cannot be found with sufficient degree of certainty are also identified, and their possible causes discussed. Although present in Greater London, some geohazard types such as shrink-swell clays and ground dissolution are not highlighted by the interpretation of PSI annual motion rates. Reasons for absence of evidence of the latter in the PSI data are discussed, together with difficulties related to the identification of good radar scatterers in landsliding areas.

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Measurement of current changes in land levels as input to long‐term planning for flood risk management along the Thames estuary

Cited by 7 publications

References 6 publications

Geological interpretation of current subsidence and uplift in the London area, UK, as shown by high precision satellite-based surveying

Geological interpretation of current subsidence and uplift in the London area, UK, as shown by high precision satellite-based surveying

Sea‐level scenarios for evaluating coastal impacts

Natural and Anthropogenic Geohazards in Greater London Observed from Geological and ERS-1/2 and ENVISAT Persistent Scatterers Ground Motion Data: Results from the EC FP7-SPACE PanGeo Project

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