Enviroscience - research and consultancy - Planning - Environmental Impact Assessment - Technology Assessment
Enviroscience - Information and Contact details
Enviroscience - Trees and Subsidence - Sustainable Management
EnviroScience - Passive Solar Energy Design ) (under construction)
EnviroScience - Micro CHP (Combined heat and Power) (under construction)
Enviroscience - SAR Interferometry (InSAR)
Enviroscience - Mining Subsidence InSAR imaging - sample images
Enviroscience - other Remote Sensing Applications - sample images
London Clay Subsidence
Subsidence maps from Space Radar
Postcode subsidence statistics
Climate change - future subsidence prediction maps
Satellite radar can now map London Clay shrink and swell subsidence between summer and winter. This space technology breakthrough enables the first high resolution surveys of London subsidence
Overview satellite image (reduced resolution) showing detected surface movement of London - Red is subsiding (<18mm) due mainly to clay shrinkage, Blue is rising (<6mm) mainly due to rising water table. Zooms (inset) show subsidence varying street by street and below, rising groundwater uplift (blue) at Stratford ©Enviroscience. European Space Agency satellite ERS2 (overlaid) ©ESA.
Subsidence causes widespread structural damage to buildings and services across London costing £millions. Radar satellite images are now capable of surveying ground movement across London due to clay shrink, swell and other factors.
These satellite images enable pixel by pixel geotechnical assessment leading to informed decisions and targeted action, a unique new service for surveyors, utilities, infrastructure, planners, insurance, property etc.
EnviroScience use satellite radar to map London Clay shrinking and swelling between summer and winter. This has enabled the first high resolution surveys of London Clay subsidence.
Subsidence causes widespread structural damage to buildings and services across London costing £millions. These satellite images enable pixel by pixel geotechnical assessment leading to informed decisions and targeted action, a unique new service for surveyors, utilities, infrastructure, planners, insurance, property etc.
Radar Satellite Interferometry (InSAR) Results
These results show surface movement of the London region surveyed on a scale not previously seen. It is simply not possible to survey such a large area simultaneously with any other current technology. Each pixel maps the detected surface height change in millimetres. Pixels are 20 metres square and cover most of urban London. Preliminary research leading to this result was a collaboration with other top expertise from the UK space sector, geologists, environmental and engineering partners.
This latest satellite imaging of London Clay deformation is probably the most subtle and widespread ground deformation yet detected and refined by this radar satellite technology. The web images shown here are at a very much reduced resolution to preserve copyright at full resolution. At full resolution, the highly variable height change seen in the zoom insets above, can be located and mapped right down to individual properties and roads etc., The survey service now launched may explain persistent utility, building and infrastructure problems such as mains bursts, rising groundwater and structural problems, with the evidence to focus appropriate engineering solutions efficiently.
London Clay Subsidence
London Clay shrinks and swells from summer to winter as the soil moisture content varies. London Clay can shrink and swell as much as 50mm. Surface drainage, vegetation, building foundation depth and pressure alters this deformation creating complex local height variation. Climate change is now increasing the seasonal extremes of soil moisture deficit and saturation, consequently affecting shrink and swell deformation. This new research now enables the first detailed surveys across the region of actual surface movement.
Vegetation may increase shrink and swell, causing structural damage if close to buildings with inadequate foundations. Thus, vegetation density (biomass) has been specially mapped, from high resolution optical satellite data. We have even mapped individual tree species (e.g. Oak and London Plane) by satellite.
London Subsidence Risk Model
In parallel to satellite maps, the London Clay has been computer modelled for shrink and swell combining soil, geology and vegetation factors, using data rigorously validated to support the radar research
