Scale of Edinburgh's 'urban creep' revealed in study
An area of Edinburgh the size of nine football pitches is being lost each year to urban creep, a study has found.
This happens when green spaces such as gardens are covered over, either by paving or home extensions.
Urban creep can cause problems because it reduces the amount of open land which can absorb rain water, putting extra pressure on drains.
It is hoped the study, the first of its kind in Scotland, will help with future flood management planning.
Researchers studying aerial images found that 11 hectares of green land in the capital is being lost annually, more than six hectares of it through urban creep.
About one hectare is being gained each year through the regeneration of former industrial areas.
The study was carried out by the Centre for Ecology and Hydrology.
Dr Clare Rowland, who led the research, said: "People might assume that most of this loss is from urban expansion, through the construction of new housing and commercial estates.
"Certainly that accounts for 4.8 hectares of the annual loss, but urban creep accounts for 6.4 hectares of vegetation loss each year.
"Home owners have added car parking spaces, conservatories and driveways, or allowed properties to be built in their gardens - all of which have contributed to the loss of greenery."
Some areas have been identified where the opposite effect - urban decrease - was taking place by creating vegetation and gardens on areas which were previously covered over.
The Quartermile development, on the site of the old Royal Infirmary, is one such example.
Dr James Miller, a hydrologist who project-managed the research, said the loss of green land increased the risk of localised flooding because it created more runoff, which could exceed the drainage capacity.
"The scale of this increase was unknown, but mapping and quantifying urban creep means we can improve our understanding of where surface water may need improved management," he said.
Satellite images and aerial photography were compared from 1990, 2005 and 2015 for Edinburgh.
It revealed that 161 hectares of land had been subjected to urban creep over that 25-year period.