Urban growth (1956-2012) and soil sealing in the metropolitan area of Valencia (Eastern Spain)

The aim of this study is to understand the urban growth dynamics from the mid-1950s to 2012 in the Metropolitan Area of Valencia, eastern Spain, and its impact on soils. The study area is a very interesting example of the many changes in land use and land cover in the landscape of Mediterranean alluvial plains. The analysis of urban growth was based on photo interpretation of aerial photographs and GIS based methodology. At a detailed scale (1:10,000), results show that there has been a highly dynamic process produced by the extent of land developed as urban area. In 1956 only 3,441 hectares (9.3% of the overall study area) were occupied by urban use. In 2012 the total sealed surface was 10,523 hectares, around 30% of the studied area. The increase in built-up areas for the whole period was 206%, representing an average annual rate of 126 ha/yr. In the Metropolitan Area of Valencia much of the land converted to urban use was once highly productive agricultural soils. Around 5,763 ha of soil types with very high and high land capability, mainly Calcaric Fluvisols, were sealed throughout the study period.