Evaluation of the urban expansion sustainability in Salamanca (1956-2018) using multi-temporal analysis of land covers changes and multicriteria analysis

The absence of urban sustainability is a widespread deficit in urban agglomerations. In the present work we present a methodology to identify the impacts caused by urban expansion over time, taking as a study area the city of Salamanca and surroundings (Spain). A multi-temporal assessment of land cover changes is carried out using Landsat images and remote sensing, while sustainability criteria (ecological, agricultural, cultural and natural risks) are analysed by means of multi-criteria analysis (MCA) using the Analytic Hierarchy Process (AHP) and Geographical Information Systems (GIS). The results show an increase in the urbanized area of 593% in the period studied (1956-2018), with up to 15% of buildings identified in restricted areas. In 71% of the cases, urbanization caused the sealing of fertile agricultural soils (2,519 ha), of which almost 20% were of the highest quality. A disproportionate increase in the urbanized area was identified in comparison to the population dynamics in recent years, causing an excessive sealing of soils that has repercussions on food production.