Detecting and modelling spatial patterns of urban sprawl in highly fragmented areas: A case study in the Flanders–Brussels region

The Flanders–Brussels region (Belgium) is one of the most urbanised regions in Europe. Since the 1960s the region is subject to urban sprawl, which resulted in highly fragmented landscapes. In this study, urban expansion in the period 1976–2000 is detected using LANDSAT satellite imagery in two contrasting study areas (highly urbanised vs. semi-urbanised) in the Flanders–Brussels area. The highly urbanised study area is characterised by a concentric growth pattern, while the urban expansion in the semi-urban area is much more fragmented. Next, the observed urban sprawl pattern of 2000 was reproduced by means of a spatial model, based on suitability maps. Employment potential, distance to roads and to motorway entry points and flood risk were used to assess the suitability for new built-up land. The observed expansion of the built-up area between 1976 and 1988 was used to calibrate the model parameters. The land cover map of 2000 was used to validate the model output. The analysis shows that the model output should not be interpreted at the level of individual grid cells. At aggregation levels of 240 m × 240 m and above the model produces significant results. The model performance is better in areas with concentric urban sprawl patterns than in highly fragmented areas. Because of its simplicity, the proposed methodology is a useful tool for land managers and policy makers that want to evaluate the impact of their decisions and develop future scenarios.