Digital Terrain Models from Historic Data Sets: The Case of Land Subsidence, Water Management and Sustainable Land Use in the Dutch Lowlands

The region surrounding Gouda, in the middle of the Dutch Delta, is one of the lowest-lying areas in the Netherlands. The historic inner city is situated at the current high-water mark (Amsterdam Ordnance Datum, or NAP). In contrast, the surrounding landscape lies between two and six meters below that due to subsidence as a result of draining the land and making it available for urbanization and agriculture. The original factors that caused the land to subside are still at play here, while relative sea level rise adds to the problem by making these areas prone to flooding. In this region, accurate digital terrain models make an invaluable contribution to data-driven governance and decision-making. These models can illuminate how changing conditions affect heritage sites and the cultural landscape. We propose and evaluate a methodology for developing accurate terrain models from historical aerial photographs. The method provides high-density, high-precision data for the past half-century. This data can provide insight into the long-term effects of local interventions on local subsidence, making the method a valuable tool for developing risk inventories for proposed interventions.