The challenge: lack of data on the banks of unnavigable waterways

Within SPW (Service Publique de Wallonie), the DCENN (Directorate of non-navigable watercourses) is responsible for the sustainable management of non-navigable watercourses in Wallonia, taking into account their hydraulic, ecological, economic and socio-cultural functions.

The DCENN faced a major challenge: the lack of accurate data on the location of the banks of these watercourses, which made it difficult for managers to effectively implement planned measures.

Xavier Legall, attaché at DCENN, explains: "We needed a complete overview of the extent of unnavigable waterways across the territory."

After a public tender, GIM's proposal was selected. "GIM proposed a detailed and coherent plan of action. Their experience in cartography, geodata and automated digital tools, in addition to their solid references, convinced us.

The solution: accurate, automated digital maps based on terrain analysis

The proposed solution uses a digital terrain model (DTM) derived from LiDAR. According to Xavier Legall, it offers many advantages. "By using GDAL and SAGA scripts, as well as FME Desktop workspaces, the application allows us to interpret the relief of the terrain from detailed data which describe the course of the waterway. Furthermore, each bank side can be precisely delineated based on its slope."

The tool also includes smart features to detect areas where it is impossible to determine the location of waterways based on relief, and replace them with a fill surface generated from adjacent plots.

This solution can be applied at the level of the Walloon Region or a specific zone for local updates. Moreover, it is scalable as it can integrate regular updates of input data and new features. "At any time, we can modify the tool ourselves and adapt the automated process to our needs," he says.

The result: more sustainable and responsible management

"Our application goes beyond digital maps," says Xavier Legall. "We are convinced that the generated data will contribute to a more efficient implementation of environmental measures and the Common Agricultural Policy."

"The information collected will be valuable for optimising the maintenance of waterways, as well as for innovation projects, bank management and estimating maintenance costs. This application can also accurately delineate public space around waterways and provide data for various European reports."

"Moreover, SPW now has a tool to update the course of waterways in case of changes in land use planning."

Xavier Legall is satisfied with the collaboration. "The GIM team was flexible, always offered a listening ear and responded quickly. Their 'agile' approach allowed us to make informed decisions throughout the project, which contributed significantly to its success."

On top of that, SPW identified new opportunities for collaboration. "Several associations have already expressed their interest in using this new geographical data to support water quality and reduce the risk of pollution from nitrates and plant protection products."