Application of the G2G Model to the Maarkebeek Catchment. Next-Generation tools m.b.t. hydrometrie, hydrologie en hydraulica in het operationeel waterbeheer. Fase 1: analyse. Perceel 1: De Maarkebeek

The aim of the research reported here is to configure the Grid-to-Grid (G2G) distributed hydrological model developed by CEH to a case-study catchment in Belgium, the Maarkebeek, using spatial datasets on landscape properties, and to assess its utility for application across Flanders for a range of water management functions. The report begins with an overview of the G2G model by way of background. Next, the Maarkebeek catchment is discussed in relation to the G2G model and data availability. This discussion embraces the hydrometric network data and spatial data support in static (e.g. terrain, land-cover, soil properties) and dynamic (e.g. radar rainfall) forms. The configuration and calibration of the G2G model at 1km model is discussed and results on performance summarised for both outlet and internal river gauging stations, including use of a form of “PDM” baseline reference for the outlet station. The assessment of G2G at 1 km scale is next extended to explore its performance when configured at sub-1 km scales (500, 250, 100 and 50 m resolutions). The project required CEH to consider new processes currently not represented in G2G that could have significance in a Flemish context. Section 6 considers inclusion of infiltration-excess runoff and the effects of frozen ground and reports on the resulting changes in model performance. The potential improvement in forecast accuracy through use of data assimilation of daily soil moisture estimates derived via remote-sensing (ASCAT: Advanced SCATterometer)is discussed in Section 7. Finally, a concluding Section 8 provides an overview of the report, its conclusion and a consideration of its findings in relation to the wider goals of the "Next generation tools for hydrometrics, hydrology and hydraulics in operational water management" project.