Flow map DHMVII (multiple flow lines)

The flow map with multiple streamlines shows the lines in the landscape where the water flows potentially concentrated after a rain shower, taking into account the topography and the watercourses present. The colouring indicates the size of the catchment area to the pixel per pixel of 5m*5m, expressed in upstream area (in ha). This area is calculated on the basis of the elevation values in the digital elevation model, without taking into account infiltration. Consequently, this drain model is not suitable for use in areas with little height difference. The calculation algorithm for the multiple streamlines connects the upstream surface that drains to a pixel proportionally to all the lower surrounding pixels, with the lowest pixel receiving the most runoff and the lowest pixel receiving the least runoff (Multiple Flow Direction). This creates diffuse flow lines that give a more realistic picture of the flow over a slope. The map is particularly useful in relatively flat or highly divergent topography, and on wide homogeneous slopes. The flow map is based on the Digital Altitude Model Flanders II (DHMVII) and the Flemish Hydrographic Atlas (VHA).