What is SplashTool?
SplashTool is software for determining runoff paths and water depths in terrain depressions. In contrast to classical flow path analysis, the water distribution is done volumetrically and the analysis does not require the definition of a fill level. At the beginning, the complete precipitation amount is applied to the DTM. In each iteration step, water flows from cell to cell until an approximately stationary state is established. The driving force is the absolute water level of a cell compared to the neighboring cells. The water levels in the cells, as well as the runoff sum through each cell, are output as GeoTiffs. You can find the detailed procedure description here.

What it isn’t
SplashTool is not a hydrodynamic simulation model. Before the start of the iteration, the entire amount of water is applied to the terrain model, so there is no temporal precipitation course. The runoff between grid cells depends only on the water level difference, without consideration of roughness values, momentum equations, etc. SplashTool indicates, in the sense of a rough analysis, the runoff accumulation paths and flood areas in terrain depressions that are essential for heavy rain. However, it does not represent a temporal course with maximum water levels along the accumulation paths and does not provide information on flow velocities on the surface.

Iteration on the Graphics Card

SplashTool performs calculations using the optimized GPU compute core on an Nvidia graphics card and enables fast computation of large areas. The CPU compute core is comparatively very slow and is no longer actively developed.

Any Questions Left?

Check out the FAQ, read the documentation in the Download area, get deeper insights in the Blog and feel free to contact me!