Aerial imagery of floodplains
For many years now, airborne LiDAR data has been used to help improve the accuracy of flood models. However, one of the challenges associated with the use of airborne LiDAR for flood modelling is that the data at the interface between water bodies and dry ground can tend to be “noisy”. This can result in LiDAR-derived digital elevation models (DEMs) for water bodies, such as lakes and reservoirs, not being “flat” or water in rivers appearing to flow uphill!
To overcome this problem, AAM has developed hydro-flattening processes that create LiDAR-derived DEMs in which water bodies and rivers are flat or flow downhill.
The processes allow hydrological rules to be imposed in two ways. First, open water bodies are forced to be flat and horizontal. Secondly, DEMs that span rivers with flowing water are forced to be “flat” from bank to bank and “sloped” at a consistent angle in the direction water is flowing.
Hydro-flattening ensures reliable and accurate DEM data for water flow analysis and flood modelling projects.
A DEM before hydro-flattening
A DEM after hydro-flattening