The model builder is used to modify Curve Numbers (CN-values) assigned to individual Grid cells of the raster based rainfall/runoff model.After the ...
...is set, the grid file with the CN-values for percolation (GW-recharge) are generated (or recalculated).
This calculation is performed using Surfer commands and it is invoked by pressing the "Surfer calc key" . The calculation is performed in a few seconds, indicated by the hour-glass cursor.
The original grids as obtained from ArcView are usually in JTM with 1000 m spacing. These grids are located in the "System Data" path as indicated at the bottom of the Core Runoff model form. The following grid file is required:
Note:The creation of this directory and the generation of the original grid from ArcView are presently still managed outside of this model. ArcView is able to generate ascii-grids in ESRI format. The conversion from ESRI to Surfer format is done within this model using the ESRI2GRD utility of the Core Runoff model.
Processing of the grid for percolation is simple.