Negative precipitation is sometimes required when net groundwater recharge has been calculated using an external program, such as DAISY GIS. In this case, the evapotranspiration may exceed infiltration leading to a net upward flux of water from the groundwater table. However, the standard precipitation module in MIKE SHE does not recognize negative rainfall. In this case, you must specify the negative rainfall using the following Extra Parameters options:
|
Parameter Name |
Type |
Value |
|---|---|---|
|
use negative precipitation |
Boolean |
On |
|
If the negative precipitation is uniformly distributed: |
||
|
negative precipitation max depth |
float |
greater than zero |
|
negative precipitation max layer |
integer |
greater than zero |
|
If the negative precipitation is spatially distributed: |
||
|
negative precipitation max depth dfs2 file |
file name |
.dfs2 file |
|
negative precipitation max depth dfs2 item |
integer |
item number in dfs2 file, greater than zero |
|
negative precipitation max layer dfs2 file |
file name |
dfs2 file |
|
negative precipitation max layer dfs2 item |
integer |
item number in dfs2 file, greater than zero |
· Max depth This represents the depth of the root zone plus the thickness of the capillary fringe and is the maximum depth from which negative precipitation can be extracted.
· Max layer This is the maximum layer depth from which negative precipitation can be extracted.
Note: The negative precipitation option will only work if there is no UZ model active.
