Unsaturated Zone storage
The Unsaturated Zone storage includes all the water between the ground surface and the water table. Thus, all water stored in the root zone is also included here.
The items listed in Table 6.4 are those found in the “Unsaturated Zone - detailed” water balance output in the water balance configuration file:
[WblTypeDefinition]
Name = 'UZ_DETAIL'
DisplayName = 'Unsaturated Zone - detailed'
Description = 'Detailed Unsaturated zone component water balance'
NoGroups = 10
Group = 'qh(uz.qh)'
Group = 'qhmp(uz.qhmp)'
Group = 'qeuz(uz.qeuz)'
Group = 'qtuz(uz.qtuz)'
Group = 'qrech(-uz.qrech)'
Group = 'qrechmp(-uz.qrechmp)'
Group = 'qgwfeedbackuz(-uz.qgwfeedbackuz)'
Group = 'duzdef(-uz.duzdef)'
Group = 'uzszstocorr(uz.uzszstocorr)'
Group = 'uzwblerr(uz.uzwblerr)'
EndSect // WblTypeDefinition
The sign convention in the UZ water balance is such that infiltration from the surface is negative (inflow) and recharge to SZ is positive (outflow). All of the items together should add to zero.
Note, however, the negative sign in front of some of the terms (e.g. uz.qRech) in the water balance definition above. This is because the recharge to SZ is a vertical downward flow in MIKE SHE - making it a negative value in the MIKE SHE results files. The negative sign in the water balance conforms the sign to the water balance sign convention of positive outflows.
Table 6.4 UZ - Unsaturated Zone items
|
Item
|
Description
|
Sign Convention in the Water balance
|
Included in Wbl Error
|
|
uz.qH
|
Infiltration from ponded water into the UZ matrix
|
Inflow - negative
|
yes
|
|
uz.qHmp
|
Infiltration from ponded water into the UZ macropores
|
Inflow - negative
|
yes
|
|
uz.qEuz
|
Direct evaporation from the top UZ node when using the Richards or Gravity flow finite-difference method
|
Outflow - positive
|
yes
|
|
uz.qTuz
|
Transpiration from the root zone
|
Outflow - positive
|
yes
|
|
-uz.qRech
|
Recharge out of the bottom of the soil column to SZ via the UZ soil matrix.
In the MIKE SHE results, recharge is a vertical downward flow (in the negative direction).
In the UZ water balance it is an outflow and must be a positive value.
|
Outflow - positive
(Note sign change in water balance definition)
|
yes
|
|
-uz.qRechMp
|
Recharge out of the bottom of the soil column to SZ via the UZ macropores.
In the MIKE SHE results, recharge is a vertical downward flow (in the negative direction).
In the UZ water balance it is an outflow and must be a positive value.
|
Outflow - positive
(Note sign change in water balance definition)
|
yes
|
|
-uz.qGWFeedBackUZ
|
Feedback from LR to UZ
This value is only non-zero if the Linear Reservoir groundwater option is used. In this case, the baseflow reservoirs will add water to the UZ as a fraction of the discharge to MIKE Hydro River.
In the MIKE SHE results, the feedback to UZ is a positive value. But, in the water balance it is an inflow and must have a negative sign.
|
Inflow - negative
(Note sign change in water balance definition)
|
yes
|
|
-uz.dUzDef
|
Change in UZ deficit.
The UZ deficit is essentially the amount of air in the profile. It is the opposite of the UZ storage.
A decreasing deficit means that the soil is getting wetter, which
equals increasing UZ storage.
An increasing deficit means that the soil is getting drier, which equals decreasing UZ storage.
Internally in MSHE, the value of dUzDef is calculated as a change in storage.
The negative sign is added to convert the change in storage to a change in deficit.
|
Negative for increasing UZ deficit
(Note sign change in water balance definition)
|
yes,
but in the error term calculation the negative sign is not used
|
|
uz.UzSzStorCorr
|
Water balance correction to account for changing thickness of the UZ zone as the groundwater table rises and falls.
|
Positive for a falling groundwater table, because the amount of UZ storage is increasing.
Negative for a rising groundwater table, because the amount of UZ storage is decreasing.
|
yes
|
|
uz.uzWblErr
|
UZ Water balance error
|
Positive if water generated (Dstorage + Outflow > Inflow)
|
|
