watershed, including the soil surface and the top and the bottom soil layers in the watershed. The sum
of GROFF2 and GROFF3 represents zone 2 and the sum of GROFF4 and GROFF5 represents zone 3.
SBS_STOR_&_FLOW_1 represents subsurface storage and flow for zone 2. GDWTR_STOR_&_
BASFLW_1 represents groundwater storage and baseflow routing for zone 2. SBS_STOR_&_
FLOW_2 represents subsurface storage and flow for zone 3. GDWTR_STOR_&_BASFLW_2 repre-
sents groundwater storage and baseflow routing for zone 3. Finally, CHNLRTNG represents a ficti-
tious channel which begins at the at the base of the watershed whose inflow is the discharge from the
watershed outlet.
In addition to the 12 sectors which represent the watershed, there are two sectors contained within
a user interface. The 13th sector, the DATA INPUTS sector, is used to program the model. The 14th
sector, the OUTPUTS sector, is used to observe the outputs from the model.
Sector hydrology
This section describes the simulated flow of water through the sectors in Object-GAWSER. Be-
fore reading this section, make sure you understand the descriptions of the sectors in the preceding
paragraph.
The flow of water in Object-GAWSER begins in the SNOMLT sector. Water leaves SNOMLT
in two ways. First, water that sublimates off the snowpack leaves SNOMLT via an object called
"SUBLM," but does not enter any other sector (sublimated water enters the atmosphere, an area not
represented by a sector in Object-GAWSER). Second, water that percolates out of the snowpack to
the soil surface goes to GROFF1, GROFF2, GROFF3, GROFF4, and GROFF5 because these sectors
represent the area underneath the snowpack. Each of the five GROFF sectors receives the same
amount of water from SNOMLT, but the amount of water that flows out of each GROFF sector is
weighted according to the aerial proportion of the watershed simulated by each GROFF sector.
Water leaves GROFF1 by two pathways. First, evaporated water from depression storage on bare
impervious surfaces leaves GROFF1 via an object called IMP_EVAP; like sublimated water from
SNOMLT, evaporated water does not enter any other sector. Second, the water that becomes runoff,
once depression storage is filled, is represented by the flow of water from GROFF1 to SRFRNF.
Water leaves GROFF2, GROFF3, GROFF4, and GROFF5 by three pathways. First, the water that
percolates from the bottom soil layer into subsurface storage is represented by the flow of water from
GROFF2 and GROFF4 to SBS_STOR_&_FLW_1 and SBS_STOR_&_FLW_2, respectively. The
water that percolates from the bottom soil layer, through subsurface storage and into groundwater
storage, is represented by the flow from GROFF3 and GROFF5 to GDWTR STOR_&_BASFLW_1,
and GDWTR_STOR_&_BASFLW_2, respectively.
Second, water that becomes runoff once depression storage is filled is represented by the flow of
water from GROFF2, GROFF3 , GROFF4, and GROFF5 to SRFRNF. Third, when the ground is bare,
evaporation from depression storage is represented by an object called EDAY, which removes a spec-
ified amount of water from GROFF2 through GROFF5. Like the evaporated water from GROFF1, the
evaporated water from GROFF2 through GROFF5 is not routed to another sector in Object-GAW-
SER.
The outputs from SBS_STOR & FLW_1, GDWTR_STOR_ & FLW_1, SBS_STOR_ & FLW_2,
and GDWTR_STOR_ & FLW_2 go to CHNLRTNG to represent the subsurface flow and baseflow
components of discharge from the watershed outlet. The output from SRFRNF goes to CHNLRTNG
to represent the surface runoff component of discharge from the watershed outlet. The total input to
the CHNLRTNG sector represents the discharge from the watershed outlet.
DATA INPUTS SECTOR
This section describes how the objects which represent input parameters are programmed in Ob-
ject-GAWSER. Input parameters are located in the DATA INPUTS sector in the main object-model
(Fig. 4).
4
Previous Page
