20
15
10
CHNL OUTFLW
(hyd 824)
5
CHNL INFLW
(hyd 223)
0
10
20
30
40
50
60
70
80
90
Time (h)
Figure 47. The Muskingum structure. CHNL_INFLW and CHNL_OUTFLW represent in-
flow to and outflow from the Muskingum structure located in the "CHNLRTNG" sector in
Object-GAWSER. hyd 223 and hyd 824 represent the inflow to and the outflow from the lag
and route structure in the Fortran version of GAWSER. The Muskingum structure is accurate-
ly modeled in Object-GAWSER because the inflow and outflow curves are identical.
CONCLUSION
A training guide and technical documentation have been written for a beta version of Object-
GAWSER, a near replication of the Guelph All-Weather Storm-Event Runoff model (GAWSER)
(Schroeter 1989). Object-GAWSER was created using an object-oriented platform and is composed
of 12 interconnected sectors that simulate the hydrologic processes that occur in bare, partially
snow-covered, and completely snow-covered, watersheds. The training guide contains pro-
gramming instructions for Object-GAWSER and modeling strategies for different kinds of wa-
tersheds. The technical documentation describes each of the 12 sectors in Object-GAWSER and how
they are linked. The technical documentation also provides graphical comparisons of Object-GAW-
SER and GAWSER outputs.
A user interface consisting of a data inputs sector and an outputs sector is described in the training
guide. The data inputs sector contains the objects which must be programmed to run Object-GAW-
SER. The outputs sector contains graphs and tables with which the major hydrologic processes that
occur in watersheds can be examined. Graphs demonstrate general behavior while the tables provide
hourly numeric values. The hydrologic processes shown in the outputs sector are the liquid water
released from the snowpack, infiltration, surface runoff, subsurface flow, baseflow, and discharge
(from the watershed outlet).
Comparison of sample outputs from GAWSER (5.4) and Object-GAWSER indicates that the
variables in the two models behave almost identically, except for those that calculate snowpack
density and infiltration.
The misbehavior of those variables that calculate snowpack density is due to the effect of large
temperature fluctuations on those variables that calculate density. Large temperature fluctuations
cause slight miscalculations of snowpack density in Object-GAWSER. For example, the GAWSER
(5.4) and Object-GAWSER estimations of density diverge upon a large temperature fluctuation be-
ginning at 26 and ending at 36 hours (Fig. 34).
The relationship between snowpack density and air temperature should be modified to improve
density calculations in Object-GAWSER. This relationship will be improved once the order of oper-
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