

Watershed Dynamics
Streamflow STELLA Model: Troubleshooting Guide
The following describe solutions to problems that students may
encounter as they use the streamflow STELLA model.
 Students cannot open
the STELLA model:
The demo STELLA program may only allow one model to be open at once. This
may include any blank “New” model. To make sure that no models
are already open, choose “Close” under the “File”
menu, and close anything the program tells you is open. Then choose “Open”
under the same menu, and select the Streamflow model file.
 Students’ screen
doesn’t resemble the description in the activity:
Students may have inadvertently opened the “Model Construction”
layer or the “Equations” layer of the model. To return to the
“Mapping” layer, find the small white box near the top of the
lefthand grey margin. This box contains a triangle or two. Click on the upwardpointing
triangle. The screen should change. If it still does not look correct, click
on the upwardpointing triangle again. If there is no upwardpointing triangle,
check to make sure that they have opened the Streamflow model.
 Students cannot move
sliders to desired values:
In the middle of the bottom of the slider box is a small box with a number
inside it. Students can click on this number box and enter a value directly.
 The slider number box
says “eqn. on”:
Students may have accidentally clicked on the small button in the lower lefthand
corner of the slider box (the button with the squiggle on it). Click on this
button again and a number should reappear.
 Students have trouble
entering streamflow predictions:
Double click on the “Predicted Flow” icon, which looks like a
tiny graph with a big colored border around it. Double clicking should bring
up a bigger graph. To “draw” on this graph, click the mouse in
the graph field in the location where you would like a line. Use the mouse
to drag the line around. When you first open the Predicted Flow graph, this
line is hidden behind the xaxis. Students may find it easier to click directly
on the xaxis, then drag upward to make the line appear in the graph’s
field. Drawing a graph takes some experimentation.
 Students cannot move
between Page 1 and Page 2 of the “Results” graph:
Students need to click on the yellow triangle in the bottom left corner of
Page 1 of the graph.
 Students cannot clear
the “Results” graph with the Dynamite tool:
Students may have accidentally “locked” the graph, which prevents
its being erased. Make sure that the icon in the lower lefthand corner of
the graph is an opened lock, not a closed lock. If it is a closed lock, click
once on the icon and it should revert to an open lock.
 Students cannot adjust
the amount of rainfall:
Double click on the “Rainfall” icon, which looks like a tiny graph
with a big colored border around it. Double clicking should bring up a big
graph. Students can adjust rainfall by clicking and dragging lines around
in the graph field, but they may have an easier time using the table on the
righthand side of the screen. The “Input” column represents the
day; the “Output” column represents the amount of rain on that
day. Output (amount of rain) may be modified by clicking on the value you
want to change and typing in a new value.
