Natural lakes and constructed reservoirs are treated in the same way by the watershed simulator. The principal difference is that there may be scheduled outflows from far below the surface of a reservoir, while a natural lake will have unregulated outflow from its surface. All catchments and upstream river segments are simulated before reservoirs. Reservoirs may be simulated as either single-segmented or multiple-segmented. The single segment model combines all of a reservoir’s segments together and simulates the reservoir with many vertical layers. The multiple segment model simulates each segment within each reservoir separately, but it requires extra input data. To view time-series output or profile output of a reservoir segment, double-click on a reservoir segment on the Map when in Output Mode.
To edit coefficients for a reservoir segment, double-click on that reservoir segment on the Map when the engineering module is in input mode. To edit coefficients for several reservoir segments at once, select the reservoir segments and then double-click on one of them with the shift key held down. Coefficients apply to all the segments in a reservoir unless otherwise noted. Following is the Reservoir Coefficients dialog box:
The name of this reservoir segment is shown in the caption of the dialog box (above, the reservoir segment being edited is called Lake James). The image in the lower left corner is a copy of the map showing the reservoir segment(s) being edited. Click on single, multiple, or CE-QUAL-W2 to switch between the reservoir model types. By default, the Physical Data tab is open when the reservoir coefficients dialog appears. When each tab is selected, a new group of coefficients appears.