You can set layers to become visible or invisible as you zoom in or out on a map window (see Primary Layers and Map Layers). This allows you to display finer levels of detail as you zoom in on a map window and avoid clutter when displaying the full area. Refer to Set Visualization Scales for more information on how to customize the visualization scales for map layers.
Some options for customization you may consider:
time series icons for less significant gages appearing as you zoom in
detailed map layers becoming visible as you zoom in
rasters or other background images appearing as you zoom in