Low Flow Graphics for Area Rivers Now Available

A new set of low flow probability graphics for select locations on streams in northern Illinois and northwest Indiana has been added to our AHPS pages. This feature, available for sites where long range probabilistic graphics are generated, provides information on the chances for river levels to fall below various water levels.

These graphs are available from the "How low will the river get?" link available on each river forecast point page.

To display a low flow graphic do the following:

  1. Click on the Rivers & Lakes AHPS link from the left menu
  2. Click on a location of interest
  3. Scroll down the page to the "How low will the river get?" link found under the Additional Information tab

The following is an example of a low flow probability graph for the Rock River at Rockton, IL

Low Flow Probabilities for Rock River at Rockton, IL

The low flow graph shows chances of the river going below various levels during the forecast period labeled above the graph. The conditional simulation (CS) line indicates chances of the river going below given levels based on current conditions. The historical simulation (HS) line indicates the chances of the river going below given levels based on "normal" or "average" conditions. These forecasts are currently updated once a month. For more information on how to interpret the low flow graph please hit the button under the graphic called "About this Graphic". This button links to a more detailed explanation of the information on this graphic.

If you have any questions or comments about this enhancement, please feel free to contact Bill Morris, NWS Hydrologist.

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