Marty,
The eddyflower gauge is correct. It is the CO DWR gauge for the South Platte near Lake George. That is the flow through Elevenmile Canyon. Pauh of EF, if you are reading, it would probably be good to use this gauge for Cheesman too, or add it as a reference.
Essentially, the guage listed on AW is right above Cheesman Reservoir, and so it is catching all the low elevation streams that come in below Lake George, like Tarryall Creek. I would imagine that later in the summer, like June and July, these two gauges would be pretty similar because the main source of water would be discharge from Elevenmile Reservoir, not tributary runoff. The situation is similar to Waterton Canyon, when it is at 600cfs, but Bailey only has 100cfs or so--most water comes in from the little creeks.
A lot of the gauges on AW are well below the actual run and therefore they aren't the most accurate indicators. So, I would keep an eye on the South Platte near Lake George gauge to find out when Elevenmile or Cheeseman is in (
Detail Graph).
Check out this thread too:
http://www.mountainbuzz.com/forums/f11/cheesman-guage-12957.html
Alex