Do you ever check the Union gage just before leaving work at 5:00 and note that the 1:30 reading looks pretty solid, above 200 cfs. Then you throw your boat in the car and race on down to the chutes: Nothing. 150 cfs, maybe. You go back to work the next day and see that the 5:30 update to the Union gage read, sure enough 130 cfs.
You see, the only reason there's water at Union is because Chatfield is releasing. Check the Chatfield Gage:
to find if water's being released upstream.
I'm not sure what the lag is from a release at Chatfield to Union, but it's probably about an hour or so.
I'm quite new to this sport, so y'all are probably sayin' "duh"
we all know this already.
Hope this helps other newbies.