The only reason the flows go up or down is based on cities or ranches requesting water down the line.  The heat wave last week no doubt meant that crops must be watered, lawns must be watered and so on.  Also if you look at the chart the guy turning the flows up and down went too high one day then too low the next day.  It is not controlled by a computer...  Just some SCWA worker turning a valve left or right.  Just like a water faucet.  At this time of year the fish just hang out in a few back eddies and dine on whatever comes by.  Don't worry the fish are fine!