edit: 205'd by Senior Franz. HI EDD!
The Unc in this stretch is basically an irrigation ditch. This data is a bit misleading as the flows change based on how many corn farmers in Delta call for water.
For an unbelieveably long time in 2014, there was more water in the Unc than in the Gunny. Between the two gages you reference, there is quite a bit dumping into the Unc via the Gunnison Tunnel
and then being diverted for irrigation before Delta.
I'm no water expert but I've been fishing this stretch for over a decade and most years I have been disappointed by the high flow thru town.