One of Edison’s central tactics in the current KR3 relicensing proceeding is to argue, “We can’t provide a bubble of rec flows in the 16-mile dewatered reach below Fairview Dam because it would decrease flows in the 2-mile Lickety section.” Edison ally Tom Moore volunteered as much during an early technical working group:

It is obviously true that because water travels faster in the KR3 tunnels than in the river, changes in the diversion will alter flows in the Lickety. Specifically, when the diversion decreases, flows in the Lickety temporarily decrease, and when the diversion increases, flows in the Lickety temporarily increase. That is the “fluctuation” that results from diversion changes.

Although no one recalls folks complaining about the fluctuation prior to the KR3 relicensing proceeding, or suggesting we shouldn’t have rec flows in the dewatered reach because of it, KRB’s recreational flows proposal takes strict account of that phenomenon and mitigates it. The data shows that within four hours of the peak diversion change, flow conditions are restored at Riverside Park — and by implication within less than four hours upstream at the KR3 powerhouse put in.

The following graphs reflect four recent recreational flow days under the current regime. The maximum change in diversion at Fairview after ramping is shown to occur each day at 10 a.m. That is when the license requires the additional flows to be in the river below Fairview Dam. (Minor increases after that are due to diurnal changes in natural inflow — not changes in diversion.) The data also shows that flows reach their nadir at Riverside Park about two hours later, and they are restored to pre-fluctuation levels two hours after that, for a total of four hours.

Unlike the current regime, KRB’s recreational flows proposal requires the maximum change in diversion to occur at 6 a.m. That means flows would begin being restored at Riverside Park by 8 a.m. and would be fully restored by 10 a.m. Flows at the KR3 put in would of course be restored a bit sooner. In sum, we do not believe this fluctuation to be a serious argument against recreational flows in the dewatered reach. KRB will continue to fight the idea that the fluctuation precludes the provision of recreational flows at times of solar glut when the water is far more valuable to society in the river below Fairview Dam instead of in Edison’s tunnels.