We found the missing four years of storage data for the Isabella reservoir. Here's the full result. And here's our updated comments. 

The USACE project mandates that storage on June 01, 2021 be capped at 72,237 acre-feet.

Over the last 50 years, the average storage in the reservoir on June 01 has been 302,904 acre-feet.

The reservoir has an "unusable" minimum of 30,000 acre-feet.

Thus, the project means useable storage on June 01, 2021 will be at 15% of average. (42,237/272,904.) The snowpack will have been substantially, if not fully, depleted. And the watermaster has never provided boatable flows with 70-some thousand acre-feet of storage. Thus, the project means there will be no summer boating season on the Lower Kern in 2021 — and perhaps a year or two after that if there are substantial project delays or if the project is followed by a season or two of drought. 

This is the adverse effect on whitewater boating the project entails. The Corps should mitigate it, in our opinion, with some regime of "bubble" rec releases.