Hetch Hetchy Water and Power reported on June 21 as follows:

An unplanned, but mandatory inspection of a facility downstream of Hetch Hetchy Reservoir is requiring us to significantly change the releases from O’Shaughnessy Dam. We increased releases last night and this morning, and will be decreasing releases from 6000 cfs Saturday to 200 cfs on Sunday. Hetchy Releases will be increased back to the 3-4000 cfs range by Tuesday afternoon.

Some details:

1. The Saturday valve move at Hetchy will occur in the afternoon – it will take a while to get to Intake / Meral’s
2. The Sunday valve moves will occur throughout the day – flows will drop throughout the day
3. Monday the Cherry Run may be open (pending Middle Fork and South Fork flows)
1. Monday KPH generation will drop from 8AM to 4PM – no spill at Intake those hours
2. Monday valve moves will start around noon – these will take a while to get to Intake / Meral’s
4. Hetchy releases could go higher than 3000 cfs on Wednesday – it will depend on the inflow pattern this weekend.

Please be prepared for variable flows throughout the weekend.

Our estimated releases are below:

Any significant changes to the schedule will be posted on the bulletin board.