Hetch Hetchy Water and Power reported on April 23 as follows:
HHWP operations will continue to impact flows on the Tuolumne River this week and coming weekend. This email signifies changes to the release schedule sent out by Chris Graham last Tuesday, April 16th. Please see the table below.
Valve Releases
UTREP-managed releases from Hetch Hetchy Reservoir began on Sunday the 21st, targeting an initial peak of 3,000 cfs. As of this afternoon, we’ve begun a temporary ramp-down with approximately 350 cfs release targeted by Sunday,
April 28th. Due to warming trends coupled with above-average snowpack conditions and rising inflow forecasts, this brief pause in valve releases will be immediately followed by a second UTREP-managed release, targeting 6,500 cfs on Tuesday, April
30th. This peak flow rate will be maintained for several days until decreasing to approximately 5,700 cfs sometime late next week. We will send another email early next week with further details.
At Cherry Reservoir, valve releases have increased to approximately 1,000 cfs as part of a DSOD inspection. At this time, valves are expected to remain at this flow rate for the next week, or until further notice.
Eleanor is currently full and spilling. Release rates in the table are estimates of the daily averaged valve releases plus spill and are subject to uncertainty of 500 cfs or more.
The table below shows the scheduled flows – as always, these are estimates and dependent on operational needs and are subject to change. We will send along additional updates if significant timing and/or magnitude changes occur. Note that
this table has peak HPH draft – actual generation will cycle per the discussion below. Sunday and Monday will both have multiple valve changes per day and are highlighted in grey.
|
Date |
Time |
Hetchy Releases |
Cherry Releases |
Eleanor Releases |
HPH Draft |
KPH Spill |
Total cfs |
|
Tuesday, April 23, 2019 |
|
2,100 |
1,000 |
1,000 |
950 |
300 |
5,350 |
|
Wednesday, April 24, 2019 |
|
1,470 |
1,000 |
1,100 |
950 |
300 |
4,820 |
|
Thursday, April 25, 2019 |
|
1,030 |
1,000 |
1,200 |
950 |
300 |
4,480 |
|
Friday, April 26, 2019 |
|
720 |
1,000 |
1,500 |
950 |
300 |
4,470 |
|
Saturday, April 27, 2019 |
|
500 |
1,000 |
1,500 |
950 |
300 |
4,250 |
|
Sunday, April 28, 2019 |
AM |
350 |
1,000 |
1,500 |
950 |
300 |
4,100 |
|
Sunday, April 28, 2019 |
PM |
700 |
1,000 |
1,100 |
950 |
300 |
4,050 |
|
Monday, April 29, 2019 |
AM |
1,400 |
1,000 |
1,100 |
950 |
300 |
4,750 |
|
Monday, April 29, 2019 |
Noon |
2,800 |
1,000 |
1,100 |
950 |
300 |
6,150 |
|
Monday, April 29, 2019 |
PM |
5,500 |
1,000 |
1,100 |
950 |
300 |
8,850 |
|
Tuesday, April 30, 2019 |
|
6,500 |
1,000 |
1,100 |
950 |
300 |
9,850 |
|
Wednesday, May 01, 2019 |
|
6,500 |
1,000 |
1,100 |
950 |
300 |
9,850 |
|
Thursday, May 02, 2019 |
|
6,500 |
1,000 |
1,100 |
950 |
300 |
9,850 |
HPH and KPH Generation
Mid-day decreases at Holm Powerhouse are still expected. However, the magnitudes of flows are not projected to swing as low as in the past week.
Kirkwood Powerhouse will be running at maximum generation, with approximately 300 cfs spill into the Tuolumne around the clock.
Expected generation will be as follows, with the usual caveats (all flows are estimates and can change at any time due to operational needs/constraints):
|
Hour Starting |
HPH cfs |
KPH cfs |
|
0:00 |
950 |
300 |
|
1:00 |
950 |
300 |
|
2:00 |
950 |
300 |
|
3:00 |
950 |
300 |
|
4:00 |
950 |
300 |
|
5:00 |
950 |
300 |
|
6:00 |
950 |
300 |
|
7:00 |
530 |
300 |
|
8:00 |
530 |
300 |
|
9:00 |
530 |
300 |
|
10:00 |
530 |
300 |
|
11:00 |
240 |
300 |
|
12:00 |
240 |
300 |
|
13:00 |
240 |
300 |
|
14:00 |
240 |
300 |
|
15:00 |
240 |
300 |
|
16:00 |
950 |
300 |
|
17:00 |
950 |
300 |
|
18:00 |
950 |
300 |
|
19:00 |
950 |
300 |
|
20:00 |
950 |
300 |
|
21:00 |
950 |
300 |
|
22:00 |
950 |
300 |
|
23:00 |
950 |
300 |
Any significant changes to the schedule will be posted on the bulletin board.