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chris
Site Admin
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Posted: Mar 21, 2015 Post Subject: Tuolumne - 2015 Release Predictions
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| Hetch Hetchy Water and Power reports as follows:
"We have received inquiries in regards to releases over the next few weeks and have provided information. We would like to share that with other interested folks. Currently we are able to reasonably predict releases from today through March 30, when a change in operations will affect stream releases. Holm Powerhouse releases into Cherry Creek are directly tied to power demand, and thus vary between weekdays and weekends.
Holm Powerhouse Release:
Weekdays: 10PM - 6AM: 300-350 cfs; 6AM - 10PM: 575-650 cfs
Saturdays: 10PM - 6AM: 300-350 cfs; 6AM - 10PM: 450-575 cfs
Sundays: 10PM - 10AM: 300-350 cfs; 10AM - 10PM: 450-500 cfs
Hetch Hetchy Releases: 35 cfs
Eleanor Releases: 5 cfs
Cherry Releases: 5 cfs
We are currently seeing 60-70 cfs combined from South and Middle Fork of the Tuolumne - these flows will depend on the weather, and can be found online at:
http://cdec.water.ca.gov/cgi-progs/staMeta?station_id=STO [cdec.water.ca.gov]
http://cdec.water.ca.gov/cgi-progs/staMeta?station_id=MTO [cdec.water.ca.gov]
The Tuolumne River is also being gaged at Wards Ferry Bridge by the USGS:
http://waterdata.usgs.gov/ca/nwis/uv/?site_no=11285500&agency_cd=USGS& [waterdata.usgs.gov];
The Clavey River is not currently gaged. If there are significant changes we will send out an update, as well as update on April operations when those plans solidify."
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows:
"Hopefully there are folks out there taking advantage of the warm spring temperatures and water on the river. We are preparing our water operations plans for the next few months and there are some short term changes that we are making. As folks know it is exceptionally dry -- I will be out measuring the historically shallow snowpack tomorrow. However, there has been some water on the river as we manage our system within the Tuolumne River Basin. Over the spring period we will provide updates and information for the length of time that we know for certain. Typically this time of year weekly has the most certainty that we can provide when high flows occur. This year is different as we are not managing high flows but managing the other extreme - which has its own set of difficulties in predicting. We will provide a longer schedule as we finalize our water operations plan.
Right now we can provide the next 7-days as a flow update:
April 1 -April 2
Holm Powerhouse Release:
10PM-8AM: 175-200 cfs; 8AM - 10PM: 300-400 cfs
April 3-7
Holm Powerhouse Release:
11AM -6AM: 175-350 cfs; 6AM - 11AM: ~950 cfs
Reservoir Releases
Hetch Hetchy Releases: 35 cfs
Eleanor Releases: 5 cfs
Cherry Releases: 5 cfs
Middle and South Fork have a combined ~50 cfs. They have not responded to the warm temperatures and sunshine, so do not count on them for extra water.
Please be patient as we work through our operations plan in this historic dry year.
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chris
Site Admin
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| Hetch Hetchy Water and Power released the PROVISIONAL 2015 release schedule, which is posted on Dreamflows here.
Hetch Hetchy Water and Power also wrote (but note that releases times are always below Holm Powerhouse. However flows in the schedule are at Meral's Pool, while flows in what follows are below Holm Powerhouse):
Spring is certainly here - along with April showers and snow. We will take it. This season will certainly be different than other years on the Tuolumne River, but flows will be at recreational levels during the April-Labor day period. We currently do not anticipate additional "spill" at the reservoirs, but would be pleased if we received a plethora of rain to make us wrong.
Additional operational releases will occur outside the recreational schedule at HPH - these are outlined below but are subject to change as we enter the spring season. The outline below is given for planning purposes as HHWP's current forecast. We will provide updates to these bullet points as we move through the season. Updates will be sent as necessary - weekly or monthly.
April 3-15
. Weekdays/Weekends
- 0600-1100 -- 950 cfs below HPH - "Rec Flow Rate"
- 1100-0600 - 250-450
April 16-30
. Weekdays
- 0700-1100 -- 950 cfs below HPH - "Rec Flow Rate"
- 1100-2200 - minimal flows
- 2200-0700 - 250-450 cfs
. Weekends
- 0700-1100 -- 950 cfs below HPH - "Rec Flow Rate"
- 1100-0700 - 250-450 cfs
May 1-25
. Weekdays
- 0700-1800 -- 950 cfs below HPH - "Rec Flow Rate"
- 1800-0700 - minimal flow
. Weekends/Holiday
- 0700-1100 -- 950 cfs below HPH - "Rec Flow Rate"
- 1100-0700 - minimal flow
May 26-31
. Weekdays
- 0600-1800 - 550 cfs below HPH - "Rec Flow Rate"
- 1800-0600 - minimal flows
- No water May 27
. Weekend
- 0600-1200 - 550 cfs below HPH - "Rec Flow Rate"
- 1200-0600 - minimal flows
June
. 0600-1200 - 550 cfs at HPH - "Rec Flow Rate"
. 1200-0600 - minimal flows
. No Water June 10, 17, &24
July 1-Sept 7
. 0700-1100 -- 950 cfs below HPH - "Rec Flow Rate"
. 1100-0700 - 250-450 cfs
. No water July 8 & 22, Aug 5 & 19, Sept 2
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows:
"Hi Tuolumne River Folks:
There have been no major revisions to the release schedule. Recreational releases will continue this and next week and throughout the summer. Additional operational releases will occur outside the recreational schedule at HPH - these are outlined below but are subject to change as we enter the spring season. The outline below is given for planning purposes as represent HHWP's current forecast. We will provide updates to these bullet points as we move through the season. Updates will be sent out as necessary - weekly or monthly.
April Reservoir releases
Eleanor Releases: 5 cfs around the clock
Cherry Releases: 5 cfs around the clock
Hetch Hetchy Releases: 35 cfs around the clock
Holm Generation
April 16-30
* Weekdays
- 0700-1100 -- 950 cfs below HPH - "Rec Flow Rate"
- 1100-2200 - minimal flows (little to no generation from HPH)
- 2200-0700 - 250-450 cfs
* Weekends
- 0700-1100 -- 950 cfs below HPH - "Rec Flow Rate"
- 1100-0700 - 250-450 cfs
May 1-25
* Weekdays
- 0700-1800 -- 950 cfs below HPH - "Rec Flow Rate"
- 1800-0700 - minimal flow
* Weekends/Holiday
- 0700-1100 -- 950 cfs below HPH - "Rec Flow Rate"
- 1100-0700 - minimal flow
May 26-31
* Weekdays
- 0600-1800 - 550 cfs below HPH - "Rec Flow Rate"
- 1800-0600 - minimal flows
- No water May 27
* Weekend
- 0600-1200 7-12 - 550 cfs below HPH - "Rec Flow Rate"
- 1200-0600 - minimal flows
June
- 0600-1200 - 550 cfs at HPH - "Rec Flow Rate"
- 1200-0600 - minimal flows
- No Water June 10, 17, &24
July 1-Sept 7
- 0700-1100 -- 950 cfs below HPH - "Rec Flow Rate"
- 1100-0700 - 250-450 cfs
- No water July 8 & 22, Aug 5 & 19, Sept 2"
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows:
"Hi Tuolumne River Folks:
There has been one revision to the release schedule. Maintenance at Holm Powerhouse will require taking one unit down all day on Thursday, April 30. This will result in reduced flows during the recreational hours. Instead of 950 cfs from 0700 to 1100, there will be 550 cfs from 0600 to 1200.
Recreational releases will continue this and next week and throughout the summer. Additional operational releases will occur outside the recreational schedule at HPH - these are outlined below but are subject to change as we enter the spring season. The outline below is given for planning purposes as represent HHWP's current forecast. We will provide updates to these bullet points as we move through the season. Updates will be sent out as necessary - weekly or monthly.
April Reservoir releases
Eleanor Releases: 5 cfs around the clock
Cherry Releases: 5 cfs around the clock
Hetch Hetchy Releases: 35 cfs around the clock
Holm Generation
April 16-29
* Weekdays
- 0700-1100 - 950 cfs below HPH - "Rec Flow Rate"
- 1100-2200 - minimal flows (little to no generation from HPH)
- 2200-0700 - 250-450 cfs
* Weekends
- 0700-1100 - 950 cfs below HPH - "Rec Flow Rate"
- 1100-0700 - 250-450 cfs
April 30
- 0600-1200 - 550 cfs below HPH - "Rec Flow Rate"
- 1200-2200 - minimal flows (little to no generation from HPH)
- 2200-0700 - 250-450 cfs
May 1-25 * Weekdays
- 0700-1800 - 950 cfs below HPH - "Rec Flow Rate"
- 1800-0700 - minimal flow
* Weekends/Holiday
- 0700-1100 - 950 cfs below HPH - "Rec Flow Rate"
- 1100-0700 - minimal flow
May 26-31
* Weekdays
- 0600-1800 - 550 cfs below HPH - "Rec Flow Rate"
- 1800-0600 - minimal flows
- No water May 27
* Weekend
- 0600-1200 - 550 cfs below HPH - "Rec Flow Rate"
- 1200-0600 - minimal flows
June
* 0600-1200 - 550 cfs at HPH - "Rec Flow Rate"
* 1200-0600 - minimal flows
* No Water June 10, 17, &24
July 1-Sept 7
* 0700-1100 -- 950 cfs below HPH - "Rec Flow Rate"
* 1100-0700 - 250-450 cfs
* No water July 8 & 22, Aug 5 & 19, Sept 2"
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows:
Hi Tuolumne River Folks:
Another mistake! Tuesday, May 12, not 13 for reduced generation.
There has been one revision to the release schedule for the week of May 7-15. On Tuesday, May 12, one unit at Holm Powerhouse will need to be taken down for maintenance. On Tuesday, May 12, generation will be 550 cfs instead of 900 cfs during the 0700-1800 recreational release period. 950 cfs generation will resume 0700-1800 Wednesday, May 13.
Recreational releases will continue this and next week and throughout the summer. Additional operational releases will occur outside the recreational schedule at HPH – these are outlined below but are subject to change as we enter the spring season. The outline below is given for planning purposes as represent HHWP’s current forecast. We will provide updates to these bullet points as we move through the season. Updates will be sent as necessary – weekly or monthly.
May Reservoir releases
Eleanor Releases: 5 cfs around the clock
Cherry Releases: 5 cfs around the clock
Hetch Hetchy Releases: 50 cfs around the clock
Holm Generation
May 1-25 (except May 12)
* Weekdays
– 0700-1800 – 950 cfs below HPH – “Rec Flow Rate”
– 1800-0700 – minimal flow
* Weekends/Holiday
– 0700-1100 – 950 cfs below HPH – “Rec Flow Rate”
– 1100-0700 – minimal flow
May 26-31
* Weekdays
– 0600-1800 – 550 cfs below HPH – “Rec Flow Rate”
– 1800-0600 – minimal flows
– No water May 27
* Weekend
– 0600-1200 – 550 cfs below HPH – “Rec Flow Rate”
– 1200-0600 – minimal flows
June
- 0600-1200 – 550 cfs at HPH – “Rec Flow Rate”
- 1200-0600 – minimal flows
- No Water June 10, 17, &24
July 1-Sept 7
- 0700-1100 -- 950 cfs below HPH – “Rec Flow Rate”
- 1100-0700 – 250-450 cfs
- No water July 8 & 22, Aug 5 & 19, Sept 2
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows:
"Hi Tuolumne River Folks:
Sorry for the repetitive updates, but there is an additional change for May 10 and May 11. Here are the details:
May 10 - 0000-2400 hrs - 950 cfs below HPH
May 11 - 0000-1800 hrs - 950 cfs below HPH
May 12 - 0700-1800 hrs - ~550 cfs below HPH
Other hours will be minimal flows as have been occurring."
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Studytime
Member
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| Posted: May 22, 2015Post Subject: Confusion.
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| Can you clarify for me the "rec flow rate"
I see it says 550cfs "rec flow rate" and also a 950cfs "rec flow rate"
Am I reading it correctly that there will only be 550cfs released during June?
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows:
Hi Tuolumne River Folks
Here is a brief update of flow conditions for the Memorial Day weekend. And a reminder that beginning May 26 through June 30th the recreational releases will be at a lower rate and be between the hours 0600-1200. There may be some variation in other hours, if it is significant we will update folks.
May Reservoir releases
Eleanor Releases: 5 cfs around the clock
Cherry Releases: 5 cfs around the clock
Hetch Hetchy Releases: 50 cfs around the clock
Holm Generation
May 23-25
* 0700-1100 – 950 cfs below HPH – “Rec Flow Rate”
* 1100-0700 – flows vary 150 to 380 cfs
May 26
* 0000 to 0600 – flows vary 220 to 280 cfs
* 0600-1800 – 550 cfs below HPH – “Rec Flow Rate”
* 1800-0600 – flows vary 300-450 cfs
May 27
* 0000 to 0600 – flows vary 220 to 280 cfs
* 0600-1900 – minimal flow – “No Water Wednesday”
* 1900-2400 – flows vary 300-450 cfs
May 28-31
* 0000 to 0600 – minimal flows
* 0600-1200 – 550 cfs below HPH – “Rec Flow Rate”
* 1200-1800 – flows vary 200-300 cfs
* 1800-2400 – minimal flows
June
* 0600-1200 – 550 cfs at HPH – “Rec Flow Rate”
* 1200-0600 – minimal flows to 300 cfs
* No Water June 10, 17, &24
July 1-Sept 7
* 0700-1100 -- 950 cfs below HPH – “Rec Flow Rate”
* 1100-0700 – 250-450 cfs
* No water July 8 & 22, Aug 5 & 19, Sept 2
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chris
Site Admin
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| Hetch Hetchy Water and Power reported today as follows:
"Hi folks,
We will be extending the rec releases today through the end of the day and will try to carry them through May 25th. Enjoy the river, sun is forecasted to return tomorrow!"
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chris
Site Admin
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| Studytime wrote: | Quote: | Can you clarify for me the "rec flow rate"
I see it says 550cfs "rec flow rate" and also a 950cfs "rec flow rate"
Am I reading it correctly that there will only be 550cfs released during June? |
Looks like it; check the schedule here
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chris
Site Admin
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| Hi Tuolumne River Folks:
A reminder that this Wednesday, June 10, there will be no generation at Holm Powerhouse from 7AM through 7PM due to scheduled maintenance. Additional no water days are scheduled for June 17 and 24.
June Reservoir releases
Eleanor Releases: 5 cfs around the clock
Cherry Releases: 5 cfs around the clock
Hetch Hetchy Releases: 75 cfs around the clock
Holm Generation
June 8 - 12
* 0600-1200 – 550 cfs at HPH – “Rec Flow Rate”
* 1200-0600 – variable flows to 550 cfs
* 550 cfs scheduled around the clock June 8 – 9. For June 11 – 12, 550 cfs is scheduled for all hours except 7PM – midnight, when variable flows < 400 cfs are scheduled. Generation after June 12 will depend on the current precipitation event.
* No Water June 10
June 13 - 30
* 0600-1200 – 550 cfs at HPH – “Rec Flow Rate”
* 1200-0600 – minimal flows to 300 cfs
* No Water June 17 & 24
July 1-Sept 7
* 0700-1100 -- 950 cfs below HPH – “Rec Flow Rate”
* 1100-0700 – 250-450 cfs
* No water July 8 & 22, Aug 5 & 19, Sept 2
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chris
Site Admin
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| Hetch Hetchy Water and Power reported earlier in the week as follows:
"I am happy to inform folks that the flows beginning July 1 will return to the normal recreational schedule. Flows outside the schedule will vary in the approximate range of 250 to 600 cfs.
Have a safe summer on the river."
Please note: the posted schedule hasn't changed. It is still posted on Dreamflows here. HHW&P is mainly drawing attention to the fact that normal summer scheduled releases have started.
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows:
"Hi River Folks,
The summer recreation season on the Tuolumne is nearly winding down - I hope it was a safe and enjoyable season. I am updating folks regarding flows during the month of September. As many have noted, there are reasonable flow levels on the "No water Wednesdays" and in hours outside of the recreational release hours. We have had a number of folks inquire about the flows for September and if there would be a predictable pattern with possibly timing that coincided with typical recreation hours.
HHWP is committed to provide at least 550 cfs below Holm Powerhouse from 0600 hrs until 1200 hr during the weekend periods:
September 11 , 12, 13, 14
September 18, 19, 20, 21
September 25, 26, 27, 28
This results in flows at the confluence of the Tuolumne River and Cherry Creek to be at least 625 cfs of project release. The pattern and rate of release is similar to the recreational release pattern of August 2012. This will be reduced to 600 cfs beginning Sept 15 - due to the change of minimum flow requirements below Hetch Hetchy mid-month.
Flows may exceed these values during the recreational release hours as we operate the system as efficiently as feasible. Flows will also not likely drop to a minimum flow following 1200 hrs. HHWP will provide weekly updates on Thursdays (beginning Sept 10) with an estimate of flows for the weekend days.
Please let me know if you have any questions and happy boating!"
My personal commment (Chris here): "similar to the recreational release pattern of August 2012" in the above translates to releasing about 550 cfs from Holm Powerhouse from around 7am to around noon, though releases were sometimes until 11AM, and fairly often until 1pm. The 550 cfs from Holm put about 700 cfs at Meral's Pool. When the flow dropped, it always dropped sharply.
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows:
"Hi River Folks:
Flows this weekend should be similar to those last weekend. The flows listed below are for below Holm Powerhouse and are listed for the main daytime hours. Releases from Hetchy have dropped - there is now an additional flow of about 55 cfs on the mainstem of the Tuolumne below Early Intake. Flows in general do increase through the morning hours and there is plenty of water on the river into the afternoon.
Flows in CFS below PH:
| Hours | 0600-0800 | 0800-1200 | 1200-1800
| | 18-Sep | 570-700 | 700-880 | 800-900
| | 19-Sep | 540-600 | 600-660 | 600-650
| | 20-Sep | 540-600 | 600-625 | 530-580
| | 21-Sep | 560-690 | 730-850 | 800-900
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