| |
chris
Site Admin
|
Posted: May 12, 2008 Post Subject: Tuolumne and Cherry Creek Releases
|
|
| Hetch Hetchy Water and Power reports as follows: "Due to the terribly dry conditions, releases at Kirkwood stopped two days ago and Holm PH has been operating to meet municipal load. That has meant releases of 600-700 cfs for the last few days during most daylight hours, into Cherry Creek.
Scheduled recreation releases from Holm (4 hours of about 950 cfs) will occur on Friday and Saturday, May 9 and 10. That results, due to other releases, accretions, and inflow from the Middle/South Fork, in flows of at least 1100 cfs at Lumsden for 4 hours. The Dreamflows site tracks the other releases, accretions, and inflows quite well: http://www.dreamflows.com/graphs/day.090.php
Sunday the 11th will see only about 300 cfs released from Holm PH. Don't forget it is Mother's Day!
Flows the week of the 12th will be lower than a scheduled flow and reach their plateau at Lumsden around noon rather than 9 am. Flows should be around 1000 cfs from noon to dark Monday, and follow that pattern the rest of the week as HHWP meets the SF municipal electrical demand. This forecast of flow is my best guess after Monday, not a committed schedule like the Friday and Saturday flows.
Wishing you safe boating, and I will be in touch again next week or sooner if changes occur."
From me: "Sorry for the delay in posting - I was out of town and my helper forgot to post for me. Hopefully posts will be more timely in future."
|
Admin
Site Admin
|
| Posted: May 15, 2008Post Subject: Water conditions for Recreation, May 15-20, 2008
|
|
| Hetch Hetchy Water and Power reports as follows: "Conditions this week will be similar to the last 7 days. The scheduled releases will occur Friday and Saturday, producing a 4-hour rise to at least 1100 cfs at Lumsden starting about 9 am. Sunday will be lower flow - look at Dreamflows for an estimate.
Flows will be a little higher than normal, and noticeably a little higher on Sunday than they typically are later in summer due to variable spills of 50-150 cfs from Eleanor Reservoir and elevated flows from the Middle and South Forks of the Tuolumne due to the heat's effect on the melting snowpack. Unregulated rivers such as the Merced may see their peak springtime flows this weekend.
Midweek power generation will be similar to last week, so midday flow is exptected to rise about 8 am at Lumsden to approximately 1000 cfs, depending on accretions from the basin and inflow from tributaries."
|
Admin
Site Admin
|
| Posted: May 15, 2008Post Subject: Recreational Release timing, May 16 & 17
|
|
| Hetch Hetchy Water and Power reports as follows: "I've just learned of a communication glitch here in my office. I'll spare you the details associated with scheduling energy into the electrical grid, but times have a different convention than used every where else. I was not specific enough, and the 4-hour release period got shifted an hour earlier (both last week and this week) and we didn't catch it until just now. It is too late to change it for this weekend.
So, flow will begin rising at Lumsden around 8 rather than 9 and falling at noon rather than 1 pm on both Friday and Saturday. I am very sorry for the inconvenience, and I doubt it will happen again soon!"
|
EdH
Member
|
| Posted: May 21, 2008Post Subject: Flow Beta for the Weekend
|
|
| | Does anyone know what the flow outlook is for Cherry Creek this weekend (Sat-Mon)? Any beta would be much appreciated. Thanks in advance!
|
Admin
Site Admin
|
| Posted: May 23, 2008Post Subject: HHWP Release Schedule May 23-29
|
|
| Hetch Hetchy Water and Power reports as follows:
"Between the cooler weather and melt out of the snowpack in the Eleanor basin, the spill at Eleanor that has been helping to support recreation for the last 10 days is coming to an end. There will be normal releases for fisheries below HHWP facilities after Saturday. The Middle and South Forks have also decreased, and inflows there are probably about 100 cfs.
As scheduled on the recreational release calendar, daily releases will be produced by Holm PH from today (Friday) through Monday that will create flows of 1100 cfs or more at Lumsden from 9 am to 1 pm.
On Tuesday, May 27, an ecological pulse flow will begin at Hetch Hetchy, and the release from O'Shaughnessy Dam will ramp up to 200 cfs by the end of the day. On Wednesday, the release will go from about 1800 cfs to about 3600 cfs at 8 am, and then up to 6200 cfs from 1 pm to 5 pm. The release will then ramp back down, reaching the normal release of 80+ cfs by noon on Thursday the 29th.
These higher releases take about 6 hours to reach Lumsden, so the 3600 cfs flow will reach Lumsden between 1 and 3 pm. Please use caution and boat safely if you plan to launch during these higher flows on Wednesday. If you are camping downriver Wednesday night, remember to pull your craft way up the bank and do rope it down so it is still there Thursday morning. The highest flow could arrive, depending on where you are, after dark."
|
chris
Site Admin
|
| Hetch Hetchy Water and Power reports as follows:
"The ecological pulse flow release from Hetch Hetchy is ramping down at this moment from yesterday's pulse, so flows will return to normal by late tonight (Thursday). I'm told there were many boaters taking advantage of yesterday's high water. The science part of the project was very successful, and a lot of valuable data were collected by staff from Yosemite National Park, SFPUC Natural Resources Division, and HHWP staff and consultants. Results from the event will guide future flow management efforts.
HHWP is shifting operations in June to further reflect the combined dryness of Mary, April, and May. The approx. 1 inch of precip over the last week at HH has NOT compensated for the lack of spring precip. The shift will mean almost no releases from Holm PH into Cherry Crk outside of the sheduled recreational releases Monday through Saturday from 7 to 11 am that produce the 4-hour flow at Lumsden that starts at about 9 am.
For the next two Sundays, June 1 and 8, there will be only minimum streamflow releases at the Project reservoirs plus accretion from tributaries such as Middle and South Forks of the Tuolumne, Clavey, etc. The next scheduled Sunday release is June 15."
|
chris
Site Admin
|
| Hetch Hetchy Water and Power reports as follows:
"Releases from HHWP facilities have been as planned since the pulse flow that was released May 27-29. Normal scheduled releases at Holm PH will continue with the 4-hour window that proides water at Lumsden at about 9 am for the next week except on Sunday.
As Hetch Hetchy nears full, there will be a release of about 250 cfs to the river at Kirkwood PH. This will start Friday (6th) morning and run for approximately 1 week. That will add to the flow at Lumsden that is normally there during scheduled releases.
Holm PH will see releases on Sunday that will be about 500 cfs, all day. Between Holm's contribution and the release from Kirkwood and other minimum streamflow releases, flows at Lumsden on Sunday will be lower than the usual 1100 cfs, but should be usable for kayaks and smaller rafts. Please check the Dreamflows site for estimated flows.
I will let you know if conditions change."
|
chris
Site Admin
|
| Hetch Hetchy Water and Power reports as follows:
"The snow fairies have blessed us with some extra water coming in to Hetch Hetchy. Starting Sunday, 6/08, releases will be going up. Due to some maintenance, from 1 am through about 1 pm, there will be about 800 cfs coming out of Holm PH. At about 1 pm, it will drop back to about 500 cfs and the release from Kirkwood will rise from 200 cfs to about 750 cfs.
The bottom line is that flows at Lumsden on Sunday will be in excess of 1100 cfs all day. This is not a regularly scheduled release.
The elevated flow of at least 1100 cfs continuously will continue through at least Thursday the 12th. Starting in about Wednesday, there may be an extra 500 - 1000 cfs coming from Hetch Hetchy, but a lot depends on the air temperatures.
When the extra inflow tapers down and releases decrease, I will let you know.
Happy boating"
|
chris
Site Admin
|
| Hetch Hetchy Water and Power reports as follows:
"The warm weather has produced faster runoff than expected, and HHWP is topping off Hetch Hetchy and Eleanor. The timing and magnitude of spill flows are hard to predict and cannot be controlled, so please check the Dreamflows website before you head out for a day.
Flows will be increasing below Holm into Cherry and below Kirkwood at Early Intake, and then spill will occur at Hetch Hetchy. An estimate by days:
Tuesday - 9 am - 1 pm, 1800-2000 cfs, the rest of the day and night - 1500-1700 cfs
Wednesday - from 9 am on, 1800-2000 cfs
Thursday - all day, 1800-2000 cfs, may increase late in day to 3,000 cfs
Friday through Sunday - cycling from 2,000-2,500 cfs during day to 3,000 cfs at night.
Please be aware of the additional risks during this spill time of year, and boat safely."
|
chris
Site Admin
|
| Hetch Hetchy Water and Power reports as follows:
"The really warm weather has shifted the rise in releases from Thursday afternoon to Wednesday morning.
Please be aware that as of Wednesday at 7 am, about 1,000 cfs will be released from Holm PH on the Cherry side, round the clock. There will also be about 2,600 cfs released below Early Intake.
That will combine to over 2,800 cfs at Lumsden. I expect this flow to continue through Monday the 16th, and I will send out another update on Friday the 13th, or sooner if there are changes.
Please boat safely."
|
chris
Site Admin
|
| Hetch Hetchy Water and Power reports as follows: "Hello water users -
In spite of the heat, snowmelt inflow into the reservoirs is tapering off as the last of the pack melts out. We are doing final operations over the next week to fill Hetch Hetchy Reservoir and are and will be decreasing release into the Tuolumne accordingly.
Combined releases from the project have been about 3,400 cfs for the last 4 days. The release at Hetch Hetchy was just decreased 400 cfs, so 3,000 cfs of Project releases plus about 200 cfs accretions shoud produce about 3200 cfs at Lumdsen for the next several days.
Holm PH is continuing to release about 950 cfs through the weekend, and that inflow is included in the 3200 cfs.
No larger releases will be made this year, and it is likely that during the week of the 16th, flows will be declining to the scheduled releases of next weekend - the usual 4-hour flow will be continued starting around 9 am at Lumsden. This coming Sunday the 22nd is NOT a weekend release day for Holm PH. If that changes, I will update this email during next week."
|
chris
Site Admin
|
| Hetch Hetchy Water and Power reports as follows: "Hello All -
Inflow to Hetch Hetchy in fading fast, and we are reducing releases to the river from the dam today. On Monday the 23rd I expect spills at Hetchy to be reduced to the usual release of about 165 cfs. Spills at Intake will continue at about 600 cfs until Monday as well, and begin to taper off after that.
Lumsden flows on Thursday and Friday will be about 2000 cfs, but Hetch Hetchy will spill and intermittently add up to 300 cfs on those days.
Lumsden flows on Saturday will be about 2000 cfs.
Sunday is NOT a normally scheduled boating day, and releases at Holm PH will be about 500 cfs due to maintenance. There will be flows in the 1300-1500 cfs range at Lumsden all day.
Monday and Tuesday will likely see a decline to 1300 to 1600 cfs at Lumsden, but there will be, at a minimum, the scheduled 4 hour release from Holm PH of about 1000 cfs that will arrive at Lumsden about 9 am."
|
chris
Site Admin
|
| Hetch Hetchy Water and Power reports as follows: "Hello fellow smoke breathers -
The air is smokey from Moccasin all the way up past Hetch Hetchy, and it doesn't seem to matter which way the wind blows. There is a 1,000 acre fire burning east of Early Intake, but firefighters from the Stanislaus NF and many other cooperating agencies are working on it, and at present there is no indication it will disrupt power operations or water releases.
An extra week of inflow appeared due to the high heat at the end of last week, and with Hetchy near full, flows at Lumsden stayed over 2000 cfs. Inflows are now falling again, and releases from Hetch Hetchy in excess of fisheries release just stopped. A release of about 600 at Early Intake will continue through at least Sunday around noon, putting about 800 cfs in the river below Intake.
Holm releases will continue at a steady 1000 cfs through Thursday, and then Friday and Saturday it will back down to 500 cfs except during the normal 4-hour release window when it puts about 1100 cfs into Cherry for the Lumsden flow window from 9 am through 1 pm. This Sunday is a scheduled recreational release day, and Holm will provide the 4-hour release, but it will be off the rest of Sunday.
The bottom line for the weekend is Saturday flows at 1700-1800 cfs during the normal release window at Lumsden and 1200 the rest of the time, and Sunday flows at 1700-1800 cfs during the release window and 500-800 the rest of the time.
Monday and Tuesday will see the usual 4-hour release from Holm, and the extra release at Intake will be tapering down - the exact amount on those days is hard to tell.
I have received inquiries about releases next Sunday, July 6, which is not a scheduled release day. About 2 weeks ago it looked like there would be at least a boatable flow on that day. I have learned that plans have changed and that there will NOT be releases from Holm on that day beyond 50-100 cfs. My apologies to folks who had locked down plans and reservations for that day. I will let you know by Friday if there is any change."
|
chris
Site Admin
|
| Hetch Hetchy Water and Power reports as follows: "Hello river recreationists -
Inflows have continued their steady drop during the last week, and extra releases beyond usual minimum streamflows and scheduled recreational releases have come to an end. The spring has been unusually dry and cool until this last month, and the extended runoff period has provided a lot of good recreational flows.
Usual recreational releases will be made this week into Cherry Crk through Saturday, producing the usual 1100 cfs at Lumsden between 9 am and 1 pm. This Sunday the 6th is NOT a scheduled release day, and flows at Lumsden will be in the 175-200 cfs range all day. Recreational releases will resume as scheduled Monday the 7th, and Sunday the 13th is a release day.
For the summer scheduled releases, please see the calendar posted on Dreamflows:
http://www.dreamflows.com/Pages/TuolumneSchedule.php
This is the last operations bulletin this summer. If conditions change due to equipment problems or other events, I will send out a bulletin as soon as I have the information. Otherwise, HHWP will do its best to follow the schedule agreed to at the start of the year. Occurrences such as fires, electrical grid problems, powerhouse problems, and other uncontrollable events can interrupt releases but are generally rare. The current North Mountain fire is about 30% contained and is unlikely to cause an interruption.
Hope everyone has a good 4th of July holiday..... and please boat safely."
|
chris
Site Admin
|
| Hetch Hetchy Water and Power reports as follows: "River users:
The 975 cfs we release into Cherry Crk from Holm PH from 7 am to 11 am depends on both Holm PH units being able to go to full load. Holm unit #2 produced serious alarms yesterday and again today, and we have decided we cannot risk runnig it again until we investigate the problem in detail.
With about 500 cfs coming down Cherry Creek during the rafting hours, and 130 from Early Intake, plus 20-40 cfs from Middle and South Forks, it puts flows at Lumsden down around 650 cfs during the typical boating time instead of 1100 cfs.
We are working on the issue with all speed, and I will send out another bulleting Friday about noon to let you know for sure about releases on Saturday. I am sorry for the hardship this will create for boating schedules."
| | | |
