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chris
Site Admin
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Posted: Apr 13, 2010 Post Subject: Tuolumne - Lower and Cherry Creek flows 2010
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| Hetch Hetchy Water and Power reports as follows:
"A quick note to let you know that after the recent storms, the snowpack is above normal and we are above normal for April precipitation as well – and we’re not even half way through the month.
Releases from HHWP reservoirs are stepping up this week in response, so recreation flows at Meral’s Pool will be rising. Releases at Hetch Hetchy will rise today to 1200 cfs, continuing through the 19th. Releases at Intake are about 400 cfs and will rise to 800 on April 20. Holm PH is releasing 975 cfs, and the Eleanor release will go to about 375 later today.
Between the 1500 cfs from Cherry Creek, the 1600 cfs from HH and Intake, plus 200-300 accretion and 300 cfs from Middle and South Fork, Meral’s Pool flows will be running between 3,500 cfs and 4,000 cfs by Wednesday the 14th. This level will continue until Tuesday, April 20, and will then drop to between 2,500 and 3,000 cfs through April 29 due to biological field work going on in the reach below Hetch Hetchy."
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Thomas M
Member
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| Posted: Apr 14, 2010Post Subject: Great news!
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| Hey Chris,
Thanks for the updates. Do you know if Eleanor will continue to release above 300 cfs? Or is there any time window for how long these releases will go? Cherry creek below the confluence with Eleanor is awesome!
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chris
Site Admin
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| | I'll get back to you with the answer when I have it.
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nathan h
Member
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| | Hey Chris, Curious if you have an update on the Tuolumne reach flows, specifically for Middle Cherry (the above Holm powerhouse flow).
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chris
Site Admin
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| | No word so far. I'll ping Hetch Hetchy again ...
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chris
Site Admin
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| In response to the question "Do you know if Eleanor will continue to release above 300 cfs?", Bruce of Hetch Hetchy Water and Power replied today as follows:
"I will keep at least 350 coming out of EL for at least the next 2-3 weeks. It may go higher when it comes up and spills in excess of the 4 valves I have and that are all open."
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows:
"Hello river folks:
During our April 15 coordination meeting here in Moccasin, the impact of a normal snowpack was discussed, and we all agreed that some periods in May were going to see some large flows. With more than 5” of precipitation in May so far, Tuolumne flows are guaranteed to be out of the range that many people find acceptable for at least 2 of the 5 weekends in May. Depending on air temperatures, we may lose an early June weekend as well.
Ecological studies have kept releases from Hetch Hetchy low for the last week, so the Dreamflows 2750 cfs at Meral’s Pool is due to Eleanor spill, Holm PH and Kirkwood PH releases, and about 550 cfs from Middle and South Forks of the T.
Starting on May 3, releases from HH will go up for a study, but come down for the weekend of May 8-9. Releases will then go back up to balance inflow into the reservoir (to allow releases to come down on Memorial Day), and stay high through 22 May. We will then cut back slowly as part of another study, and be back down for the Memorial Day weekend. Releases will go up midweek to continue the study, and come down for the June 5-6 weekend. They will go up again midweek for the third part of the study, and then come down for the June 12-13 weekend. Beyond June 15, Meral’s flows will be tapering off as Eleanor spill slows down, and the other tributaries back off as well.
To assist your planning, I am providing some likely flow ranges that Meral’s Pool may see, by weekend. You all know, however, that as I write these in April, May weather can easily undo my estimates by either landing 3 weeks of 80 degree weather, or cool and rain, or ...
| Weekend | Merals Flow Range
| | May 1-2 | 3500-4000 cfs
| | May 8-9 | 2700-3300 cfs
| | May 15-16 | 6000-7000 cfs
| | May 22-23 | 5000-6000 cfs
| | May 29-31 | 3500-4500 cfs
| | June 5-6 | 3500-4500 cfs
| | June 12-13 | 3000-4000 cfs
| | June 19-20 | 2500-3500 cfs
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Starting this Wednesday or Thursday, I’ll start my weekly note to let you know HHWP plans for the coming weekend and early part of the following week."
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows:
"River folks –
It has been pretty interesting weather the last few days – 8-10 inches of new snow in the high country and 2.5” of precip at Buck Meadows USFS in the last 10 days. We are at over 200% of normal for April precip at Hetch Hetchy. I think winter is going away, however, and it will get quite warm next week….snowmelt bigtime.
Releases at Holm PH plus spill from Eleanor continue to send 1700 cfs down Cherry to the confluence with the Tuolumne. Releases from HH have been a modest 75 cfs due to ecological studies, but will rise gradually through the weekend to 300 cfs, and then go up to 3500 cfs by late Monday the 3rd. About 400 cfs is being released at Intake, and the Middle and South Forks are adding 500 cfs. Flows at Meral’s Pool from Tuesday the 4th through Friday May 7 will be between 6,000 and 7000 cfs.
Meral’s flows will drop for next weekend while effects from the pulse flow are inventoried by biologists below Hetch Hetchy. Flows at Meral’s will be in the 2,700 to 3,500 cfs range.
Starting on May 10 we will begin ramping back up to even higher releases at HH. More on that later.
Please recreate safely and wear the appropriate PPEs.
Thanks"
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows:
"Hello river recreationists –
This flow update covers more than the usual next 7 days due to the serious planning that has been going on as to how to manage the very large snowmelt inflow volume that will occur in May. To have a chance of being able to control releases for the Memorial Day weekend, we have to have some very large releases for 10-14 days in the middle of the month.
Even with the moderate temperatures, flows have been increasing over the last 5 days. Considerable low-elevation snow is melting, and these increases will continue through the third week of May. Eleanor is spilling 700 cfs, Cherry is on the way up and will see some controlled releases, and an ecological pulse flow was released from Hetch Hetchy this week that took flows at Meral’s Pool to over 6000 cfs.
HH releases are now ramping down to collect data after the pulse flow, and they will be 100 cfs for Saturday and Sunday. We will continue to have about 1700 cfs below Holm PH, the Middle and the South Forks are contributing a total of 750 cfs, and the Clavey downstream has been averaging about 1200 cfs.
Meral’s will be between 3000 and 3400 from Friday through Monday. It will then rise steadily and by Thursday 5/13 it will exceed 5,000 cfs. It will rise by Friday to about 9000 cfs, and from Saturday 5/15 through Saturday 5/22, flows will range from 10,000 to 11,000 cfs. I regret losing boating on these two weekends, but if we don’t release HH water during this period, Memorial Day weekend will also see flows too high for almost all users.
From Saturday, 5/22 through Friday 5/28, releases from HH will be ramping down for a bank stability study. Although the weather uncertainty for the Memorial Day weekend is considerable, from Friday 5/28 through Monday 5/31, flows at Meral’s should be between 4,000 and 4,500 cfs.
June will still see considerable upper elevation snowmelt, and the temperature regime will play a big role in HHWP releases. I will update this information next week. Please be extremely careful during the very high flows that will begin by next Thursday, and wear your safety gear.
Regards"
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows:
"Hello River Folks –
After some really unseasonably cool weather with snow down to 4500 ft early in the week, we are back to warmer days and increasing snowmelt in the Tuolumne basin. Lower-elevation streams are picking up (Middle Fork Tuol), but inflow to Hetch Hetchy is taking its time to get rolling. Forecasts call for it to double in the next 4 days.
Releases from the Cherry side are staying high at 2300 cfs due to a release from Cherry, spill at Eleanor, and the release from Holm PH. Eleanor spill will increase through the weekend. Kirkwood PH release will increase from 400 to 800 cfs on Saturday. The Middle and South Forks are adding nearly 600 cfs and they will rise as it warms.
We have ramped up from the low flow below Hetchy Hetchy last weekend that allowed data collection and instrument placement for the coming high releases and studies. The release from HH will reach at least 7,000 cfs today by 5 pm.
The Meral’s Pool put-in will be running about 11,000 cfs Friday (tomorrow) morning, and it will continue in the 11,000 to 12,000 cfs range through Wednesday, May 19. Flow will fall at Meral’s on Thursday May 20 to about 10,000, and then to 9,000 cfs on Friday. It will then drop about 500 cfs per day through Thursday, May 27.
The plan is to control flows for the Memorial Day holiday and cut releases so that there is 4,000 cfs or less for the 3-day weekend. I’ll report on this issue next week. Nature is working against us in that peak inflow to the reservoirs is also going to occur during that weekend, and only some of them are under control. Stay tuned, and for those going out on the river in the very high water, please be very careful and wear your best safety gear."
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows:
"River folks -
The gage below Early Intake is malfunctioning, and is reading about 3500 cfs low. The Dreamflows site uses that gage and others to calculate the flow at Meral's Pool, and is reporting about 6,600 cfs today.
THE TRUE FLOW AT MERAL'S IS ABOUT 10,000 CFS. PLEASE BE CAUTIOUS DUE TO THIS VERY HIGH FLOW.
The USGS techs will repair the streamgage below Intake on Monday, but until that time, its readings are in error. I have contacted Dreamflows to ask them to make adjustments, but I do not know when that will happen."
Note: I'm including the above message for completeness and so you can see what a bang-up job Hetch Hetchy is doing to keep us informed, and so when you look at the graphs you understand what caused the jump. However I've now updated the Mushroom and Meral's Pool estimates to account for the Early Intake gauge error, using a Hetch-Hetchy supplied temporary fix, and the currently reported flows should again be accurate. I'll go back to the normal estimating models when Hetch Hetchy confirms the Early Intake gauge is fixed.
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows:
"Hello river folks –
The cool weather has slowed down the snowmelt runoff as May weather continues to surprise all of us. The forecast is for another set of showers next week, and possibly more during the Memorial Day weekend. Who would have thought?
As inflows have dropped, the release at Cherry stopped today, and the release from Hetch Hetchy started to decrease a week earlier than planned and will be 1400 cfs on Sunday instead of 6000 cfs. It will stay down through Memorial Day. All the water that has not arrived this week (and next) is waiting for the first 3 weeks of June.
Flows today at Meral’s Pool are 7500 – 8000 cfs, and they will decrease to 7000 cfs Friday afternoon, to 6500 cfs on Saturday afternoon, and then down to 5000 cfs on Sunday afternoon. They will stay in the 4,500 to 5,000 cfs range through next week (and probably Memorial Day) unless the cool weather pushes Eleanor spill and Middle & South Fork flows farther down, or unexpected rain pushes those flows up.
If you plan to go out on the river, dress warmly – I’m seeing forecasts for the mid 40’s at night over this weekend and cloudy days. I’m told the Tuolumne can be pretty tricky in the 5,000 cfs range, so please boat safely."
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows:
"Hello river folks –
Well, in spite of the rain and hail falling around you now, and the snow tonight above 7000 ft, heat is coming on Sunday. Next week will be quite warm, and the snow melt tidal wave will begin to flow. There is room in Hetch Hetchy to store water, and HHWP will do what it can to lower flows on weekends, but the rest of the watershed is actually driving this bus.
Flows at Lumsden will stay below 4000 cfs through Sunday, May 30, and then rise to 5000 cfs by the end of Memorial Day. Holiday trips should seek to conclude as early on Monday the 31st as you can unless you are good with rising water. Flow will continue to rise Tuesday and reach 9000 cfs late Wednesday the 2nd. They will ease slightly Thursday and Friday, and dip below 6000 on Saturday and Sunday. Late launches Saturday will see lower water than 9 am launches.
Flows will come back up again Monday the 7th through Wednesday the 9th and hit 10,000 cfs. They will then come back down to below 6000 cfs Friday the 11th through Sunday the 13th. If possible, I may be able to reduce that a bit more, but it all depends on the weather.
Flows at Lumsden will stay in the 4000 to 6000 cfs range between June 13 and about June 23, and then things will start to slow down, again depending on the weather.
Several newspapers have run the traditional “be cautious around the rivers during snowmelt” articles already. I know I can count on all of you to exercise caution during these very high flows."
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows:
"Water folks –
I hope everyone had great recreational experiences over the Memorial Day weekend! The flows at Lumsden and the weather were perfect.
My note last week laid out a plan for this week that included sharply rising flow to 8,000 cfs during the week and then back down to 4500-5500 cfs for next weekend. Due to the delay in inflows, the rise in release this week has been postponed until next week.
Flows from Cherry, Eleanor, and the Middle and South Forks will combine to produce about 4,500 cfs at Meral’s Pool the rest of this week and through the weekend. I hope to ramp up for study purposes on Monday the 7th, resulting in flows during the week of 9,000 cfs stepping down 6,000 during the week, and then down to 4,500 cfs again for the weekend of the 12th.
However, the peak inflows for this year will be occurring between June 8 and 10, so at this point my plans are still not certain. I will let you know how the plans are developing on Thursday."
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows:
"Recreation folk –
This spring is turning out pretty much the exact opposite of what I like, which is a gentle warm up and the start of snowmelt in early May, and then a cool June with moderate inflow rates. Instead, we have had an icebox at the higher elevations all May, and now we have 90’s down here in Moccasin, 60’s at high elevations, and a very powerful sun that is melting snow very fast. Inflows will peak Monday or Tuesday of next week.
Eleanor spill is rising toward 1000 cfs, 500 cfs is being released at Cherry in addition to 1000 cfs discharge at Holm PH, and a total of 1200 cfs is in the river below Intake and will continue through Saturday. Middle and South Forks are rising and will reach a total of 900 to 1000 cfs soon. The 4,600 cfs shown on the Dreamflows site this morning will rise slightly through Saturday but stay below 5000 cfs.
On Sunday, HHWP will start the second ecological pulse flow test and ramp up from 500 cfs below Hetch Hetchy to 5500 cfs by Monday, June 7, end of day. Flows at Meral’s Pool Tuesday June 8 will be in the 10,000 cfs range. They will step down about 750 cfs/day during the week, and then drop to 2500 cfs on Friday the 11th and hold steady through the weekend. That will still suggest a weekend flow at Meral’s in the 6500 to 7000 cfs range.
I suspect flows will stay above 5000 cfs at Meral’s through Friday, June 18, due to the 140% of normal runoff that is forecasted this year – especially since a below-normal amount came off the landscape in April and May. It is all arriving now.
Please be very cautious around the river, and take thorough safety precautions."
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