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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows:
"Hello river recreationists –
Peak runoff from most Stanislaus, Tuolumne, and Merced River tributaries occurred on Monday, 7 June. Runoff began to decrease yesterday, and the cool weather affecting our area today through Saturday will keep flows lower than at the start of the week.
Snowmelt runoff equals inflow to the reservoirs, and the HHWP (and other) reservoirs have risen rapidly this week. Eleanor is still spilling, and Hetch Hetchy and Cherry Reservoirs are expected to be spilling by this time next week. Once that occurs, we will be passing inflow on down stream through the spillways, so flow study release changes will be largely over.
Flow at Meral’s Pool is currently about 8200 cfs, and that will drop to about 7500 cfs on Friday, and then to about 6,000 cfs for Saturday. A warming trend is forecast for Sunday through Tuesday, so flows will increase back up to about 7000 by Tuesday as Middle and South Forks of the Tuolumne and Eleanor Creek rise with accelerating snowmelt. The Clavey is running around 1000 cfs.
Exact timing associated with Hetch Hetchy and Cherry spill is still dicey, so I will issue a bulletin about Tuesday of next week to let you know what the expected timing and effect is likely to be. It is likely that Meral’s flow will increase by about 6,000 cfs when reservoir filling is no longer affecting inflow. Meral’s flows are likely to be in excess 12,000 cfs from about 16 June through at least 23 June.
Please boat safely, and warn those unfamiliar with swift, cold water dangers that the expected flows will be amazingly powerful and are deserving of extreme caution."
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows:
"River recreationists –
Last week’s high flow forecast was based on sustained triple digit heat forecasts for the Valley, and the NWS has now moderated those temperatures and is even forecasting below normal temperatures. As a result of that change and corresponding operational changes, a revised flow forecast follows and does not include flows over 8,000 cfs. My apologies for the false alarm.
The current Meral’s Pool flow of about 5200 cfs will drop to about 4000 cfs tomorrow (Tuesday) and that flow will be sustained through Thursday. As Hetch Hetchy reaches its spillway, Meral’s flows will ramp up through Friday to about 6500 cfs at end of day, and keep rising to about 7500 cfs by Saturday morning if the current weather forecasts of cooler than normal temperatures hold. Sunday may begin to see a decline to about 7000 cfs, and I expect it to continue to taper down unless a heat wave arrives.
I will update the forecast again on Thursday to incorporate temperature forecast updates."
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows:
"Hello river recreationists –
The cool weather has decreased snowmelt and is helping us have an extended season. Meral’s Pool flows of 3800 cfs for the last couple days have been due to spill at Eleanor, Holm and Kirkwood operations PH, and Middle and South Fork Tuolumne flow. Releases from Hetch Hetchy have been low due to reservoir filling operations.
Friday morning will see the start of spill at HH and a small release at Cherry, and with the lag for the spill to reach Meral’s, flows will begin rising there Saturday morning. Meral’s flow Saturday morning will be in the 4,250 cfs range and slowly rise through the day to 5,000 cfs. Sunday morning flow will be in 6000 cfs range and again slowly rise during the day to about 7300 cfs by the end of the day. At that point, most of the inflow to HH will be passing over the spillway, and flow will vary due to temperature. The day after a “hotter” day, flows will rise 500 cfs or so. Monday-Wednesday temperatures are forecasted to go up a few degrees, so I expect flows at Merals to be in the 7000 to 7,500 cfs range Monday through Wednesday.
Overall, flows should start tapering off about 500-1000 cfs per week through July 4, but rise and fall as we get warm and cool spells. Cherry and Eleanor should stop spilling in about 2 weeks, and HH should stop spilling sometime after July 4.
Please recreate safely."
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows:
"Hello river recreationists –
Last Thursday’s flow bulletin predicted rising flows over the weekend but they were delayed due to equipment issues. The higher flows (5300 cfs) began to arrive at Meral’s Pool late Sunday afternoon, and the rise will continue today. By tomorrow (Tuesday) morning, Meral’s Pool flows should be running around 6500 cfs, and they should stay in the 6,000 to 7,000 cfs range through Thursday.
The weather forecast calls for warmer conditions on Tuesday and Wednesday, so additional snowmelt may be seen at the Middle and South Forks, Hetchy, and Eleanor. I do not expect large increases, however, and cooler weather should return for the rest of the week.
I will send the usual bulletin on Thursday, 6/24."
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nathan h
Member
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| | Are there any predictions for what will happen on Cherry Creek above holm powerhouse this weekend (Middle Cherry run)? It's holding at 350 now, which is good for middle cherry, but it seems to be changing every couple of days. It would be nice to know whether or not it's going to be stable through the weekend.
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows:
"Hello river users –
Warm weather is here to stay – it is either hot or really hot these days in Moccasin, and that is causing snow melt and reservoir inflow to hold reasonably steady. Hetch Hetchy is being held about 5 feet from full, and Cherry and Eleanor are being topped off and will be full in a few days as inflow drops off.
As projected in my Monday email, Meral’s flow rose and has been hovering in the 6,000 cfs to 7,000 cfs range this week. Tributaries like the Middle and South Fork combined are down to 400 cfs, and the Clavey has dropped but will hold in the 500 cfs range for a few more days. Cherry and Eleanor inflows are also mostly steady but will be stepping down in another week.
Flows at Meral’s will remain in the 5800 – 6500 cfs range through Monday, 6/28. Flow will drop to 4,500 to 5,500 cfs on Tuesday the 29th, and then rise to 6,500 to 7,500 cfs for Wednesday (an additional 2000 cfs will be released from HH Tues late afternoon through Wed. morning for ecological study purposes). Thursday, Meral’s Pool flows will return to 5500 to 6200 cfs.
Flows for the July 4 weekend should be in the 4,800 to 5,800 cfs range or lower, depending on the heat wave that is forecasted to start June 28.
Enjoy the warm weather but please continue to take precautions around the swift, icy water near the end of snowmelt runoff 2010."
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chris
Site Admin
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| | Nathan - about Cherry Above Holm - I'll ask, get back to you.
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chris
Site Admin
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| Hey Nathan, Hetch Hetchy came back with:
"The middle Cherry is in transition as CH and EL fill. The 350 cfs above Holm is shortlived, unfortunately for Nathan. Cherry will hit the top of the flash boards today, and I am giving orders to start a valve release this morning to moderate the flow over the spillway and across the road. It will be another few days before Eleanor spills, but it will happen maybe Sunday, depending on the cool down. Flows Nathan can use will happen in another week or so - maybe next weekend???"
I hope that helps - if not let me know.
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jmr
Member
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Posted: Jun 27, 2010 Post Subject: Tuolumne Flows
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| | Any ideas on what the flow at Merals will be on the weekend of July 9-11?
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows:
"River recreationists –
The very hot weather, large inflow, and full reservoirs have caused a delay in the pulse flow release I had planned for June 29-30. I hope to do it July 6-7, but many uncertainties exist.
Instead, we just have high flows at Meral’s due to Cherry spilling 800 cfs, and Eleanor will add 250 cfs extra later today when it spills, totaling 500 cfs in Eleanor Creek. That makes for 2300 cfs at Cherry below Holm PH, a continued 5500 cfs below Intake, and 300 from Middle and South Forks.
Dreamflows is showing about 7,800 cfs now, and it will rise to a bit over 8,000 when Eleanor spills. I expect that to continue Tuesday, and then back down to 7,000 to 7,500 by Thursday morning. Although the holiday weekend is still a ways off, I would expect flows to drop a bit more by then and be in the 6000-7000 range, depending on temperatures."
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nathan h
Member
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| Hey Chris,
Thanks so much for being such a great intermediary between us boaters and the power companies. Just wanted to express some appreciation for all your hard work with that and keeping the gauges online. And thanks for checking on the Middle Cherry flows too.
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows:
"Hello river users –
With the cooler weather and the retreat of the snowpack to the highest elevations, flows in the west slope Sierran rivers have backed down significantly. Cherry and Hetchy have held on a little longer than most, but they too have no more 5-10 days of significant flow. Reservoir filling operations at Cherry and Hetchy will also decrease rafting flows during the next 3-5 days. Hetchy release went from 4000 cfs to 3000 cfs yesterday, and it will decrease 800 cfs by the end of today.
Dreamflows is lagging today and showing yesterday’s flow of 7,000 cfs at 1600 hrs. Meral’s flow is actually about 6,000 cfs this morning. It will drop to 4500 cfs by tomorrow (Friday) morning, and decrease through Sunday the 4th to about 4,000 cfs. The temperature forecast is for warmer Sunday and Monday, so flow may go back up to 4500 cfs.
We are currently planning to make the pulse flow we delayed last week. It will be on July 6, Tuesday, but the peak will be very short and will pass Meral’s Pool and all but the lowest portion of the river reach during nighttime hours. I expect the peak of about 8,500 cfs to reach Meral’s at 4 am on Wednesday the 7th, and it should be below the 2-day trip camping zones by 9 am. Flow will drop after this peak to 2,500 to 3,500 cfs, depending on temperature.
I am concerned that boats will be washed away during the nighttime pulse, and that campers sleeping near the river will be unpleasantly surprised by water coming into their sleeping bags. With the cooperation of the outfitters and the Forest Service, I will be making special efforts to inform everyone of the high flow in the early hours of Wednesday the 7th to avoid losing boats and washing away porta potties. Please share the news. I will send a bulletin out Monday the 5th and Tuesday the 6th to confirm the pulse and remind people of the night time high water.
It is likely that by Friday, July 9, flows between the Cherry and Tuolumne confluence down to Lumsden will be in the 1800-2000 cfs range. I will keep you posted on this prediction.
Please boat safely, and enjoy the holiday weekend."
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows:
"River users -
As a result of declining snowmelt and reservoir inflow, there will NOT be a pulse flow for Hetch Hetchy late at night on Tuesday, July 6.
Flows at Meral's are running lower than predicted last Thursday, and are in the 2800 cfs range. They will edge up a few hundred cfs today as Eleanor finishes filling and starts to spill again. Meral's will rise again late Wednesday or Thursday when HH fills and starts to spill 600 - 800 cfs.
The Cherry Creek run will not be in the preferred range until probably next weekend when HH spill backs down below 300 cfs. I'll try to provide a better forecast of that even later this week."
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chris
Site Admin
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| Sorry, I was out of town. Yesterday (Wednesday), Hetch Hetchy Water and Power reported as follows:
"River users –
Flows at Meral’s have been modest since July 2 due to the filling of Hetch Hetchy Reservoir. That process is complete, and that extra inflow is becoming spill that will now ramp up and start to be seen at Intake around noon today, and at Meral’s later this afternoon. The current 2400 cfs value at Dreamflows will rise to about 2800 cfs by Thursday morning. It will continue to rise during Thursday to around 3,000 cfs.
Friday’s flows at Meral’s will vary due to Holm PH’s schedule, but will be between 2,400 and 3,000 cfs all day. Saturday and Sunday at Meral’s will be flatter, between 2,300 and 2,700 cfs. Monday’s range could be a few hundred cfs lower.
The Cherry Creek users have been hoping that this weekend would be the start of their season, and up to today I thought there was a good chance. However, after additional analysis of high-elevation snow extent and comparison with past years, I believe flows will be in excess of 2100 cfs below the confluence of Cherry and the Tuolumne mainstem from Thursday through at least Monday. Although flow below Holm PH will only be in the 800-900 cfs range, releases at Intake of 800 cfs will be joined by uncontrollable spill from Hetch Hetchy of 400-700 cfs. By Wednesday the 14th, I expect spills at HH to be negligible, resulting in a suitable Cherry Creek flow range.
As spill at HH stops, the primary source of recreational water will be Holm PH operations, and we will be following the release calendar established back in April. In July, the non-release Wednesdays are July 7 and 21. Spill is covering flows today, so the next non-boating day will be 7/21."
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mikes
Member
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| Posted: Jul 10, 2010Post Subject: Holm PH schedule?
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| Chris, I am looking for a release schedule for Holm PH you make mention of in your last post. Is there a link? Is there one available? I can only find the 2009 schedule. Thanks for your help.
peace mike.
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