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chris
Site Admin
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Posted: Aug 15, 2008 Post Subject: URGENT - Saturday 16th Reduced Flows at Lumsden
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| Hetch Hetchy Water and Power reports as follows: "River users -
Our attempts overnight to repair Holm Unit 2 have NOT been successful, and we plan to continue working on it through Sunday and into next week as needed.
In the meantime, we are currently running the other Holm unit at maximum during the normal release period, and we will do the same on Saturday. Both today and Saturday will therefore see about 650 cfs at Lumsden during the 9 am to 1 pm launch period.
Sunday is not a scheduled boating day, so no release was planned for that day.
We have a similar schedule as today planned for Monday - Wednesday of next week. I hope to have better news for those days after three more days of analysis and repair efforts. I will provide another update by noon on Sunday the 17th, or earlier if definitive news occurs.
My apologies for the disruption to your schedules and bookings."
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows: "
Several of you have inquired about the continuation of releases past Sept. 1, and I met with our energy scheduling folks to look into that issue. Due to a large snowpack and late melt in the Pacific NW, electricity market prices are low in Cal. and expected to remain that way through September. Based on that forecast, there is no plan to run Holm PH in such a way that would produce boating opportunities in the first several weeks of September. I expect intermittent Holm releases of up to 250 cfs at various times of the day to assist meeting SF municipal load that is mostly met with Kirkwood and Moccasin PHs.
Last year we did continue to make releases through September due to our need to get Cherry Reservoir down for October maintenance on the pumps that bring water over from Eleanor. I suspect the belief that there will be September flows stems from the memory of last year.
I'm very sorry that our operations plan this year does not extend your season into the first few weeks of September. If anything changes I will let you know immediately."
Note: I received this post and the one about reduced flows at Lumsden at the same time, and since the reduced flows one was URGENT posted that by itself. However, the information in this posting was sent out before the URGENT message, so no scheduled releases in Sept have nothing to do with the generator crisis. In fact, I suppose it's more likely there will be some flows in September since they're not using all the allocated water now. We'll have to wait for the generator to come back online before pursuing that angle, though.
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows: "River users -
We are still unable to identify the cause of the problems on Holm Unit 2. We have several electrical and mechanical crews working there today and more work scheduled tomorrow, Monday the 18th.
As a result, flows tomorrow will be as they were Friday and Saturday, about 650 cfs from the 9 am to 1 pm release period at Lumsden.
I will let you know tomorrow (Monday) by noon what the outlook for Tuesday and Wednesday is in terms of resuming normal releases.
I'm very sorry for the disruption to your schedules."
Note: for various logistical reasons, Dreamflows will miss the noon update tomorrow, and I'll probably only update this page late tomorrow night with whatever Hetch Hetchy sends during the day. If you critically need to know what's planned for Tue/Wed before then, please contact the Groveland Ranger Station at 209-962-7825.
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows: "River Users -
Testing and analysis continues on Holm Unit 2 to determine the source of the electrical problem that has shut it down to avoid potential serious damage to the generator. Tests and repairs are now scheduled to last through Thursday.
We hope to have the unit back up and running on Friday and through the weekend, but I cannot make any promises at this point. I will send out the next update on Wednesday by 4 pm.
The recent flow pattern will continue through Wednesday - about 650 cfs at Lumsden between 9 am and 1 pm, and 250-400 cfs in other hours. Thursday the flow will be in the 250-400 cfs range all day - no 650 cfs peak for 4 hours.
I apologize for the disruption to everyone's schedule' and business, and hope to have better news on Wednesday."
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows: "River Users -
In response to yesterday's note, I learned that trips are launching with smaller boats, and there is continued use of the river.
HHWP will make at least the 650 cfs 4-hr releases at the usual time to support those users, from today (Tuesday) through Sunday the 24th.
I will let you know as soon as we can return to the 1000 cfs release, and you will hear from me again by 4 pm Wednesday with a condition update.
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows: "River users:
Our crews worked all today setting up instruments and checking monitoring systems, and we will be monitoring the unit tomorrow morning during a one-third output test to further evaluate the electrical disturbance that is threatening the generator. We have expert outside consultants evaluating the results, and we are seeking advice from electrical specialists at other utilities. Our electrical and tech staff are entirely focused on solving the problem at the earliest opportunity.
While we will know more tomorrow about this time, I know the outfitters need to know sooner than Thursday afternoon to allow customers to change plans for Friday. I believe that there is less than a 20% chance we will be able to produce the 1100 cfs at Lumsden on Friday.
I am more hopeful about Saturday and Sunday, but releases on those days are certainly not confirmed at this poin. I will be back to you again around 4 pm tomorrow (Thursday) with another update, and hopefully better news. We will continue to run one unit during the normal time and produce the 650 cfs at Lumsden.
My apologies over the situation and the disruption to your schedules and commitments."
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chris
Site Admin
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| Hetch Hetchy Water and Power reports as follows: "River Users -
Numerous tests were run today, and the data will be analyzed on the electrical disturbances in Unit 2. They are just now concluding numerous tests, and analysis will begin tomorrow. It is possible some strategies for curing the problem will be tried tomorrow, Friday. We are unable to be sure that running the Unit is not causing serious damage until the analysis is done.
My best guess is that we will not be able to run Unit 2 and resume 1100 cfs flows at Lumsden until early next week. I know that losing this weekend's rafting is a big blow to both commercial and private boaters.
Tomorrow is certainly out for full releases. I believe there is less than a 20% chance for Saturday or Sunday. It is too early to tell for Monday - work will continue through the weekend to return the Unit. We will continue to run the 650 cfs during the normal time.
I will provide another update tomorrow around 4 pm, and I am very sorry for the continued run of bad news."
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chris
Site Admin
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| Good news! Barring another failure, expect full/normal/scheduled Tuolumne releases this weekend and through Sept1. Hetch Hetchy Water and Power reports as follows: "River Users -
After a lot of tests and analysis by both HHWP staff and consulting electrical engineers, new instruments are in place and changes have been made to operating systems to attempt to control the electrical disturbances that had triggered a shutdown of Unit two last week. We now believe the Unit is stable enough to operate, and we plan to run it through the remainder of the rafting period to produce the usual boating releases.
This is the specific language I received from the manager and engineering/electrical tech team:
Hetch Hetchy's Engineers and Technicians have identified several potential causes that contributed to the HPH #2 trip event occurring on 8/13. Although not all anomalies have been fully resolved at this time, Hetchy management has evaluated risk to the generator and based on troubleshooting efforts and resolutions, to date, is willing to resume rafting flows through September 1 using modified operating parameters. After this date HPH #2 will, again, be taken offline to complete further diagnostics. We would like to emphasize the problem has not been fully vetted, and therefore another trip occurring next week would likely result in the unit being down the remainder of the rafting season. Under any scenario, we will continue with four hours generation from the single unit at HPH through September 1.
This means that we are planning to run both Holm units tomorrow and through September 1 from 7 am to 11 am to produce the 1100 cfs at Lumsden from 9am to 1 pm. However, if our modifications do not control the electrical disturbances and the unit has an emergency shutdown, it make take us more than a week to figure out why and to make repairs.
My thanks to those who have worked long hours to get us back on line, and my thanks for the recreation communities patience during this interruption.
I will not send out another update unless the situation changes and news is warranted. Please boat safely!"
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