Cherry Creek and Lower Tuolumne Release Schedule for 2008

[cvshack]

I'm attending the annual Hetch Hetchy coordination meeting on Wednesday. This meeting will discuss scheduled releases from Holm Powerhouse during late spring and summer. The timing and magnitude of these releases affect both the Cherry Creek and Lower Tuolumne runs.

So if you run either Cherry Creek or the Lower "T", questions for you. How happy are you with the release schedule we've been having in recent years, and what would you change? And why?

For historical scheduled releases, see the last two entries at the very bottom of http://www.dreamflows.com/schedules.php

[Greg in Reno]

I would love to have a boatable Sunday release during the summer. Weekdays are not an option for me and I won't drive ten hours for one day on the river.

Greg

[haji]

I agree sunday releases would be good. It would also be cool if they ran the water till 5 or so instead of stopping at noon.

[Cornbread]

I thought last year the Sunday releases were HUGE! It would be awesome if we could get some of those again and the longer releases even lasting until noon were pretty nice too instead of cutting off at 11am.

[Keith]

Hey Chris,

Thanks a million for attending the meeting! I think the every other Sunday release is a good compromise. Obviously every Sunday would be nice, but I would rather have a longer release. That would give the people who run Cherry Creek a little extra time in the morning. Maybe the weekends that have the Sunday release could have an extra hour or two of water. They did it last year on the Labor day weekend. Couldn't hurt to ask.

[timmontana]

It's tough to manage a double run with the flows only running for a few hours. A little longer time for the tap to be open would be great. Thanks for attending the meeting and asking boof.com what we thought. Cheers.

Tim

[Nathan H]

Will this meeting also discuss the releases from Hetch Hetchy into the main Tuolumne (ie. the 10-15 miles upstream of the Creek)? I have been trying to catch that one for a few years and I can never predict the ramp down schedule. It gets close to 400 and then cuts off completely. Can we get more information to at least help predict this one?
-Nathan

[cvshack]

Will this meeting also discuss the releases from Hetch Hetchy into the main Tuolumne (ie. the 10-15 miles upstream of the Creek)? I have been trying to catch that one for a few years and I can never predict the ramp down schedule. It gets close to 400 and then cuts off completely. Can we get more information to at least help predict this one?
-Nathan

I'll find out and let you know. Plus - what flows would you like?

[cvshack]

The Hetch Hetchy coordination meeting last Wednesday was productive. The current proposal for 2008 Holm Powerhouse releases is similar to what we had last year, including several Sundays. There's a question in the last para of this long post, so if you start yawning during what follows, please jump to there.

I asked for longer releases, and here's the deal. In any given year, there's a limited water budget. In low-water years they have to preserve their reserves in case it's a poor year next year, and in better water years they're building up the reserves they lost in a low-water year. We will have large amounts of water to play with only in successive big-water years. Like that. So - they have only so many acre-feet to play with, and the question is how to use them best.

You may have noticed how the Holm Powerhouse flows drop to about 500 cfs during the afternoon, so I suggested chopping an hour short at the end of the day and releasing that water between 11am and noon instead. The answer is that San Francisco needs the power generated by those 500 cfs during the afternoon. They release what they need to cover their power obligations to libraries, police stations, etc, and if they were to chop the releases short an hour early, they'd have to buy the lost power from somewhere else (at high prices).

Could we release starting an hour later on some days (e.g. release from 8am to 11am instead of from 7am to 11am on Tuesdays, and get an extra hour on Saturday or Sunday)? Well, no, the commercial rafting companies need that early release, because the water needs to travel all the way down the Lower "T" so two-day trips can get off the river. In other words, today's 7am release gets yesterday's two-day trip off the river.

Could releases start say 15 minutes later or end 15 minutes earlier during the week, to give longer releases on the weekend? Well, no. Power is sold in blocks of an hour (top of the hour to top of the hour), so chopping 15 minutes off would invalidate the whole hour.

Other stuff came out. Hetch Hetchy would prefer not to release on any Sunday, that's their down day for powerhouse maintenance. Anglers would likewise prefer no releases on Sundays. So we're lucky to get Sunday releases at all. Anyway, as you can see, it's an interesting interlocking water/power management puzzle going on here.

Bottom line: the budget has been very carefully worked out over the years to balance out the various needs. Seems I may have been the first private sector Cherry Creeker to have graced their meeting in a long while, perhaps ever, so they were glad I was there and listened to what I had to say. And they will try to give us an extra hour if they can, but it's going to be a juggling act; chances are 50:50 that it's not going to prove possible.

So - question for you. Assuming they can give us an extra hour one day a week, or perhaps one day every two weeks ... when would you like that hour? On Saturdays? On special-release Sundays? Some other day? Cast your vote if you want to be heard :-D ...

Chris

[cvshack]

Will this meeting also discuss the releases from Hetch Hetchy into the main Tuolumne (ie. the 10-15 miles upstream of the Creek)? I have been trying to catch that one for a few years and I can never predict the ramp down schedule. It gets close to 400 and then cuts off completely. Can we get more information to at least help predict this one?
-Nathan

Hey Nathan. The answer is that they have to react very quickly to changing circumstances, to make space for snowmelt, and eventually to top Hetch Hetchy off but to stop it from spilling. Hetch Hetchy is right up there near the source, and snowmelt tends to be high (8000 cfs inflow to Hetch Hetchy is not uncommon), so they have to continuously monitor what's going on. It's a juggling act. The result is the sudden rises and falls you mentioned.

So - Bruce - the Hetch Hetchy guy - says he can give no long-term predictions and definitely no promises, but if you call him on any given day he'll be happy to share his thoughts with you. Or with anyone else interested in that reach of course. I don't want to put his email or phone number out on the web, but if you or anyone else wants his contact info, please send me email - chris@dreamflows.com

- Chris