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paul martzen
Member
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Posted: Oct 28, 2005 Post Subject: San Joaquin - Squaw Leap
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| Kerchoff #1 powerhouse which feeds water into the Squaw Leap section of the San Joaquin River, started operating a few days ago and is expected to continue through Friday Nov 18th.
See more information about the run at:
http://www.americanwhitewater.org/rivers/id/4197/
In the past the powerhouse has usually been either off or running about 1700 cfs, which is a very moderate flow in that river. It will most likely be on in the afternoon and evening, but can run at any time during the day. On a few ocasions I have seen it run at some lower flow for some period before turning on oll the way. Sometimes i have seen it stop and start during the day. Looking at what 24 hour average inflows to Millerton have been; 800 cfs and higher, the powerhouse will have to run full for close to 12 hours at least. This means that flows should be pretty dependable.
The Millerton lake inflow graph linked on the river page cited above does not seem sensitive enough to detect when this powerhouse turns on or off, despite what i say on the river page. The bigger downstream powerhouse can have a very noticable effect and I keep hoping that this smaller one will cause some detectable blip on the elevation changes.
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paul martzen
Member
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| Posted: Oct 31, 2005Post Subject: Patterson spill
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| I just checked the Millerton elevation graph and realized there are big inflows at night. This is only possible if spill is occuring into Patterson Bend. Sure enough, the gauge for Patterson Bend is showing dramatic spikes during the night.
http://cdec.water.ca.gov/cgi-progs/queryplot?clock=y&trans=y&interval=96hours&width=600&height=350&id=7968
I do not think it is physically possible for flows to really be quite as high as the graph shows (5,000 cfs), but it is at least possible that flows could be 3,600 cfs. 2,000 cfs at the most seems more likely though. Seems possible that the readings are a gauge error due to the sudden pulse of flow.
Maybe does not matter much since the spills are mostly at night. Patterson is a beautiful run, if the flows were happening during the day.
If you paddle Squaw Leap and additional flows are coming down Patterson, the run will naturally be more serious. Of the two biggest drops in the middle of the run, the first can be ski jumped as described in Holbeck and Stanley, or portaged on the right. The second drop is very difficult to portage or scout at higher flows. Fortunately the line is down the left wall the whole way. At normal lower flows, the left side entrance is too choked and a center falls is run before finishing down the left side channel.
The high flows at night also means that the hours of operation of powerhouse during the day may be less dependable.
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