Thursday, September 4, 2008

Tahoe's lake level

unedited july 08 tahoe mt. news

By Kathryn Reed

Record highs in May. Smoky skies in June. Highest temps of the year expected this month. Thunderstorms predicted to bring rain.
That about sums up the weather forecast for the next couple of months – nothing out of the ordinary.
However, people in the water business are keeping their eyes on the Lake.
“I anticipate by late fall or early winter the Lake to be down very close to the rim,” said Garry Stone, federal water master in Reno.
Lake Tahoe’s natural rim is 6,223 feet. Full capacity is 6,229.1 feet. In late June it was sitting at 6,225.26 feet – and dropping about one-hundredth of an inch a day.
Part of the drop is evaporation. Part is the 281 cubit-feet per second of water that is sucked out of the Lake to satisfy water agreements downstream, like in Reno.
The water year runs Oct. 1-Sept. 30. On the first day of this water year the Lake was sitting at 6,225.7 feet. The low for the year was on Jan. 3 when it hit 6,224.64 feet.
It came up a little in January and February, before drooping in March and April. The record temps brought it up a bit in May as the runoff started. The high watermark for the runoff season hit June 4 at 6,225.5 feet. This is lower than the mark at the start of the water year last October.
In a wet year, the Lake level will usually max out in July. It can be August if the snow was super abundant. But that has not been the case the last two winters.
On top if being a low snow year, a condition called sublimation occurred. This is when the snowpack goes from freezing to gas state without going through the liquid stage. Low humidity, warm temps and windy conditions provoked this turn of events.
Even though Gov. Arnold Schwarzenegger has declared the state in a drought, the basin is not changing how it is operating things.
Within the South Lake Tahoe Public Utility District boundaries, water rationing has been in effect since 2003 – with landscape watering occurring on alternating days. The district is 100 percent reliant on well water.
It did lose capacity during the MTBE crisis that started in 1997 and culminated in 2001 with a multi-million dollar settlement in STPUD’s favor because the fuel additive tainted the water. New wells were drilled between 1998-2005.
“This year when we put the new Bay View well at Al Tahoe online we have recapture all of the lost capacity from MTBE and we gained a little additional capacity,” said Dennis Cocking, STPUD spokesman.
With California requiring all residences be on meters by 2025, this could change use patterns when the pay structure will be per gallon and not a flat, essentially unlimited amount, as it is now. Commercial customers are already metered here.
Schwarzenegger and Nevada Gov. Jim Gibbons have an eye toward climate change. So does South Tahoe PUD. Cocking warns that if the Sierra snowpack “usual” winters turn into what is now considered “bad” years, that down the road his district’s aquifers could be affected.
In Nevada, the public has until Aug. 1 to comment on the report by the Climate Change Advisory Committee. It’s available at http://gov.state.nv.us/ClimateSurvey.asp.

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