today at mono lake

the mono-logue

mono lake live

live webcam images

calendar of events

Member-only content is enabled for all users in this directory while we upgrade our login method.

click here to log in to other parts of the Website
 

register
login help


The Mono-logue


Major Categories   Search Blog:

The Mono-logue » Hydrology

Posts Tagged ‘Hydrology’

Mono Lake likely to rise four feet over the next year

Tuesday, March 21st, 2017 by Greg, Information & Restoration Specialist
Share...Share on FacebookTweet about this on TwitterShare on Google+Pin on PinterestShare on LinkedInShare on RedditShare on TumblrEmail this to someone

Last week the Los Angeles Department of Water & Power (DWP) released its preliminary runoff forecast based on record-breaking March 1st snow surveys: 195% of average runoff for the April 1, 2017 through March 31, 2018 runoff year. This volume of runoff is very similar to 1983, the wettest runoff year on record. Due to the warm storms in January and February, the lower-elevation snowpack below about 9,000 feet above sea level is much lower than in 1983, so we are assuming that record runoff is a high-end scenario. That forecast also assumes median precipitation over the next year.

Based on 1983 as a high end, 1995 as a probable scenario, and 2006 as a lowest possible scenario, we modeled the likely rise in Mono Lake based on those past year inflows and probable reservoir operations this year. The result? A 3.8-foot rise in Mono Lake is likely over the next year. Expected Grant Lake Reservoir operations add about half a foot to our forecast.

A 3.8 foot rise in Mono Lake is likely over the next year. (Click on the graph to enlarge it.) Graph by Greg Reis.

All three scenarios have little or no rise before May and a similar rise in May and June, since snow can only melt so fast, (more…)

Mono Basin March 2017 snowpack breaks March and April records

Tuesday, March 7th, 2017 by Greg, Information & Restoration Specialist
Share...Share on FacebookTweet about this on TwitterShare on Google+Pin on PinterestShare on LinkedInShare on RedditShare on TumblrEmail this to someone

After the wettest February since 1986 at some survey sites, Mono Basin snowpack is more than double the March 1st average!

Snow water equivalent (SWE) ranges between 205% and 244% of average at the five snow survey sites in the Mono Basin (called snow courses). Gem Pass, Ellery Lake, and Saddlebag Lake have the highest March SWE on record. At the lowest-elevation snow survey site—Gem Lake at 9,150 feet above sea level—SWE was about 10 inches shy of the 1969 record, but it had reached the 1983 amount. The Tioga Pass snow course was 5 inches shy of the 1983 record. In the map below showing the snow courses, portions of the Lee Vining Creek (top) and Rush Creek (bottom) watersheds are outlined.

At Ellery Lake and Saddlebag Lake, in the Lee Vining Creek headwaters, March 1st SWE was already higher than the record April 1st SWE set in 1983. Map by Robbie DiPaolo.

At Ellery Lake and Saddlebag Lake, in the Lee Vining Creek headwaters, March 1st SWE was already higher than the record April 1st SWE set in 1983! Map by Robbie DiPaolo.

(more…)

Mono Basin snowpack is 200% of average for February 1

Sunday, February 5th, 2017 by Greg, Information & Restoration Specialist
Share...Share on FacebookTweet about this on TwitterShare on Google+Pin on PinterestShare on LinkedInShare on RedditShare on TumblrEmail this to someone

February 1 snow surveys conducted over the past week revealed an approximately 200% of average snow water content in the Mono Basin. This puts the April 1 average at just over 120%.

Outlook for April 1, 2017 peak snowpack at the Mono Basin's five snow courses based on February 1 snow surveys and historic data.

The current outlook for April 1, 2017 peak snowpack at the Mono Basin’s five snow courses based on February 1 snow surveys and historic data. Graph by Greg Reis.

It is still early in the season, but even with a dry February and March, it will be an above-average year, and with an average end to the season it will be a wet year. With a wet February and March, new April 1 records could be set!

Mono Basin precipitation is among the wettest years so far

Thursday, January 26th, 2017 by Greg, Information & Restoration Specialist
Share...Share on FacebookTweet about this on TwitterShare on Google+Pin on PinterestShare on LinkedInShare on RedditShare on TumblrEmail this to someone

At the end of the wettest January in the 29-year record for Lee Vining, how do Mono Basin season totals for precipitation and snowfall compare to other years? The season precipitation total (since October) of approximately 15.84 inches of water is among the wettest years recorded since 1989. It is the second-wettest year to date (1997 was the wettest) that we’ve recorded in 29 years as of the end of January.

Lee Vining Monthly Precipitation

Lee Vining monthly precipitation. Graph by Greg Reis.

At Cain Ranch, five miles south of Lee Vining and more representative of the precipitation that falls on Mono Lake itself, the 2017 seasonal total of 9.44″ to date is sixth-wettest in 86 years. For both Cain Ranch and Lee Vining, these totals fall into the wettest 7% of years. (more…)

DWP completes this year’s export of 4,500 acre-feet of water from the Mono Basin

Saturday, November 5th, 2016 by Greg, Information & Restoration Specialist
Share...Share on FacebookTweet about this on TwitterShare on Google+Pin on PinterestShare on LinkedInShare on RedditShare on TumblrEmail this to someone

When Mono Lake is between 6377 and 6380 feet above sea level, and the final May lake level forecast (and any subsequent projections) shows that it will stay above 6377 feet, the Los Angeles Department of Water & Power (DWP) is permitted to export 4,500 acre-feet of water that year. Any time Mono Lake falls below, or is projected to fall below 6377 feet, exports must stop.

Photo by Bartshe Miller.

A blustery day in mid-October kicked up clouds of alkali dust over Mono Lake’s eastern shore. Mono Lake may drop below 6377 feet above sea level next year, which means no water may be exported to Los Angeles. Photo by Bartshe Miller.

Operations plan guidelines state that the water should be exported late in the summer, and this year, DWP exported this water September through early November, allowing more water to remain in Grant Lake Reservoir during the summer—a good thing that kept the reservoir higher during recreation season and likely kept water temperatures cooler for fish in Rush Creek. (more…)

Fifth wettest October on record in the Mono Basin

Wednesday, November 2nd, 2016 by Greg, Information & Restoration Specialist
Share...Share on FacebookTweet about this on TwitterShare on Google+Pin on PinterestShare on LinkedInShare on RedditShare on TumblrEmail this to someone

At Cain Ranch, a precipitation station five miles south of Lee Vining that is representative of precipitation patterns on Mono Lake, October 2016 precipitation was 2.1 inches. This was the fifth-wettest October since 1931 and about 325% of average. Two of those other wet Octobers occurred in 2009 and 2010.

rainy-october-2016-10-30-north-basin-rainbow-elj_9161

October 2016 was also the sixth-wettest month at Cain Ranch in the last decade, and curiously three of those months were the Octobers mentioned above. The other three months that were wetter than October 2016 were December 2010 and 2012 and May 2015. Aside from the wet Decembers, this pattern is unusual, since December and January and February are usually the wettest months of the year.

The rain in the last week raised all the creek flows and also raised Mono Lake from 6377.12 to 6377.19 feet above sea level, putting it back on track with the lake level forecast DWP made in the spring.

A wetter but still below-average winter in the Mono Basin

Thursday, February 25th, 2016 by Greg, Information & Restoration Specialist
Share...Share on FacebookTweet about this on TwitterShare on Google+Pin on PinterestShare on LinkedInShare on RedditShare on TumblrEmail this to someone

The strong 2015–2016 El Niño winter is likely to turn out below-average in the Mono Basin. The 90% of average February 1st snowpack, and an 80% of average preliminary runoff forecast based on that snowpack, were followed by a dry February. In the next week, March 1st snow surveys will reveal how bad things are. A wet March might be able to catch things back up to average, but it would take a very wet spring to shift the snowpack and snowmelt runoff above average at this point. From 1980–2010, the lowest March snowpack that resulted in above-average runoff was 110%. (more…)

Happy New Water Year 2016 from Mono Lake

Thursday, October 1st, 2015 by Greg, Information & Restoration Specialist
Share...Share on FacebookTweet about this on TwitterShare on Google+Pin on PinterestShare on LinkedInShare on RedditShare on TumblrEmail this to someone

October 1st marks the start of a new water year. The 2016 water year runs October 1, 2015–September 30, 2016. It measures the fall-winter precipitation and the rain that falls in the following growing season all in one 12-month period.

Here is how last year stacks up for Lee Vining precipitation: 11.84 inches, or 84% of average. The remarkable thing is that the fall-winter was the lowest on record, at only 34% of average, meaning the snowpack was the lowest on record. Summer was highest on record, at 285% of average.

The remarkable thing about the 2015 water year was that it was the driest fall-winter on record and the wettest spring-summer on record.

The remarkable thing about the 2015 water year was that it was the driest fall-winter on record and the wettest spring-summer on record.

The Mono Basin’s wettest July since 1965

Thursday, July 16th, 2015 by Greg, Information & Restoration Specialist
Share...Share on FacebookTweet about this on TwitterShare on Google+Pin on PinterestShare on LinkedInShare on RedditShare on TumblrEmail this to someone

At the Cain Ranch weather station, five miles south of Lee Vining, as of July 13, 1.57 inches of rain had fallen in July. That makes this month already the second-wettest July on record after the 1.98 inches of rain in July 1965. Records at this location began in 1931. Rain fell on all but two days between July 1 and 10, and while it has been dry there since July 10, it still has been raining in other parts of the Mono Basin almost every day.

The wet July continues the wet May-June centered on Mono County. This map from the Western Regional Climate Center shows April-June precipitation in percent of average.

This wet July continues the wet May–June centered on Mono County. This map from the Western Regional Climate Center shows April–June precipitation in percent of average.

Lee Vining Creek above the Los Angeles Department of Water & Power (DWP) diversion dam experienced its peak flow of about 124 cubic feet per second on July 11, from rain and melting fresh snow. Below the dam, the minimum flow is being released, and the floodwaters are being diverted to Grant Lake Reservoir, which has been slowly rising since May.

Aside from brief floods due to thunderstorms, the Mono Basin’s creeks are dropping to the very low levels that were otherwise expected this summer. If the thunderstorms stop, we will start seeing new low flow records later this month, especially in watersheds without glaciers, such as Walker Creek. The April–September snowmelt runoff forecast issued by DWP in May predicted 19% of average runoff, with a lower bound of 7% and an upper bound of 32%. Nineteen percent is less than half of the runoff measured in 1977, the driest year on record; 32% is still much drier than the driest year on record. Thanks to the recent wet weather, Mono Basin runoff is on track to reach 32%.

Extreme precipitation amidst extreme drought

Friday, July 3rd, 2015 by Greg, Information & Restoration Specialist
Share...Share on FacebookTweet about this on TwitterShare on Google+Pin on PinterestShare on LinkedInShare on RedditShare on TumblrEmail this to someone
On the evening of July 1st, rain falling on Mono Lake during thunderstorms could be heard two miles away. Photo by Geoff McQuilkin.

On the evening of July 1st, rain falling on Mono Lake during thunderstorms could be heard two miles away. Photo by Geoff McQuilkin.

The Mono Basin is a land of extremes, and this year’s weather is no exception. Temperatures since January are the warmest on record. October–March precipitation in Lee Vining was the lowest on record. April–September precipitation, on the other hand, already is the highest on record—and we are only halfway through that time period! This water year (October 1, 2014–September 30, 2015) is the first time Apr–Sept precipitation has exceeded Oct–Mar. This reversal of the warm and cold season Mediterranean precipitation patterns has allowed invasive plants like cheatgrass to (more…)

The Mono-logue is powered by Wordpress
Subscribe to entries with RSS or by Email. Subscribe to comments (RSS).

Find us on Facebook

 

Follow us on Twitter

 

Print this page
print