Thursday, 14 August 2014

A historic drought is unfolding in California and the West and the impacts are everywhere: fallow fields, drying wells, shrinking rivers, and perilously low reservoirs triggering mandatory water conservation and rationing around the state.

Mono Lake's receding shoreline at Old Marina. Photo by Arya Degenhardt.
In January, Governor Jerry Brown declared a drought emergency for the state while the US Department of Agriculture designated roughly half of the state’s counties as natural disaster areas—including Mono County. The February 1 statewide snow survey revealed a snowpack at only 12% of normal, an all-time record low that shattered the previous record of 21% from 1963 and 1991.
On January 31, the Department of Water Resources indicated it would halt all water deliveries along the State Water Project (SWP) in order to conserve the remaining water in storage. This is the first time in the history of the SWP that a “0″ allocation has been declared. Even if significant storms arrive soon, the chance of achieving anything close to a normal water year is slim.
Lake level forecast
This year is the third year in a row of below-average precipitation for California and the Eastern Sierra. Locally, the February 1 Mono Basin snowpack is at 25% of average. A single January winter storm on the 30th dropped over an inch of water (mostly as snow) along the Sierra crest and Highway 395. The precipitation brought Mono Lake up about two inches and brought much-needed relief to the parched Eastern Sierra. Mono Lake will rise slightly as the spring runoff commences, but not by much. Overall the lake will drop through the summer and fall. In the worst case, with no more significant winter  precipitation, Mono Lake could drop as much as two feet by late fall.
What a lower lake means
Mono Lake rises and falls according to wet and dry years. This natural cycle was accounted for in 1994 when the California State Water Resources Control Board chose a management level for the lake. Currently Mono Lake is 11.5 feet below its management level of 6392 feet above sea level. This current drought will set the lake back further, and depending on future wet years, the lake may require between 7 and 38 years to achieve its management elevation based on Mono Lake Committee model projections.
Visitors will notice the impact. A white bathtub ring is already obvious around the lake from last year’s drought. This will grow as the lake drops. More tufa will be exposed at Old Marina and at South Tufa. Gaines Island, the land bridge island between Black Point and Negit Island, will grow in size as the water level recedes from this shallow stretch of lake; however, Negit Island will remain an island. Dust events will tick up in frequency and scale as more lake bottom is exposed along the north and east shores. Visitors will also continue to see plenty of brine shrimp, alkali flies, and birds—a productive and robust ecosystem that has endured thousands of years of change.
Mono Lake has survived droughts in the past. She is an old lake. Beneath her waters and around her shores are clues to extreme climate swings: epic droughts, wet periods, and larger glacial and interglacial episodes. Yet, Earth’s dynamic climate could not do what recent decades of excessive water diversions almost accomplished—transforming Mono into a barren and briny sump. Fortunately, this disaster was averted after years of effort by the Mono Lake Committee and others. The 1994 State Water Board decision reversed the course, and balanced the needs of Mono Lake and its streams with the water needs of Los Angeles.
Anticipating 6380′
Mono Lake will naturally fluctuate on its way to 6392 feet above sea level, and water diversions to Los Angeles will fluctuate as well. Total annual diversions depend on the specific level of Mono Lake each year on April 1. If Mono Lake falls below 6380′ by April 1, the Los Angeles Department of Water & Power (DWP) is restricted to 4,500 acre-feet of water export (about 4,500 football fields of water one foot deep) from Mono’s tributary streams. As long as Mono Lake remains above this level, DWP can export 16,000 acre-feet per year.
If Mono Lake were to fall even further, to 6377′, diversions to LA would be suspended. The more water Mono has, the more there is to share. When the lake reaches its management elevation DWP can export 35,000 acre-feet or more depending on runoff conditions. This will be a time to celebrate—Mono Lake will have reached a level that protects its public trust values. In the meantime, there is a plan for lake stabilization in times of drought.
It is unlikely that by this April the lake will fall below 6380′. As of press time, Mono Lake sits at 6380.6′. However, without a snowy winter, by April 2015, it’s a reasonable bet the lake will be below 6380′ and Los Angeles exports will be reduced accordingly.
Solutions and drought security
Los Angeles and Southern California are drought resilient. Past droughts, along with efforts to protect Mono Lake and other environmental values, helped to positively transform water efficiency and supply management. Today, LA is the lowest per-capita water consumer of any city over a million people—per-capita residential water use is just under 85 gallons per person, per day. The city has added a million residents over the last 40 years but total water use remains static. LA and Southern California have invested in water conservation, water recycling, groundwater storage, and other solutions. The Mono Lake Committee supported this effort, successfully lobbying for state and federal funds that contributed to developing water recycling infrastructure.
Like Mono Lake, Los Angeles is a veteran of drought. This one is particularly severe and climate change may be a contributing factor. Fortunately, water efficiency investments in LA and the State Water Board decision at Mono Lake remind us that we can successfully balance water resource values during times of uncertainty. It will be hard to watch the lake level drop, but there is a plan in place, and eventually, this drought will be a memory.

Mono Lake at approximately 6381.5 feet above sea level as seen from Mt. Dana. Photo courtesy of David Gubernick.
What’s up with this drought?
An unprecedented, dominant, high pressure ridge has persisted over the Eastern Pacific and west coast, shunting Pacific storm systems well north of California. High pressure ridging is a regular, intermittent feature of the California rainy season, but as of February 2014 this ridge has been largely stagnant for 14 months straight. Other large-scale weather anomalies in the Northern Hemisphere are taking place as well: extreme precipitation and warm temperatures in Alaska, extremely cold conditions and snow in the Eastern US, and all-time records for precipitation and flooding in the United Kingdom.
Modern, satellite-based weather observation is not even 50 years old, but there is evidence that California has experienced much worse prehistoric epic droughts. Digging into the underlying cause to this drought leads to a world of larger climate concepts with endless acronyms … ENSO, PDO, NAO, PNA, and more.
Scientists are always gathering data and learning more about these dynamic processes, while accelerating climate change has made analysis more complicated. Some scientists are drawing attention to research that shows that the loss of Arctic sea ice may be driving the high pressure ridge anomaly observed over the last year.
Regardless of the underlying cause—natural variability, climate change, or both—the way we respond today will determine how well we cope with the next severe drought.
This post was also published as an article in the Winter & Spring 2014 Mono Lake Newsletter.

Could be used as good visual example ie, white ring where water level was. Also receding shoreline.

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