sierras

Two Lost Lakes Return To California | Earth Wise

May 10, 2023 By EarthWise Leave a Comment

The recent siege of powerful storms in California driven by a series of atmospheric rivers has had a significant effect on the severe drought that has plagued most of the state for many years. Many of the state’s reservoirs are at the highest level they have been for decades. The snowpack in the Sierras is well over 200% of its historical average. Many parts of the state are no longer considered to be in drought conditions, and, in fact, flooding has been a serious problem in some areas. This flooding has had some surprising results.

Two California lakes that drained a century ago have reappeared as a result of floodwaters from the recent storms.

Tulare Lake, in California’s Central Valley used to be fed by rain and snowmelt from the Sierras. A system of dams and canals constructed in the early 20th century to support regional agriculture diverted water away from the lake. It used to be the largest freshwater lake in the West but farmers ultimate planted crops in the dried lakebed.

The atmospheric river events in March inundated that farmland and once again there is water in Tulare Lake.

Owens Lake, on the eastern side of the Sierra Nevada, was long fed by mountain streams. The 1913 construction of the Los Angeles Aqueduct redirected water to that city and desiccated the lake. Floodwaters in March caused a partial collapse of the aqueduct and when the spill gates on the aqueduct were opened to drain the damaged areas, floodwaters poured in and partially refilled the lake.

California has suffered from drought for many years. With its massive snowpack, as the weather warms, the state may face even more flooding.

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Two Long-Drained California Lakes Refilled by Floodwaters, Satellite Images Show

Photo, posted November 10, 2014, courtesy of CN via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

California: Drought Or No Drought? | Earth Wise

April 26, 2023 By EarthWise Leave a Comment

Just a few months ago, millions of people in California were living under challenging water conservation rules. The past three years were the driest on record and reservoirs were depleted, landscapes dried up, and the snowpack in the Sierras at very low levels.

But in recent months, a dozen atmospheric river storms have brought huge amounts of rain and snow to the state. Twelve out of 17 major reservoirs in the state have been replenished, the snowpack is over 240% of normal, and brown hills are blooming once again.

So, is the California drought over? According to the experts, the answer is: sort of.

The record snowpack and heavy rains have erased the most severe aspects of the drought in many parts of the state. Only 9% of the state is now experiencing “severe” or “exceptional” drought, down from 55% last fall.

But the changes are basically all at the surface. Groundwater in the state is still extremely low and the state’s cities and farms are still using more of it than is appropriate. The state has been unwisely overusing its groundwater aquifers because of the drought and this one year of heavy rains cannot replenish levels that have been dropping for years.

California has been rolling back many of the most severe drought restrictions that had been imposed but has not entirely lifted the drought emergency status. Meanwhile, the massive snowpack in the mountains will begin to melt as the weather warms and, in many areas, Californians will face flooding. Water is a complicated business in California.

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Drought or no drought? California left pondering after record winter deluge

Photo, posted August 28, 2019, courtesy of Joyce Cory via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Saving Giant Sequoias | Earth Wise

October 13, 2022 By EarthWise Leave a Comment

Last year, the KNP Complex Fire burning in Sequoia National Park drew global attention as the General Sherman, the world’s largest tree, was wrapped in tinfoil-like material in order to repel the flames from the fire. Hundreds of firefighters labored for weeks trying to save giant redwood trees. Despite these efforts, the U.S. Forest Service estimates that wildfires killed 13% to 19% of the world’s giant sequoias in 2020 and 2021.

This past July, the Washburn Fire burned through part of Yosemite’s Mariposa Grove and the giant sequoias there were surrounded by automated sprinklers trying to shelter them from the flames.

For a century, government agencies have worked to extinguish all natural wildfires and prohibited Native people in the region from lighting the fires they traditionally used to manage their lands. As a result, forests have grown far thicker with trees that can fuel fires. The Sierras are now home to more than three times as many trees as when they were managed by indigenous communities. But more than 100 million of those trees had died by 2016 because of drought.

Add to this massive amount of kindling the effects of climate change – a hotter and drier environment – and there is the perfect storm for megafires among the giant sequoias.

There is federal legislation pending that would provide resources for prescribed burning and other forms of active forest management. It is controversial. It has attracted support from the Nature Conservancy, the Save The Redwoods League, and others, but also opposition from more than 80 environmental groups.

What is not controversial is that the Giant Sequoias are in the midst of a crisis and urgent action is needed.

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In California, a Race to Save the World’s Largest Trees From Megafires

Photo, posted December 10, 2014, courtesy of Laura Camp via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Saving The Giant Sequoia | Earth Wise

April 22, 2021 By EarthWise Leave a Comment

Giant sequoia trees are some of the most remarkable living things on earth. They can live up to 3,000 years. The tallest specimens tower over 300 feet, but it is their girth that really sets them apart. They are usually 20 feet in diameter, and some are up to 35 feet across at the widest. The largest tree in the world by volume is the General Sherman tree, which has a volume of 52,508 cubic feet. At 2,100 years old, it weighs 2.7 million pounds and is not only the largest living tree, but also the largest living organism by volume on the planet.

Giant sequoias are incredibly hardy. To have survived thousands of years, the oldest of these trees have endured hungry animals, diseases, fires, snowstorms, El Niño events, years-long droughts, and the efforts of loggers during the 19th and 20th centuries.

In February, unusually high winds knocked down 15 giant sequoias in Yosemite National Park. While sequoias are amazingly adapted to their narrow range in California’s Western Sierras, it appears as though climate change is altering their habitat faster than the species can migrate or adapt. Shorter cold seasons have meant more rain instead of snow, leading to floods and mudslides in the winter. Fires are more likely with less snowpack. Hotter, drier summers put sequoias under greater stress.

Forest managers work to preserve existing groves through fire mitigation, supplementary water, and careful stewardship of young trees in existing groves. If these efforts are successful through the ensuing decades, climate change may be just one more thing the sequoias outlasted. But at least some conservationists are now considering planting a new generation of sequoias in colder, nearby habitats.

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To Save Giant Sequoia Trees, Maybe It’s Time to Plant Backups

Photo, posted June 8, 2008, courtesy of Joi Ito via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.