|December 29, 2014|
Once desert springs, now dry
|As a boy in the late 1940s, Harry Quinn hiked with his family to a desert spring in the Santa Rosa Mountains where cool water flowed into an oasis filled with tadpoles.|
Now the spring is dry. The tadpoles and toads are long gone. Four palm trees remain in the dry canyon, two of them dead.
"This was a special place," said Quinn, now 75, as he walked through the remnants of the oasis known as Dos Palmas. "You just can't come here and get a drink anymore."
Quinn has accumulated a lifetime of experience hiking through these mountains, and he has noticed that many of the waterholes he used to visit and wade through have vanished. He has long suspected a link to decades of decreased snowfall in the mountains, and a new scientific study lends support to that theory.
The study, which was commissioned by the Bureau of Land Management and released this month, involved surveys of springs across the Santa Rosa and San Jacinto Mountains National Monument. Those small waterholes --- often just a few pools fed by groundwater seeping up through rocks --- sustain wildlife ranging from bighorn sheep to bobcats, frogs and birds.
For years, hikers have been noticing some oases drying up in the national monument. Those who have spotted the change include Cameron Barrows, an associate research ecologist at the UC Riverside Center for Conservation Biology. Some of the spots where he would always find water in the 1980s, for instance, have long been dry.
Barrows began the study to assess how widespread the change has been and to try to determine why it might be occurring. He said the results indicate that, while more studies are needed, climate change is likely playing a role. As average temperatures have been climbing, there has been less snowpack in the mountains --- especially in the Santa Rosas --- and that has meant less water seeping into the ground to recharge the aquifers and the springs.
Fellow researcher Geoffrey McGinnis spent months hiking to remote watersheds carrying out surveys for the study. During one of those outings, he ended up at a dry stream bed in a ravine in the Santa Rosa Mountains.
"I didn't expect it to be dry today," McGinnis said, standing near cottonwood trees where birds were trilling above the dry gulch.
In all, McGinnis surveyed 216 sites in the Santa Rosa and San Jacinto mountains where water sources have historically existed, some of them clustered near each other. "We've gone up almost every major canyon throughout the entire range."
In order to determine places where water used to be found, McGinnis interviewed Quinn and others who recalled the locations of springs decades ago. Barrows also examined past surveys and aerial images showing oases of palm trees and clumps of vegetation marking water sources.
There are dozens of palm oases in the mountains, and the ground has to be wet for the trees to flourish.
"When you go into these palm oases today, they're almost all dry," Barrows said. "There's a few that still have water, but they're almost all dry. So what are the changes happening?"
The study involved visits to 71 sites in the San Jacinto Mountains, and 19 of them turned out to be dry --- 27 percent of the places where water historically has been found. In the Santa Rosa Mountains, 145 sites were surveyed and 83 of them --- or 57 percent --- were dry.
That striking difference of 30 percentage points between the two mountain ranges raised a question: Why have so many more springs that used to exist in the Santa Rosa Mountains gone dry? Barrows said the storm that dusted Mt. San Jacinto with snow in mid-December illustrated the apparent answer: The San Jacinto Mountains, which rise to higher elevations, have been receiving more snow over the years than the lower elevation Santa Rosa Mountains.
And both mountain ranges have had decreasing amounts of snowfall. That's apparent in long-term weather records for Idyllwild, which show that heavy accumulations of snowpack have dropped off in the mountains since the 1970s.
"What we believe is that the real issue is this long-term lack of heavy snowpacks, especially on the Santa Rosas, but also to a smaller extent on the San Jacintos as well," Barrows said. He examined other possible factors, such as pumping from wells in small communities nearby, geologic shifts along the fault zone that runs through the mountains, and the spread of non-native plants such as water-guzzling tamarisk trees. But considering all of those possibilities, he said, the decline in snowpack seems to be the biggest factor.
"What we ended up coming up with was that the most likely explanation is probably climate change," Barrows said.
Desert springs have not been well studied in the past, and it's difficult for scientists to establish firm links to changes in climate --- including both natural shifts and the impacts of human-caused global warming. It's also difficult for scientists to separate the immediate effects of this year's severe drought from long-term changes in climate. But Barrows said the weather records point to a long-term change.
"The 30- to 40-year trend is very clear that we are not having the heavy snowfalls that we have had in the past." Barrows said. "And it's probably those heavy snowfalls that really made the difference in terms of recharging these springs and keeping them going."
That trend fits a pattern that other scientific studies have predicted. In one 2013 study, for instance, atmospheric scientists at UCLA projected that Southern California's mountains will probably lose about one-third of their snowfall on average by the middle of the century if substantial actions aren't taken to limit global warming.
"Less snowfall, higher snow line means that there's less percolation into the aquifer," Barrows said. "So if there's less going in, there's less coming out."
Some springs have nevertheless continued to flow. In fact, Barrows said he was surprised that one waterhole had remained wet in an area surrounded by others that have gone dry.
In the study, Barrows said the research indicates the amount of water available for wildlife in the national monument has diminished over the last several decades. However, he recommended that the surveys be repeated within five to 10 years to check on the water sources.
"Long-term monitoring is what's necessary to really get a firm handle on whether that drying is in fact a climate change-related phenomenon, or is it a weather pattern change, or is it a response to drought," said Jim Foote, manager of the national monument for the Bureau of Land Management. "And then once we have a firmer grip on that, then perhaps the management implications in how we want to address that will become more clear."
Other research has shown that many species of trees and shrubs have been gradually shifting uphill in the Santa Rosa Mountains as conditions have grown hotter and drier. In one study, scientists determined that between 1977 and 2007, trees and shrubs had shifted upslope by an average of more than 200 feet. The researchers said the plants had died out at lower elevations and were flourishing at higher elevations.
Weather records show the region has grown considerably hotter in recent years. A recent Desert Sun analysis of national climate data from more than 30 weather stations across the Southwest, in places from Palm Springs to Tucson, found that average monthly temperatures were 1.7 degrees Fahrenheit hotter during the past 20 years as compared to the average before 1960 --- a timeframe often used by scientists in studying climate change.
During the past 12 months, the average temperatures in California have been the hottest on record.
Quinn, a geologist, archaeologist and paleontologist, said that for many years, there has been much less snow falling on the mountains than when he was young. At the same time, many of the animals he used to see have become rare.
"We had the raccoons. We had skunks. We had a few badgers up here. We had lots of bird life. Quail were everywhere, doves. It was very nice," Quinn said. Some animals seem to have largely disappeared, he said, because they no longer have enough sources of water.
Quinn lives in Pinyon Pines near a cabin that his grandparents bought in 1941. In his home, his flipped through a scrapbook showing black-and-white photographs of his family during hikes to the nearby springs and creeks.
"That's all dried up, too. That's gone," he said, showing a photo of a manmade reservoir where they used to swim.
"The whole area used to have a lot more water. We never used to carry a canteen," Quinn said. "We could go hiking all through this countryside and just go from spring to spring."
In one of the photographs, Quinn's family rested on the sand at Dos Palmas when it was a wet oasis. He explained that it used to be a favorite place for family outings every Fourth of July. In one photo, he and his mother sat next to each other on a boulder.
Another photo showed a spring that used to provide water for his subdivision. That spring has nearly gone dry, he explained, and the neighborhood now draws its water from another spring farther up on the mountain.
Driving along a curvy stretch of State Route 74, Quinn motioned out the window to spots where springs used to flow. "There used to be a big spring right back there, too."
He stopped along the road to point out a band of pinkish-orange rock marking the fault line. This zone acts as an underground barrier and pushes up groundwater to the surface, creating springs.
Driving off the road, Quinn navigated a rutted path through the desert, brush scraping against the sides of his four-wheel-drive pickup. Parking, he hiked down a hill dotted with cholla and pinyon pines, then he stopped and pointed.
"There's your palms," he said. "Now you're at the old oasis."
His feet crunched in the sand as he walked along the dry stream bed, where he used to catch tadpoles. He paused and remembered one of the photos: "That's where everybody was laying on the sand."
Quinn said the place brought back good memories. It all looked similar to the pictures in his scrapbook, including the tip of a boulder --- now partially buried in sand --- where he once sat and posed for a picture next to his mother. The main difference now is that the water is gone. And for many of the springs that Quinn once enjoyed visiting, that has become the norm.
Desert springs drying up
Researchers studied 216 sites in the Santa Rosa and San Jacinto Mountains National Monument where springs and waterholes have historically existed. They determined locations where water used to be found using information from several sources, including past surveys, interviews with people who lived in the area decades ago, aerial images showing locations with vegetation, and the current locations of palm oases.
The study involved visits to 71 sites in the San Jacinto Mountains, of which 19 sites --- or 27 percent of the total --- were found to be dry. In the Santa Rosa Mountains, 145 sites were surveyed and 83 of those sites --- or 57 percent --- were found to be dry.
Cameron Barrows of the UC Riverside Center for Conservation Biology, who led the study, said it's likely that climate change is playing a role and that the trend appears linked to long-term declines in snowpack.