Photograph by Patrick T. Fallon

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The sun sets on the San Gabriel River in the San Gabriel Mountains. The region is to be named the U.S.'s newest national monument.

Photograph by Patrick T. Fallon

Newest National Monument Will Encompass Wild Mountains Near Los Angeles

Obama is expected to announce the San Gabriel Mountains National Monument.

The rugged San Gabriel Mountains near Los Angeles will encompass the United States' next national monument, President Barack Obama is expected to announce this week, putting an end to decades of debate about the site.

Obama is expected to designate about 350,000 acres of public land in the Angeles National Forest, which make up about half of the San Gabriel Mountains, as a new monument. He will make the announcement from Los Angeles County on Friday, according to a White House official who spoke to National Geographic on background.

The mountains represent about 70 percent of the open space in Los Angeles County and provide about a third of the area's drinking water. Some 17 million people live within an hour's drive of the 10,000-foot mountains, which naturalist John Muir once described as "pure and untameable as the sea."

More than three million people visit the mountains annually for hiking, camping, angling, mountain biking, and kayaking, making it almost as popular as the Grand Canyon and Yosemite, says area Congresswoman Judy Chu, a Democrat.

"The San Gabriel Mountains provide one of the few natural outdoor spaces to our region, which is otherwise one of the most park-poor areas in the country," Chu wrote on her website.

Chu had been working on legislation to declare the 655,000-acre mountain range a national recreation area. When those efforts stalled in Congress, she asked Obama to designate the area as a national monument.

Local activists have been seeking greater protections for the mountains since the early 2000s.

In 2003 then-Congresswoman Hilda Solis worked to pass a bill that launched watershed studies of the area. That helped begin to show how important the range is to the local environment, says Daniel Rossman, chair of San Gabriel Mountains Forever, a coalition of civic groups that for years has been advocating for greater protections for the area.

Some San Bernardino County residents have long objected to federal protections for the land, saying it could limit development and impact fire management. "The reason for [monument declarations] is to protect and preserve, which means restrict and regulate," Glendora Mayor Judy Nelson told local media Monday.

According to the 1906 Antiquities Act, the president can designate a national monument if an area is unique and considered worthy of protection for future generations. This will be the 13th time Obama has used his authority under the Antiquities Act to protect an environmental area. He did so in mid-September around Pacific remote islands; other examples include the César E. Chávez National Monument in California in 2012, and the Organ Mountains-Desert Peaks National Monument in New Mexico in May 2014.

Open Space in an Asphalt Quilt

Rossman says "these mountains are truly of national significance."

He has been working with Chu on a national monument designation and says the mountains offer a unique mix of Mediterranean climates that support diverse plant life, from conifers to broadleaves to chaparral, and many animals, from pumas to coyotes to eagles.

The range is also home to endangered species such as Nelson's bighorn sheep, mountain yellow-legged frogs, and endemic fish called Santa Ana suckers.

An August poll by Public Opinion Strategies found that four in five Los Angeles County voters expressed support for protecting the San Gabriel Mountains and the area's rivers.

Rossman said the monument designation will help combat a growing litter problem by increasing staffing and enforcement and will open the door to more federal funding. The activist hopes the monument will give momentum to broader efforts to protect open space in the "growing asphalt quilt of Los Angeles."

Republican Assemblyman Tim Donnelly of Twin Peaks announced plans to protest the monument on Friday, calling it a "federal land grab."

But Andre Quintero, the Democratic mayor of the 115,000-resident city of El Monte in the San Gabriel Valley, welcomed the news, saying the monument designation "would help augment the resources in that area."

Los Angeles Mayor Eric Garcetti said the designation "will ensure its resources are managed properly and protected for future generations to enjoy."

In a statement, he called the San Gabriel Mountains "a vital natural and cultural resource."

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