Hours after another storm soaked Southern California, LA County’s principal stormwater engineer Sterling Klippel stands at the base of the San Gabriel Dam, looking like a kid in a candy store. He gazes in awe at the thousands of gallons of stormwater rushing through this dam every second.
“Just this October, this facility was completely drained,” he says.
This dam is almost 300 feet deep in the middle, and it went from empty to full in less than six months. And it’s just one of more than a dozen dams in the county.
The water released from the San Gabriel Dam flows down into the equally full Morris Dam before it’s captured further downstream. Photo by Caleigh Wells.
Soggy Southern California has gotten more than two feet of rain this season – so far, about double an average year, making it one of the top 10 wettest years on record.
“It's amazing to see it when it's here, and every drop is precious. So we do our best to capture every drop of it,” says Klippel.
Los Angeles County is on track to capture enough stormwater this year to quench the year-round water needs of more than a quarter of the county’s residents. It’s good news, but there is still a lot of work to do to meet local water use goals.
“A good job of for the infrastructure we have”
To prevent the San Gabriel Dam from overflowing, thousands of gallons of water are released to get collected downstream every second. After it moves through the Morris Dam, some is collected at spreading grounds downstream while the rest flows into the ocean. Photo by Caleigh Wells.
“We're making strides, and we just need to make sure that we don't let our foot off the gas,” says Bruce Reznik. He leads the nonprofit LA Waterkeeper, which is the city’s self-proclaimed water watchdog. “We have done a good job, for the infrastructure we have.”
That’s thanks to nearly century-old infrastructure that’s still working.
The San Gabriel Dam was a civil works project to help employ people in the Great Depression in the 1930s. Photo by Caleigh Wells.
Trickling waterfalls in the San Gabriel Mountains typically drain into giant dams like the San Gabriel Dam, which was built in the 1930s. When they get full, public works officials open the floodgates at the bottom of the dams to send the water downstream.
“From there, we release it and we send it down to our spreading grounds, which are these large basins,” says Klippel. “The water then will percolate through this kind of sandy gravelly geology here and recharge these local aquifers where later it's pumped out for local municipal water use.”
“A century worth of poor planning”
Uninterrupted acres of land in LA County for spreading grounds like this one are difficult to come by, making large opportunities for new groundwater recharge projects rare. Photo by Caleigh Wells.
Klippel says LA County gets about a third of its water from those aquifers while the rest is imported either from Northern California or from the Colorado River.
But the City of LA’s goal is to flip that equation by 2035, using two-thirds local water and cutting Southern California's dependence on imported water. Reznik says the local infrastructure is just not set up for that yet.
“A lot of that is because … so much of LA is channelized and concretized and urbanized, that we're not letting Mother Nature do its job of capturing the stormwater, letting it recharge our groundwater,” he says. “We are trying to undo a century worth of poor planning around water, and it's going to take us a while.”
LA is so developed and has such high flood risk that for decades the county has focused on funneling water as quickly and safely as possible straight to the ocean.
In big storms like we’ve seen this winter, that’s happening no matter how hard Klippel tries to stop it. “With so much water in the system at this point, there is some water that's still making its way to the ocean.”
Klippel estimates in the past 10 years, 95% of the water in the San Gabriel River and these spreading grounds has been captured. The unusually high amount of rain this year has brought that percentage down. Photo by Caleigh Wells.
Infrastructure woes can get solved with big investments, but Californians decided years ago that two-thirds of voters need to approve new taxes for stormwater capture. That’s an extremely high bar.
“Unfortunately, it's actually very hard to fund stormwater projects,” says Resnik. “There has been a decade's long lack of funding for stormwater infrastructure.”
Which is why people like Reznik were so thrilled when county voters passed Measure W five years ago that devotes $280 million each year to water projects.
But as the climate crisis worsens, more money has to go toward maintaining current infrastructure. For example, wildfire burn scars result in more loose soil falling into the dams and leaving less space for water.
Officials had to drain San Gabriel Dam last year to remove soil that eroded into the dam from the Bobcat Fire, leaving less room for water. Even newly excavated, the dam is now filled to the brim with water. Photo by Caleigh Wells.
Officials anticipate it’ll take several billion dollars to hit that 2035 goal to use mostly local water.
“Which seems pretty ambitious to me,” says USC Assistant Professor of civil and environmental engineering Dan McCurry. He says stormwater capture is actually one of the best tools we’ve got for cutting down our reliance on imported water.
“We're not talking about complicated, energy-intensive, expensive engineering treatment processes like we have to do for wastewater reuse. So in some sense, stormwater capture – when it's available – is low-hanging fruit.”
