The Meaning of Hahamongna

The original settlers of the region were sometimes called the Hahamongna Indians. The word means "Flowing Waters, Fruitful Valley" in the native Tongva language.

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The Devil’s in the Details


Everyone agrees that sediment behind the Devil’s Gate Dam must be removed to prevent flooding. But does stunning wetland habitat really need to be destroyed to make that happen?




Matthew Fleischer


Pasadena Magazine


In the predawn hours of Jan 11, 2011, four people climbed high into the branches of separate massive oak trees in Arcadia and refused to move. As the sun rose, social media began buzzing about the climb, and a crowd that included actress Daryl Hannah gathered in support of the tree-sitters. The four were environmental activists who had decided to risk their lives to save eleven acres of old-growth oak woodland from destruction.

Throughout the day, the tree-sitters sat in their perches and watched as Los Angeles Department of Public Works bulldozers felled the entire woodland around them-249 trees in all. Realizing the cause was lost, the climbers came down and were promptly arrested. The four remaining trees were uprooted behind them.
Unlike many environmental battles in Southern California, this bold attempt to save an untouched forest wasn’t a protest against rapacious development, pitting evil comic-book capitalists against heroic environmentalist stewards of the land.

This time, the culprit was sediment. The DPW claimed it had to bulldoze the woodland to create a deposit site for sediment culled from behind the Santa Anita Dam. An existing DPW deposit site had room for only 250,000 cubic yards of sediment-half of what the department said needed to be extracted from behind the dam. Failure to uncork the sediment fully could leave the region susceptible to catastrophic floods.

An excess of sediment, the eroded detritus of the geologically volatile San Gabriel Mountains and the tar and ash from various wildfires, is a largely unexamined reality of life in Southern California-an unyielding problem that has the potential to touch every corner of Los Angeles County. Now Pasadena and Altadena are the latest communities to face its grim-and expensive-challenges. A major battle is brewing over what to do with a giant pile of sediment lodged behind the Devil’s Gate Dam near the Jet Propulsion Laboratory. The DPW is proposing a plan that makes the work at Santa Anita look like kids playing in a sandbox-trucking out 2.4- to 4-million cubic yards of sediment over five years. Local residents say that a removal project on that scale will turn their bucolic neighborhood into an environmentally ravaged industrial zone.

What everyone can agree on is that sediment removal is an essential necessity of living in the San Gabriel Valley, one that will exist as long as we decide to dam and channelize our natural waterways. With every rainstorm, sediment washes down our floodways and stacks behind the dams we’ve built to store our drinking water and keep our homes from being washed away. If it isn’t removed, sediment diminishes a dam’s capacity to handle floodwaters and can clog emergency spillways. How best to handle the process, however, is far from decided.
In recent decades, the county’s approach to this dilemma has been largely to ignore it. Routine dam maintenance has been forgone in favor of massive one-off emergency sediment removals like the one at the Santa Anita Dam.
This strategy allows county residents to stay blissfully ignorant of the potential danger of living near an unpredictable watershed-until they’re suddenly shocked back to reality every twenty years with predictions of devastating floods and curative industrial-scale removal projects.
The DPW hasn’t cleaned out the Devil’s Gate Dam since 1994, and the department says neglected maintenance in addition to the tar and ash washed down from the 2009 Station Fire has created an emergency situation.

“In one or two years since the Station Fire, one million cubic yards of sediment has entered into the reservoir behind Devil’s Gate,” DPW Public Affairs Manager Kerjon Lee says. “That accumulation alone is ten percent of the material that has ever been introduced into the reservoir in its ninety-year lifespan.”
Failure to clear that sediment would mean that if a severe “fifty-year” rainstorm hits, low-lying areas in Highland Park and South Pasadena could see serious flooding. In order to access that sediment and remove it, however, the county is drafting an environmental impact report for a plan that would potentially bulldoze between 76 and 120 acres of stunning wetland habitat in Altadena behind the dam. Then, once the trees and vegetation are cleared, the DPW would send in upward of 400 trucks a day to cart the sediment away for a period of six months a year for the next five years.

For Altadena residents Lori Paul and Marietta Kruells, this is not an acceptable plan.

The two took me on a tour of the proposed project site on a crisp morning in late December. Though the word “sediment” makes it sound like the area is a giant sludge pit, the space in question is quite stunning, covered in native brush and trees-and highly used. As I talked with Paul and Kruells, joggers and dog walkers passed by in droves, enjoying the fresh air. Meanwhile, cinnamon teals and dozens of other species of birds bathed in the reservoir water below.
“You’re going to spend up to one hundred million dollars to destroy this beautiful space and turn it into an industrial site?” an incredulous Paul asked.
“How much flood protection could you build in Highland Park for that kind of money?” Kruells added.

Paul and Kruells aren’t alone in their skepticism, or their outrage, over the county plan. Activists like Tim Brick, former chairman of the Metropolitan Water District of Southern California who is now[JB5] the managing director of the Arroyo Seco Foundation, are speaking out about the need for a smarter plan.
“What the county is going to leave at the end of its program is many acres of permanently denuded riparian habitat,” Brick says. “This is the only stream in Pasadena. It has tremendous environmental value. There is a way to provide flood protection downstream without turning this land into an intensive industrial operation.”

Brick maintains that while it’s true that some sediment removal at Devil’s Gate is required to keep low-lying areas safe, the work can be done gradually, over a period of twenty years-all while preserving a much larger swath of the natural habitat behind the dam.

“The county is approaching this as a sediment trucking program and that’s it. We want to take an integrated approach. How do you manage a stream that occasionally has floods while preserving quality-of-life and the environment?”
DPW spokesperson Lee says that Brick’s more gradual approach is one the department has heard-and is weighing-but that it isn’t without problems. “You’re extending the impact period,” he says. “Instead of five years of trucks, now you have twenty.”

Lee also notes that a slower approach has potential flood-control consequences: “The level of risk to downstream communities would be there for a longer duration.”

But what if the department’s depiction of the flood danger is overly dire, its solution unnecessarily desperate? Many activists think that’s the case. The DPW has made urgent projections about the need for sediment removal before in the name of flood protection-predictions that have been dead wrong. That was what happened, in fact, just three years ago when they razed the oak forest by the Santa Anita Dam.

After all the controversy, the site of the bulldozed oak grove remains unused. As it turns out, the DPW’s sediment projections were off by nearly half. The existing sediment pit had more than enough space to handle the Santa Anita Dam deposits. The oaks never needed to die.

Arcadia residents are still outraged about what happened-the woodland was arguably the last old-growth oak grove in the San Gabriel Valley. They are especially incensed that their objections to the project during the planning process were ignored. For Cam Stone, who lives near the dam and used to hike in the woodlands, the whole affair is still an open wound.

“The site where the oaks were is completely barren,” he says. “It was destroyed for nothing. The department doesn’t do maintenance, they wait until a crisis, then they start screaming about flooding, and then they get to do whatever they want.” He has a stern warning for Altadena: “They are trying to pull the exact same thing at Devil’s Gate they did in Arcadia.”

DPW spokesman Lee says he was there when the trees were removed, and it was a “very, very difficult choice. We agree that habitat should be prioritized whenever possible.” But, by necessity, the plans that the department presents to the County Board of Supervisors and the public are based on predictions. “We didn’t get rainfall that might have been anticipated through a normal rainfall year,” he says. “Sediment we thought was going to come down to Santa Anita didn’t come down. It doesn’t mean spreading grounds won’t be used. It just means it wasn’t used for this project.”

That explanation doesn’t hold water with Arcadia residents like Stone, who says the county masked its true intentions in removing the oak grove.
“The DPW committed a serious fraud against the people of Arcadia,” Stone insists. “By scraping the woodland, they now have the capacity to bring sediment into Arcadia from outside the area. We were told at the time it was all about flood control.”

Activists in Pasadena and Altadena say they fear the DPW could be planning a similar bait-and-switch at Devil’s Gate. The water that flows from the Hahamongna Watershed into the reservoir behind the Devil’s Gate Dam is currently released to the sea via the L.A. River system. The DPW has a plan to change that by installing a pipeline to funnel Devil’s Gate water to a nearby reservoir in Eaton Canyon. Among other things, this would potentially increase the supply of local drinking water.

Could the DPW be using the threat of flooding to sell a different project?
Lee says no.

“We don’t even know how it would impact the pipeline project if the Devil’s Gate sediment dredge didn’t happen. It hasn’t even been studied yet.”

But residents like Paul and Kruells say there are still too many unanswered questions, and they won’t let the DPW bulldoze forward with its current plan without a fight. Sediment, after all, is a problem that will never go away.
“Neglect is not an excuse to ruin this beautiful space,” Paul says. “There is a

Author: Matthew Fleischer • Date: 03/10/2014 • Category: Features