On the southwest corner of Hahamongna Watershed Park — between Oak Grove Drive and the county’s Devil’s Gate Dam sediment removal project — is a canyon area Pasadena officials and environmental activists hope to transform from a trash heap to a treasure.
Since the late 1960s Berkshire Creek has diverted rainwater runoff from nearby La Cañada High School and the Foothill (210) Freeway through storm drains battered by half a century of surges that sometimes triple the watershed’s 40 cubic-feet-per-second capacity.
“The storm drain was built by Caltrans when they built the 210 Freeway,” said Pasadena assistant city engineer Brent Maue. “Over the course of the last 40 years the river that storm drain leads out to has become severely eroded — our idea is to put some earth back in.”
Working with a $1.8 million made available through Proposition 84 and other water-related grants, engineers with the city of Pasadena are teaming up with local environmental group the Arroyo Seco Foundation to revitalize and restore the creek and 4.7 acres of surrounding land into a native garden and oak meadow.
In a June 19 walk-through, representatives from both groups explained the scope of the project to interested residents and would-be volunteers. A 30-inch concrete drain under Oak Grove will be replaced with two pipes of different lengths and outfall locations, one for low flows and one for high flows.
Once the new infrastructure is in place, the project proposes to raise the creek bed to allow for habitat restoration in a creek that is currently a silty soup laden with beer cans, an old tire and other trash.
A crumbling parking lot adjacent to the creek would be rebuilt with a pervious surface to assist groundwater percolation and a bridge over the canyon would allow crossing even during periods of heavy rain.
Help will be needed to plant 900 native species and cultivate 7 pounds of seeds collected from the Arroyo Seco Foundation’s nearby Hahamongna Cooperative Nursery. Replanting is a critical part of restoring wildlife habitat and improving the quality of the watershed, said AFC President Tim Brick.
“We’re going to be growing things in the nursery and taking out all the non-native plants as well,” he told a group of about 25 residents. “This is an opportunity for you to sign up for continual involvement in the program so you can say, ‘I helped the Berkshire Creek project grow.’”
Foundation members began talks with Pasadena’s Public Works Department several years ago but recently resumed the collaboration in earnest and are now working with a June 30 deadline. Maue said he hopes construction could begin as early as September.
La Cañada resident Lori Moody came to the walk-through with husband David Haxton. She’s used the 1,300-acre Hahamongna Park recreationally for years and was interested in learning about the area’s ecological underpinnings.
“It seemed like it was going to fall apart at any minute, so it’s nice to come here and find out what the plans are,” Moody said. “I think this would be a great thing to do with my kids, or to get a group of friends together — if you’re doing something out there in the community and see the progress, you’re more invested.”