Canyon sediment gushes out on Pacific Highway near Solar.
A Bankers Hill volunteer group – along with San Diego Canyonlands – has lined up a $2 million federal grant for work in Maple Canyon to stabilize and restore it – and to prevent tons of sediment from streaming down hill into Solar Turbines and jamming neighborhood storm drains as it goes.
The work has never been more urgent. In the past two weeks, new sinkholes and bluff collapses followed the rainy winter as stormwater came from above the canyon. It’s a cheap solution for the city, and they’re not taking it. Instead, project managers within the Stormwater and Transportation Division are claiming the nonprofit’s plan as their own and plan to pursue up to $50 million in funding – starting with the $2 million grant that Friends of Maple Canyon and Tershia D’Elgin worked for four years to put together.
It’s not a sure thing that the city could even get the $2 million from the U.S. Economic Development Administration. “All we need is for the city to sign off on our project – all the other agencies support it,” says Tershia D’Elgin, who has worked on the canyon for four years. “What they’re doing now puts our funding at risk and it means the erosion damage will continue until they put together their own grant application. That’s bad for us, for the people downhill and terrible for the canyon.”
Maple Canyon is a little slice of deep green and quiet that curves low from Maple Street just west of State, to Third Avenue between Quince and Redwood, including going under the First Avenue and Quince Street bridges. It is surrounded on high by homes and office buildings, and is owned by the city – a gift from CalTrans that originally planned to use it for a spur off the 163.
Its drainage is problematic; water rushes in from high above, picks up filth and pushes it through the neighborhood, jamming up drains and then flowing downhill where it makes a path under Solar Turbines, across Pacific Highway and to the bay. It eats away at and reshapes the canyon. Ancient drainage pipes that would be illegal today create water chutes that carve signatures throughout the canyon.
Areas stripped of plants are erosion hot spots, says Eric Bowlby, the executive director of Canyonlands. “Delay in stabilizing Maple Canyon’s creek will have a dangerous domino effect,” he wrote in an email response. “The unchecked stormwater flows will cause erosion of the stream banks and sediment will flow through the streets into downstream storm drain pipes,” he wrote in an email response. “In addition to muddy, slippery streets, tis flooding has resulted in stoppage of traffic on Pacific Coast Highway.”
The city’s efforts in the canyon have been largely botched by the lack of a comprehensive plan. An asphalt overlay put in a year ago is already crumbling and undermined by the streaming water. But for the city, which relies on conventional approaches that start with grading – moving huge amounts of soil – projects can cost tens of millions and require California Environmental Quality Act review, which can take years.
That’s the beauty of the volunteers’ plan with Canyonlands: the group worked hard to come up with an innovative plan that requires no grading. The state’s Regional Water Quality Control Board and the Army Corps of Engineers are ready to sign off on the permits – but they all need the city’s blessing.
“We worked with the city for four years on this, their input informed the design and we worked well together,” D’Elgin says. “And then they get a new person, and she decides to take our plan for the city, tank the funding and start looking for so much more money to do it with a plan they don’t have yet.” D’Elgin worked with an engineer and soil hydrologist who donated their time to come up with an approach that innovates on the standard grade and plant method. Their grant includes five years of hands-on maintenance and support after the work is finished, D’Elgin says.
“Nobody believed we could come up with a plan that doesn’t include grading and will work; they called it a moonshot,” D’Elgin says. “Now the agencies agree we can do this without grading and the plan has the potential to change the way this kind of restoration is done.”
Bowlby applauds the innovative approach that avoids grading – risky when rain will continue to move the soil – and comes with five years of maintenance. Many urban canyons are besieged by stormwater from homes and buildings above the rim, and stormwater rushing into dirt bottom urban canyons commonly cuts deep gullies because there’s no vegetation there to slow it and absorb the energy, the silt and the water.
“Restoring our canyons’ natural functions would not only reduce pollutants that wind up closing our beaches after every rain, it would reduce downstream flooding. Native vegetation is also the most efficient method we have to mitigate climate change.”
Chiara Clemente, a senior environmental scientist with the San Diego Regional Quality Control Board, confirmed that the water board is fully behind the $2 million grant plan. The water board has twice let the city know that it stands ready to issue the permit – the bureaucratic version of nudging things forward. Similarly, the Army Corps says the plan meets their requirements and they’re ready to give permission once the city signs off. But the money from the US Economic Development Administration’s disaster recovery fund is first-come, first-served and this year’s funding is going fast. With new gouges and slides in the canyon, getting started now seems like a no-brainer.