Stream Restoration Below Devil's Gate Dam

The face of the Devil, gunited over a generation ago, scowls over the area just below Devil's Gate Dam. The dam has now been closed to allow the demolition work to proceed in the area underneath the 210 freeway. Beneath the 210 freeway is one of the most interesting and natural stretches of the Arroyo Seco. Although the stream flows naturally through an unchannelized stretch here, concrete debris has littered the area since the construction of the freeway bridge 35 years ago.
Demolition equipment is needed to break up the massive concrete slabs that clog the trails and the stream beneath the freeway bridge. Landscape architect Lynne Dwyer, project manager, and contractor Greg Calvillo pose proudly in front of the concrete trophies they are yanking out of the stream.
The Arroyo Seco stream is still wet from the record winter rains, but that does not stop the work to restore the stream in the region. Erosion control techniques and plantings of appropriate stream vegetation will anchor the stream banks, protecting them against future flood flows.

For years people have puzzled about the massive concrete slabs that lie beneath the 210 Freeway bridge over the Arroyo Seco just south of Devil's Gate Dam. This is one of only two stretches in the Arroyo Seco that have not been paved with a concrete channel, so these slabs were even more puzzling. Some thought the slabs part of a failed attempt to channelize this area for flood control purposes. Others argued they were debris left over after the freeway construction in the early 70s. Some zanies even contended they were the landing pad for an extra-terrestrial craft visiting nearby JPL.

Now finally the concrete is being removed from the Arroyo stream by the Arroyo Seco Stream Restoration Project sponsored by the City of Pasadena. The program is restoring stream and habitat values in two ten-acre patches of the Arroyo south of Devil's Gate Dam. The first area extends from the dam south to Brookside Golf Course; the second extends from the Holly Street Bridge to the Colorado Street Bridge beneath the 134 Freeway.

Since these areas have not been degraded by the massive concrete flood channel that bisects the rest of the Arroyo, they still have tremendous natural values characteristic of untouched Southern California stream. The bobcat frequently seen there seems to agree. These lush stream or riparian zones are powerful reminders of what the Arroyo once was and models of what a restored Arroyo Seco can be.

Last Fall both stretches were cleared of non-native invasive trees to allow the restoration of native habitat, like sycamores, willows and oaks. Now a second phase of the project has begun with the demolition and removal of the mysterious concrete slabs that have littered the area beneath Devil's Gate Dam for decades.

It is the vision and tenacity of Rosa Laveaga, Pasadena's Arroyo Seco Supervisor, that is directing the project. Rosa wouldn't let any obstacle get in the way of improving the stream habitat in the two project areas. Landscape architect Lynne Dwyer, who has long been involved in tree-planting and Arroyo restoration activities, is the project director. As executive director of North East Trees several years ago, Lynne was instrumental in shaping the Arroyo Seco Watershed Feasibility Study. Her role in this project has been to coordinate the demolition and restoration elements and to pursue the long list of permits that have been required by agencies like California Fish & Game, the Los Angeles Regional Water Quality Control Board, Caltrans, and even the US Army Corps of Engineers. The cooperation of the Los Angeles County Department of Public Works was also required to cut the flow from Devil's Gate Dam so the concrete could be removed. Assembly Member Carol Liu, Mayor Bill Bogaard and Pasadena City Manager Cynthia Kurtz all pitched in at key times to help the project along.

The Arroyo Seco Restoration Project, one of the first Arroyo Seco Master Plan projects to be implemented, is supported by the California Resources Agency with funds from the Safe Drinking Water, Clean Water, Watershed Protection and Flood Protection Act of 2000 (Proposition 13).

Breaking up the concrete, restoring habitat and improving natural stream conditions are all important steps forward in the restoration of the Arroyo Seco. We hope that you will support these activities and get actively involved in watershed restoration activities.

View A Video of the Concrete Demo
Official Pasadena Fact Sheet