One of the more stubborn consequences of a city on the sea is the interplay between the water underground and the highway underpasses. Castillo Street, where it leads from the residential Westside toward Santa Barbara City College overlooking the Pacific Ocean, must be the high-water mark of repeat engineering challenges for Caltrans. The Castillo roadway under Highway 101 was built in 1961 and has resisted all attempts to dry it out ever since.
Digitally recorded history notes the past three fixes attempted — one was an underground “electro-osmosis system” in 2006 to move the water away from the surface of the underpass, according to The Channels, plus a cement slab seven feet in thickness. Other experiments utilized pavers — which flipped around, became slippery, and captured bicycle tires — and a “geo-synthetic drain” and floating underground slab.
The seeping water is inevitable, given the proximity of the ocean, water table height, Mission Creek, and Mesa cliffs nearby. During the next four weeks, Caltrans is implementing the latest plan: “a series of underdrains” beneath the eastern sidewalk, said Genelle Padilla, spokesperson for Caltrans District 5, at a cost of about half a million dollars. It’s either that or $100 million to fully reconstruct the interchange and the seal slab, Padilla relayed from Caltrans staffers.
That sidewalk will be closed as of Monday, November 11, when worked is expected to begin. Pedestrians will be directed to the sidewalk on the west side of the underpass. Until the project is completed, the southbound on-ramp will close to vehicle traffic intermittently between 8 p.m. and 6 a.m., as will lanes on Castillo Street. The northbound shoulder, bike path lane, and sidewalk on Castillo will also close. Updates can be found @CaltransD5.
