There’s a tunnel running beneath downtown SLO? See what lies in city’s hidden underbelly
San Luis Creek is the reason for the city.
First the Chumash, then later Spanish missionaries selected the creekside location for settlement.
With it, water and abundant fish were resources at the front door. The watershed also provides the easiest road between the coast and the Salinas River Valley via the Cuesta Grade.
The creek has also been treated as a sewer and garbage dump: More than once in the 1960s, there were mass fish kills in the creek. At least one was attributed to chlorinated water released from the Nuss Pool.
In the early 20th century, almost three blocks blocks of creek were walled and buried under Higuera Street — though exactly when that happened is something of a mystery.
What is known is that in 1966, a group of Cal Poly students thought it was the perfect event venue and held a dance, the “Sewer Stomp,” under the town. Years later in 2000, San Luis Obispo spent almost $2 million to replace the steel and concrete lid over the creek.
The story below guesses that the construction to wall in the creek was by the Works Project Administration in the 1930s, but that is not likely.
A Sanborn fire insurance map from 1909 shows the creek already being paved over.
The creek was mapped with a stone wall along Higuera Street, that looks like the Bishop Peak stone that was quarried for many projects around town in the early 1900s.
There were also bridges crossing at Chorro, Morro, Court and Osos streets. Buildings were starting to span the creek at the corner of Higuera and Morro streets and at 870 Higuera St., today home to Thrifty Beaches.
Bob Anderson wrote this Telegram-Tribune story Sept. 9, 1975:
Tunnel vision
There’s a unique side to San Luis Obispo relatively few people see — the underside.
It’s there for those who had at least a small sense of adventure and don’t mind taking a chance on getting their feet a little wet. Winding under downtown San Luis Obispo is a tunnel. Its main purpose ostensibly is to carry San Luis Creek.
The creek disappears under the balcony of a beer bar between Marsh and Higuera streets and reappears from under a restaurant at Mission Plaza. Between those points, not a trace of the creek can be seen from downtown streets. Most people realize, if they think about it, that the creek must be somewhere under downtown. But looking at the tunnel from Mission Plaza, it looks like a dark, dull place, simply a duct for water, possibly a slimy one at that.
There are no great surprises in the San Luis Creek tunnel. But there are a few pleasant small ones.
Near the upstream end, an unexpected feature is towering rock walls, built from boulders a few feet across. No one around City Hall can remember who built them, although some think they might have been a Depression-era project of the Works Project Administration. Whoever mortared them together, their effect is something like the entrance to a medieval dungeon.
Once inside, an explorer no longer hears the sounds of the city. No cars, no horns, no talking. Just the soft sound of splashing water, echoing in the dark. The upstream half of the tunnel, where the creek runs over sometimes slippery solid rock, is almost pitch black. Light enters from a few street-surface gratings.
Mid-way in the tunnel is an unexpected oasis of light. Near the corner of Higuera and Morro, next to the Anderson Hotel, the tunnel opens up to the sky. The open space is completely walled by the vertical back-sides of buildings. Down to the creekbed filter the clinking and jingling of dishes and silverware being washed in a restaurant kitchen.
Pigeons use the shaft to get to their roosts in the crannies of the tunnel ceiling.
From mid-point to Mission Plaza, the tunnel has been paved with concrete. Another small skylight, also walled in and invisible to ground-level pedestrians, looks up at the weathered bricks of the rear of the Wickendon Building, which fronts onto Chorro Street.
In the concreted section of the tunnel, the faded paint of a past fraternity party is still visible. So is a maze of sewer, water and other pipes and ducts overhead, hanging from the undersides of downtown stores and offices.
City Public Services Director Dave Romero is one of the few semi-regular tunnel walkers. He tries to walk the tunnel every year to check these pipes and wires for flood damage. In a heavy flood, the tunnel fills. (Need it be said a walking tour is best made during the low-water stage of late summer.)
It should be noted that a walk through the tunnel is not pure pleasantness. In places, the aromas are not exactly perfume.
Probably quite a few San Luis Obispo residents have seen all of this, especially those who lived in the city when they were young. If there’s one thing the tunnel does well besides carry water, it arouses curiosity.
It provides a mysterious place for kids of all ages to explore.
