Gunnels

The Gunnels, or Gunn Tunnels, are a pair of culverts forming the Barron Creek Diversion Channel that divert the waters of Barron Creek under Bol Park, connecting it with Matadero Creek in times of heavy rain. They are walkable during the dry season and have for years been a popular location for Gunn students to "hang out". Graffiti covers most of the tunnel walls and large parts of the floors.

The tunnels are visible on OpenStreetMap but not Google Maps. You can view them at this link.

Entrances

The Barron Creek Diversion Channel begins at a flood control basin just outside the N building, next to the Bol Park Bike Path. A heavy grate is meant to prevent debris and people from entering the Gunnels, but students have propped it open with a small log, creating a roughly 2-foot high opening that is possible to crawl through.