Washburn Tunnel

The Washburn Tunnel is a two-lane underwater motor-vehicle tunnel connecting Galena Park and Pasadena, two suburbs of Houston, Texas. Completed in 1950, it travels north-south underneath the Houston Ship Channel. It was named after Harris County, Texas Auditor Harry L. Washburn. It is the largest and first toll-free vehicular tunnel in the Southern United States.OverviewMerritt Chapman and Scott Corporation of New York engineered the $7 million project. First, a trench 90x40 feet had to be dug. Second, these sections had to be locked into position 85 feet underwater. Finally, the last touches, such as tiling the inside, were completed.It is the only underwater vehicle tunnel currently in operation in the state, as the Baytown Tunnel was replaced in 1995 by a bridge. The tunnel consists of a single bore, 895 meters (2,909 feet) in length, with a six-percent roadway grade outward from the center towards each exit. Forced transverse ventilation is potentially provided by three automatic high-speed Westinghouse Sturtevant blower fans located in a tower at the north entrance. These fans are designed to keep the air free from high-levels of carbon monoxide.In the event of electrical failure, a generator can support the electrical needs of the tunnel. Every twelfth light is powered by a generator. The light intensity at the portals is three times brighter than the interior. This prevents temporary blindness when entering the tunnel.