Located four miles downriver from Rio Vista, Threemile Slough Breaks off the Sacramento River just northeast of Decker Island and continues on south to the San Joaquin River at Twitchell Island.
Use NOAA Chart 18661.
Characteristics: The bridge has a closed vertical clearance of 10 feet, with an open vertical clearance of 105 feet. In the center span, 150 feet of horizontal clearance is available. Depths in mid-channel on Threemile Slough range from 11 to 36 feet.
The bridge is tended 24 hours a day and will open on command. You can reach the bridgetender on VHF Channel 09, or via phone at 916-777-6649.