33 CFR § 117.171 - Middle River.
(a) The draw of the San Joaquin County (Bacon Island Road) highway bridge, mile 8.6 between Bacon Island and Lower Jones Tract, shall open on signal from May 15 through September 15 from 9 a.m. to 5 p.m. From September 16 through May 14, the draw shall open on signal from 9 a.m. to 5 p.m. from Thursday through Monday. At all other times, the draw shall open on signal if at least 12 hours notice is given to the San Joaquin County Department of Public Works at Stockton.
(b) The draw of the Burlington Northern Santa Fe railroad bridge, mile 9.8 near Middle River Station, shall open on signal if at least 12 hours notice is given to the Burlington Northern Santa Fe Railway Manager of Structures at San Bernardino.
(c) The removable span of the Woodward Island Bridge, mile 11.8 near Discovery Bay, shall be removed as soon as possible upon notification by the District Commander that an emergency exists which requires its removal.
(d) The California Route 4 Bridge, mile 15.1, between Victoria Island and Drexler Tract need not open for the passage of vessels.