Stock Photo - Sediment_laden Galveston Bay and surrounding communities are featured in the east_southeast_looking, low_oblique photograph. Much of the sediment enters Galveston Bay from the mouth of the Trinity River slightly above left center. Covering the former mouths and estuaries of both the Trinity River and San Jacinto River, Galveston Bay is a shallow bay with an average depth of 12 feet 4 meters. Dredging allows the entrance of large merchant ships into the bay from the Gulf of Mexico and access to the Port of Houston, the third_busiest port in the United States. Apparent is the snakelike Houston Ship Channel, 57 miles 92 kilometers long, 200 feet 61 meters wide, and 34 feet 10 meters deep, bounded by petrochemical facilities, oil refineries, and numerous other industries along its banks. Visible are Interstate Highway 45 traversing from the center of Houston southeastward to Galveston Island, Lake Houston lower left, and Clear Lake City, home of the NASA Lyndon B. Johnson Space Center right of center.