Galveston Bay

Excerpts from "A State of the Bay: A Characterization of the Galveston Bay Ecosystem" by the Galveston Bay National Estuary Program

Galveston Bay is typically only six to 12 feet deep. The effects of winddominate many physical processes, and biologically, extensive oyster reefs,marshes, and open water habitats predominate. The bay's 600 sq mi of surfacearea is commonly divided into four major sub-bays; Galveston Bay, Trinity Bay, West Bay and East Bay.

Galveston Bay receives the outflow of the San Jacinto River and much of thelocal drainage from the City of Houston via Buffalo Bayou and the HoustonShip Channel. Trinity Bay receives the outflow from the Trinity River, alarge river system with a watershed that extends north to encompass theDallas-Fort Worth region. The Trinity Basin contributes 54 percent of theinflow to Galveston Bay, compared to 28 percent for the San Jacinto Basin.West Bay is situated landward of Galveston Island, and receives runoff fromChocolate and Mustang Bayous and other local streams. East Bay lies landwardof Bolivar Peninsula and receives inflow from Oyster Bayou and other runofffrom Chambers County. Christmas Bay and Bastrop Bay are two relativelyundisturbed secondary bays in the far southwestern part of the estuary thatare somewhat isolated from the rest of the estuary.

There are three tidal inlets to the bay, but only two are of majorimportance with regard to flow. Bolivar Roads (between Galveston Island andBolivar Peninsula) accounts for over 80 percent of the tidal exchangebetween the bay and the Gulf of Mexico. Bothsides of Bolivar Roads have long jetties that were built to extend out intothe Gulf and stabilize the inlet. San Luis Pass, between the western end ofGalveston Island and Follets Island to the southwest, is a natural inletthat provides slightly less than 20 percent of the b ay's tidal exchange butprovides important access for commercial and recreational fishermen.Rollover Pass is a man-made cut through Bolivar Peninsula that providesminor tidal exchange between the Gulf and East Bay.

The total shoreline length of Galveston Bay is a difficult parameter todefine. It is greatly dependent upon the scale of resolution employed; asthe scale becomes finer, the measured shoreline length increases. Forexample, an estimate of 232 miles used by Paine and Morton (1991) to measure erodable shoreline along Galveston Bay varies significantly from the743-mile figure used by Orlando et al. (1988). The latter measurementincludes such features as small boat basins, service canals, and other formsof modified shoreline that subs tantially expand the measurable length ofthe Bay shoreline. While the measurements vary considerably, each is validin the context of its intended use.

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Last Modified: Wed, Aug 12, 1997