The State-owned submerged lands of Texas encompass nearly 6,000 square miles (15,540 km²) and extend from Mexico to Louisiana. The area includes the bays, estuaries, and lagoons, as well as the inner continental shelf 10.3 miles (16.6 km) seaward of the Gulf shoreline (fig. 1). Many uncertainties exist regarding the future utilization of the State submerged lands, and one cannot anticipate all potential uses for these areas.

The Upper Triassic Dockum Group of Texas and New Mexico is composed of 200 to 2,000 feet of complexly interrelated terrigenous clastic facies ranging from mudstone to conglomerate. The lower 200 to 1,000 feet of the Dockum accumulated in a fluvial-lacustrine basin defined by the Amarillo Uplift - Bravo Dome on the north and the Glass Mountains on the south.

Bastrop, Blanco, Burnet, Caldwell, Fayette, Hays, Lee, Llano, Travis, and Williamson Counties make up the Capital Area Planning Council (CAPCO) region in Central Texas (fig. 1). The region covers 8,427 square miles (21,826 km2) and includes land of great physical diversity. It contains five geographic provinces with elevations ranging from 187 to 1,904 feet (57 to 581 m) above sea level. Parts of four river systems cross the area. Six major categories of soils as well as six natural vegetation assemblages are present.

Mapping based on Landsat imagery was initiated along the Texas coast for four test sites selected for contrasting vegetation, environmental geology, and levels of economic development. Standard Landsat transparencies of part of a 1:1,000,000 band 7 image were optically enlarged to fit an existing 1:125,000 map base. Land-water, cropland, and other distinctive boundaries were extracted from the enlargement and compiled on an overlay on which additional unit boundaries from other bands and from the false-color composite of bands 4, 5, and 7 were added.