When the river reaches the escarpment that crosses the watershed on a line from Georgetown to Waco, the topography changes to gently rolling, then to an almost featureless plain down to the coast. The floodplains are narrow, and improvements came slowly and comparatively late. From this point the Brazos descends to the Gulf at a rate diminishing from 3½ feet a mile to one-half foot a mile.īelow the Caprock escarpment the Brazos traverses an area of rolling topography in the vicinity of Palo Pinto County, where low escarpments cross the watershed and the basins of the Brazos and its tributaries are deeply trenched and confined in narrow valleys with steep sides or bluffs. The elevation of the streambed at the confluence of the two forks is 1,500 feet above sea level. It has all of the varied characteristics of a trans-state stream, from the plains "draw" drainage through canyons at the breaks of the Llano Estacado, the West Texas rolling plains, and the Grand Prairie hill region, to its meandering course through the Coastal Plain. It is the longest river in Texas and the one with the greatest discharge.
![brazos cad brazos cad](https://thumb.bibliocad.com/images/content/00080000/3000/83832.gif)
The two forks emerge from the Caprock 150 miles above the confluence, thus forming a continuous watershed 1,050 miles long, which extends from New Mexico to the Gulf of Mexico and comprises 44,620 square miles, 42,000 of which are in Texas. The Brazos River rises at the confluence of its Salt Fork and Double Mountain Fork near the eastern boundary of Stonewall County (at 33☁6' N, 100☀1' W) and runs 840 miles across Texas to its mouth on the Gulf of Mexico, two miles south of Freeport in Brazoria County (at 28★3' N, 95☂3' W).