The Ogallala Aquifer is a shallow water table aquifer surrounded by sand, silt, clay, and gravel located beneath the Great Plains in the United States. As one of the world's largest aquifers, it underlies an area of approximately 174,000 sq mi (450,000 km²) in portions of eight states. It was named in 1898 by geologist N. H. Darton from its type locality near the town of Ogallala, Nebraska. The aquifer is part of the High Plains Aquifer System, and resides in the Ogallala Formation, which is the principal geologic unit underlying 80% of the High Plains.

The Colorado River is an approximately 862-mile (1,387 km) long river in the U.S. state of Texas. It is the 11th longest river in the United States and the longest river with both its source and its mouth within Texas.

The Brazos River, called the Río de los Brazos de Dios by early Spanish explorers, is the 11th-longest river in the United States at 1,280 miles (2,060 km) from its headwater source at the head of Blackwater Draw, Roosevelt County, New Mexico to its mouth at the Gulf of Mexico with a 45,000-square-mile (116,000 km²) drainage basin. Being one of Texas' largest rivers, it is sometimes used to mark the boundary between East Texas and West Texas.

The Trinity River is a 710-mile (1,140 km) river, the longest with a watershed entirely within the U.S. state of Texas. It rises in extreme northern Texas, a few miles south of the Red River. The headwaters are separated by the high bluffs on the southern side of the Red River.

The Pedernales River is a tributary of the Colorado River, approximately 106 miles (171 km) long, in Central Texas in the United States. It drains an area of the Edwards Plateau, flowing west to east across the Texas Hill Country west of Austin. The name "Pedernales", first used in the middle 18th century, comes from a Spanish word for the flint rocks characteristic of the riverbed.

Lake Livingston is a reservoir located in the East Texas Piney Woods. Lake Livingston was built and is owned and operated by the Trinity River Authority (TRA) of Texas under contract with the City of Houston for water-supply purposes. The lake is the third-largest lake located in the state of Texas. The Livingston Dam, constructed across the Trinity River about 7 miles (11 km) southwest of the city of Livingston is 2.5 miles (4 km) in length and has an average depth of 55 feet (17 m).

Cross Bayou is a 38.0-mile-long (61.2 km) river in Texas and Louisiana. It is a tributary of the Red River, part of the Mississippi River watershed.

Pine Island Bayou is a tributary of the Neches River located in southeast Texas. It runs about 55 miles from the northwest corner of Hardin County, Texas and flows in a southeastern direction through western Hardin County, turning east and defining the southern Hardin and Jefferson County boundary for about 20 miles until its confluence with the Neches River. Two significant tributaries of Pine Island Bayou are Mayhaw Creek and Little Pine Island Bayou. The lower ten miles of Pine Island Bayou and much of Little Pine Island Bayou are protected from development in the Big Thicket National Preserve. Excluding the last few miles north of Beaumont, the area is not densely populated, and some small towns include Sour Lake and Saratoga, the latter the birthplace of country singer George Jones.

Clear Creek is a small river in Southeast Texas in the United States, which channels much of the run-off in southeast Harris County into Clear Lake and Galveston Bay. Much of the length of the stream forms the boundary between Harris County and Galveston County and all of the boundary with Brazoria County. It originates in the Blue Ridge Oilfield in Fort Bend County.