Texas lakes map

Caddo Lake, on Big Cypress Bayou in Harrison and Marion counties, is the only large lake in Texas that formed without a dam. It was created by the Great Raft, a logjam that choked the Red River for well over a hundred miles and backed water up its tributaries. When the raft was cleared in the 1870s the lake drained, and the steamboat port at Jefferson lost its route to the Mississippi. A dam built in the early twentieth century restored the water level, so the lake that exists today is natural in origin and artificial in maintenance. Its bald cypress swamp and maze of boat lanes have no equivalent anywhere else in the state.

Texas does have other natural water bodies, just not large permanent ones. Oxbow lakes sit in the abandoned meanders of the lower Brazos, Colorado and Red rivers. Tens of thousands of shallow playa basins pit the High Plains and fill after heavy rain, then dry out again — they are the main recharge for the Ogallala Aquifer. On the coast, Sabine Lake and the Laguna Madre are often called lakes but are estuaries and lagoons rather than freshwater lakes.

Texas rivers alternate between flood and trickle, and the cities that grew along them needed both protection and a dependable supply. Most of the large dams went up between the 1930s and the 1970s, built by the U.S. Army Corps of Engineers, the Bureau of Reclamation, or one of the state's river authorities — the Lower Colorado River Authority, the Brazos River Authority, the Trinity River Authority, the Sabine River Authority and their counterparts on other basins. Each reservoir has two pools: a conservation pool held year round for water supply and recreation, and a flood pool above it that is meant to be empty and is deliberately drawn back down after a storm.

The result is that a Texas lake's shoreline moves. Lakes built mainly for flood control, such as Whitney and Belton, swing more than water-supply lakes do. Lake Meredith on the Canadian River has swung the furthest of any big reservoir in the state, dropping to a fraction of its full-pool surface during the drought years and recovering since.

Two river systems carry chains of reservoirs rather than single lakes. On the Colorado, the Highland Lakes run one into the next above Austin: Buchanan, Inks, LBJ, Marble Falls, Travis and finally Lady Bird Lake in the middle of the city. Buchanan and Travis are the two storage reservoirs; the others are pass-through lakes held at a nearly constant level, which is why lakefront property there does not strand during drought.

The Trinity basin does the same job for the Metroplex. Ray Roberts, Lewisville, Grapevine, Eagle Mountain, Benbrook, Lavon and Ray Hubbard together supply Dallas and Fort Worth, and Livingston catches what gets past them, 200 river miles downstream.