Rio Grande Wild and Scenic River
In 1978, a 196-mile section of the Rio Grande, from the Chihuahua/Coahuila state line in Mexico (at Mariscal Canyon) to the Texas Terrell/Val Verde County line, was designated by Congress as a Wild and Scenic River, a designation the Rio Grande shares with over 150 other rivers in the United States. Rivers that bear this designation are to be preserved in their free-flowing condition, their ecosystems actively protected in their natural state. Only 2% of the rivers in the U.S. are free-flowing and pristine enough to qualify for Wild and Scenic designation. The designation came as recognition of the ecological importance of the riparian and canyon habitat of the portion of the river that borders Big Bend National Park. The Rio Grande Wild and Scenic River is managed as a unit of the national park system by Big Bend National Park.