The Rio Grande, the second longest river in the United States, is no longer a naturally flowing river. Extensive networks of diversions and dams control flows on both the Rio Grande and the Rio Conchos. Neither river is currently managed to provide an in-stream flow needed to sustain riparian habitat. Persistent drought conditions have existed in northern Mexico and southwest Texas for over six years. The drought withered crops and caused severe malnutrition among the Tarahumara Indians in the highlands of Chihuahua. Livestock died or had to be slaughtered early.