Nation Why the Rio Grande is switched on and off to supply water for New Mexico, Texas and Mexico June 9, 2021June 9, 2021 Algernon D'Ammassa, Las Cruces Sun-News Comments Off on Why the Rio Grande is switched on and off to supply water for New Mexico, Texas and Mexico The Rio Grande's flows in southern New Mexico and Texas have grown lower, and the river has been visible for less of the year.