The Salado and its tributaries drain the Tehuacán and Cuicatlán valleys.

The Tehuacán-Cuicatlán valleys extends northwest-southeast through southeastern Puebla and northern Oaxaca.

The confluence of the Salado and Grande rivers forms the Santo Domingo River, which flows eastwards through the Sierra Madre de Oaxaca to join the Papaloapan River, which then empties into the Gulf of Mexico.

[1] The Tehuacán and Cuicatlán valleys are in the arid rain shadow of the Sierra Madre de Oaxaca, and the climate of the valley floor is semi-arid to arid.

The valleys are home to a great diversity of native plant species.