Rio Sonoyta

Quitobaquito Springs and pond are part of the Rio Sonoyta watershed. Here’s a map of the watershed taken from Groundwater Isotopes in the Sonoyta River Watershed, USA-Mexico: Implications for Recharge Sources and Management of the Quitobaquito Springs, Zamora et al 2020 (https://doi.org/10.3390/w12123307). Not shown on the map is the terminus of the river in the Sea of Cortez. Note the green and yellow oval to left of the river as it turns sharply south. Those are the volcanoes of the Sierra del Pinacate, which started to erupt 4 million years ago. Before that, the Rio Sonoyta was a tributary of the Colorado River. At some point the uplift of the Pinacate blocked the river, causing it to swing south and dump directly into the Sea of Cortez. That Isolated the plants and animals of the Rio Sonoyta from the much broader Colorado River watershed. That resulted in some of those evolving into separate species and/or subspecies.