Hydrology

The Dolores River is 402 km in length, originating in the San Juan Mountains of Colorado. The river passes through the Bonderman Field Station at Rio Mesa some 395 km downstream of the headwaters, and just upstream of where the Dolores River enters into the Colorado River. Except for the McPhee Dam located near the headwaters, the Dolores River is a largely unregulated river and exhibits large changes in seasonal and interannual flow rates in response to winter precipitation, spring melt, and summer monsoons. A USGS gauging station on the Dolores River is located at the Bonderman Field Station at Rio Mesa and has been operational for almost 60 years.

Water quality and sediment loads are equally dynamic in the Dolores River, reflecting the strong coupling of terrestrial and aquatic ecosystems in the Colorado Plateau.