5.4 YAMPA RIVER BASIN
The Yampa River basin is located in north-central and northwestern Colorado. With its tributaries, the Yampa River drains all of Routt, most of Moffat, northeastern Rio Blanco, and a small portion of northeastern Garfield counties. The Colorado portion of the drainage basin encompasses an area of approximately 6,765 square miles, and is a part of Water Division 6 with the divisional office in Steamboat Springs. As of early 2001, there were approximately 340 alluvial wells of record in the Yampa River basin. The occurrence and distribution of alluvium along the Yampa River are shown in yellow on Figure 5.4-1.
The headwaters of the main stem are within the Park Range in western Routt County. The Yampa River drains the Colorado portion of the Wyoming Basin. The Yampa is a tributary of the Green River and their confluence is near the western border of Moffat County in Dinosaur National Monument. The historical average annual outflow for the Yampa River leaving Colorado is approximately 1.66 million acre-feet, or about 15% of the total stream flow that leaves Colorado. Principal tributaries of the Yampa are the Little Snake River, Williams Fork River, Fortification Creek, and Elk River.
Alluvial ground-water resources in this basin are used for domestic, livestock, and low demand commercial purposes. Based on the 2000 census, the Yampa River basin contains a population of approximately 33,000.