5.2 ARKANSAS RIVER BASIN
The Arkansas River basin drains a 28,273 square mile area in the southeastern quarter of Colorado (Figure 5.2-1). The basin defines Water Division 2 with the divisional office in Pueblo. As of early 2001, there were over 5,450 alluvial wells of record in the Arkansas River basin.
The Arkansas River has its origin high in the Rocky Mountains near Leadville, Colorado, flowing south-southeast through the mountains before it turns east and enters the plains near Pueblo. Well known tributaries include the Purgatoire, Huerfano, Cucharas, and Apishapa Rivers, and Fountain and Big Sandy Creeks. The total annual flow in the Arkansas River within Colorado is approximately one million acre-feet. There are 10 major trans-basin diversions of surface water into the upper Arkansas River that provide an additional source of recharge to the underlying alluvial aquifer. The diversions consist of tunnels and ditches that routed 144,288 acre-feet of water into the basin in 1998. Over 1.8 million acre-feet of water are stored in 19 reservoirs within the basin.
John Martin Reservoir is the largest water storage facility on the
Arkansas River. Photo by U.S. Army Corps of Engineers.
Current land use in the upper Arkansas River valley is primarily recreation and tourism with limited agriculture and industry. Land use in the lower Arkansas River valley is heavily agricultural, with both surface and ground water being utilized to grow a significant amount of farm crops, including the famous Rocky Ford cantaloupes. The alluvial aquifer is an important source of ground water in the plains.