NASA7-723-069 Keystone Reservoir, Tulsa, Oklahoma Spring, 1998 Sediment-laden Keystone Lake and the city of Tulsa (white and gray) can be seen in this west-northwest-looking view. Keystone Reservoir, covering an area of 263000 acres (105200 hectares), is fed by the Cimmaron and the Arkansas Rivers. The reservoir provides hydroelectric power to the region and is a major resort and recreational area. In addition to its oil resources, Tulsa is a major manufacturing, financial, cultural, medical, and educational center. With the opening of the Arkansas-Verdigris Waterway in 1971 at Catoosa, a small suburban town just east of Tulsa, the city gained navigation to the Mississippi River, and became a major inland port. The Osage Indian Reservation sits to the northwest of the city. Sediment-laden Skiatook Lake is discernible just to the north of Keystone Lake and is within the boundaries of the reservation. Near the bottom right of the image, Fort Gibson Lake is visible. The reddish-color of the water features in the photograph are due to the heavy sediment loads. Much of the sediments are deposited in the various lakes (which are actually reservoirs) when the water slows down as it enters the reservoirs.