Rapid City, the second largest city in South Dakota, is located at the eastern edge of the Black Hills about 9 miles downstream from Pactola Dam. It is bisected laterally by Rapid Creek, and longitudinally by the eastern flank of the Black Hills. Canyon Lake, a samll recreation reservior having a surface area of 35 to 40 acres, is located near the west city limits on Rapid Creek.
The floods of June 9-10, 1972, covered a relatively small area of the eastern hills, extending from Sturgis on the north to Hermosa on the south and the west to Pactola Dam. THe area is mountainous with very steep heavily wooded slopes. Channels are shallow and generally are confined in narrow, winding canyons.
Flood of June 9-10, 1972, at Rapid City, South Dakota