SHOALING CONDITIONS IN LOCK AND DAM 13 POOL, ARKANSAS RIVER; HYDRAULIC MODEL INVESTIGATION.

Lock and Dam 13 is located at mile 292. 8 on the Arkansas River. The dam was designed to provide a minimum depth of 9 ft to Lock and Dam 14 at mile 319. 7. Following initial operation of Lock and Dam 14 in January 1971, shoaling in the upstream end of Lock and Dam 13 Pool became a chronic problem, occurring each time flows exceeded 50,000 cfs. This study was conducted to: develop a system of channel structures in the reach just downstream of Lock and Dam 14 that would appreciably reduce the required maintenance dredging without significantly increasing water-surface elevations or velocities; determine the effectiveness of overdepth and overwidth dredging in delaying the need for required maintenance dredging; and locate the optimum site for two mooring cells upstream of Lock and Dam 14. A movable-bed model, 1:120-scale horizontally and 1:80-scale vertically, reproduced the reach of the Arkansas River from mile 313. 2 to 322. 4. Results of the study indicate that: The dredging required to maintain a 250-ft channel downstream of Lock and Dam 14 could be reduced considerably by a system of dikes.