Navigation Conditions at Robert S. Kerr Lock and Dam, Arkansas River: Hydraulic Model Investigation

Source: https://erdc-library.erdc.dren.mil/jspui/ The Robert S. Kerr Lock and Dam, proposed for construction on the Arkansas River about 395 miles above the junction of the Mississippi and White Rivers, will provide a navigable pool for 37 miles upstream to Webbers Falls Lock and Dam. The project comprises a nonnavigable gated dam with eighteen 50-ft-wide by 44-ft-high tainter gates, a 110- by 600-ft lock on the left bank with a maximum lift of 48 ft, and a four-unit powerhouse with a 110,000-kw generating capacity on the right bank. A 1:120-scale, fixed-bed model, reproducing approximately 3.3 miles of the Arkansas River, was used to determine flood stages at the dam, navigation conditions in the lock approaches, and tendencies for sediment deposition in the lower lock approach, and to develop modifications required to provide satisfactory navigation conditions. The investigation has resulted in the development of modifications in the original design required to produce satisfactory navigation conditions in the approaches to the lock. In general, the results have indicated the following : (A.) A fill or dike is required along the left side of the upper lock approach channel to eliminate the adverse effects of currents moving across the approach channel from the overbank toward the spillway. With the fill, navigation conditions near the upper guard wall would be better with some ports in the wall. (B.) Water-surface elevations at the dam embankments can be lowered by excavating the channel approaching the spillway more and by placing spoil along the right overbank. (C.) Flow from the powerhouse with no flow through the spillway produces a large eddy that extends into the lower lock approach. Currents in this eddy would adversely affect upbound tows attempting to approach the lower guard wall. Satisfactory navigation conditions with powerhouse flow can be developed with a dike extending from the end of the lower guard wall. Shoaling of the approach channel can be expected from sediment moving from the area downstream of the spillway and powerhouse. The effect that sediment deposited over the lock-emptying outlet will have on lock-emptying operations depends on the amount of deposition and on the difference in water-surface elevations inside and outside the lock chamber.