Lake Hamilton is the middle of three lakes located in series on the Ouachita River in Southwestern Arkansas. Following the initial release of water through the penstocks from the upper newest lake, a subsurface current was detected in Lake Hamilton. During the summer of 1960, physical-chemical tests were made at nine stations along the channel to determine the extent of the current. Data collected showed the water remained oxygenated from the surface to the bottom. Cold water drawn from below the thermocline of the upper lake becomes oxygenated in the tailrace and slides under the warm upper stratum of water in the Lake Hamilton. Existing temperature ranges and sufficient dissolved oxygen levels, as were found in the channel, should sustain trout throughout the critical summer months.