Laboratory Results of Salt Water Intrusion

The intrusion of salt water into tideless estuaries is of great interest to hydraulic and coastal engineers. Extensive laboratory studies on two important aspects of the problem were carefully conducted by Keulegan. His first series of experiments on the arrested salt wedge (a still form which is established as the intrusion ceases) have a direct bearing on the natural occurrence. His second series of experiments on the motion of saline fronts in still water extends the understanding of the mechanism governing density currents. Considering his other findings from these experiments, two of Keulegan's most important results are regrouped herein by replacing the water depth with the hydraulic radius as the length scale in the Reynolds number which characterizes the resistance to intrusion. This regrouping seems to offer a much better correlation of results obtained from experiments conducted in channels with various width-depth ratios.