Modification of River Tides by the Discharge

The effect of an increased discharge on the tide progressing into a river is evaluated quantitatively by gaging the signal recorded at upstream stations against a reference station, during intervals of effectively constant discharge; this process is repeated for progressively larger values of the discharge. Upstream, the tidal range is reduced by an increased discharge; the time of arrival of low water is accelerated, while high water is retarded. The changes in range and in time may be represented by simple regression relations. Downstream an increased discharge causes a decrease in the effective friction during flood and an increase in it during ebb. Low water is retarded and high water is accelerated; some tidal components may actually be amplified over a segment of the river.