Floods in Arkansas, magnitude and frequency

This report presents methods by which the magnitude and frequency of expected floods for most streams in Arkansas may be determined. Flood data have been used to define flood-frequency curves applicable to the State.

Composite frequency curves have been defined showing the relation of the mean annual flood to floods having recurrence intervals of 1. 2 to 50 years. Other curves express the relation of the mean annual flood to drainage basin characteristics. For the northern part of the State, it was found that the slope of the composite frequency curve varies with drainage area size, and an adjustment curve was drawn for use in conjunction with the composite curve for this area.

By combining data from the composite and mean annual flood curves a flood-frequency curve may be drawn for any stream in Arkansas, not materially affected by works of man, within the limits of drainage area and recurrence interval defined by base data.