CERTAIN FLOOD-FLOW PHENOMENA OF IOWA RIVERS

1. Elongated water-sheds of Iowa streams—The characteristic long and narrow water-sheds of Iowa rivers produce unique phenomena in flood hydrographs capable of analysis to a degree not possible for most streams with fan-shaped water-sheds. The principal Iowa rivers originate in Iowa or Minnesota near the Minnesota border and flow diagonally across the State. The basins are usually narrow, with a length 8 to 30 times their average width.