Hydrology of various delta types

Abstract

The hydrology of deltaic regions is characterized by the interaction of fluviatile and marine changes in water level, by the small gradients that may cause extensive inundations, and by the influx of saline sea water into fresh surface- and groundwater. Deltas possess a large development potential, both for agricultural and industrial purposes, provided water management and flood control is adequate. The measures taken may profoundly change the natural hydraulic environment. Several large deltas, in particular in Asia, still are in a primitive stage of hydrologic development, although they belong to the most productive and densely populated regions of the world. Hydrological water management depends on the characteristics of the river basin (variable discharge, speed of flooding) and of the ocean (astronomical tides and storm surges). Agrohydrologically, the climate in a delta region is of prime importance. Examples are provided from deltas in the temperate (Rhine), arid (Nile) and humid tropical (Ganges, Irrawaddy and Mekong) climatic zones.