Abstract

Features of river mouth areas (river mouths) as peculiar geographical objects, their types and subdivision into the parts are considered. Natural processes forming the river mouths and their governing factors are described. Emphasis is given to the most important hydrological-morphological processes: dynamics of waters, sediments, channels, beds, and coasts within a river mouth. Processes of erosion and deposition and features of sediment budget at river mouth are considered. Processes of redistribution of water and sediment discharges between delta branches are also analyzed. Peculiarities of evolution of present-day deltas and estuaries in the world are discussed. Present-day tendencies to a decrease of effect of riverine and an increase of marine governing factors on river mouths and to abrasion of coastal parts of many deltas in the world are revealed. Some measures of rational use and protection of river mouth are also discussed.

Keywords: river, sea, mouth, delta, estuary, water runoff, sediment yield, sea level, delta formation, water management