River delta slope offshore, waves will make river deltas smoother. Waves can also be responsible for carrying sediments away from the river delta, causing the delta to retreat. For deltas that form further upriver in an estuary, there are complex yet quantifiable linkages between winds, tides, river discharge, and delta water levels. Erosion is also an important control in tide-dominated deltas, such as the Ganges Delta, which may be mainly submarine, with prominent sandbars and ridges. This tends to produce a "dendritic" structure. Tidal deltas behave differently from a river- and wave-dominated deltas, which tend to have a few main distributaries. Once
Indus River Delta behind salts in the delta's soil. During the winter the winds in the delta come from the northeast. The summer monsoonal winds also contribute to high wave energy levels. In fact, the delta is subjected to the highest wave action of any river delta in the world. (The amount of wave energy the Indus delta receives in a single day is greater than that received by the Mississippi River Delta in a year.) Throughout history the delta has survived this wave action because of the large discharge of fresh water to counter the erosional impact of waves. This large amount