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 of the population in the active delta depend on the fishing industry. The population suffers from the lack of health facilities and medical staff. Only about a third of the population has access to clean drinking water. Ethnic groups of lower Sindh can be found in the delta region: Mallaah, Mohano, Soomro, Samma and Jat. All of these groups speak Sindhi and follow Islam. The delta falls within the districts of Thatta and Badin of the Sindh province. Pakistan's fifth largest city, Hyderabad, lies about 130 miles north of the mouths of the Indus. Towns are found throughout the delta,