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
Yangtze River Delta If based on the greater Yangtze River Delta zone, it has over 140 million people in this region. Having a fertile soil, the Yangtze River Delta abundantly produces grain, cotton, hemp and tea. In 2017, the Yangtze River Delta had a GDP of approximately US$1.5 trillion (or US$3.0 trillion in PPP), about the same size as Russia. Since the fourth century, when the national capital was moved to Jiankang (present-day Nanjing) at the start of the Eastern Jin dynasty (AD 317–420), the Yangtze River Delta has been a major cultural, economic, and political centre of China. Hangzhou served as the