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
Colorado River Delta of the largest desert estuaries in the world. Spread across the northernmost end of the Gulf of California, the Colorado River delta's vast riparian, freshwater, brackish, and tidal wetlands once covered 7,810 km² (1,930,000 acres) and supported a large population of plant, bird, aquatic, and terrestrial life. Because most of the river's flow reached the delta at that time, its freshwater, silt, and nutrients helped create and sustain a complex system of estuarial wetlands that provided feeding and nesting grounds for birds, and spawning habitat for fish and marine mammals. In contrast to the surrounding Sonoran Desert, the Colorado River