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
Saskatchewan River Delta northwestern region of the delta. For example, Cumberland Lake, the largest lake in the SRD, has become shallower --- from pre-avulsion depths of over 6 meters to average depths of less than 1.5 meters today --- through sediment infilling following the avulsion. The 1870s event also contributed to the demise of sternwheeler riverboat traffic on the Saskatchewan River in the late 1800s and early 1900s because of difficulties in navigating through the modified channel networks resulting from the diversion. Developmental and avulsion history of the lower delta is more poorly known although evidence of multiple historical channels is apparent from