 Sediment supply is now almost zero which has produced a significant imbalance to the near shore sedimentary budget, creating major erosion and shifting of sediment along the coast.The effects of sediment trapping due to dams can be exacerbated when combined with other activities such as in-stream gravel mining.Excavation of gravel from a river bed forms pits within the channel profile which can trap much of the incoming bed load sediment, preventing or slowing it from reaching the coastline.