Silt deposited in the lake ranges in size. Little is deposited in the east basin. Silt finally gravitates to the deeper parts of the former Molonglo channel, deepest behind the Scrivener Dam. 82 to 96 percent of river borne sediment is deposited in the dam. Over the next hald century no serious reduction in dam depth should aoccur, requiring restorative action. Only normal routine maintenance will be necessary along the foreshores.