Australia: Soil erosion is filling vital inland river waterholes, putting the squeeze on fish, turtles and crayfish

During droughts, Australia's inland rivers dry up, leaving waterholes as the only wet places in a parched landscape. Fish, turtles, crayfish and other aquatic animals retreat to these vital refuges. But our research, published today, reveals these waterholes are in danger of filling up with eroded soil from farms. This is putting a big squeeze on life in the river. When drought breaks, the water flooding into the river carries soil along with it. In theory, soil deposited in waterholes could be flushed out again by large floods. Studies in the 1990s suggested as long as floods continued to occur, waterholes would maintain a natural balance of sediment. But these studies focused on the Cooper Creek, in the Kati Thanda (Lake Eyre) Basin, where waterholes have a sandy base underlying clay-dominated soil that can be easily washed out again. Many Australian rivers are different. So what happens elsewhere? Our new ...