While Tasmanian river basins have been found to be generally less impacted by flow alterations than other catchments across Australia, some river basins (such as the Mersey and Pipers–Ringarooma river basins) are heavily impacted by hydro-electric schemes, with the use of in-stream barriers reducing the dispersal potential of the crayfish. Water extraction for irrigated agriculture and urban water use is of concern to a lesser degree, however there has been an identified lack of contingency plans in the event of reduced environmental flows in waterways. Anecdotal reports indicate that low environmental flows caused the death of giant freshwater crayfish in several catchments in the north-west and north-east of Tasmania in 2006–07