Oral Presentation Australian Society for Limnology Congress 2013

Hydro Tasmania’s first dam removal: rehabilitation of Lagoon of Islands (#103)

Carolyn Maxwell 1
  1. Hydro Tasmania, Hobart, TAS, Australia

Restoration following dam removal is occurring in many places around the world, but there have been only a handful of dams decommissioned in Australia. Lagoon of Islands, on Tasmania’s Central Plateau, has had poor water quality since 1988. Hydro Tasmania decided the dam had outlived its usefulness in Tasmania’s hydro-electric system. Hydrological management changed accordingly: the major inflow, Ripple Creek Canal, was decommissioned in May 2010, water level was reduced and the dam that impounded this once unique wetland was dismantled in April 2013. Lagoon of Islands is now on its way to becoming a healthy wetland.
Hydro Tasmania has decided not to intervene, but rather to let nature dictate the rehabilitation of Lagoon of Islands. It is still early days, but the changes in hydrological management have caused a significant change to the dominant processes structuring the ecosystem. Currently (August 2013), Lagoon of Islands has no algal bloom for the first time in over 5 years. Nutrient concentrations have fallen by an order of magnitude, and turbidity has dropped by two orders of magnitude.