Catagunya Power Station is a hydropower facility located on the Derwent River owned and operated by Hydro Tasmania.  It operates on water delivered to the turbines via a long flume leading from Lake Catagunya.  This flume includes a lateral spillway which casts flow over a steep unlined spillway. Hydro Tasmania is considering changes to the operation of the power station which may lead to increased frequency and magnitude of spills from the flume spillway. To assist with assessing these changed operations, Hydro Tasmania was seeking to understand the business and safety risks that may arise from ongoing erosion of the unlined spillway under these spillway flows. Hydro Tasmania engaged Pells Consulting to undertake the study.

Pells Consulting commissioned Geological Consulting to provide the study’s geological inputs. This included developing a geological model and assigning geological domains on the unlined slope, which is similarly vulnerable to erosion. Interpreted rock mass indices were also provided.