This study was prepared for the East Gippsland CMA in June 2011 and involved a detailed hydraulic assessment of the impacts of the Snowy River Rehabilitation Project on the river and floodplain. The study incorporated an iterative hydraulic and geomorphic approach to assessing the implications of the river rehabilitation and also to assess risks associated with potential avulsion sites. A two-dimensional hydraulic model was developed to spatially resolve the effects of changes in vegetation communities along the floodplain and riparian zones on flood levels across the study area. The assessment also considered the effect of in-channel bars under a range of flow conditions, with the results indicating a high level of correlation between increased flood level and channel bar formation. Sensitivity testing of the hydraulic model also revealed that the inclusion of bed scour in the model is a critical assumption, as if the bed does not scour through the system during flood events, water levels and overbank flows are expected to be dramatically raised in a number of reaches, with follow-on effects downstream.
East Gippsland CMA
Snowy River, NSW