Parks Victoria has actively managed litter in the lower Yarra and Maribyrnong Rivers for 20+ years. To review the performance of existing litter traps, Streamology undertook an innovative data-based study for Parks Victoria, that focussed on assessing the typical operational hydrodynamic conditions, the performance of currently used and alternative litter trap designs and locations to optimise the management of litter in both waterways.
The study was conducted in three stages. Stage 1 consisted of hydrodynamic and particle tracing modelling, together with field assessments using time lapse camera monitoring, to assess litter particle pathways through both waterways and assess the effectiveness of existing litter traps to capture and contain floating litter. Stage 2 built on Stage 1 to identify improvements, including alternative locations for existing traps and the application of alternative litter interceptor technologies. In Stage 3, knowledge from the previous stages was built on to develop an integrated program that includes combinations of different suitable interceptors to target a wider range of litter types and optimise capture efficiency within Parks Victoria’s known operational constraints.
The study shows that trap location is a key determinant of success and relocating existing traps can significantly increase performance. The effectiveness and feasibility of different litter interceptors was related to the type of litter the device targets (e.g. small, medium or large) and its location within the waterway (hydrodynamic conditions).
A scenario comparison shows how litter management within urban waterways requires an integrated approach, combined with knowledge of the targeted litter types, sources and pathways.