1. Piers Larcombe RPS MetOcean WAMSI Perth 21 st Feb 2013 5 mins Shelf sediment transport in NW Australia over decades to centuries: a knowledge gap for science, development & regulation Marine Scientists Environmental Regulators Marine Engineers Developers & Operators Marine developments: Design of structures Assessment of environmental impacts

2. 2 NW Australia has: much of ecological value Key ecological features represented in the North- west Commonwealth Marine Reserves Network

3. NW Australia has: many cyclones

4. NW Australia will have: bed sediment transport pathways Scales = relevant to developments >decades 10s-100s km Ecology = f ( sedimentology ) Engineering = f ( sedimentology ) (NB – this is not transport AT the coast) 4 Belderson et al. (1982)

5. NW Australia has: major development projects 8 proposals requiring ‘substantial’ dredging Total ~200 M m 3 Pilbara / W. Kimberley Dredged channels, up to >30 km long Durations >many decades WA EPA (Oct. 2012) Dredging volume >150 M m 3

6. NW Australia has: …knowledge gaps that WAMSI can help fill to enhance: environmental management & project design 6 Shelf Sedimentary Research To define the pathways’ location and extent e.g. Where are the critical regions? Wrt removal (dredging) and addition (disposal) of sediment At EIA stage - Improve assessment of pathways Many aspects, but esp. testing of directions Bedforms, Deposits, Spatial gradients Assess in-situ sediment production rates (biogenic sediment)