Assessment of Sediment Dynamics via Historical Nautical Charts on A High Energy Temperate Shelf

A new paper is JUST published in Continental Shelf Research, to asses the relevance of historical nautical charts in sediment dynamic assessments at four locations along the swell-dominated west coast of Victoria, Australia. The paper is entitled :"Relevance of historical nautical charts in sediment dynamic assessments on a high energy temperate shelf".

Carvalho et al. (2021)

Shipping has been of critical importance for European colonisation and development in many parts of the world. These required the charting of safe shipping approaches, which gradually evolved into our modern nautical charts. Colonial charts provide an unique historical perspective and are of global scientific relevance for understanding the sedimentary dynamics and quantifying human alterations in the coastal zone. In areas where significant changes occurred, volumetric differences can be calculated providing a relative degree of certainty, whereas in broader areas the uncertainties are greater than the volumetric changes. In this study they looked at bathymetric and shoreline change since the mid 19th century based on information available on historical charts. They compared lead line soundings to contemporary Multibeam Echosounding (MBES) bathymetry and Light Detection and Ranging (LiDAR) data at four locations along the swell-dominated west coast of Victoria, Australia.

Shorelines extracted from these charts were also used in conjunction with aerial photography and satellite imagery to show how changes following the construction of coastal infrastructure has affected natural processes of sediment transport and had long-term impacts on the adjacent coastline. They demonstrate how the construction of the port of Portland breakwaters trapped approximately 1,450,000 ± 550,000 m3 of sand, an equivalent amount of material eroded from the downdrift coastline; the closing of the southwest passage and the construction of the training walls of Port Fairy reduced the availability of sand to East Beach; the viaduct and breakwater construction at Warrnambool created a sand trap that accumulated 1,028,181 ± 575,613 m3 of sand, which made the shoreline prograde fast and reduced the harbour depth; and the dredging required to maintain the port of Apollo Bay created new land with the deposition of 291,712 ± 265,203 m3 of sand adjacent to the disposal area but caused erosion further downdrift.

Research funds for this project, as well as the aerial photographs and the statewide MBES/LiDAR were provided by the Victorian Department of Environment, Land, Water and Planning as part of the Victorian Coastal Monitoring Program (VCMP) supported by the Sustainability Fund, Deakin University and the University of Melbourne. The satellite imagery was accessed via the educational and research program of Planet Labs (Planet.com).

This publication was led by the DU Marine Mapping Group Member Rafael C. Carvalho, and group members Mary Young and Daniel Ierodiaconou also contributed to the publication.

Congrats to Raf, Mary, Dan and the DU Marine Mapping Group!

To read the full article, click here.

Last edited on the September 29th, 2021.