Date: Friday, 1 July 2022
 

Monitoring Team: Todd, Peter, Natasha, Clive, Nick, David
 

Analysis & Report: David Bills-Thompson, PFCG Technical Officer and Data Co-ordinator

Commentary: A partial beach monitoring of East Beach between Manifold Street and Golfies car park was conducted on East Beach on 1/07/2022. In the attached charts, the thicker red line is a laser measurement and the thin red line is from UAV mapping. Note, it may improve legibility if you change the pdf magnification to 200%.

Summary.
A significant accretion down the beach was detected at Manifold Street; 66cm since April 2022 (by laser monitoring only). Sand loss of around 0.5 metre was detected in the vicinity of the general waste tip site, mainly in front of the WEDs however there is no indication that the secondary dune behind the WEDs is in any danger of being lost.
The loss in those areas is characteristic for this time of year. (Accretion and loss information is available in the spreadsheet Transect Elevation Tables at the dates associated with the green and pink shaded areas of the tables.)

General.
This monitoring was part of the VCMP regular (approximately every 6 weeks) UAV mapping conducted by Todd from Deakin University and assisted by our group pilots Natasha and Peter and Clive. As noted in April, there were unexplained results in the validation of UAV results using the direct measurements of sand height at the posts; some errors were in the order of 60cm.

A second team of beach monitoring (Nick and David) conducted laser monitoring over the same area of beach in order to track where the differences in measurements were occurring.

There was generally very good agreement between the laser results and those obtained from UAV mapping except at the post where the previous validation measurements were based. The difficulties in accurately measuring sand height at the post will be discussed at the next meeting.

Note that the laser and UAV charts at post 8 do not track correctly because it is nearly impossible to measure along the same transect over the rocks but beyond 10m (in front of the rocks) there is excellent correlation between the two different measuring systems.