Appendix B - Geotechnical Assessment Report

Mr Tony Rossiter                                                                                           21436-001-Rev0
                                                                                                         18 November 2021

2.2      Laboratory Testing
One sample was forwarded to Morrison Geotechnic, a NATA accredited laboratory, for testing comprising
Emerson class number (ECN), particle size distribution (PSD) and Atterberg limits. Laboratory test
certificates are attached and results are summarised in Table 1 below.
Table 1: Summary of Laboratory Soil Classification & ECN Testing

                                                  Plasticity Limits                              PSD
        Sample
                          ECN
       Location                      Plasticity     Liquid            Linear       Silt / Clay   Sand        Gravel
                                     Index (%)     Limit (%)      Shrinkage (%)       (%)*       (%)**       (%)***

           BH5
                            6           19             37              9.5             42         53           5
      (1.0 m-1.5 m)
*Taken as % passing 2.36 mm sieve **Taken as passing 2.36 mm sieve minus passing % passing 75 µm sieve
***Taken as sum of % retained of sieves 2.36 mm and larger

Material test results indicate that the soil tested comprises medium plasticity, sandy clay with a trace of
gravel. ECN testing indicates a low dispersion potential.

2.3      Topography
As illustrated in Text Figure 5, on a wider scale, the allotment is located on north-west facing slope that
crests at the southern boundary.




                        Proposed
                      dam location                                      Lot boundary




Text Figure 5: Image showing ground surface contours (courtesy NC Interactive Maps)


Ground slope angles were estimated from measurements on site during the walk-over using a hand-held
clinometer. The dam site is located on a generally linear slope that dips to the north-west at angles of up to
about 6°.

Photographs illustrating the site conditions are given overleaf in Text Figures 6 and 7.




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