Reference Document - OPW25 0085 (AS Published)

and design CBR value of 5 % for the natural clayey sands. A presumptive CBR value of 10 % could be
adopted for design in areas of deeper cut where very low strength (or stronger) weathered rock is
exposed consistently over the full width of the road.
Considering the site and soil conditions, it is recommended that on-site effluent treatment and land
application for each new lot should comprise a household sewage treatment plant producing a minimum
of Secondary standard effluent and connected to shallow subsurface or surface irrigation system. Based
on site and soil evaluation and including conservative slope reduction and design irrigation rate, a
minimum land application area of 350 m2 will be required for the new residences. There is sufficient
room on the proposed lots to accommodate this.




Geo-Environmental Investigation for Proposed Subdivision
7 February 2025 | 24386-001-Rev0                                                                     iii