Geotechnical Investigations for Subdivisions

Prior to submitting an Application for Subdivision Consent, a geotechnical investigation and reporting is required to assess the suitability of the site for the proposed subdivision and address the hazards outlined in Section 106 of the Resource Management Act (1991). These hazards include erosion, falling debris, subsidence, slippage, or inundation.

Project example

Eliot Sinclair were engaged to prepare a geotechnical subdivision report for a rural site. A desktop study was undertaken to identify the soil profile, ground level and nearby watercourses. The study indicates the site is underlain by shallow gravel that expends to a considerable depth and comprises flat topography with a shallow water race which runs along its south boundary. Given the confidence in soil profile, deep investigation is not warranted. The second stage of investigation includes a site walkover to identify any ground damage and undertake shallow site investigation to determine the soil profile and the inferred bearing capacity. The density of the site investigation was based on MBIE’s guidelines requirements.

Outcome

The results of the desktop study and geotechnical investigation on site confirm the site is not at risk of erosion, falling debris, subsidence or slippage. However, Environment Canterbury flood modelling indicates a number of areas across the site may be subject to inundation risk and should not be considered as a suitable platform for future construction. In general, the site was not subject to filling and the insitu gravels were clean with no sign of contamination, therefore effluent disposal and stormwater can be safely discharged to the ground. The discharge system should be designed to comply with the regulations of the concerned authorities.

Closing Statement

At Eliot Sinclair we always seek to challenge ourselves at all levels, with great opportunities for junior staff to up skill and complete complex subdivision works to the highest of standards. We work closely with our professional teams of surveyors and planers to provide our clients complete and most professional subdivision work.