Assessing the risk associated with areas underlain by dolomites and limestones

A Competent person with engineering expertise shall investigate any proposed townships or existing township areas which are underlain by dolomites/limestones and shall prepare a clearly motivated report in which the township stability is zoned in terms of prevailing professional practice. The detail report must detail any precautionary measures which are required  to reduce the risk of sinkhole formation/ subsidence and any restrictions of land usage, layout, erf sizes, density, services etc.  The report shall be submitted to the Council for Geoscience to obtain confirmation that these investigations are consistent with sound professional practice and the investigations meet all legal requirements pertaining to such stability investigations.

The report will included the impact of the stability of borehole installations and the construction of swimming pools and briefly outline the condition and nature of existing storm water systems and wet set services.   It should also specify any requirements or precautionary measures.

In townships zoned with precautionary measures (D2 and D3) where services have already been installed, the report shall outline where such services fail to meet the minimum requirements and to observe those precautionary measures set out.

This Competent Person should also liaise with the local authority under whose jurisdiction the proposed township lies and include a statement by such authority on their services risk management systems in dolomitic/limestone areas.  These statements must be signed by the relevant chief executive office and include the authority’s policy and procedures which it has in place in respect of the installation of bulk water and sewer services, measures to prevent land invasion on areas zoned as D4, maintenance of township services and enforcement of any special provisions and/or restrictions which may be imposed on individual erven.

In sectional title developments, we would prepare and submit a services risk management plan for inclusion in the constitution of the body corporate which is to be established together with a firm undertaking that this plan be incorporated in the constitution which is put before the first body corporate meeting for adoption.

Furthermore, the use of existing investigation reports on the township in order to reduce the amount of additional investigations is required if adequate and valid.