Applying the principle of sustainability to coastal sand mining: The case of Pakiri-Mangawhai Beach,New Zealand

The purpose of New Zealand's Resource Management Act (1991) is to promote the sustainable management of natural and physical resources. Coastal sand mining may be consistent with this purpose where: (1) extractions occur from sediment systems open to inputs of sediment, and the volumes extracted do not limit the natural development, physical characteristics, and ecological diversity of the coastal environments affected; or (2) extractions from palimpsest or relict sedimentary deposits occur at a rate where the rate of extraction is insignificant compared with the volume of the resource. The response of coastal sand mining companies and consent-granting authorities to the requirements of the Resource Management Act (1991) are examined with respect to recent applications to mine sand from a coastal sand body in the Hauraki Gulf, New Zealand. The assessments of environmental effects (AEE) submitted in support of these applications do not establish the sustainability of the sand mining operations. Specifically they do not define the dimensions of the active sediment system, quantify the volume of the related resource, or state the period within which sustainability is achievable. Further, the AEE do not consider the cumulative effects of the extractions, either in terms of the total volume of sand mined or the cumulative effects of different anthropogenic activities. The test of sustainability demands a quality of information and understanding of coastal systems that is well beyond that obtained in the past or accepted at present. There is a clear need for New Zealand's resource management legislation to be supplemented by technical guidelines that help ensure the test of sustainability is rigorously applied.