Mapping Significant Natural Areas of the Waikato region: the physical basis for the identification of karst ecosystem sites (updated methodology report)

Report: TR 2022/03

Author: Bruce W Hayward

In 2017, Waikato Regional Council hosted a Karst Workshop of local experts on karst, caves and their biota, and nominated 58 sites as potentially meeting the needs for protection of significant karst ecosystems in the region. This report outlines the way these nominated sites have been assessed for their geoheritage values and diversity and then mapped. This exercise resulted in the deletion or merging of several nominated sites and addition of several others that were already included and mapped in the New Zealand Geopreservation Inventory and four caves that were known to have particular biotic values. The resulting sites meet the criteria for significance under sections 6 (b) and (c) in the RMA, and their protection will maintain and enhance the best examples of ‘originally rare’ ecosystem types at a national level.

The following criteria were used to assess and document the geoheritage values of all sites:

a. The extent to which the landform or cave contributes to the understanding of the geology.
b. The rarity or unusual nature of the site or feature.
c. The extent to which the feature is an outstanding representative example of the diversity of Waikato Region's karst landforms and caves.
d. The extent to which the feature is part of the Waikato SNA karst group of features.
e. The extent to which the feature contributes to the aesthetic values of the wider landscape.
f. The extent of community association with, or public appreciation of, the values of the feature or site.
g. The potential value of the feature or site for public education.
h. The potential value of the site to provide additional understanding of the geological or biotic history.
i. The state of preservation of the feature or site.
j. The extent to which the feature is associated with a historically important natural or human event.
k. The importance of the site to mana whenua was not assessed here, as this is more appropriately undertaken by local iwi.

GIS mapping was undertaken at a scale of 1:10 000 using the same GIS aerial photography base map (WRAPS 2012) as used by Waikato Regional Council maps. The preliminary GIS mapping from the NZ Geopreservation Inventory and Waitomo District proposed ONF mapping project were used as a starting point for many sites. Other sites were mapped from scratch in a desk-top exercise using published cave maps, topographic contours, Google Earth satellite images and oblique aerial photographs supplied by Waikato Regional Council. A total of 58 sites are now included, documented and mapped and five catchment areas that are particularly sensitive for the protection of the biota in caves have also been mapped. Data on all these sites is summarised in this report with more detailed information available for each site in digital spreadsheet format.