Strategic Planning and Resource Managment Team Leader
Waikato District Council
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Waikato District Council - Proposed District Plan (Stage 2 Natural Hazards), Notified 27 July 2020. This layer is a spatial representation of an overlay in the Proposed District Plan and indicates where land use will be regulated by various associated rules. It will be used as a guide in the regulatory process of implementing the Proposed District Plan and managing land use, subdivision, the environment and economy. This dataset is subject to changes undertaken through the Resource Management act. Note individual Proposed Plan rules can have different statuses, some may have current legal effect and others will not until the Proposed Plan becomes operative. This data is provided for use in the District Plan only.
The Mine Subsidence Risk Area identifies land in Huntly East that is currently at risk of subsidence due to historic underground coal mining activities and the subsequent closure and refilling of the Huntly East underground mine. An assessment has been carried out to confirm the likelihood of ongoing mine subsidence and methane gas migration from mine workings to the ground surface above the Huntly East mine and the South Headings as a result of the closure of the Huntly East Mine and subsequent flooding of the underground mine workings (see Appendix 5(c) of Section 32 report Natural Hazards and Climate Change). This belongs to the series of data relating to Natural Hazards which includes the following groups - coastal erosion, coastal inundation, inland flooding, and land subsidence. This layer belongs to the land subsidence group (this is the only layer in this group).
METHODOLOGY: hand digitised. Includes both subsidence and gas hazard. Methodology for determining gas hazard area is based on methodology used to predict where natural gas (and oil) can be found due to the configuration of confining strata. More detail on methodology is described in Appendix 5 (c) (IRBA, Oct 2018, "Report on hazard following mine closure, Huntly East"). SOURCE DATA: Shapefile provided by IRBA on 5 August 2019, via email (archived in ECM 2379763). Name of shapefile: hazard_area_small_columns_gas SPATIAL REFERENCE SYSTEM: EPSG2193 SPATIAL REPRESENTATION TYPE: vector ADDITIONAL NOTES: Related documentation: Report was peer reviewed and a risk assessment undertaken (see appendix 5(d) and 5(e) of Section 32 report.