Historic Shorelines

This dataset contains a number of historical shorelines mapped from surveys and aerial photographs. Data is available at a number of locations around the Waikato Coast, mostly in areas with development at risk from coastal erosion. Purpose: Data collected for evaluation of historic shoreline change and coastal hazard line definition.

1. Lines showing Historic Foreshores containing attributes stating year of survey, survey plan and shoreline type (toe of dune, edge of vegetation, MHWM, MSL etc). 2. Lines and areas showing Historic Shoreline Erosion containing attributes stating year of survey, survey plan and erosion type (blowout, storm scarp, mound or seep)

Waikato Region

Shoreline records from as early as 1850s through to present.

The hard copy plans were scanned and registered using underlying CRS parcel data. The ability to register accurately was limited by the amount of parcel data on the maps. Registration was ‘best fit’. Lines were then digitised and attributes populated. Some of the plans were compilations of survey records specifically drawn for EW to show several years of historic shorelines. Frequency of collection: Irregular.

See method above. Gaps in collection: Not all available photographs and surveys have been mapped. Data quality: Based on the hard copy plans. As all plans are of survey quality it can be assumed that the foreshore definitions are to the same standard. Some of the plans weren’t very clear in areas where several historic shorelines crossed each other particularly because of them being in black and white. If absolute accuracy is required it must be obtained from the underlying survey plan. Attribute accuracy: Based on the hard copy plans so therefore assumed to be reasonably accurate. Completeness: Dataset generally focusses on areas where development is threatened by coastal hazards. Most data is therefore available for the sandy beaches of the Coromandel Peninsula, and River mouths on the West Coast.

Data is available in hard copy maps to be viewed at Environment Waikato. All data is also available electronically in most GIS formats.

Assessment of coastal hazards and development of coastal development setbacks and coastal hazard policy.

Data freely available from Environment Waikato Sensitivity/Confidentiality: No confidentiality.

Further shorelines will be added as data collected during future studies.