20201021 16201200 1.0 FALSE RelativeWetnessGradient_Highlands 002 Projected GCS_NZGD_2000 Linear Unit: Meter (1.000000) NZGD_2000_New_Zealand_Transverse_Mercator <ProjectedCoordinateSystem xsi:type='typens:ProjectedCoordinateSystem' xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xmlns:xs='http://www.w3.org/2001/XMLSchema' xmlns:typens='http://www.esri.com/schemas/ArcGIS/2.4.0'><WKT>PROJCS["NZGD_2000_New_Zealand_Transverse_Mercator",GEOGCS["GCS_NZGD_2000",DATUM["D_NZGD_2000",SPHEROID["GRS_1980",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Transverse_Mercator"],PARAMETER["False_Easting",1600000.0],PARAMETER["False_Northing",10000000.0],PARAMETER["Central_Meridian",173.0],PARAMETER["Scale_Factor",0.9996],PARAMETER["Latitude_Of_Origin",0.0],UNIT["Meter",1.0],AUTHORITY["EPSG",2193]]</WKT><XOrigin>-4020900</XOrigin><YOrigin>1900</YOrigin><XYScale>450445547.3910538</XYScale><ZOrigin>-100000</ZOrigin><ZScale>10000</ZScale><MOrigin>-100000</MOrigin><MScale>10000</MScale><XYTolerance>0.001</XYTolerance><ZTolerance>0.001</ZTolerance><MTolerance>0.001</MTolerance><HighPrecision>true</HighPrecision><WKID>2193</WKID><LatestWKID>2193</LatestWKID></ProjectedCoordinateSystem> 20200205 14011400 20201019 16331800 150000000 5000 Esri ArcGIS 12.4.2.19948 Relative Wetness Gradient Uplands This layer comes from the Mapping of Northland's Wetness Gradients report which was produced by Land and Water Science. <DIV STYLE="text-align:Left;"><DIV><DIV>1 Overview Approximately 95% of Northland’s original wetlands have been lost. Northland Regional Council (NRC) have been working to improve knowledge of existing wetlands, to better understand how best to prevent further loss, to identify suitable restoration sites, and to provide landowners with better advice for wetland protection and management. This document details the associated metadata for the mapping of hydric soils and wetlands integrating radiometric and satellite (Sentinel) imagery for the Northland Region. Background information on the theory, method, validation and outputs can be found within Rissmann et al. (2019; Envirolink Grant: 1955-NLRC214 and 1956-NLRC215). The GIS layers that were integrated to produce Northland’s Relative Wetness Gradient Layer (NRWGL) classification included: • Percentage gamma-ray attenuation derived from Radiometrics • Normalised Differential Wetness Index (NDWI) derived from Sentinel Satellite • Topographic domain, ‘upland’ and ‘lowland,’ derived from NASA’s MERIT Digital Elevation Model The gamma-ray attenuation layer, 50 x 50 m resolution (0.25 Ha), forms the basis of a perennial wetness gradient layer for the Northland Region that also identifies the existence of peat deposits and hydric soils. Importantly, gamma-ray attenuation mapping identifies peat deposits and hydric soils independent of vegetative cover, providing insight over the extent of former wetland complexes that have been cleared for productive purposes. Sentinel satellite derived Normalised Differential Wetness Index (NDWI) appears most relevant to land cover gradients and MERIT based terrain analysis provides an objective basis for evaluating the association between geology, topography, and perennial wetness gradients derived from gamma-ray attenuation. The resultant NRWGL provides a classification of wetness gradients as a function of gamma-ray attenuation, wetness index, and topographic position. Across the ‘lowland’ domain there are 3 main families that define a wetness continuum from wettest (Family 1) to driest (Family 3). Within each of the 3 families the relative wetness gradient is defined by each class (high to low). Family 1 encompass most of Northland’s known wetlands (Wetlands 1000, Top 150 and LUCAS) and/or areas of likely former wetlands that are now associated with productive land cover. There is also a strong association between this family and the QMAP geological classification of peat deposits and the NZLRI classification of organic and poorly drained (hydric) soils. Although the work was unable to define wetland by vegetative species, when combined with the LUCAS land cover layer and Northland Regional Councils 1000+ wetlands, it provides a basis for: • Better defining wetness and vegetative cover gradients within recognised wetland areas. • Identifying the location and extent of former wetland areas that have been modified for productive purposes. • Discrimination of perennially and intermittently wet wetlands. • Identifying areas of wetland with or without wetland vegetation that have not formerly been recognised, and; • Evaluating the relationship between topography, geology, land cover, soils and wetness gradients. 5 Northland Relative Wetness Gradient Layer (NRWGL) 5.1 Raw data and rationale To produce an integrated picture of the landscape and land cover factors governing perennial wetness gradients, topography, gamma-ray attenuation and MNDWI layers were integrated to produce a classification for Northland of Relative Wetness. Integration also provides a basis through which a single image layer can be interrogated against existing classifications, such as Northland’s ecological districts, LUCAS (land cover), Northland’s Top 1,000 wetlands, geological, soil and property layers. 5.2 Method Gamma-ray attenuation and MNDWI rasters were weighted and indexed relative to each other before being normalised and standardised for phylogenetic classification. Phylogenetic assessment revealed a total of 10 meaningful classes or ‘clusters.’ The 10-class layer was then subdivided into ‘lowland’ (100) and ‘upland’ (200) domains from which zonal statistics were generated for each class within each domain (Table 3). Lakes (300) and Towns (400) were also added to the raster layer. The resulting Relative Wetness Gradient Layer (NRWGL) was then polygonised and combined with Northland Regional Council’s Known Wetland layer and Heathland layer and the latest LUCAS land cover layer (MfE, 2019). For a more detailed explanation please refer to the Mapping of Northland’s Wetness Gradients utilising Radiometric and Satellite imagery report - GIS Metadata (Land and Water Science 12/11/2019)</DIV></DIV></DIV> Land and Water Science (Clint Rissmann, Lisa Pearson, Jessie Lindsay, and Matt Couldrey); Northland Regional Council Relative Wetness Gradient NRC Land & Water Science Land and Water Science Radiometric Satellite Imagery Wetness Gradient <DIV STYLE="text-align:Left;"><DIV><DIV>For internal purposes only.</DIV></DIV></DIV> File Geodatabase Feature Class dataset EPSG 7.9.4(9.0.0) 0 Simple FALSE 0 TRUE FALSE RelativeWetnessGradient_Highlands Feature Class 0 OBJECTID OBJECTID OID 4 0 0 Internal feature number. Esri Sequential unique whole numbers that are automatically generated. Shape Shape Geometry 0 0 0 Feature geometry. Esri Coordinates defining the features. DN DN Integer 4 0 0 _BRmean _BRmean Double 8 0 0 _BRmedian _BRmedian Double 8 0 0 _BRstdev _BRstdev Double 8 0 0 _BRmin _BRmin Double 8 0 0 _BRmax _BRmax Double 8 0 0 _tcmean _tcmean Double 8 0 0 _tcmedian _tcmedian Double 8 0 0 _tcstdev _tcstdev Double 8 0 0 _tcmin _tcmin Double 8 0 0 _tcmax _tcmax Double 8 0 0 _mndwimean _mndwimean Double 8 0 0 _mndwimedi _mndwimedi Double 8 0 0 _mndwistde _mndwistde Double 8 0 0 _mndwimin _mndwimin Double 8 0 0 _mndwimax _mndwimax Double 8 0 0 _ndwimean _ndwimean Double 8 0 0 _ndwimedia _ndwimedia Double 8 0 0 _ndwistdev _ndwistdev Double 8 0 0 _ndwimin _ndwimin Double 8 0 0 _ndwimax _ndwimax Double 8 0 0 Shape_Length Shape_Length Double 8 0 0 Length of feature in internal units. Esri Positive real numbers that are automatically generated. Shape_Area Shape_Area Double 8 0 0 Area of feature in internal units squared. Esri Positive real numbers that are automatically generated. 20201019