Description: Attributes associated directly with network:FieldTypeDescriptionCatareaRealWatershed area in m2CUM_Area RealArea upstream of a reach (and including this reach area) in m2.NzsegmentIntegerReach identifier to be used with REC2 (supercedes nzreach in REC1).nz_fnodeIntegerUnique number of preceding river segment's outlet node.nz_tnodeIntegerUnique number of following river segment's inlet node.LengthdownRealThe distance to coast from any reach to its outlet reach, where the river drains (m).HeadwaterIntegerNumber (0) denoting whether a stream is a “source” (headwater) stream. Non-zero for non-headwater streams.HydseqIntegerA unique number denoting the hydrological processing order of a river segment relative to others in the newtork.StreamOrderIntegerA number describing the Strahler order a reach in a network of reaches.euclid_distRealThe straight line distance of a reach from the reach “inlet” to its “outlet”.upElevRealHeight (asl) of the upstream end of a reach section in a watershed (m).downElevRealHeight (asl) of the downstream end of a reach section in a watershed (m).upcoordXRealEasting of the upstream end of a river segment in m (NZTM2000).upcoordYRealNorthing of the upstream end of a river segment in m (NZTM2000).downcoordXRealEasting of the downstream end of a river segment in m (NZTM2000).downcoordYRealNorthing of the downstream end of a river segment in m (NZTM2000).sinuosityRealActual distance divided by the straight line distancegiving the degree of curvature of the streamnzreach_rec1IntegerThe REC1 identifiying number for the corresponding\closest reach from REC1 (can be used to retrieve the REC management classes)headw_distIntegerDistance of the furthermost “source” or headwater reach from any reach (m).Shape_lengthRealThe length of the reach (vector) as calculated by ArcGIS.SegslpmaxRealMaximum segment slope along length of reach.SegslpmeanRealMean segment slope along length of reach.LIDIntegerLake Identifier number(LID) of overlapping lake.ReachtypeIntegerA value of 2 is assigned if the segment is an outlet to the lake, otherwise 0 or null.nextdownidintegersegment number of the most downstream reach
Description: The wetland assessment considered definitions and classification from the National Policy Statement for Freshwater Management (NPS-FM) and the Wetland Types in New Zealand document (Johnson and Gerbeaux, 2004). Mapping effort was focused on identifying natural wetlands rather than artificial or improved pasture type wetlands. Wetland polygons were smoothed using the Polynomial Approximation with Exponential Kernel (PAEK) method with a smoothing tolerance of 20 m. Farm ponds smaller than 1,000 m² were not mapped, and some wetlands highly likely to fall under the pasture exclusion criteria or former wetlands were excluded. Overall, a total of 2,755 individual wetlands were delineated and classified in the Waipaoa, Waiapu, Hangaroa-Ruakituri, Uawa, Waimata, and Wharekahika-Waikura catchments.Data delivered by Morphum Environmental August 2022
Description: Overland flow paths were derived from a flow accumulation surface that was extracted from a hydrologically corrected DEM. Flow paths were defined using a flow accumulation threshold of 500 cells, i.e. to qualify for inclusion in the flow path network, a minimum catchment area of 2,000 m2 was required (500 cells x 4 m2 each). OLFPs were delineated iteratively, with additional burn lines created with each iteration to correct flow paths that spill out of their channels and follow an incorrect trajectory. This is often caused by manmade structures such as bridges but also natural features such as dense vegetation incorrectly included within the DEM (as opposed to the surface model or DSM). Several iterations using this approach were conducted until a fair representation of the flow paths was obtained. Flow paths were first converted to vector polylines and smoothed to give a more appropriate visual representation. The resulting feature class can be visualised by symbolising on the catchment area field using the break values shown below.DiscalimaerThis overland flow path layer provides a high-level understanding of routes where surface stormwater may flow during rainfall events. It is subject to the following limitations:The layer uses a surface generated by LiDAR only and does not account for the stormwater reticulation network or for any surface obstructions such as buildings or fences.The layer is subject to limitations in the LiDAR data. These include lower precision under dense foliage and lack of LiDAR data in some rural areas in the District.The layer is generated through a GIS algorithm which divides terrain into a grid of squares. Water is modelled to flow from each grid square to the lowest adjacent grid square. This method means that fine features such as kerbs may not be accurately represented.The layer does not include any assessment of depth, width, or rate, of flows.In some locations, change to landform since LiDAR was generated will have altered overland flow paths from those displayed on the layer.These limitations mean that overland flow paths represented on the layer should not be considered definitive and are subject to further investigation. Likewise, flow paths that exist in reality, may not be represented on this layer.A draft disclaimer for the depression storage layer is provided as follows for your consideration.The depression storage layer provides an indicative extent of where ponding may form during prolonged rainfall.It is subject to the following limitations:It is assumed that the depression storage areas shown would fill to capacity prior to spillingThe depression storage areas shown exceed the following minimum criteria regarding ponding area, storage volume and depth.Surface area > 100 m2 Maximum depth > 0.20 m Volume > 30 m3The layer uses a surface generated by LiDAR only and is subject to the limitations of LiDAR. In some locations, change to landform since LiDAR was generated will have altered the potential depression storage area from those displayed on the layer.
Description: Overland flow paths were derived from a flow accumulation surface that was extracted from a hydrologically corrected DEM. Flow paths were defined using a flow accumulation threshold of 500 cells, i.e. to qualify for inclusion in the flow path network, a minimum catchment area of 2,000 m2 was required (500 cells x 4 m2 each). OLFPs were delineated iteratively, with additional burn lines created with each iteration to correct flow paths that spill out of their channels and follow an incorrect trajectory. This is often caused by manmade structures such as bridges but also natural features such as dense vegetation incorrectly included within the DEM (as opposed to the surface model or DSM). Several iterations using this approach were conducted until a fair representation of the flow paths was obtained. Flow paths were first converted to vector polylines and smoothed to give a more appropriate visual representation. The resulting feature class can be visualised by symbolising on the catchment area field using the break values shown below.DiscalimaerThis overland flow path layer provides a high-level understanding of routes where surface stormwater may flow during rainfall events. It is subject to the following limitations:The layer uses a surface generated by LiDAR only and does not account for the stormwater reticulation network or for any surface obstructions such as buildings or fences.The layer is subject to limitations in the LiDAR data. These include lower precision under dense foliage and lack of LiDAR data in some rural areas in the District.The layer is generated through a GIS algorithm which divides terrain into a grid of squares. Water is modelled to flow from each grid square to the lowest adjacent grid square. This method means that fine features such as kerbs may not be accurately represented.The layer does not include any assessment of depth, width, or rate, of flows.In some locations, change to landform since LiDAR was generated will have altered overland flow paths from those displayed on the layer.These limitations mean that overland flow paths represented on the layer should not be considered definitive and are subject to further investigation. Likewise, flow paths that exist in reality, may not be represented on this layer.A draft disclaimer for the depression storage layer is provided as follows for your consideration.The depression storage layer provides an indicative extent of where ponding may form during prolonged rainfall.It is subject to the following limitations:It is assumed that the depression storage areas shown would fill to capacity prior to spillingThe depression storage areas shown exceed the following minimum criteria regarding ponding area, storage volume and depth.Surface area > 100 m2 Maximum depth > 0.20 m Volume > 30 m3The layer uses a surface generated by LiDAR only and is subject to the limitations of LiDAR. In some locations, change to landform since LiDAR was generated will have altered the potential depression storage area from those displayed on the layer.
Description: Surface depressions can be mapped to define zones of potential inundation should the primary network become blocked.Depressions can be delineated under the assumption that these areas would fill to capacity prior to spilling. To qualify for inclusion in the depression’s dataset, individual depressions need to meet the following set of criteria relating footprint area, storage volume and maximum depth. Surface area > 100 m2Maximum depth > 0.20 m Volume > 30 m3The Field "RETAIN" can be used to identify those depression features that meet the above criteriaDisclaimerThis overland flow path layer provides a high-level understanding of routes where surface stormwater may flow during rainfall events. It is subject to the following limitations:The layer uses a surface generated by LiDAR only and does not account for the stormwater reticulation network or for any surface obstructions such as buildings or fences.The layer is subject to limitations in the LiDAR data. These include lower precision under dense foliage and lack of LiDAR data in some rural areas in the District.The layer is generated through a GIS algorithm which divides terrain into a grid of squares. Water is modelled to flow from each grid square to the lowest adjacent grid square. This method means that fine features such as kerbs may not be accurately represented.The layer does not include any assessment of depth, width, or rate, of flows.In some locations, change to landform since LiDAR was generated will have altered overland flow paths from those displayed on the layer.These limitations mean that overland flow paths represented on the layer should not be considered definitive and are subject to further investigation. Likewise, flow paths that exist in reality, may not be represented on this layer.A draft disclaimer for the depression storage layer is provided as follows for your consideration.The depression storage layer provides an indicative extent of where ponding may form during prolonged rainfall.It is subject to the following limitations:It is assumed that the depression storage areas shown would fill to capacity prior to spillingThe depression storage areas shown exceed the following minimum criteria regarding ponding area, storage volume and depth.Surface area > 100 m2 Maximum depth > 0.20 m Volume > 30 m3The layer uses a surface generated by LiDAR only and is subject to the limitations of LiDAR. In some locations, change to landform since LiDAR was generated will have altered the potential depression storage area from those displayed on the layer.