This web map can also be accessed via the LINZ Storymap about NZ Key Datasets for Resilience and Climate Change https://storymaps.arcgis.com/stories/b4dd46f15cea4234a098b4c8caae5b3d The River Environment Classification (REC) is a database of
catchment spatial attributes, summarised for every segment in New
Zealand's network of rivers. The attributes were compiled for the
purposes of river classification, while the river network description
has been used to underpin models. Typically, models (e.g. CLUES and
TopNet) would use the dendritic (branched) linkages of REC river
segments to perform their calculations. Since its release and use over
the last decade, some errors in the location and connectivity of these
linkages have been identified. The current revision corrects those
errors, and updates a number of spatial attributes with the latest data.
REC2 provides a recut framework of rivers for modelling and
classification. It is built on a newer version
of the 30m digital elevation model, in which the original 20m contours
were supplemented with, for example, more spot elevation data and a
better coastline contour. Boundary errors were minimized by processing
contiguous areas (such as the whole of the North Island) together, which
wasn't possible when the REC was first created. Major updates include
the revision of catchment land use information, by overlaying with land
cover database (LCDB3, current as at 2008), and the update of river and
rainfall statistics with data from 1960-2006. The river network and
associated attributes have been assembled within an ArcGIS geodatabase.
Topological connectivity has been established to allow upstream and
downstream tracing within the network. REC2 can be downloaded as a zip file and used directly in ArcMap. Alternatively, the layers can be extracted as shape files. The three REC2 based layers contained within this web map consist of the following (metadata is contained in the Layers section below).NZ Large Catchments, are basically the local watersheds of the REC2V5 dissolved into large sea draining catchments.River Environment Classification REC2 V5 (as National and local rivers) NZ Rivers and Names is a cut down version of the REC2V5 with river and waterway names added where available.
Field
Type
Descriptions for all REC2 associated feature layers within this webmap.RivName The names for any waterway where available taken from original topo data ( only for the NZ Large Catchments and NZ River and Names layers)
Catarea
Real
Watershed area in m2 CUM_Area
Real
Area upstream of a reach (and
including this reach area) in m2. Nzsegment
Integer
Reach identifier to be used with
REC2 (supercedes nzreach in REC1).
Lengthdown
Real
The distance to coast from any
reach to its outlet reach, where the river drains (m). Headwater
Integer
Number (0) denoting whether a
stream is a “source” (headwater) stream. Non-zero for non-headwater streams.
Hydseq
Integer
A unique number denoting the
hydrological processing order of a river segment relative to others in the
network.
StreamOrder
Integer
A number describing the Strahler
order a reach in a network of reaches.
euclid_dist
Real
The straight line distance of a
reach from the reach “inlet” to its “outlet”. upElev
Real
Height (asl) of the upstream end
of a reach section in a watershed (m). downElev
Real
Height (asl) of the downstream
end of a reach section in a watershed (m).
upcoordX
Real
Easting of the upstream end of a
river segment in m (NZTM2000). upcoordY
Real
Northing of the upstream end of
a river segment in m (NZTM2000). downcoordX
Real
Easting of the downstream end of
a river segment in m (NZTM2000).
downcoordY
Real
Northing of the downstream end
of a river segment in m (NZTM2000). sinuosity
Real
Actual distance divided by the
straight line distance giving the degree of curvature of the stream nzreach_re
Integer
The REC1 identifiying number for
the corresponding\closest reach from
REC1 (can be used to retrieve the REC management classes) headw_dist
Integer
Distance of the furthermost
“source” or headwater reach from any reach (m). Shape_leng
Real
The length of the reach (vector)
as calculated by ArcGIS.
Segslpmean
Real
Mean segment slope along length
of reach.
LID
Integer
Lake Identifier number(LID) of
overlapping lake.
Reachtype
Integer
A value of 2 is assigned if the
segment is an outlet to the lake, otherwise 0 or null. nextdownid
integer
segment number of the most
downstream reach
NIWA acknowledges funding from the MBIE SSIF towards the preparation of REC v2.5 River Environment Classification._________________Item Page Created: 2021-07-09 05:37 Item Page Last Modified: 2025-04-05 18:53Owner: steinmetzt_NIWANZ River Names (REC2)Item id: 502212e71bce4c029de8a82cd5bc6302NZ Regional Rivers (REC2)Item id: 502212e71bce4c029de8a82cd5bc6302NZ National Rivers (REC2)Item id: 3a4b6cc2c1c74fbb8ddbe25df28e410cNZ Large River CatchmentsItem id: 28d23ad94c2a4846b7634f4cdbba178f
