Welcome to NZ River Maps

NIWA has calculated estimates of environmental conditions across the entire New Zealand river network, including hydrology, ecology and water quality metrics. This interactive webtool allows you to map and interrogate these estimates (see National Estimates tab). In addition, you can intersect the NIWA estimates with publicly-available council planning layers (see Council Layers tab) and view a simplified representation of the river network.

Please refer to Help tabs on both the National Estimates and Council Layers tabs for more information about the different datasets and how you can interrogate them. Some commonly asked questions are addressed in the FAQ tab.

All data unless specifically stated is licensed under a Creative Commons Attribution 3.0 New Zealand License and must be attributed back to its original creator.

Suggested citation

Booker, D.J., Whitehead, A.L. (2017). NZ River Maps: An interactive online tool for mapping predicted freshwater variables across New Zealand. NIWA, Christchurch. https://shiny.niwa.co.nz/nzrivermaps/

Contact us

Please email us at nzrivermaps@niwa.co.nz for more information about NZ River Maps or to provide feedback. We welcome comments about how to make this webtool more useful.


This webtool was developed by Dr Doug Booker and Dr Amy Whitehead, with funding from NIWA's Sustainable Water Allocation Programme (SWAP). Research on hydrological indices, wetted width, bed sediment cover, fish habitat and invertebrate indices was also funded by SWAP. Estimates of fish presence/absence and whio habitat suitability were funded by the Department of Conservation and the University of Canterbury, respectively, while research on water quality state and consented water use was funded by the Ministry for the Environment. Thank you to various Regional Council staff for making spatial data available.


Whilst NIWA has used all reasonable endeavours to ensure that the information contained in this website is accurate, NIWA does not give any express or implied warranty as to the accuracy of the information contained herein. National estimates at unvisited sites are designed to represent regional patterns and should not be used to replace site-specific studies. This website has been reviewed internally by NIWA and meets NIWA standards for website delivery.

Select the Create Colour Bins option to categorise numeric data into three classes. The popup slider can be used to set the breaks.

Select a reach marker to draw the predicted flow duration curve (top plot) and wetted useable width under different flows for selected species (bottom plot).


Select a reach on the map to highlight the connected upstream and downstream reaches. Select X and Y variables to generate plots of the highlighted reaches (top plots) compared to all mapped reaches (bottom plot).

Understanding the National Estimates

NIWA's national estimates are based on statistical models that relate observed patterns with landscape-scale patterns and then generate estimates on the entire New Zealand river network. The estimates represent conditions in the recent past. A range of hydrological, ecological, environmental and water quality-related metrics have been plotted onto Version 1 of the National River Network (River Environment Classification, RECv1).

Circles represent the centre of an NZReach (a segment of river between two confluences), with the size of the circle indicating the stream order. Each circle is coloured by the estimated value of the selected variable, indicated by the map legend. A description of each variable can be viewed when the variable is selected in the Options tab under National Estimates or the Plots tab under Council Layers . A reference and link (where available) to the relevant paper or report is also provided for more information about how the metrics were calculated.

Map Panel

The Map Panel allows you to visualise a range of spatial data, including NIWA's national estimates, some publically-available Regional Council layers and a simplified version of the New Zealand river network. These data can be turned on and off using the check boxes in the top right of the map panel.

Options Tab

The Options tab allows you to change how the national estimates are viewed by switching variables, transforming the data to allow better differentiation between sites and changing the number and size of reaches that are plotted using the stream order slider. We don't recommend selecting all stream orders across a whole region as they are very slow to plot.

Flow and Habitat Tab

The Flow and Habitat tab allows you to view the estimated flow duration curve and estimates of the weighted usable width (WUA) for various fish species for the selected reach.

Catchment Plots Tab

The Catchment Plots tab allows you to graph estimates of the selected variable upstream and downstream of a specific reach. Check Enable Tracing to identify reaches upstream and downstream of any selected reach marker.

Select available Regional Council layers to map and colour them by the metadata provided using the two dropdown menus. Click on individual layer features (i.e. points, lines or polygons) to see council-provided details.

Click on a mapped council feature to see the associated metadata.

Click on a council feature on the map to plot the estimates for the predicted variable selected in the dropdown box below.

The blue boxes/bars represents the distribution of the NIWA estimates for all NZReaches that overlap the selected council layer, while the red boxes/dots shows the NIWA estimates for each NZReach within the selected feature.

Understanding the Council Layers

The Council layers provided in this webtool represent layers relevant to freshwater management, including regional planning data and areas of natural, recreational or ecological importance, that have been provided to the public by Regional Councils.

These spatial data are represented on the map as polygons, lines or points depending on the underlying data type. Each feature (i.e. an individual point or polygon) is coloured by the metadata provided in the layer, as indicated by the map legend.

Note that this webtool currently only provides spatial data from Environment Canterbury & Greater Wellington Regional Council to evaluate whether this functionality is useful. We welcome feedback via nzrivermaps@niwa.co.nz .

NIWA acknowledges that this is not a complete set of planning layers available from these Regional Councils. For more information about available spatial data, please refer to the individual Regional Council websites provided in the bottom left corner of the map.

Map Panel

The Map Panel allows you to visualise a range of spatial data, including NIWA's national estimates, some publically-available Regional Council layers and a simplified representation of the New Zealand river network. These data can be turned on and off using the check boxes in the top right of the map panel.

Options Tab

The Options tab allows you to switch between the available spatial data for a given council using the Select shapefile dropdown menu. Features can be coloured using the Colour map by dropdown menu to select attribute data provided by the council. You can also click on a feature on the map to see the available attribute data.

Plots Tab

Use the Plots tab to plot the range of NIWA's National Estimates within the boundary of selected Regional Council spatial layers. The plot shows the range of the selected national estimate, both within the selected feature and within all features in the selected spatial layer.

Frequently Asked Questions

Click on the questions below to reveal the answers. Please email us at nzrivermaps@niwa.co.nz if you have any further questions.

Can I download these data?

NZ River Maps is designed to allow users to explore regional and national patterns in various predicted conditions. It is not designed to be a download service. However, some water quality and hydrological indices data are available for download via the Ministry for the Environment download service. All data in NZ River Maps, unless specifically stated, is licensed under a Creative Commons Attribution 3.0 New Zealand License and must be attributed back to its original creator.

Why do the predicted values in NZ River Maps differ from the conditions I see in the field?

The predictions shown in NZ River Maps represent the outputs of models that have been made at the national scale. While these predictions are as accurate as possible, given the data used to make them, national predictions at unvisited sites are designed to represent regional patterns and should not be used to replace site-specific studies.

How is NZ River Maps different from LAWA?

NZ River Maps provides the ability to visualise national-scale predictions of metrics describing hydrology, ecology, water quality and landscapes. These predictions have been generated by NIWA and represent a static snapshot of predicted values across all New Zealand river reaches. Land, Air, Water Aotearoa (LAWA) presents actual or observed data on fresh water and other environmental domains at a number of monitoring sites around New Zealand.

Why is NZ River Maps based on REC1?

Most of the NIWA predictions have been made using data available for version 1 of the River Environment Classification (REC1). At this stage, most of the predictor variables used to make these predictions are not available for version 2 of the River Environment Classification (REC2).

Why is there no Council Data available for my region?

The Council Data currently available in NZ River Maps was downloaded from publically-accessible webservers provided by some Regional Councils. Not all Regional Councils provide such a service, restricting our ability to include spatial data for all regions. In addition, the NZ River Maps team has had limited resources to obtain spatial data from Regional Councils during this pilot phase. Please contact us at nzrivermaps@niwa.co.nz if you would like to request the addition of council data for a specific region or are able to provide such resources.

Why do the river lines look strange?

The blue river lines in the background of the map are somewhat stick-like. For this app, we opted to show a caricature of the rivers to aid understanding of the connectedness of river locations whilst maintaining a reasonable plotting speed. This has resulted in some strange looking river lines, particularly within lake boundaries. Note that the river lines can be toggled on/off by using the controls on the map. River lines will plot to 5th order streams when all catchments within a region are plotted, while selecting a specific catchment will result in river lines for all order streams being plotted.

Why are there no national predictions for lakes?

NZ River Maps is dedicated to mapping NIWA predictions that have been made for New Zealand rivers. Therefore, this website does not show any predictions for lakes.

Where do the catchment names come from?

The catchment names provided in the National Predictions dataset were derived from river names identified by the Soil Conservation and River Control Council in 1956. Where these are not directly named after the commonly-used river name, they typically describe the location of the outlet to the sea. For example, the Lake Ellesmere catchment describes all waterways that are upstream of Lake Ellesmere.

What's happening in the Lower Rakaia and Lower Clutha?

The national river network was designed to represent confluences; where two rivers join as they flow downstream. A few rivers in New Zealand have diffluences; where the river splits into two channels as it flows downstream. These diffluences are not well represented in the river network due to ambiguities in their upstream characteristics (e.g. their upstream area). Estimates downstream of diffluences (e.g. the Lower Rakaia and Clutha rivers) are therefore problematic.

Is habitat suitability transferable between rivers?

Generalised physical habitat predictions are derived from many site-specific studies of hydraulic and substrate conditions. These conditions are compared with habitat suitability criteria to assess the quality and quantity of available physical habitat. Habitat suitability criteria describe the preferences of fish for a range of depths, velocities and substrates. In many cases habitat suitability have been derived from several studies in several locations. However, these studies have often taken place in wadeable streams, making their transferability to deeper locations uncertain.

Why can't I select a NZReach marker?

If you are having trouble clicking on an NZReach marker (a coloured dot), it is likely that there is a Council Data layer sitting on top of the reach marker. Try unchecking the Council Data box in the top right corner of the map.

Why does NZ River Maps keep crashing?

We've found that NZ River Maps sometimes runs into issues when using Internet Explorer and will ask you to reload the page. To avoid this potential problem, we recommend that you use either the Google Chrome or Mozilla Firefox browsers. If you continue to have problems, please let us know at nzrivermaps@niwa.co.nz so that we can try and resolve the problem.