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 on a simplified representation of the river network.

Click on the Map options tab to get started or refer to Help tab for more information about the different features and answers to some frequently asked questions.

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

Whitehead, A.L., Booker, D.J. (2020). NZ River Maps: An interactive online tool for mapping predicted freshwater variables across New Zealand. NIWA, Christchurch. https://shiny.niwa.co.nz/nzrivermaps/

For more information, please see Whitehead, A.L., Booker, D.J. (2019) Communicating biophysical conditions across New Zealand’s rivers using an interactive webtool. New Zealand Journal of Marine and Freshwater Research 53: 278–287. [pdf]

Contact us

Please email us at [email protected], for more information about NZ River Maps or to provide feedback. We welcome comments about how to make this webtool more useful.

Acknowledgements

This webtool was developed by Dr Amy Whitehead and Dr Doug Booker, with funding from NIWA's Environmental Flows (eFlows) Programme. Research on hydrological indices, wetted width, bed sediment cover, fish habitat and invertebrate indices was also funded by eFlows. 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.

Disclaimer

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.


1. Select map view

Select an option below to choose which rivers are visible on the map.

- All catchments: View all rivers, with more detail plotted as you zoom into the map & click Update map
- Whole region: Click on a reach to view all rivers ≥ stream order 3 within that region.
- Single catchment: Click on a reach to view all reaches within that sea-draining catchment.


2. Map predictions

Use these menus to choose which prediction variable is displayed on the map. Predictions are grouped within variable type.


3. Alter map appearance

Use these options to transform or group the data and change the colour of the riverlines.

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


Description of mapped data

Select a reach to draw the predicted flow duration curve.

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Flow duration curves are generated using the methods of Booker and Woods (2014).

Booker DJ, Woods RA. 2014. Comparing and combining physically-based and empirically-based approaches for estimating the hydrology of ungauged catchments. Journal of Hydrology 508:227-239. [View online]


The data provided in NZ River Maps is made available to download free of charge to allow you to use it for your own research. 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. See the About tab for a suggested citation for NZ River Maps.

  1. Select your desired metrics. All predictions within a selected metric will be added shown in the table below and will be added to file for downloading.
  2. Choose the desired spatial scale for the download. Visible on map will only download data for those reaches currently shown on the map. You can alter the map view using Select view mode on the Map options tab.
  3. Click the Download data button to download a csv file of the selected data.
  4. Click the Download metadata button to get an html file with information about the downloaded data, including units and the original data source.

1. Select metrics


Data available for download

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 2 of the National River Network (River Environment Classification, RECv2.4). Each river reach is coloured by the estimated value of the selected variable, with the line thickness representing the Strahler stream order. A description of each variable can be viewed when the variable is selected in the Map options tab. 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 on the New Zealand river network. Zooming into the map will provide higher resolution data. After zooming or panning the map, press the Update map button on the Map options tab to redraw the map and see more detail.

Map options Tab

The Map options tab allows you to change how the national estimates are viewed by switching variables, and allowing better differentiation between sites by changing the colour scheme and/or transforming the data. Use the Select view mode option to toggle between viewing all rivers or all reaches for a selected catchment.

Plot flow Tab

The Plot flow tab allows you to view the estimated flow duration curve for the selected reach. Enter a discharge flow into the text box to calculate the predicted time that this flow won't be exceeded.

Download data Tab

The Download data tab allows you to download NIWA's national predictions for your own use. Select the metrics of interest and the appropriate spatial scale. You will be able to view the data table prior to download. Data downloads are provided as .csv files. A metadata file that describes your downloaded data is also available for download as an .html file. 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. Please cite the original source of the data provided in the metadata.

Frequently Asked Questions

Click on the questions below to reveal the answers. Please email us at [email protected] if you have any further questions.

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 can't I see more detail when zoomed to a large scale?

NZ River Maps has been developed to allow users to visualise predictions for all of New Zealand. However, for practical reasons, we have restricted the stream orders that are visible at each zoom level to speed up the plotting on the map. You can view the data at a higher resolution either by 1) zooming closer into the map and pressing the Update map button or 2) selecting a single catchment using the Select view mode option. If you wish to make more detailed maps, we suggest that you download the data of interest and map these in a GIS software. The underlying REC2.4 shapefile is available at https://niwa.co.nz/freshwater-and-estuaries/management-tools/river-environment-classification-1 and can be joined to data downloads from NZ River Maps using nzsegment.


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 Te Waihora/Lake Ellesmere catchment describes all waterways that are upstream of Te Waihora/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.


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 [email protected] so that we can try and resolve the problem.