The Canadian Hydrospatial Network (CHN) is an analysis-ready geospatial network of features that help enable the modelling of surface water flow in Canada. The six main layers and feature types are: flowlines, waterbodies, catchments, catchment aggregates, work units, and hydro nodes. Where possible the CHN is derived from high resolution source data such as Light Detection and Ranging (LiDAR) derived Digital Elevation Models (DEMs) and aerial imagery, to name a few. If existing provincial or territorial hydrographic networks meet the standards, they are incorporated into the CHN, otherwise automatic extraction methods are used on the high-resolution source data. To provide full network connectivity, if neither of these methods is possible in a region, the NHN is converted into the CHN until higher-resolution source data is available.Additional value-added attributes are included in the CHN to aid modelling, such as stream order and reach slope. The CHN physical model and features are also closely aligned and harmonized with the USGS 3DHP hydrographic network, which aids trans-border modelling. Where possible geonames (i.e. toponyms) are also added.The CHN is produced and disseminated by hydrologically connected geographic areas called work units. Work units can contain just one watershed, several small adjacent watersheds outletting into a large body of water, or be one of many parts of a larger watershed. In all cases, the features of a work unit are hydrologically connected. This is a more natural approach to data delivery, in comparison to data that is split into tiles. A generalized work unit index file is provided in the downloads to help users decide which files to download.For more information on the CHN please visit the project webpage: https://natural-resources.canada.ca/canadian-hydrospatial-network

The Water Survey of Canada (WSC) is the national authority responsible for the collection, interpretation and dissemination of standardized water resource data and information in Canada. In partnership with the provinces, territories and other agencies, WSC operates over 2800 active hydrometric gauges across the country. WSC maintains and provides real-time and historic hydrometric data for some 8000 active and discontinued stations. This dataset consists of a set of polygons that represent the drainage areas of both active and discontinued discharge stations. Users are encouraged to report any errors using the “Contact Us” webpage at: https://weather.gc.ca/mainmenu/contact_us_e.html?site=water

Water level and discharge data are available from Water Survey of Canada’s Hydrometric Network. The Water Survey of Canada (WSC) is the national authority responsible for the collection, interpretation and dissemination of standardized water resource data and information in Canada. In partnership with the provinces, territories and other agencies, WSC operates over 2500 active hydrometric gauges across the country, maintains an archive of historical information for over 7600 stations and provides access to near real-time (water level and stream flow) provisional data at over 1700 locations in Canada.

The Global Ensemble Prediction System (GEPS) carries out physics calculations to arrive at probabilistic predictions of atmospheric elements from the current day out to 16 days into the future (up to 39 days twice a week on Mondays and Thursdays at 00UTC for calculating forecast anomalies). The GEPS produces different outlooks (scenarios) to estimate the forecast uncertainties due to the nonlinear (chaotic) behavior of the atmosphere. The probabilistic predictions are based on an ensemble of 20 scenarios that differ in their initial conditions, their physics parameters which are randomly perturbed by a Stochastic Parameter Perturbation (SPP) method, and the stochastic perturbations (kinetic energy). A control member that is not perturbed is also available. Weather elements include temperature, precipitation, cloud cover, wind speed and direction, humidity and others. This product contains raw numerical results of these calculations. Geographical coverage is global. Data is available on some fifteen vertical levels on a global latitude-longitude uniform grid with 0.5 degree horizontal resolution (about 39km). Predictions are performed twice a day.

This product provides runoff data with each contour line corresponding to an average amount of annual runoff (in millimeters). Runoff data were derived from discharge values from hydrometric stations with natural flows. Not all years are included for every region of the country due to data quality and availability issues. Data cover the period 1971 to 2013 for the south and 1971 to 2004 for the north. These files were produced by Statistics Canada, Environment, Energy and Transportation Statistics Division, 2017, based on data from Environment and Climate Change Canada, 2015, Water Survey of Canada, Archived Hydrometric Data (HYDAT), www.ec.gc.ca/rhc- wsc/default.asp?lang=En&n=4EED50F1-1 (accessed December 3, 2015); Spence, C. and A. Burke, 2008, “Estimates of Canadian Arctic Archipelago runoff from observed hydrometric data,” Journal of Hydrology, Vol. 362, pp. 247–259. For more information about methods, results and limitations see Appendix D in Statistics Canada, 2017, “Freshwater in Canada,” Human Activity and the Environment,Catalogue no. 16-201-X.The purpose of the dataset is to present runoff values as derived from Statistics Canada's Water Yield Model on a national scale map of 1:32,000,000.This product is intended to be used for reference or mapping purposes. The product ends at the shoreline of Canada as defined by the drainage region boundaries supplied for drainage regions of Canada. It does not include the Arctic Islands.