NHN Index


WARNING: NHN Work Unit Limits are not official boundaries for watersheds or drainage areas. For more information, please refer to the NHN Work Units section and to the text box at the bottom of this page.

Each NHN dataset corresponds to a NHN Work Unit Limit that delimits the drainage area covered by the dataset. These limits make up the territorial divisions from which are produced and distributed NHN datasets. The NHN Index is a national index that groups together all “NHN Work Unit Limits” at a specific time “T” for the entire Canadian territory. This index is updated on the GeoBase Web portal at interval according to a “per release” approach, synchronized with NHN data publication. Update frequency of the index is thus determined according to NHN data publications.

The NHN Index is provided as vector geospatial data in the SHAPE (ESRITM) format. For quick reference, a CSV (Comma separated values) text file (ASCII) offering a subset of the NHN Index attributes is also available, as well as a PDF document describing the NHN Index.

NHN Index coverage Overview

WARNING: NHN Work Unit Limits are not official boundaries for watersheds or drainage areas.

Watershed and drainage area boundaries available in Canada can be downloaded from the following sites:

  • GeoGratis portal for information on the Water Survey of Canada Drainage Areas and Drainage Areas from the Atlas of Canada. Search under the All Collections section: Atlas of Canada 1,000,000 National Frameworks Data, Hydrology - Drainage Areas.
  • Agriculture and Agri-Food Canada portal for information on the Prairie Farm Rehabilitation Administration (PFRA) watersheds. Search under the Data section and then under Access Geospatial Product to get access to PFRA Watershed Boundaries.