Sunday, March 23, 2008

Canada’s drainage areas info released in celebration of World Water Day

In celebration of United Nations World Water Day this Saturday (March 22), National Hydro Network (NHN) data for 839 drainage areas across Canada are now available without cost or restriction and under common licensing terms.

The NHN is a new dataset that describes and models features of the inland surface-water system of Canada. The NHN enables water flow analysis that can aid in the management of watersheds and the species that live in them.

In emergency situations such as flooding or toxic spills, NHN data can be used to monitor conditions and to assist decision-making processes to minimize flood damage or optimize control of a spill. For planning, the NHN can be used to decide where to most effectively place a dam or power plant. NHN data can also be an important tool in managing and monitoring drinking water and fresh water supplies.

The NHN is represented by geospatial data describing:

Hydro features, such as lakes, reservoirs, rivers, streams, canals and islands;
The directional flow of surface water by a linear network;
The toponymy (geographical names) of hydro features.

Also available without cost or restrictions and under common licensing terms at the GeoBase Web site are:

A new NHN data web viewer service;
A new national index of NHN drainage area limits.
Three NHN data releases for about 100 drainage areas each will be released in June, October and December to complete the national coverage of more than 1,100 areas.

NHN data can be integrated and combined with other geospatial data such as the GeoBase National Road Network, Orthoimagery, Geographical Names, Geopolitical Boundaries, Geodetic Network Data, and Digital Elevation Data.

GeoBase ( is a federal, provincial and territorial government initiative that is overseen by the Canadian Council on Geomatics ( Since 2003, GeoBase has provided consistent, accurate and current geospatial data that is produced, updated and distributed through key partnership agreements among Natural Resources Canada, other federal government agencies, plus provincial and territorial governments, with the support of GeoConnections (

Details on the NHN, including technical specifications, plus information on GeoBase are available at:
GeoBase Web site (English)


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