Ontario Integrated Hydrology (OIH) data

Ontario Integrated Hydrology (OIH) data is used to generate watersheds and support provincial-scale hydrology applications including:

watershed generation
hydrologic modelling
watercourse network analysis

Four key datasets are represented in each data package:

stream network (Enhanced Watercourse)
hydrology-enforced digital elevation model [DEM ] (Enforced DEM)
flow direction grid (Enhanced Flow Direction - EFDIR)
raster representation of the stream network (StreamGrid)

Technical information

For the first time, OIH data is complete for the entire province making it possible to create a watershed for any location in Ontario. This includes areas flowing in from neighbouring provinces and Minnesota with the following exceptions:

points on the international border that drain to Lake Superior, south of Pigeon River
points on the international border that drain the Great Lakes connecting channels and St. Lawrence River stateside
points along the Ottawa River that drain from Quebec

Special note: North West package

The North West package contains hydrography data for the entire Rainy River Basin, an area which straddles the international border between Canada and the United States.

The data stateside originates from the National Hydrography Dataset (NHD) as of February/March 2014. This data has been harmonized with the Ontario Hydro Network (OHN) to create the Enhanced Watercourse and Integrated Waterbody layers found within the North West package.

For more information on when the data was initially extracted and incorporated, refer to these fields stored in the attribute table of each vector layer in the geodatabase:

Effective Date (EFF_DATE)
Geometry Update Date (GEO_UPD_DT)

The data stateside is a static snapshot of NHD intended to support regional modeling. Please refer to the United States Geological Survey (USGS) website for the most current version of NHD.

Data is updated after the completion of major updates to source data (such as OHN and/or the Provincial DEM).

Ministry contact: Provincial Mapping Unit

Additional information

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watersheds watersheds

hydrologic modelling hydrologic modelling

Arc Hydro quaternar... Arc Hydro quaternary watersheds
Geographic coverage: Ontario
Maintainer: Provincial Mapping Unit
Maintainer branch: Mapping and Information Resources Branch
Last Validated Date: July 11, 2023
Update frequency: As required