ORMGP Topological Sub-Watersheds

Description

The Provincial Digital Elevation Model (PDEM) offered by the Ontario Ministry of Natural Resources and Forestry has been up-scaled and conditioned to acquire continuous flow paths. This product has been used to delineate 4,238 ~10km² sub-watersheds covering the extended ORMGP jurisdiction (~40,000km²). These sub-watershed are topologically correct, meaning that every sub-watershed is defined by its upstream and downstream neighbouring sub-watersheds.

• Type
  • Vector - Polygon shapefile.
• Geographic Extent
  • The extended ORMGP Study Area covering the Niagara peninsula to the Bay of Quinty.
• Maintenance Standard
  • Periodically updated in coordination with HDEM updates.

Georeferencing and Accuracy

• Horizontal Datum
  • North American Datum 1983
• Ellipsoid
  • GRS 1980
• Prime meridian
  • Greenwich
• Projection
  • Ontario MNR Lambert (EPSG 3161)
• Horizontal Accuracy
  • 1.5m
• Unit
  • metre
• Information source
  • Ontario Ministry of Natural Resources via Conservation Ontario.

Data Sources and Restrictions

• Use Constraint
  • None - in accordance with ORMGP disclaimer
• Citation
  • Oak Ridges Moraine Ground Water Program (2023) Sub-Watersheds.
• Agency Originator
  • Oak Ridges Moraine Groundwater Program (ORMGP)
• Agency Distributor
  • Oak Ridges Moraine Groundwater Program (ORMGP)

Methodology

• Data Source - Hydrologically Conditioned Digital Elevation Model (HDEM)
  • See source metadata.
• Data Source - Ontario Hydro Network (OHN) - Waterbody
  • See Source metadata
• Vector Processing

  • All waterbodies greater than 9km² are defined as sub-watersheds.

  • A hill-climbing algorithm is applied to the HDEM from all “outlet” points until an area close to 10km² is covered. the process repeats until the entire HDEM is covered.

• Replaces or Updates
  • Oak Ridges Moraine Groundwater Program (v2020) sub-watershed layer.
• Contact
  • email (support@owrc.ca)

Last Modified: 2024-03-24