Skip to Main Content

Watershed Study

Watershed study & assessment: cartographic resources

Watershed Study & Assessment


Niagara Air Photos

  • All flight line indexes
  • Historical imagery 1921 – 1972 can be viewed from the website
  • Orthoimagery 1995 - 2020 can be viewed from the website
  • This is an essential source for Niagara imagery
  • Provides an excellent resource for detecting landscape changes over a time period
  • (Air photo interpretation for identifying certain features will be essential)

Paper Maps

NPCA Watershed Explorer

  • Thematic layers related to watershed management: ELC Community Natural Areas [NAI]: a classification of natural areas, i.e marsh; forest, etc.; Water quality Network, and Groundwater Network (Watershed Monitoring)
  • 2020 imagery, Watershed Planning Areas, Sub-watersheds (Boundaries)
  • Contour interval is 1 metre

NPCA Watershed Health  

NPCA Open GIS Data Portal

Ontario Flow Assessment Tool (OFAT)

  • OFAT creates watersheds, calculates watershed characteristics, executes hydrology models and reports water flow statistics.
    ***Good tool for mapping data sampling sites; adding annotation; creating boundaries.

Google Maps

  • Useful for navigating and viewing areas using ‘Street View’
  • ‘Earth’ view (bottom left corner) can also be useful for viewing some of the most recent imagery

Mapping GPS Data (tutorial)

  • Instructions for using GPS to capture data sampling sites and mapping them in a GIS, or other mapping tool.
  • ArcGIS Online also accepts a CSV data file for mapping x, y data.

Upper Twelve Mile Creek Action Plan

HOW TO Reference Maps & air photos (pdf)