Bathymetric features of Ontario lakes from historical maps

However, between the 1940s and 1990s, the Ontario Ministry of Natural Resources and Forestry produced bathymetric maps for over 11,000 lakes across Ontario. These maps have been scanned and are publicly accessible via Ontario's Open Data Portal (data.ontario.ca/dataset/historic-bathymetry-maps). From these historical maps, maximum depths were manually extracted and compiled into this dataset.

In addition to maximum depths, lake geometry has been derived using lake polygons provided by the National Hydro Network (NHN) from Natural Resources Canada open.canada.ca/data/en/dataset/a4b190fe-e090-4e6d-881e-b87956c07977). Morphometric metrics such as circularity, shoreline complexity, and relative depth were calculated from these polygons and the bathymetric data. This dataset offers a critical resource for understanding the geomorphological and biogeochemical dynamics of lakes across Ontario, Canada.