Bathymetry is the measurement of water depth in lakes. From the 1940s to the 1990s, the Ministry of Natural Resources and Forestry produced bathymetry maps for over 11,000 lakes across Ontario. The data can be used by the general public and GIS specialists for: * climate change modelling * fish monitoring and other ecological applications * hydrologic cycle modelling * recreational fishing maps * watershed-based water budgeting The maps were created using simple methods to determine lake depths. They were meant for resource management purposes only. Little effort was made to identify shoals and other hazards when creating these bathymetric maps. Since this data was collected, many constructed and naturally occurring events could mean that the depth information is now inaccurate, so these maps should not be used for navigational purposes. In many cases, these maps still represent the only authoritative source of bathymetry data for lakes in Ontario. __Technical information__ These maps are being converted to digital GIS line data which can be found in the [Bathymetry Line](https://geohub.lio.gov.on.ca/datasets/mnrf::bathymetry-line) data class. The [Bathymetry Index](https://geohub.lio.gov.on.ca/datasets/mnrf::bathymetry-index) data class identifies if GIS vector lines have been created and the location of mapped lakes. The historic paper maps have been scanned into digital files. We will add new digital files to this dataset if they become available. The digital files have been grouped and packaged by regions into 13 compressed (zipped) files for download. Note: package 99 contains scanned maps where the location shown on the map could not be determined.

All available bathymetry and related information for Medicine Lake were collected and hard copy maps digitized where necessary. The data were validated against more recent data (Shuttle Radar Topography Mission 'SRTM' imagery and Indian Remote Sensing 'IRS' imagery) and corrected where necessary. The published data set contains the lake bathymetry formatted as an Arc ascii grid. Bathymetric contours and the boundary polygon are available as shapefiles.

All available bathymetry and related information for Crowsnest Lake were collected and hard copy maps digitized where necessary. The data were validated against more recent data (Shuttle Radar Topography Mission 'SRTM' imagery and Indian Remote Sensing 'IRS' imagery) and corrected where necessary. The published data set contains the lake bathymetry formatted as an Arc ascii grid. Bathymetric contours and the boundary polygon are available as shapefiles.

All available bathymetry and related information for Claude Lake were collected and hard copy maps digitized where necessary. The data were validated against more recent data (Shuttle Radar Topography Mission 'SRTM' imagery and Indian Remote Sensing 'IRS' imagery) and corrected where necessary. The published data set contains the lake bathymetry formatted as an Arc ascii grid. Bathymetric contours and the boundary polygon are available as shapefiles.

The attribute table included in the dataset provides some limited metadata information that is specific to each lake. This includes the: * survey year * survey method * original map scale This dataset should be used for discovery of Bathymetry data. It provides no bathymetric information, but allows users to discover where bathymetry data exists and in what format. Related datasets: * [Ontario waterbody location identifer](https://data.ontario.ca/dataset/ontario-waterbody-location-identifier)

All available bathymetry and related information for Lac Sante were collected and hard copy maps digitized where necessary. The data were validated against more recent data (Shuttle Radar Topography Mission 'SRTM' imagery and Indian Remote Sensing 'IRS' imagery) and corrected where necessary. The published data set contains the lake bathymetry formatted as an Arc ascii grid. Bathymetric contours and the boundary polygon are available as shapefiles.

All available bathymetry and related information for Gap Lake were collected and hard copy maps digitized where necessary. The data were validated against more recent data (Shuttle Radar Topography Mission 'SRTM' imagery and Indian Remote Sensing 'IRS' imagery) and corrected where necessary. The published data set contains the lake bathymetry formatted as an Arc ascii grid. Bathymetric contours and the boundary polygon are available as shapefiles.

All available bathymetry and related information for McLeod Lake were collected and hard copy maps digitized where necessary. The data were validated against more recent data (Shuttle Radar Topography Mission 'SRTM' imagery and Indian Remote Sensing 'IRS' imagery) and corrected where necessary. The published data set contains the lake bathymetry formatted as an Arc ascii grid. Bathymetric contours and the boundary polygon are available as shapefiles.

All available bathymetry and related information for Chestermere Lake were collected and hard copy maps digitized where necessary. The data were validated against more recent data (Shuttle Radar Topography Mission 'SRTM' imagery and Indian Remote Sensing 'IRS' imagery) and corrected where necessary. The published data set contains the lake bathymetry formatted as an Arc ascii grid. Bathymetric contours and the boundary polygon are available as shapefiles.

Digitization of long-term water chemistry data collected between 1920's - 1990's from lakes across Saskatchewan by the Saskatchewan Fisheries Research Laboratory. Samples were collected using methods from the Standard Methods for the Examination of Water and Wastewater (APHA, AWWA and WPCF). This data serves as a baseline for water quality.This dataset is a digitization from paper records of water chemistry data across Saskatchewan collected by the Saskatchewan Fisheries Research Laboratory. Data ranges from the 1920's to the 1990's and were sampled using methodes from the Standard Methods for the Examination of Water and Wastewater (American Public Health Association, American Water Works Association and Water Pollution Control Facility) This long-term water chemistry data serves as a baseline for water quality. Different variables of water chemistry are organized into individual fields. The units of measurement appear at the end of each field name. Due to the historical nature of the data some uncertainty exist in values.  Additonal notes on data: ND: no detection Trace: trace amounts Nil: zero NA: no data