Retirement note: please note that this dataset has been retired and replaced by Ontario Integrated Hydrology Data, which is available from the Land Information Ontario (LIO) Warehouse.

HYDAT is a water database containing data on daily and monthly means of flow, water levels and sediment concentrations (for sediment sites).

This data is stored as series of shapefiles. The spatial layer symbolizes known HYDAT FLOW gauge locations that are part of the Environment Canada/Ontario Ministry of Natural Resources Cost Share agreement. For each of these gauges, there is a shapefile containing a watershed. The name of the watershed shapefile contains the StationID of the gauge. Watershed boundaries were defined using NRVIS data and the Provincial Digital Elevation Model produced by the Water Resources Information Program (WRIP).

A separate MS Access database stores a series of watershed characteristics that can be linked to the shapefiles. These characteristics include;

• watershed area
• watershed perimeter
• lake area
• wetland area
• other water area (double line streams, reservoirs)
• terrestrial area
• reach slope
• length of longest stream
• longest stream slope
• stream order
• gauge elevation
• geolgy summary
• landcover summary
• length of all streams
• and number of first order streams

Most watersheds and gauges are characterized but is incomplete. Use this dataset with caution when conducting analysis, one point appears to have been located incorrectly. Modifications/revisions to this dataset may be required before any analysis can begin.

Supplementary data in shapefile and Table format can be used and are available for download from the additional documentation section.