Assessment Watersheds are mesoscale aquatic units designed to replace the 3rd order 1:50K watersheds. Assessment Watersheds are based on groupings of fundamental watersheds using FWA watershed code and local code, with a target size of between 2,000ha and 10,000ha.

Note: This data has been replaced by the [Ontario Watershed Boundaries (OWB)](https://geohub.lio.gov.on.ca/datasets/mnrf::ontario-watershed-boundaries-owb). We are no longer updating this data. It is best suited for historical research and analysis. A watershed, also known as a catchment basin, includes all land that is drained by a watercourse and its tributaries. Watersheds are split into four categories: * primary * secondary * tertiary * quaternary These divisions are based on the federal framework originally known as the Water Resources Index Inventory Filing System. Ontario has 3 primary watersheds: * Great Lakes – St. Lawrence * Southwestern Hudson Bay * Nelson River Secondary watersheds are subdivisions of primary watersheds in Ontario. Most secondary divisions are either large river systems or groupings of small coastal streams. Tertiary watersheds are subdivisions of secondary watersheds in Ontario. Quaternary watersheds are subdivisions of tertiary watersheds. There are more than 1000 quaternary watersheds in Ontario.

Units dividing the Columbia Basin in to BC Hydro reservoir-based watersheds

This collection represents the authoritative watershed boundaries for Ontario. The data is based on a framework similar to the [Atlas of Canada Fundamental Drainage Areas](https://open.canada.ca/data/en/dataset/a4b190fe-e090-4e6d-881e-b87956c07977) and the [United States Watershed Boundary Dataset](https://www.usgs.gov/core-science-systems/ngp/national-hydrography/watershed-boundary-dataset?qt-science_support_page_related_con=4#qt-science_support_page_related_con), however it adopts a more stringent scientific approach to watershed delineation. The Ontario Watershed Boundaries (OWB) collection includes five data classes: * OWB main: all levels from primary to quaternary and 5th and 6th levels in select areas * OWB primary: all primary watersheds or major drainage areas in the Canadian classification * OWB secondary: all secondary watersheds or sub drainage areas * OWB tertiary: all tertiary watersheds or sub sub drainage areas * OWB quaternary: all quaternary watersheds or 6-digit drainage areas. The OWB data replaces the following data classes: * [Provincial Watersheds, Historical](https://data.ontario.ca/dataset/provincial-watersheds-historical)

10 year peak flow isolines in cubic metres per second (m3/s) for 100 square kilometre watersheds and 10 year return period

The dataset contains data for placer watersheds locations. The dataset covers 18 watersheds within the Yukon Territory. The following watersheds form the principle boundaries of the dataset: Big Creek, Big Salmon River, Forty Mile River Indian River, Klondike River, Mayo River McQuesten River, Nisutlin River, Nordenskiold River Pelly River, Sixty Mile River, Southern Lakes (Yukon) Stewart River, White River\*, Yukon River North Yukon River South, Alsek River, Liard River \*Note - A small portion of the headwaters of the Tanana River (Yukon) watershed is associated within the boundaries of the White River watershed .Distributed from [GeoYukon](https://yukon.ca/geoyukon) by the [Government of Yukon](https://yukon.ca/maps) . Discover more digital map data and interactive maps from Yukon's digital map data collection.For more information: [geomatics.help@yukon.ca](mailto:geomatics.help@yukon.ca)

This dataset was developed to provide a complete record of salmon rivers within the province of Newfoundland and Labrador. It is organized by DFO detachment area and can be used for resource planning and management purposes. It is suitable for general mapping, visualization and query. It is derived from the National Hydro Network (NHN) data.The geodatabase contains feature datasets for each of the 8 DFO detachments in Newfoundland and Labrador (Bay Roberts, Clarenville, Goose Bay, Marystown, Rocky Harbour, Springdale, Stephenville, Twillingate). Each of the feature datasets contain 4 feature classes that describe aspects of the salmon rivers within each detachment area. The RiverBasins feature class contains polygons outlining the extent of each of the salmon river watersheds that fall within that DFO detachment area. Polygons were delineated using provincial DEMs, National Hydro Network (NHN) river features, the DFO detachment area boundary, and tools contained in the ArcHydro toolset for ArcPro GIS software. The SalmonNetwork feature class contains lines which show the flow (undirected) of the river network through each of the salmon river watersheds that fall within that DFO detachment area. The flow is depicted by lines that run through rivers and streams and through waterbodies. The lines were imported from the National Hydro Network (Primary Directed Flow feature class) and then organized by salmon river watershed, to create a dataset with one line feature for each watershed. The SalmonRivers feature class contains lines which show salmon rivers within each of the salmon river watersheds that fall within that DFO detachment area. The lines were imported from the National Hydro Network (SLWater feature class) and then organized by salmon river watershed, to create a dataset with one line feature for each watershed. Only "single-line" rivers are included. Larger, "two-sided" rivers are depicted as polygons in the "Salmon Waterbodies" dataset.This SalmonWaterbodies feature class contains polygons which show salmon waterbodies within each of the salmon river watersheds that fall within that DFO detachment area. The polygons were imported from the National Hydro Network (Waterbody feature class) and then organized by salmon river watershed, to create a dataset with one polygon feature for each watershed. Larger, "two-sided" rivers are also depicted as polygons in the "Salmon Waterbodies" dataset.The geodatabase contains attribute information on the name, zone and class of each salmon river as reflected in the following documents: (i) Anglers' Guide - Scheduled Salmon Rivers of Newfoundland and Labrador and (ii) Conservation and Protection - Scheduled Salmon Rivers & DFO Detachment Regions Newfoundland and Labrador. It also provides links to online information on current in-season status

286 LiDAR derived Watersheds modified for coastal flooding by the Resource Inventory & Modelling Section. There is an increase from the 260 original watersheds to aid in mapping flood scenarios over smaller areas.

The “PFRA Sub-basins of the AAFC Watersheds Project – 2013” dataset is a geospatial data layer containing polygon features representing the 47 sub-basins within the Agriculture and Agri-Food Canada (AAFC) Watersheds Project, tailored for the Prairie Farm Rehabilitation Administration (PFRA) business needs.

A Fisheries Sensitive Watershed (FSW) is a mapped area with specific management objectives intended to guide development activities which may adversely impact important fish values . FSWs within this set of data are currently in the review and consultation stage of the area designation process. As FSWs are designated they will be moved into the [Approved Fisheries Sensitive Watersheds](http://catalogue.data.gov.bc.ca/dataset/fisheries-sensitive-watersheds) dataset and thus often this dataset is empty.