The Drainage Areas dataset is largely based on the Water Survey of Canada (WSC) drainage area boundaries at the sub-sub-basin level. The data model supports the derivation, from the Fundamental Drainage Areas dataset (sub-sub-basin level), of the WSC and Atlas of Canada drainage area hierarchies and the data is available in all three schemes. Drainage area definitions for both WSC and Atlas of Canada boundaries were reviewed resulting in some modifications. Larger scale reference data sources were used for further manual boundary adjustments. This dataset has been integrated with other National Scale Frameworks hydrology datasets and is considered a component of the Hydrology Theme (see Supplemental Information for more details about the Atlas of Canada National Frameworks data at the 1:1,000,000 scale). The Atlas Frameworks are a set of integrated base map layers which form part of a larger National-Scale Frameworks data collection. These data have been compiled at a scale of 1:1 000 000 with the primary goal being to indicate correct relative positioning with other framework layers rather than absolute positional accuracy. 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 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)

This dataset is the digital hydrologic unit boundary layer for the 8-digit subwatershed boundaries for the conterminous United States. This dataset is intended to be used with the following two tabular dBase files: https://water.usgs.gov/lookup/getspatial?ds573_tillage_lu92e and https://water.usgs.gov/lookup/getspatial?ds573_tillage_lu01. The two tabular datasets contain the Tillage Practices in the Conterminous United States, 1989-2004---Datasets Aggregated by Watershed. This dataset and the two tabular datasets can be linked using the common attribute HUC8_N. Information about how the tabular data and geospatial data can be related are given in the data series report: https://pubs.usgs.gov/ds/ds573/ .The original dataset is the 12-digit Subwatershed boundaries (WBD_archive_17nov2009_9.2_file). The 12-digit boundaries were dissolved to 8-digit boundaries to be used with the two tabular .dbase data files containing the tillage practice data for the United States. ORIGINAL METADATA: This data set is a complete digital hydrologic unit boundary layer to the Subwatershed (12-digit) 6th level for the entire United States. This data set consists of geo-referenced digital data and associated attributes created in accordance with the "Federal Guidelines, Requirements, and Procedures for the National Watershed Boundary Dataset; Chapter 3 of Section A, Federal Standards, Book 11, Collection and Delineation of Spatial Data; Techniques and Methods 11-A3" (04/01/2009). http://www.ncgc.nrcs.usda.gov/products/datasets/watershed/index.html . Polygons are attributed with hydrologic unit codes for 4th level sub-basins, 5th level watersheds, 6th level subwatersheds, name, size, downstream hydrologic unit, type of watershed, non-contributing areas and flow modification.

This dataset is the digital hydrologic unit boundary layer for the 8-digit subwatershed boundaries for the conterminous United States. This dataset is intended to be used with the following two tabular dBase files: https://water.usgs.gov/lookup/getspatial?ds573_tillage_lu92e and https://water.usgs.gov/lookup/getspatial?ds573_tillage_lu01. The two tabular datasets contain the Tillage Practices in the Conterminous United States, 1989-2004---Datasets Aggregated by Watershed. This dataset and the two tabular datasets can be linked using the common attribute HUC8_N. Information about how the tabular data and geospatial data can be related are given in the data series report: https://pubs.usgs.gov/ds/ds573/ .The original dataset is the 12-digit Subwatershed boundaries (WBD_archive_17nov2009_9.2_file). The 12-digit boundaries were dissolved to 8-digit boundaries to be used with the two tabular .dbase data files containing the tillage practice data for the United States. ORIGINAL METADATA: This data set is a complete digital hydrologic unit boundary layer to the Subwatershed (12-digit) 6th level for the entire United States. This data set consists of geo-referenced digital data and associated attributes created in accordance with the "Federal Guidelines, Requirements, and Procedures for the National Watershed Boundary Dataset; Chapter 3 of Section A, Federal Standards, Book 11, Collection and Delineation of Spatial Data; Techniques and Methods 11-A3" (04/01/2009). http://www.ncgc.nrcs.usda.gov/products/datasets/watershed/index.html . Polygons are attributed with hydrologic unit codes for 4th level sub-basins, 5th level watersheds, 6th level subwatersheds, name, size, downstream hydrologic unit, type of watershed, non-contributing areas and flow modification.