This standard was approved as a departmental standard on February 16, 2009.
The Standard Drainage Area Classification (SDAC) is Statistics Canada's official classification of drainage areas in Canada. The SDAC provides unique numeric codes for the levels in the hierarchy of drainage areas: major drainage areas, sub-drainage areas and sub-sub-drainage areas. The three geographic areas are hierarchically related; a 4 character code is used to show this relationship. In addition to the drainage area classes, a classification variant of the sub-sub-drainage areas by drainage regions and ocean drainage areas is included. The relationship between these geographic areas is illustrated in the diagram showing the Standard Drainage Area Classification and the hierarchical structure of the classification.
Major drainage areas are presented in the major drainage areas and sub-drainage areas map of Canada.
The Standard Drainage Area Classification (SDAC) 2003 is based on Version 5 of the National Scale Frameworks Hydrology - Drainage Areas, Canada. The National Scale Frameworks Hydrology was developed by a partnership consisting of Natural Resources Canada, Environment Canada and Statistics Canada.
Variant of SDAC 2003
The classification variant of SDAC is a set of customized groupings that use SDAC sub-sub-drainage areas as building blocks. In Statistics Canada, variants are created and adopted in cases where the version of the classification does not fully meet specific user needs for disseminating data or for sampling in surveys. A classification variant is based on a classification version such as SDAC 2003. In a variant, the categories of the classification version are split, aggregated or regrouped to provide additions or alternatives (e.g. context-specific additions) to the standard structure of the base version.