This feature layer depicts the watershed boundaries of Canada and provides a detailed look at drainage areas and water flow for the entire land mass of Canada. This map service references the Water Survey of Canada (WSC) data. The WSC has a 3-level hierarchy of drainage areas established in 1927 for the purpose of managing hydrometric stations (recording water levels or rates of flow). They are: Major Drainage Areas, Sub Drainage Areas and Sub-sub Drainage Areas. This map service includes all three drainage area boundaries as well as the highest order boundary, the ocean drainage area.