Data and Related Links

Streamflow Information

Reservoir Project and Storage Information

Natural Flow Data

The historical apportionment and natural flow data for the transboundary river basins administered by the Accredited Officers of the St. Mary and Milk Rivers are provided in the links below. The data sets represent records provided in the Annual Reports to the International Commission on the Division of Waters of the St. Mary and Milk Rivers.

Data sets are provided for the following transboundary river basins (the years for which data are available are in parenthesis):

  • St. Mary River (1919 to 2017) - dam3 | ac-ft
  • Milk River (1985 to 2017) - dam3 | ac-ft
  • Eastern Tributaries of the Milk River

The data sets include the following information for apportionment periods:

  • natural flow of the watercourse at the international boundary (as calculated in the Procedures for the Division of the Waters of the St. Mary and Milk Rivers);
  • U.S. or Canada share of natural flow (as provided in the Boundary Waters Treaty of 1909);
  • recorded flow of the watercourse at the international boundary;
  • flow received by U.S. or Canada above or below the country’s share;
  • data sets are available in units of dam3 and ac-ft.