International Gauging Stations (IGS)
Since 1909, Canada and the United States have worked cooperatively in monitoring
the amount of water in transboundary watersheds. Under the Boundary Waters
Treaty (1909), monitoring stations required for determining the quantity of water
crossing the Canada/USA border or water levels in a shared water body are identified
as "international gauging stations". The Treaty also established the
International Joint Commission (IJC) to help to identify and formalize international
monitoring obligations.
Subsequently, two federal statutes (the
International Boundary Waters Treaty Act (1911) and the
International Rivers Improvement Act
(1955)) and some 32 water treaties, conventions and agreements have been
established, resulting in the significant increase in the number of
hydrometric stations1 in these shared basins. The data from
these stations are used to address a broad range of issues: apportionment of
natural flow between the two countries, flood mitigation, hydroelectric development,
fisheries, watershed management, ecosystem health and protection, etc.
1
In 1985, a comprehensive review
2
was completed that established which specific hydrometric stations in the
transboundary watersheds are considered to be essential by both countries and have
been given the official designation of an International Gauging Station (IGS).
A station can only be designated an IGS by means of either of two formal processes
according to the guide:
- Approval in support of IJC activities and,
- Bilateral diplomatic approval.
The review resulted in the designation of 79 stations (57 discharge
and 22 water level stations) in Canada and 62 (38 discharge and 24 water
level stations) in the United States as IGSs (
map/
table
).
These stations are a small sub-set of the actual number of hydrometric stations
being operated in transboundary watersheds. There are many more stations that
provide supportive data for apportionment calculations or monitor flows into the
Great Lakes that although important, are not considered to be a specific obligation
under this process.
Since the list was established, 9 stations (8 discharge and 1 water level) on the
Canadian side have been discontinued based upon mutual agreement of both countries.
Also, no new designations were made during this period.
These stations are operated in accordance with procedures and standards of the
host country. In Canada, the national standards are those that are established
and documented by the Water Survey of Canada, part of the Meteorological Service
of Canada. The data and information from these stations are reviewed by and are
freely exchanged between the two countries.
References
- Bruce, J. and B. Mitchell, 1995. Broadening Perspectives on Water Issues, Canadian Global Change Incidental Report Series No., IR95-1.
- Huberman, S., J.E. Slater and A. Condes, 1985. Procedural Guide for International Gauging Stations on Boundary Waters between Canada and the United States of America, WRB Report IWD-HQ-WRB-PG-85-1, Internal Environment Canada Report.
Definition:
-
Hydrometric station or gauging station is a location where systematic records of stage (water level) or stage and discharge (flow) are obtained.
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