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Coordinating Committee on Great Lakes Basic Hydraulic and Hydrologic Data


The Great Lakes - St. Lawrence River System extends from the headwaters of tributary streams in northern Minnesota and western Ontario, to the Gulf of St. Lawrence in the Atlantic Ocean. The drainage basin covers more than 1,000,000 km2 (400,000 square miles) from Duluth, MN to Trois Rivières, QC. Eight U.S. states and two Canadian provinces border this vast system of shared waters.  Joint use of these waters by the people of Canada, the United States, First Nations and Native Americans, requires internationally-coordinated basic hydraulic and hydrologic data.

Prior to 1953, responsible Federal agencies in Canada and the United States independently collected and compiled data pertaining to the hydraulic and hydrologic characteristics of the Great Lakes and St. Lawrence River, with only superficial and informal coordination of some of the data. As a consequence, the same basic data developed on different bases and datum planes, were often not compatible. Remedying this situation required a concerted effort to study and evaluate the data used by both countries.

With the advent of extremely high lake levels in 1952 and the impending hydroelectric power and navigation developments in the St. Lawrence River system, Canadian and U.S. agencies recognized that continued independent development of basic data would be illogical. They realized that early agreement on the hydraulic and hydrologic characteristics of the system was of paramount importance. Therefore, the U.S. Army Corps of Engineers and the Canadian Departments of Transport, Mines and Technical Surveys and Resources and Development, opened negotiations early in 1953 for the purposes of establishing a basis for development and acceptance of identical data by both countries. The negotiations culminated in a meeting of representatives of the interested agencies in Ottawa on 7 May 1953.

At that meeting, the Coordinating Committee on Great Lakes Basic Hydraulic and Hydrologic Data was established.


Terms of Reference

  1. The Coordinating Committee is an ad hoc committee of experts from Federal agencies of the United States and Canada charged with the responsibility for collecting, compiling, use, or dissemination of data related to hydraulics, hydrology, vertical control and water levels for the Great Lakes – St. Lawrence River System.
  2. The geographic scope of interest is the Great Lakes, their connecting channels, and the St. Lawrence River.
  3. The Coordinating Committee serves in an advisory capacity and provides international standardization of hydrologic and hydraulic data for the Federal agencies involved in monitoring and managing water quantity within the Great Lakes, connecting channels and the St. Lawrence River. 
  4. The role of the Coordinating Committee is to support and facilitate agreement on the methods and procedures used by the agencies in collecting and computing related data as well as the publication and distribution of coordinated data and results.  
  5.  To the extent practicable determine and report the uncertainty in the basic data that are coordinated.
  6. The Members of the Coordinating Committee should be those actively involved in the joint federal agencies that have water management or related oversight of the Great Lakes.
  7. The size of the membership (of the Coordinating Committees and its Subcommittees) should be maintained within economic means and workable numbers. 
  8.  These terms of reference shall be reviewed at least every five years.



The Committee is an ad hoc group comprised of Federal experts from interested agencies.  The current agencies supporting the Committee include the U.S. Army Corps of Engineers, Environment Canada, the National Oceanic and Atmospheric Administration, the Canadian Hydrologic Service, the U.S. Geological Survey, and Natural Resources Canada.  The Committee consists of six Members: a Co-Chair, Member and Secretary for each of the two countries. The Committee generally meets twice annually, alternating locations between the United States and Canada.  Co-Chairs share the general management of the Committee and lead the meetings.  Secretaries share in the preparation of meeting minutes, the booking of meeting venues, the handling of correspondence, and overseeing of general administrative duties.  Members aid in the management of the Committee as necessary.

The Committee currently has three Subcommittees: Vertical Control - Water Levels, Hydraulics, and Hydrology. These Subcommittees are directed to conduct the required technical studies through collaboration with the appropriate agencies of Canada and the United States.  Subcommittees typically have two Co-Leads, one each from the United States and Canada.  The Subcommittee Co-Leads share in the general management of the Subcommittees and lead Subcommittee meetings/teleconferences.  The Subcommittees host meetings at least twice per year to discuss data coordination, methods of data collection, messaging initiatives and other topics defined by conditions.  Subcommittee Co-Leads are encouraged to name Secretaries to assist them in the preparation of minutes, reports and other administrative tasks.  Occasionally, additional Subcommittees are formed in order to accomplish certain tasks.