1. The Niagara Control Board has the honour to submit herewith a report covering the work performed by the Board in connection with the diversion of water from the Niagara River for power purposes.
2. The work of the Board has been in conformity with views expressed in a despatch dated 8th February, 1923, from the Secretary of State of the United States to the Ambassador of Great Britain at Washington and concurred in by the Government of Canada under date of the 10th July, 1923, wherein reference was made to existing and projected hydraulic turbine installations at Niagara Falls, which if operated to capacity would be capable of diverting water for power purposes in excess of treaty limitations, and refers further to the desirability of appointing a joint Board to secure uniformity and closer cooperation in the method of measurement of the water diverted and proper observance of treaty provisions.
3. Under Article 5 of the Boundary Waters Treaty of 11th January, 1909, the diversion within the State of New York of waters of the Niagara River for power purposes is limited to an amount not exceeding in the aggregate a daily diversion at the rate of 20,000 cubic feet of water per second, and within the Province of Ontario, 36,000*cubic feet of water per second. Of the existing diversions for power purposes, all are returned to the lower Niagara River with the exception of 500 cubic feet per second, which has been reserved by the United States for diversion for power purposes through the New York State Barge Canal, and such portion of this 500 cubic feet as is actually used is returned to Lake Ontario east of the Niagara River.
4. The Board adopted a method of determining the amount of water diverted by the several power companies on the Canadian and American shores of the Niagara River at Niagara Falls, and directed that hourly records be kept of the diversions by these companies. The method of measurement adopted determines at hourly intervals the power output of the various plants by watt meter readings, and by computation therefrom the amount of water used by the various hydro electric units is obtained by means of curves showing the relation between water consumption and power output for the different units, as determined by efficiency tests.
5. The efficiency tests were made under the direction and in the presence of the Board or its representatives. They consisted of measuring the amount of water used and the amount of electrical energy delivered by a unit at various gate openings. The electrical measurements were made by carefully calibrated electrical instruments of standard type. The measurements of water consumption were made by the "Gibson" method. This is a fairly recent development in hydraulic art, by which the amount of water flowing in a penstock is computed from a pressure time diagram showing the changes in penstock pressure caused by a closure of the turbine gates. The Board investigated this method very carefully and secured such convincing evidence of its accuracy and convenience that it was adopted as a standard method for use throughout the operations of the Board. These measurements were made on each type of unit in each power house, and, where more than one unit of the same type and capacity was installed at least one unit from each five or less identical units in a plant was tested.
6. For many years the United States power companies at Niagara Falls have been required to submit reports of hourly measurements to the War Department indicating the amount of water diverted from the Niagara River. An inspection of these records from the time it was physically possible from the status of installation of machinery to have exceeded the treaty limitations definitely shows that the diversion of water by these companies has at no time exceeded in the aggregate a daily diversion at the rate of 19,500 cubic feet of water per second.
7. With respect to the remaining 500 cubic feet per second reserved by the United States for diversion for power purposes through the New York State Barge Canal, accurate measurement of this diversion has not yet been made by the Board, such action being delayed pending definition of water rights and allocation of water diversions by the Federal Power Commission. From inspection of the waterway, information on hand, and reports of measurements submitted by the New York State Engineer, the Board believes that the 500 cubic feet per second reserved for this purpose has not been exceeded.
8. A careful inspection and investigation by this Board of records of the several power companies on the Canadian side of the Niagara River, from the time it was physically possible from the status of installation of machinery to have exceeded the treaty limitations, definitely shows that the diversion of water has at no time exceeded in the aggregate a daily diversion at the rate of 36,000 cubic feet of water per second.
9. It is pertinent to refer here to the fact that while hydraulic installation on both sides of the boundary is now such that it is physically possible to divert water in excess of the treaty limitations, the policy pursued in both countries has been that of partial closure of the older and more inefficient plants and the utilization of the water in the newer and highly efficient plants.
10. Since January 1, 1925, hourly measurements have been made at the power plants on both sides of the Niagara River at Niagara Falls, and show that all the power plants have been and are being operated in entire compliance with the provisions of the treaty.
11. Weekly inspections of the various power plants are made by the Board or its representatives, at irregular hours. It is believed that, under the method of supervision adopted, no violation of treaty limitations is possible without prompt detection by the Board.
12. Hourly records of diversions and frequent inspections by the Board will be continued and additional efficiency tests made from time to time as changes in conditions warrant or require.
Calvin Coolidge, State Department Statement on the Report of the Niagara Control Board Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/328774