canal as at present constructed can carry more than one-half of this quantity. The second difficulty is that after St. Mary River has been turned into Milk River water may be taken from the latter stream in Canada. Such a diversion is possible, and plans are now being made for the construction of a canal diverting water from the north side of Milk River in Canada, about 12 miles below the junction of North and South forks. The dimensions of this canal are as follows: Bottom width, 25 feet; depth, 5 feet; side slopes, 14 to 1; grade, 0.0002, or 1 foot to 1 mile; computed discharge, 330 second-feet. The general course of the canal follows the line of the Alberta Railroad Company. The water is to supplement the irrigation system from St. Mary River above described, and will irrigate lands in the vicinity of Lethbridge, Alberta, Canada. To thoroughly settle the question of water diversion from St. Mary River and Milk River it will probably be necessary to come to some international agreement between this country and Canada. The main supply of the Canadian Northwestern Company is from St. Mary River. They, however, can only use the natural flow of the stream, as no storage facilities exist above the head of their canal in Canada. This country, however, has the advantage of storage in St. Mary Lakes by the construction of the St. Mary dam, in which the flood waters of this stream, can be conserved and afterwards utilized for irrigation purposes. An agreement might be reached that if the Canadian Government will allow to pass down without diversion the water turned into Milk River, the Canadian canal from St. Mary River will be furnished sufficient water by the reservoir on St. Mary River. WATER SUPPLY. A gaging station has been in operation on Milk River at Havre, since May, 1898. Other stations were established in 1901 and 1902 in St. Mary as well as in Milk River Basin, when the project under discussion was systematically taken up. The run-off data for the various stations have been published from year to year in the hydrographic reports, but they are again given in the tables below with considerable additional data. In a number of cases the winter discharge, when the rivers are low, has been estimated, and the figures have been entered in the tables in order that the total yearly run-off may approximately be known. |