Plan Water diverted from Clark Fork River is carried through a gravity distribution system which originates at Frenchtown Diversion Dam. The Frenchtown Diversion Dam, an earth and rockfill structure, is on a side channel of the Clark Fork River about 6 miles west of Missoula, Montana. The dam is 16 feet high, has a crest length of 489 feet, and contains 12,000 cubic yards of material. The Main Canal originates at the Frenchtown Diversion Dam and extends 17 miles along the northeast side of the Clark Fork River to a point near Huson. The canal has an initial capacity of 170 cubic feet per second.
Laterals distribute the water to the project lands.
The project has been operated and maintained by the Frenchtown Irrigation District since December 31, 1938. The lands of the project were settled in 1860 by French-Canadian immigrants. The farms were operated without irrigation and with varying degrees of success until the irrigation features of the project were completed. Although the Reclamation Service and a consulting engineer studied the irrigation possibilities in the valley as early as 1919, it was not until 1935 that a concerted effort was made by local farmers to develop an irrigation project. In 1935, the farmers organized the Frenchtown Irrigation District and petitioned the Bureau of Reclamation for assistance in developing irrigation.