The Western Irrigation District's roots are firmly planted in the history of Alberta. The federal government agreed to grant arable land to the Canadian Pacific Railway in payment for the construction of a railroad joining Canada from coast to coast. Included in this grant was land previously described as fit for homestead only if an irrigation system could be supplied. With the mountains in the background and the vast prairies to the east, the slope of the ground was ideal to construct a gravity irrigation system.
In order to attract settlers to the area, the CPR began construction of a network of irrigation canals and reservoirs starting with a diversion weir across the Bow River in Calgary in 1904. With the construction of Main Canal, water was carried from the Bow River into Reservoir #1 (Chestermere Lake) and in 1905 it was filled for the first time. By 1910 secondary canal systems were constructed and settlers had already received delivery of irrigation waters.
Following the collapse of the economy in 1929, the CPR planned to divest itself of the two irrigation districts which had been developed. On May 1, 1935, the Eastern Irrigation District (EID) was formed. Originally the CPR had planned on closing the western section but after two years of meetings between the farmers and the CPR, the Western Irrigation District (WID) was born on May 1, 1944.