The allotment system provides landowners with a seasonal volume of water for irrigation. The allotment is set annually by the trustees and is expressed as a volume of water for each acre of water rights on a parcel of land. Typically, during normal supply years the allotment per acre of water rights will be the same as the drought year water requirement of the district (the drought year water requirement is the estimated water demand of the district during very dry conditions).
The drought year requirement of the district is equal to 2.25 acre feet of water per acre of irrigated land. How much water is that? It is equal to one acre of land with 2.25 feet (27 inches) of water on it. This is equal to 733,162 U.S. gallons (USG), or 2,775 m3 per acre of irrigated area.
The total allotment for each property is calculated from the water rights of that property. For example, if a parcel of land has five acres of water rights and the annual allotment is set at 733,162 USG per acre of water rights, then the allotment for the property would be 3,665,810 USG (5 acres X 733,162 USG = 3,665,810 USG).
The annual allotment for each irrigation season is determined in the spring prior to the irrigation season and all landowners with metered irrigated services are notified by mail of the annual allotment for their property. The board has full discretion as to the amount of the allotment, although in average supply years the allotment will generally be the drought year requirement described above. In low supply years the allotment may be less than the drought year requirement.