One million acres of irrigated land is located in Area 1. The land is irrigated by diverting flows from The Idagon. The irrigators grow a combination of alfalfa, wheat and potatoes. The sale of these crops brings gross revenues of over 500 $/yr per acre. The irrigators pay variable costs of just under 400 $/yr per acre, so the return per acre is somewhat over 100 $/year. (These results may be checked by opening the "Crop Income Report" if you are using an advanced version of the model.)

The diversion requirement depends on the efficiency of the delivery canals and the efficiency of irrigation in the fields. A typical requirement is 10 feet/year per acre, so the one million acres would require diversions of 10 MAF/year. Around 70% of the diverted water enters the aquifer through percolation, both as percolation from the delivery canals and percolation from the fields. About 20% of the diverted water is lost through evaporation and transpiration (E&T losses). The remaining 10% returns to the Idagon via surface runoff. These flows may be checked by opening the "Water Use in Area 1" report. The efficiency of irrigation in Area 1 may be controlled in advanced versions of the model.

The model assumes that the American Lake reservoir will be operated to meet as much of the irrigation needs as possible. But it may not be possible to meet 100% of the needs depending on the amount of land, the efficiency of irrigation and the minimum flow requirements at American Lake. The existing land in Area 1 is broken down into land with senior water rights and land with junior water rights. The land with junior water rights is first to be interrupted when it is not possible to irrigate all the land.

If you elect to expand the amount of land in Area 1, the new land will be irrigated with the same efficiencies as the existing land. And the new irrigators will face the same market conditions as the existing irrigators. But the water rights associated with the new land are junior to the rights of all the existing irrigators.