One million acres of irrigated land is located in Area 3. 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. There is no aquifer under Area 3, so there are no percolation flows in this area. Around 20% of the diverted water is lost through evaporation and transpiration (E&T losses). The remaining 80% returns to the Idagon via surface runoff. These flows may be checked by opening the "Water Use in Area 3" report. The efficiency of irrigation in Area 3 may be controlled in advanced versions of the model.

The Lake Idagon reservoir will be operated to meet 100% of the needs in Area 3. This simple policy is based on the observation that there is usually more than enough water to serve the needs of Area 3. But to check whether this policy is feasible in your experiments with the model , you should open the graph "Fullness_of_Eastern_Reservoirs" to learn if there is enough water to refill Lake Idagon each year.