The purpose of this task report is to present the methodology for determining practicably irrigable acreage (PIA) for the San Juan Watershed. The test for PIA requires that the revenues exceed the cost. The land under consideration when cropped and irrigated must return sufficient net positive income to pay for the costs of providing irrigation water to the farm headgate In order to determine PIA it is necessary to conceptually design an irrigation transmission system to deliver water to the farm headgate for each arable parcel. The annualized cost of the off farm irrigation water transmission system is compared to the net positive income payment capacity of the parcel.