Observation of the irrigation practices used on dairy farms indicates that many of the irrigation schemes are used inefficiently. As such it is generally accepted that many of the regions irrigated pastures are producing well below their potential thus leading to the inefficient use of scarce water resources and increasing the already high cost of irrigated pasture. Further, since the commencement of this project changes to the regulation of and supply of irrigation water such as stream flow management plans and ground water supply protection areas have reduced the quantities of water available for irrigation in the region.

The principal objectives were to determine the optimum start-up times and subsequent irrigation schedules by means of practical, farmer useable methods; quantifying the losses from sub-optimal irrigation practices and to assess the performance and suitability of commercial irrigation schemes currently in use in the region.



WestVic Dairy Irrigation Scenario Decision Assistance Model (WISDAM) was developed to assist dairy farmers in southwest Victoria when making decisions regarding investment into irrigation.

WISDAM is a discounted cash flow model used to assess the financial viability of various irrigation scenarios on a dairy farm.  A discounted cash flow model discounts the value of money to be received or spent in the future back to what it would be worth in current dollar terms. WISDAM models a period of twenty years, with year one being the year of initial investment.

WISDAM spreadsheet
WISDAM spreadsheet manual


Further Resources

SouthWest Victoria Irrigation guide
Using nitrogen to grow more pasture under irrigation