Annual Crop Water Demand

Tables A & B

Table A provides the annual irrigation water demand for current crop and irrigation systems for the year 2003 using average irrigation management, and Table B provides the same data for 1997.




The outdoor irrigated acreage in the ALR for RDN is 1,018 hectares (ha). The total annual irrigation demand for this area was 6,917,243 m3 in 2003 (a dry year), and dropped to 3,106,927 m3 in 1997 (a wet year).

Of interest is that during a wet year like 1997, the demand was only 45% of a hot dry year like 2003.

Another point to consider is that the actual water demand supplied by an irrigation system may be less than the numbers shown above. The reason is that the Model does not have an adjustment for water supplied to the crop by high water tables. In coastal regions, agriculture is often located in areas which have predominantly high water tables due to the climate.

The high water tables will reduce irrigation demand that is not accounted for in the model outputs. The numbers should therefore be considered the highest estimate demand.

In addition, the Model also calculates demand based on relatively good practices. As such, actual use may actually be higher or lower than what is calculated by the Model.

The predominant irrigated agriculture crop in RDN is forage.

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Model Results

The Model can use three different irrigation management factors: good, average and poor. Unless otherwise noted, ‘average’ management was used in the tables. Learn more about the Model.