Efficient Sand Integration

How Much Water?

Evaporation

Long-term average evaporation

If access to actual daily evaporation is not available then using long-term average daily evaporation figures can provide a useful guide for scheduling irrigation. Long-term average daily evaporation (in millimetres) for west Gingin is shown below in Figure 2.

When scheduling using long-term average evaporation, adjustments can be made for variations in weather as shown in Table 1.

Table 1: Longterm evaporation (mm/day) for Medina Research Station, Western Australia
Month Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec
Daily Evaporation Avg. 8.8 8.8 6.8 4 2.6 2 1.9 2.3 3.3 4.8 6.6 8.4
Cooler less Windy days 6 4 3 2 1 1 1 1 2 3 4 5
Hotter more windy days 11 10 9 6 5 3 3 4 6 7 10 11

 

Estimated Daily Pan Evaporation
Figure 2. Estimated daily pan evaporation (Epan) at West Gingin, WA

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