Available Water (PAW) is an estimate of the total amount
of moisture (mm) that plants can access in the soil
profile (15-85cm). For each of the weather stations sites
the graph shows the amount of moisture in the soil profile
that is readily available to plants at any one time.
The PAW figure for each site is obtained by a combination of measurement (capacitance probe) and observation (watching the probe results over a full season to determine the amount of moisture a profile can hold). In practice this process has to be repeated and refined over a couple of years: in a dry year, the profile may never wet up; in a very wet year it may not dry out completely. But, the longer we continue, the better our estimate of PAW is.
The current PAW estimate for each weather station site is:
Flaxman Valley: 120mm