Regarding water loss due to ET in a CWs, information available
from literature is not always wholly reliable and, in some cases,
entirely lacking.
showed, for example,
that in HSSF system, ET is generally found to be on average
between 0 and 50mm/d, depending on the species, whilst found that it can reach up to 200mm/d
in very hot periods. As ET is a physical process, it tends to vary
through out the course of the day, with maximum values in early
afternoon and minimum values during the night