WATER LOSS

(1) The sum of water lost from a given land area during a specified time period by transpiration, evaporation, and interception. (2) In irrigation, seepage and evaporation from land and ditches; excess water drained from the land surfaces and the deep percolation. The basic concept is that water loss is equal to Evapotranspiration, that is, water that returns to the atmosphere and thus is no longer available for use. However, the term is also applied to differences between measured inflow and outflow even where part of the difference may be Seepage.