RESEARCH ADVANCES IN IRRIGATION METHODS FOR EFFICIENT WATER APPLICATION: SOUTH AFRICA - Management, Performance, and Applications of Micro Irrigation Systems - page 49

irrigation water-use situations or scenarios in order to expose underlying issues that
can be addressed to improve water management, rather than simply using the calcula-
tion of input-output ratios as done in the past.

FIGURE 1 ICID water-balance framework for irrigation water management [9].

The basis of the framework is that any water withdrawn from a catchment for
irrigation use contributes either to storage change, to the consumed fraction, or to
the nonconsumed fraction at a point downstream of the point of abstraction. The wa-
ter that is consumed will either be to the benefi t of the intended purpose (benefi cial
consumption) or not (nonbenefi cial consumption). Water that is not consumed but
remains in the system will either be recoverable (for reuse) or nonrecoverable (lost to
further use).
In order to improve water availability in a catchment, the relevant authority needs
to focus its attention on reducing nonbenefi cial consumption and nonrecoverable frac-
tions; the activities undertaken to achieve this result can be called best management
practices. The ICID water-balance framework, based on Perry's model [9], is shown
schematically in Fig. 1.