The comparison between different methods for estimating consumptive use of water in Iraq

الملخص EN

There are many empirical methods which has been used in determining consumptive use of plants.

The present study deals with using of three of these methods namely Blaney-Criddle, Thorenthwet, and Penmans.

These methods are used to calculate consumptive use in Karbala city for twelve months for period from 1980 to 1999.

The results of comparison showed that these methods give different results of consumptive use.

The maximum values of consumptive use are (341.4, 173.4, 225.3) mm / month based on Blaney- Criddle, Thorenthwet, and Penmans methods respectively while these methods give minimum values of consumptive use of (49.5, 38.7, 155.40) mm / month respectively.

It is worthy to note that the main aim of this paper is to show the expected variations of values of consumptive use estimated by these three methods rather than studying the consumptive use values of others Iraqis governorates.

It is recommended to use Blaney-Criddle method to calculate consumptive use in Iraq because it easy to apply and it provides seasonal and monthly estimates of actual consumptive use in terms of two main climatic parameters these are temperature and the number of sun shining hours.