الفهرس 
LITERATURE REVIEWOnly 14 pages are availabe for public view
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Abstract
Sustainable water resources management has become more urgent in areas
where water supplies are limited and where mismanagement has caused a
water scarcity situation and/or water quality degradation. Seepage from
unlined canals, high intensity of irrigated agriculture regardless of soil and subsoil conditions and deep percolation losses are the most obvious examples for this mismanagement. In Egypt uncertain scenarios related to climate change like decreasing rainfall volumes and number of rainy days and increasing in temperature are forecast and have been already observed. For this reason sustainable water resources management technique is becoming increasingly urgent with the goal of controlling mismanagement that may lead to a water scarcity situation. One possible strategy to improve water use in agriculture is using controlled drainage to control ground water fluctuation. Controlled drainage is the practice of using a water control structure in a main, sub main, or lateral drain to vary the depth of the drainage outlet to conserve water by reducing drainage outflow. The current study was conducted in Tina plain in the north-western Mediterranean coast of Sinai, Egypt, with a general objective of evaluating the long and sustainable beneficial effects of controlled drainage. Specific
objectives were to estimate soil salinity and crop productivity under
different irrigation water salinities and modified drainage system design for a continuous period of time using the water management model DRAINMOD. DRAINMOD is a computer simulation model developed by Dr.Wayne Skaggs at the Department of Biological & Agricultural Engineering, North Carolina State University, Raleigh, NC in 1980. The model latest version DRAINMOD 6.0 was field-tested using weather, soil and hydrology data from experimental plots, planted with winter wheat and summer corn crop rotation and managed using controlled drainage. Based on the results of the study it is concluded that DRAINMOD 6.0 can be used for long-term simulation and planning of water table management under the semi-arid conditions of Tina plain of Sinai. The results of the field study and the simulation outputs indicate: 1- Controlled drainage should be used with caution if the irrigation
water contains high salt content.
2- Controlled drainage is a very promising strategy to grow crops with
high salt tolerance in Egypt especially in regions suffers from lake of irrigation water.
3- Salt management in the shallow soil profile should be considered if
using controlled drainage concept (monitoring is a vital need).
4- Controlled drainage could be used to conserve water (needs less
irrigation amounts and takes advantage of rainfall events).
5- For sensitive crops like corn results demonstrated that drainage
improvements are a long-term investment and may not provide yield
benefit in every year.