INTEGRATED ASSESSMENT OF ON - FARM WATER MANAGEMENT UNDER IMPROVED IRRIGATION SYSTEM IN THE NILE DELTA OF EGYPT

Abstract

The study showed that the inflow of water into the canal was neither continuous nor based on the conventional rotational system. Meanwhile,it depends on both supply from the main canal and a connection with made even more uncertain by the fact that around half with variationin water levelsfrom 0.6 m at the head to around 1.3 m at the tail/end of the canal, which shows a major head-tail difference in water distribution and no equity in water distribution. Decreasing the pump discharge and shortage of water led to increasing the number of pumping events. It was noted that the percentage of events less than 30 minutes was about 37% of the total. This shows that around one time out of three farmers are successful in pumping water because of the too limited quantity of water available at the in front of the pump intake. Farmers prefer to startirrigation early in the morning for areas, which suffer from a shortage of water. This is because of the decreasing water pumping at night, which increases the water stored and level in the canal and as well as at theend of the day. Pump operations are not distributed well between different pump units at the studied pumps due to the water shortage especially for the pumps of thebig area served led to operating two pump units with thetotal discharge 83 l/s to cover the actual crop requirements of the big area served in the pump station. The value of water use index (WUI) was less than one, especially during the high water demand period in summer. This means a difference between the actual crop requirements and the actualapplied water in the two pumps, which mean the canal is suffering from a shortage of water and facing water problems leads to increasing un-official reuse of water. The salinity of used water in the study area varied from around 500 µs cm-1 at the head to 3000 µs cm-1 at the end of the canal and drains, shows quite high values that mean that crops irrigated at those specific times must have their yield affected by the high salt content. Although pump station were supposed to replace individual pumps (IP), but observed data analysis find an intensive use of individual pumps was very common (more than 200 IP) were used overall the area served on both canal and drains shows one major issue. Increasing unofficial reuse of drainage water will be able to solve the shortage of water and have asmallnegative impact on soil and/or productivity. With the passage of time without good management to the field, the soil classification will be changedto saline or alkaline soil. In addition, the high reuse of drain water will have a negative impact on the salt balance especially in the North Delta. The management of the pump stations and the distribution pipe systems were found to be quite an effectiveespecially in the area of water shortageand the benefits for marwaimprovements were very high comparing with masqa improvement. Increasing thecultivated rice area from 46 -