الفهرس | Only 14 pages are availabe for public view |
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 variation in water levels from 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 start irrigation 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 the end 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 the big area served led to operating two pump units with the total 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 actual applied 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 a small negative impact on soil and/or productivity. With the passage of time without good management to the field, the soil classification will be changed to 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 effective especially in the area of water shortage and the benefits for marwa improvements were very high comparing with masqa improvement. Increasing the cultivated rice area from 46 - 60% provides significant impacts on the field water conditions as well as yields of the other crops and rice itself. Then, the rice production area is to be controlled especially under water shortage conditions The variation in productivity of rice and summer crop was not high from different location in the canal. In the same time, it did not achieve the international productivity and this due to shortage of water, soil properties and economic factors such as seeds variety, fertilizer and harvest method. Finally, the study suggests the following: 1. The improving irrigation in areas which having water deficit problems and water scarcity areas will not achieve the goals and will have a negative impact. 2. The Marwa improvement at on- farm level has a positive impact on improving water applying efficiency and save water (such as social - economic view). 3. Reusing water will solve problems of water deficit problems. But it is necessary to put some policies to legalize the situation as official reuse to decrease negative impact on salt balance. |