Irrigation Improvement System plays an important role in optimizing the use of the available water quantity from the River Nile; this will be achieved by saving some quantities of water which are lost in seepage from the water streams, evaporation from the surfaces of the open water streams and farmers' bad use of water. The major part of the Improvement System is the replacement of the existing earthen Mesqas with raised and lined Mesqas or buried pipeline Mesqas. These kinds of Mesqas are intended to eliminate the seepage of water through their cross sections; the end of these Mesqas is closed to prevent water losses to drains. Also, the area of the open water surfaces of the improved Mesqas will be less than the area of the open water surfaces of the earthen Mesqas. So, the amount of evaporation from the open water surfaces will reduce. In Beni Adi el Bahariya Village (the study area) in Assiut Governorate, according to the Irrigation Improvement Management (IIM) in Assiut Governorate, June 1999 (end of the feasibility study in the study area), the area of the open water surfaces of the earthen Mesqas has been estimated to be about 19840 square meters. After finishing the improvement process; this area was reduced to be about 6250 square meters. So, the reduction in the amount of evaporation in Beni Adi el Bahariya Village (the study area) due to the Irrigation Improvement System is about 69 % of that was before improvement. The improved Mesqas are intended to eliminate the seepage of water through their cross sections, so; the amounts of water that are lost by seepage from the earthen Mesqas which are about 270000 m3 annually are saved after the improvement. In addition to the benefit of the Irrigation Improvement System in saving some quantities of water which led to increase the inflow discharge to the study area, there are other benefits (according to Monitoring and Evaluation Reports of IIM in Assiut Governorate, 2009). These benefits are land saving: where, there is about 3 % of the total area served by Mesqas which is about 1 % of the total command area saved and made available for agriculture and roads. Also, irrigation time reduced by 50 % to 60 % of that was before improvement process which made water available all the time in the Mesqas with the adequate quantities, the cost of pumping reduced by 64 % which was a result of a single point lifting on the Mesqa and The increase in crop yields (according to agricultural association in Beni Adi el Bahariya village, 2009) due to the better conditions of water availability, Increase in wheat, cotton and maize were estimated at 10 %, 18 % and 9 %, respectively. Irrigation Improvement System couldn't achieve increasing of on-farm efficiency because of farmers' bad use of water, where; they used to irrigate by high flow rates which lead to increase leakage from the farm land. Therefore, Field design and irrigation management practices have a significant impact on surface irrigation performance. Reductions in management variables such as irrigation time and design flow rate of the system can lead to improvements in irrigation efficiencies and water saving.