Whereas the irrigation water transmission open channel network in Egypt, is one of the largest and longest networks all over the world that dogged in permeable soil (about 33500 km in length). In a country that suffers greatly from an increasing shortage of limited available irrigation water quantities, ignoring the expected huge quantities of irrigation water losses through transport operations is a path of madness, to bridge the accelerated gap between what is required, and what is exist. Irrigation water conveyance losses include seepage, evaporation, and transpiration losses. Such losses are differentiated according to, type of soil, weather condition, and beneficiaries' traditions and behaviors. So, conducting field studies in various agricultural representative regions in Egypt, would be the most effective way for estimating the lost quantities of irrigation water all over the country through seepage, evaporation, and transportation basses. This way, decision-makers can use such acquired quantities for solving the problems of lack or non-arrival of irrigation water to the ends of some canals. In the present paper, the results of a field study carried out on one of the main irrigation canals in Assiut governorate in middle Egypt is introduced, as a case study represents the region of Middle Egypt area. The results of this field study in combination with similar studies conducted in various agricultural regions across Egypt, can provide the decision-makers with the needed documented data, on the basis of which, water resources can be managed at the state level in the way, that maximizes the return from the available limited water, for irrigation and contributes to solve some irrigation problems of the large deficit between the available and required of irrigation water. Almanna canal belongs to Abnoub Irrigation Engineering Administration in Assiut, was chosen to conduct the present field study as a representative open channel having specific properties from different technical points of view, soil type, weather condition, and the length with its off-taking canals. The used data in this research were collected from the field and through the official Ministry of water resources and irrigation authority in Assiut governorate. Results indicate that, the total loss of irrigation water from Almanna canal and its branches (79.90 Km length) reaches about 16.05 million cubic meters per month, which represent 23.90% of the actual discharges that give to the Almanna canal and its branches. The lost water through only seepage reaches about 15.95 million cubic meters per month, representing 99% of all lost irrigation water. While, the rate of increase in the evaporation losses at earthen sections more than the designed sections losses can be neglected. Thus, the lining of Almanna canal and its branches is the most effective solution for saving such a huge amount of water, and directed it to irrigate some newly reclaimed areas, in addition, to solve the problems of non-arrival of the irrigation water to the ends of some irrigation canals. At the same time, improving the environmental situation of the surrounding agricultural community.