Irrigation canals network in Egypt for all levels suffer from water deficit and un-equitable distribution of irrigation water among beneficiaries. So, its modernization became omnipresent to overcome the problem of water shortage by the end of canals. One of the improvement sectors of irrigation canals network is replacing an earthen mesqa by upraised lines or buried pipes. The hydraulic performance of the improved irrigation system is explored using a case study canal, where buried pipes system is applied as improved mesqa system. The case study is for the Hadaya canal which is one of the distributary canals that located in Assiut governorate. This canal services 19 mesqas with different lengths and area served. The hydraulic performance of mesqas is examined through different scenarios of operation of the mesqa pumping station and area served. Three scenarios of mesqa valves operation are considered .The first scenario is when all valves are operated at the same time all over the week. The second is when one valve operates for two days per week and the third is when all valves operate for one day. Also, three scenarios are considered for pump operation 14, 16 and 18 hours per day. Moreover, effect of different scenarios of mesqa operation on sudden transition of flow in pipes due to pump shut-down is studied. EPANET software was used for the hydraulic analysis. It was found that operating the pump 14 hours per day fulfill the minimum monthly cost. Also, operating the outlet valves according to scenario no. (3) gives the least operating cost. The maximum velocity in the pipeline is less than 1.2 m/s for all operating scenarios. Besides, effects of mesqas off-takes on the flow in distributary canal are studied.