An investigation on marza diversion head-work is carried out for this research work and attempt is made to understand the failure problems encountered. This serve for different purposes such as for construction of new diversion structure (either as replacement for existing structures, or as an entirely new structure), rehabilitation of existing structures (from minor repairs to complete re-engineering either to maintain existing function, or to meet new requirements). Hydraulic and hydrologic failures of marza irrigation project were assessed by using primary and secondary data, from design document, other official documents and reports. Moreover, hydrologic failure was evaluated by Soil Conservation Service (SCS) method. An attempt was made to understand the design problems with respect to hydrologic, hydraulic and structural design aspects. The main constraints that contributed to the malfunctioning of the irrigation system in the schemes associated with planning, social, operational and economic parameters were also assessed. Absence of maintenance and operation of the scheme were observed in Marza head work evaluation and monitoring issues. This investigation shows that the main cause of marza weir failure is due to the weak foundation condition of the weir and underestimation of design discharge and the absence of necessary operational and maintenance of the scheme. Finally, the rehabilitation (remedial) design for the weir is recommended.