Abstract:
Wadla woreda is located in south western parts of north wollo zone at latitude of
11°36'35.03" N and longitude of 38°55'54.06"E. This study appraises the design practice
and failure of the river diversion structure for irrigation in the study area and identifying,
analyzing and categorizing of the main problems were focus points. This study
considered by selecting five existing river diversion structures in different Kebeles of the
woreda to understand the causes of the major failures of the structures by considering
different aspects such as pre- and post-construction, institutional aspects, planning
problems, social and operational problems and initial design documents. In order to
identify and characterized the existing irrigation schemes field observation and
measurements, group discussions, interview and questionaries’ were used to achieve the
objectives of this study and analyzed by SPSS statistical software. Arc-GIS 10.1 was
applied to delineate the watershed of the study area, pick discharge estimated by Soil
conservation system (SCS) and Auto CAD -2007 used for design purposes. The design
practice of the studied area is very poor. In these study areas most of the implemented
schemes are suffering from problems attributed to design, construction, and operation &
maintenance that lead to major failure of the structures. From the analysis the maximum
value of hydrology and sedimentation consideration, hydraulic design of weir and
structural design of weir problems showed that 31%, 49% and 20%, respectively. Based
on the questioner, interview and group discussion, results the maximum value indicates
absence of project idea of the community, water user association and lack of community
participation on construction are 100%, 96% and 100% respectively. Finally, failures
were due to the problems in the hydrologic, hydraulic and structural design of diversion
systems in addition to improper management of the schemes.
