Challenges To Efficient And Effective Irrigation Water Management In Ghana – The Case Of Bontanga Irrigation Project

Abstract

Irrigation projects in Ghana have suffered from poor water management practices and this has been so because over the years irrigation system operation has been limited to construction of new projects and sometimes rehabilitation of existing ones. Post construction management of irrigation projects has not received the needed attention because adequate provisions in terms of manpower and resources are not made available to make that possible. There are always water flow measuring structures installed in irrigation projects but they are hardly used due to the sophisticated nature of measuring the flow of water using such structures. Water flow measuring devices installed on irrigation projects in Ghana are weirs and flumes. Calibrating such water flow devices will ensure the effective and efficient water management practices on those irrigation projects because the right quantities of water will be delivered to the fields from the water reservoirs. This research undertook a process of calibrating the two flumes on both the right bank and left bank canals of the Bontanga Irrigation Projects to ensure that the water levels in the canals can easily be converted into volumetric flow to allow for the water bailiffs to gauge the quantity of water being released into the canals. The relationship between the water level (h) in the canal and the discharge (Q) for the right bank flume was determined as Q = 4.425 h and that of the left bank canal was determined as Q = 4.066 h. The research also measured the average runoff and sediment deposition into the Bontanga Irrigation reservoir. As a function of rainfall (P) the runoff (R) in the catchment was established as R = 0.16P and the annual sediment deposition around the right bank intake was 6.60cm whilst that around the left bank intake was 6.35cm. It is recommended that effective and efficient water management practices must be stepped up on the Bontanga Irrigation project if the country wants to derive the needed benefits from the project.