Evaluation of Hydrologic Data for Irrigation System Design: A Case Study

Abstract

The scope and the efficient operation of an irrigation system, depends on systematic collection, collation, and analysis of the hydrological/meteorological data of the project area. Relying on existing rainfall records, the peak rainfall, mean rainfall, rainfall frequency and effective monthly rainfall were established. Atayi stream discharge characteristic curve was used to determine the stream stage-discharge relationship while the instantaneous rate of discharge of the stream was determined using float. The generated data were plotted on hydrographs to obtain 2.64m³/s.  The high-level volume discharge and the low-level flow per annum were found to be 29.08m³ and 18.33m³ respectively. For the crop evapotranspiration, the Penman open water evaporation was deployed using climatic data for Igwu scheme as collected by Umudike Research Institute, Umuahia to obtain 1871 mm per annum compared to 2200mm by Piche or Pan evaporation. The site hydrologic data collected and analyzed supports the adequacy of basic hydrologic factors for irrigated paddy rice cultivation in the study area.