Abstract
Rice, a major crop in Myanmar, is traditionally grown with monsoon rains. For a rising demand of a growing population, double crop cultivation of rice and other crops has been introduced in lower Myanmar. Second crop cultivation is not profitable due to water constraints in pre-monsoon season. Ngamoeyeik irrigation project was implemented to supply irrigation water for second cropping in the pre-monsoon season. Since it was a newly established irrigation system in a traditionally rain fed cultivation area, the concrete rules of irrigation operation and management have not been well developed. This study aims to improve water management practices in lower Myanmar focusing on three water management levels: reservoir system, canal system, and terminal system. In this paper, we analyze the rainfall, inflow, and storage release of the reservoir system, the water supply and distribution of the canal system, and estimate the reference crop evapo-transpiration, ET_0, for on-farm water requirements of the terminal system. Our results show that full storage could be caught even in drought year. Potential rainwater can be harvested in the upstream catchment of the existing reservoir. We propose a typical irrigation release pattern for an effective storage use. The estimated reference ET_0 is near to observed pan evaporation data. The pan evaporation data can be used for an estimation of reference ET_0 for other irrigation systems in the lower Myanmar where complete meteorological data are not available.
