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.

View full abstract

Monitoring networks are designed based on a developed methodology linked contaminant transport simulations and optimization models. Advection and dispersion simulation generates plume realizations while the use of Latin Hypercube Sampling, one of the Monte Carlo techniques, accounts for uncertainty in transport parameters and in contaminant source characteristics. Optimization model using Genetic Algorithm provides a given number of wells in order to maximize the detection probability. Application of the method to a two-dimensional hypothetical domain with steady state flow illustrates the utilization of the developed method and provides monitoring networks with sufficiently high accuracy under the condition with or without preexisting wells as well as various flow magnitudes. Results reveal that designed well locations adequately cover the vacant area where plumes pass through, leading to increasing the detection probability. Results also show that wells are located relatively close to the source and the detectable limit and probability distribution affect on monitoring network design. In addition, the effect of the number of generated plume realizations on the network design is investigated.

View full abstract