| dc.description.abstract | The uncertainty of water resources system is getting worse due to climate change impact, which enhance the importance of water resources planning and management on regional and global scale. Agricultural water account for 70% of nation’s water usage, which can be managed more precisely and efficiently. In this study, a system dynamic model was used to establish a unique agricultural irrigation method called pond irrigation system in irrigated area of Taoyuan. It’s function was not only to assist the irrigation water supply, but also used for water storage during rainfall. No.10 Sub Canal of Taoyuan main canal is the major irrigation water supply. The system dynamic model was simulated for 1st and 2nd crop season of paddy rice in 2017. Canal water and precipitation was the major irrigation supply while pond irrigation was considered as secondary supply. The main objective was the analysis of pond irrigation system under various operating scenarios. The rainfall for 1st and 2nd crop season of 2017 have the characteristics of high and low, respectively. Therefore, both seasons were simulated separately. Based on agricultural water transfer, the 1st crop season estimated that the proportion of canal water supply can be reduced without affecting the growth of crops in the field while, the 2nd crop season, based on the low rainfall, simulated the water shortage of irrigation area under extreme weather conditions.
According to the simulation results, it was observed that at normal pond supply, it can effectively alleviate the shortage of water in the irrigation area. It also operates at its best operating capacity under normal condition in comparison to partial operation. In partial operation, pond has more overflow due to restricted pond water supply. The 1st crop season simulation result shows that the reduction of canal water supply up to 60% without affecting the farming area under normal operation, while during partial operation there is no reduction in channel water supply. In the 2nd crop season, no irrigation group can maintain normal farming without farming area reduction. It was analyzed that when 80% farming area is reduced, the pond operation can maintain the crop period water supply normally. The regression analysis indicated strong correlation between Pond Benefit Depth (PBD) and the number of days to wilting point (D) as shown in regression equation D=75.94PBD+22.
Keywords: Taoyuan Main Canal, Pond irrigation system, Vensim model, Paddy field
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