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The groundwater recharge schemes accomplished in Pingtung Plain are Chi-Yang artificial lake, Chang-Lung ASR plan, Linbien River upstream artificial lake, and a series of River-Hydraulic-Weir for water source conservation. This study focuses on the benefit analysis between above schemes and present the construction of sub-weir across the riverbed at up stream.
From the analysis of the study, the effect of groundwater recharge by the construction of sub-weir at alluvial fan of Pingtung Plain is recommended. It is estimated that the invest 4,447 million $NT can result 407 million m3 of groundwater recharge per year, and the averge investment benefit is 0.0915 m3 of water per NT dollar. Besides, the investment cost of sub-weir construction across Ailiao Riverbed is 708 million $NT, it can obtain 85 million m3 of groundwater recharge per year and produce 0.12 m3 of water per NT dollar of investment benefit, 0.1 m3 of water per NT dollar for Laolung River, 0.06 m3 of water per NT dollar for Lili River, 0.05 m3 of water per NT dollar for Linpien River respectively.
Due to groundwater abstraction in Pingtung Plain increases dramatically, and public resistance also obstructs large-scale water resource exploitation schemes, the construction of sub-weir at upstream riverbed for groundwater recharge is an alternative scheme.
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