李 相潤，石井 敦，申 文浩，谷口智之，佐藤政良, 韓国近代以前における河川灌漑田の利水安全度, 農業農村工学会論文集, 85(1), 105-115, 2017.
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https://www.jstage.jst.go.jp/article/jsidre/85/1/85_I_105/_article/-char/ja/
韓国を対象に, 近代前期における主要河川流域の河川灌漑田の利水安全度を求め, 日本と比較してその開発過程の特性を考察した．河川灌漑田の利水安全度は, 主要河川の生起確率ごとの夏期渇水時流量によって灌漑可能な水田面積を算定し, これと文献資料より得た実際の韓国近代前期の河川灌漑田面積とを比較して求めた．結果として以下が明らかになった．1）韓国の主要河川の夏期渇水時比流量は日本と比べ極めて小さい, 2）漢江を除き水不足の年発生確率が40～90 %で利水安全度が低く, 近代前期で夏期渇水時流量をほぼ使いきって灌漑田が開発されていた, 3）漢江の利水安全度が高いのは, 治水等の問題で開発できる水田が限られたためと推察された, 4）利水安全度が低い灌漑田と天水田が多かった背景要因として, コメ需要に対する安定的な夏期渇水時流量の少なさが推察された．
キーワード: 韓国, 利水安全度, 渇水時流量, 日本統治時代, 河川灌漑, 水田開発
This study aimed to analyze safety levels of the water supply for irrigated rice paddy fields in the major river basins of Korea in the early modern era, and discussed its process of development in comparison with that of Japan. The area of rice paddy fields that can be irrigated in a river basin was estimated based on drought low flow discharges at different occurrence probabilities, and the safety level of the water supply for rice paddy fields was evaluated based on those occurrence probabilities. The results were as follows: 1) summer low flow discharges of Korean rivers are much smaller than those of Japan; 2) safety levels of the water supply for irrigated rice paddy fields were rather low at 40-90 % a year of the water shortage probability, except for the Han River, which means that by the early modern era, Korea had developed rice paddy fields to use all summer low flow discharges; 3) the high safety level in the Han River basin is presumably attributed to the difficulty of paddy field development because of frequent flood damage; and 4) the fact that the total amount of stable summer discharge in the river basin is much less than the required amount of water to support the strong rice demand in the era is believed to be a background factor that contributed to the excessive expansion of irrigated paddy fields as well as rain-fed paddies.
Keywords: Korea, Safety level of river water supply, Low flow discharge during drought, Korea under Japanese rule, River irrigation, Development of rice paddy field