2014 年 70 巻 4 号 p. I_283-I_288
This paper first focused on the influence of the Water User Association through a case study of the Aichi Irrigation Scheme using field surveys and census data for Aichi prefecture. In the authors' opinion, the most serious influence is now appearing as the start-up condition of an irrigation project based on an agreement of more than 66% of cultivators as representative condition based on Land Improvement Act. The representative condition assumes that the percentage of agreed cultivators is nearly equal to that of the farmland area. The expansion of large cultivators negated the assumption. The percentage of agreed area estimated by percentage of agreed cultivators is called the EI (Equality Index). The authors developed the Lorenz curve of cultivated area of Aichi prefecture. By using this, EI of area is 0.38 in 1960 and 0.2 in 2010. In 2010, the value shows conflict of agreement of cultivators and that of area.
