@article{oai:repository.naro.go.jp:00002356,
 author = {廣瀬, 裕一 and HIROSE, Yuichi},
 journal = {農村工学研究所報告, Bulletin of the NARO, Rural Engineering},
 month = {Mar},
 note = {This study assesses the function and value of Irrigation Water Wheels (IWWs) in order to develop a scheme for sustainable utilization of IWWs. On the basis of field surveys and literature review, IWWs are thought to have two classes of functions. One is the intrinsic function, i.e. pumping of water, and the other is the “derived” function such as an object of sightseeing. Specifically, in 2011, 104 IWWs were used for irrigation purposes and 25 IWWs used for sightseeing and conservation purposes. The number of IWWs used in 2011 was 35％ compared to the early 1980s. Interviews revealed IWWs are more economical to use than pumps and can regulate irrigation water without using a diversion weir. Reasons to discontinue IWWs include abandonment of cultivation, changes in canal systems and reduction in the number of IWW carpenters. Classification of IWWs shows the average diameter of IWWs using irrigation, tourism and conservation is larger than IWWs using only irrigation. And beneficial paddy fields of IWWs using irrigation, tourism and conservation is smaller than IWWs using only irrigation. Conditions for continuation of IWWs for irrigation include diameters from 1.5 m to 2.5 m, beneficial paddy fields less than 0.2 ha and bed slope less than 0.2％. From an interview, the residents who participate in the conservation action of IWWs recognize that IWWs has regionality. The value of the intrinsic function is examined using hydraulic model experiment of IWWs, and found to be the utilization of small hydropower in irrigation canal and contribution to greenhouse gas reduction. Specifically, dimensions of model waterwheels are normally 2.0 m in diameter and 0.8 m in width and the tube has a total volume of approximately 17ℓ. We measured the pumping discharge and number of rotations with changes in the flow rate and water level for a waterwheel with a 1.0 m width waterwheel installed in an experimental channel. The following results were obtained. A) Outset of damming: Rise in the water level with installation of IWWs was generally less than 30 mm. B) Relationship between angle of the tube and the amount of pumping: Angle of the tube for the best performance was 35°～50°. C) Relationship between submerged depth and the amount of pumping: If the submerged depth of the plate was less than 200 mm, the amount of pumping was less than 250 mm. D) Relationship between pump rotation and the amount of pumping: The amount of pumping increased in proportion to pump rotation. However, if pump rotation exceeded or didn't reach certain values, the amount of pumping decreased. In this experiment, the amount of pumping decreased at 3 or less rpm and 8 or more rpm. E) Best performance for this experiment: If pump rotation was between 3 and 8 rpms, and the submerged depth of the plate more than 250 mm, the maximum pumping discharge was approximately 7.0 m3/h and maximum pumping efficiency was approximately 75％. F) Energy utilization characteristics: In this experiment, power of IWWs was almost 20W and energy-use efficiency approximately 30％. The value of using IWWs for pumping water as fundamental function is that small energy in open channel is utilizable and running cost can reduce. The value of the derived function is examined using interviews and questionnaires, and found to be the formation of regional identity and landscape, which is regarded ‘beautiful’ and ‘friendly’ by residents. Specifically, many residents evaluated IWWs as good. Factors of the determinants for these preferences differed depending on the attributes of the evaluators. The key determinant for the preferences of both farmers and non-farmers was ‘regionality’. Farmers focus on convenience to determine preference for IWWs and IWWs are adopted based on regionality and history. Non-farmers focus on ‘affinity’ and ‘beauty’ to determine preference for IWWs. However, non-farmers with a birthplace near the IWWs focus on affinity, which is strongly affected by regionality, when they determine preferences for IWWs. Non-farmers with a remote birthplace focus on beauty that is strongly affected by landscape formation to determine preferences for IWWs. Therefore, the functions of landscape and regionality are the “derived” functions of IWWs. These functions show that IWWs are valuable so residents evaluate IWWs as beautiful and familiar. Derived function which has an effect on motivations to participate in IWW conservation is regionality. Therefore, function of regionality is relatively important. There is some value in use of IWWs. One is that IWWs can use small energy in open channel and reduce running cost. Another is that residents perceive IWWs as beautiful and familiar when the “derived” functions which are the functions of landscape and regionality are also apparent.},
 pages = {1--61},
 title = {灌漑用揚水水車の機能と価値の評価に関する研究},
 volume = {53},
 year = {2014},
 yomi = {ヒロセ, ユウイチ}
}