Regional Ecosystem Modeling and Assessment of Near-Natural Engineering for Irrigation and Drainage Canals and Irrigation Ponds

1.通过对Tedori河冲积扇及日本石川县北川周边地区灌排沟渠的研究表明，流速及水温、沉积物厚度等相关因素对沟渠内水生生物的多样性和分布有影响。然后，另一项关于小运河底栖动物的研究表明，底栖动物的物种丰富度与流速的多样性密切相关。研究结果表明，增加沟渠流速多样性和改善沟渠滴水结构的鱼道对维持灌渠生物多样性具有重要意义。讨论了滋贺县Minakuchi镇Higashiike的营养物质质量平衡。研究表明，入流中7.5%的氮和30%的磷在池塘中积累，70%的磷在池塘中被浮游植物固定。研究了在爱知县五河水渠底部每隔500米建造的鱼塘（0.5米深，20米长）的有效性。研究结果表明：(1)鱼塘为鱼类提供了栖息地，特别是在不进行灌溉的情况下；(2)小鱼不易从一个鱼塘迁移到另一个鱼塘；(3)在灌溉期间鱼塘流速不小。根据研究结果，建议在欧河排水渠的基础上增设鱼塘屏障和保护水生植物。在岐阜大学校园汉湖进行了浮游生物和水体化学性质的调查。在调查结果的基础上，利用元胞自动化建立了浮游生物种群迁移预测模型。该模型显示了用该方法预测浮游生物种群迁移的可能性。

1.The studies in the irrigation and drainage canals in the alluvial fan of the Tedori river and the area around the Khokugata, Ishikawa, Japan, suggested that flow velocities and relevant factors such as water temperatures and sediment thickness have an impact on the diversity and the distribution of aquatic creatures in the canals. Then, another study on benthic animals in small canals, suggested that the species richness of benthic animals correlate closely with the diversity of flow velocities. The studies revealed the importance of increasing the diversity of flow velocities in canals and improving fish-ways at drop structures, in order to maintain the biodiversity in irrigation and drainage canals.2.Mass balance of nutrients in the Higashiike, Minakuchi town, Shiga Prefecture, was discussed. The study suggested that 7.5% of nitrogen and 30% of phosphorus in inflow are accumulated in the pond and 70% of phosphorus accumulated in the pond is fixated by phytoplankton.3.Effectiveness of fish ponds (0.5m depth and 20m length) constructed at intervals of 500m, at the base of the Ohe Drainage Canal, Aichi Prefecture, was examined. The studies suggested that (i) the fish pool provides habitat for fishes particularly when irrigation was not being done, (ii)it is not easy for small fishes to migrate from one fish pond to another fish pond, and (iii) flow velocities in fish ponds are not small during the irrigation period According to the results, installation of fish-shelter-blocks and conservation of aquatic plants were proposed in addition for the Ohe Drainage Canal.4.The surveys on plankton and chemical properties of water were conducted in the Hangaike at the campus of Gifu University. Based on the survey results, the model for predicting the population movement of plankton was established by using cellular automation. The model showed the possibility for predicting the population movement of plankton by this method.