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A nature restoration project has been conducted in the Oku River in the northem part of Okinawa Main Island. The purpose of this project is to restore the habitat of Ryukyu-ayu，which is extinct in the wild in Okinawa Main Island. The removal of drop structure and the restoration of pool by withdrawing the river bank were conducted to prevent the water leak as subsoil water and revive the structure of riffle and pool. The restoration for fish habitat was indicated by the results of investigation on fish and riverbed forms. These river improvements were evaluated in terms ofbed deformation using numerical simulation. The results of numerical simulation indicate that the removal of drop structure induces the change of the longitudinal profile into original one，and the restored pool maintains the function as a pool over the next ten years., 論文

Dialogues with community constituents are indispensable for scientists whose research fields and applications are closely related with communities throughout the research processes of consensus building on executions of research projects, making decisions on research policies, sharing the products of the projects, corrections. What kind of guidance is required for scientists to maintain a dialogue with the society? Using mailing list and web portfolio, we recorded a process of planning and executing a science cafe with two researchers who research for reintroduction of Crested Ibis (Toki) into Sado Island. Additionally, to understand the reality of the research, we observed the field research by the scientists in Sado Island. This record and analysis about difficulty and the solution of the science cafe serves scientists as a effectively guidance.

金沢大学理工研究域機械工学系, 渡良瀬遊水地内に設置した1系列当たり面積50m2の実験施設を用いて, 表面流方式, 浸透流方式 (ろ材: レキ) 及び浸透流方式 (ろ材: 人工メディア) の3種類の湿地浄化法を比較した. その結果, 浸透流方式の2系列は, 表面流方式の1/3～1/10の面積で同等の浄化効果を有することが明らかとなった. ただし, 2系列の浸透流方式においてろ材による浄化効果の差はあまり無かった. 浸透流方式は特に夏期の窒素除去が優れており, 水温が15℃以上, 溶存酸素が3mg・1-1以下の条件下で硝酸対窒素の除去率が66～77%であった. この硝酸対窒素の除去は脱窒によると推察された., Compact wetland was developed using subsurface flow (SF) and more porous artificial filling. This paper mentions comparison of three experimental wetlands, which are a free-water-surface wetland (FWS), SF wetland with gravel filling and SF wetland with artificial filling. Each wetland has an area of 50m2. Two kinds of SF wetlands purify water better than FWS wetland, however there is not obvious difference between two kinds of SF wetlands with gravel and artificial fillings. Two SF wetlands are able to remove nitrate nitrogen efficiently with a removal ratio of 66 to 77 percentage under the condition of water temperature is less 15 degree Celsius and dissolved oxygen is less than 3mg/l.

The aim of this study is to examine the cooling functions of the water area at tidal flats and in mangroves, which act as a nursery for Ryukyu0ayu (Plecoglossu altivelis ryukyuensis). Ryukyu-ayu is one of the cold water sphere fishes inhabiting a subtropical region, Amami-oshima Island. These fishes are now endangered. During juvenile stages, they live in the estuary or the nearshore zone. However, developments at the river mouth and coast may have caused an increase in the water temperature of their habitats, which could be one of the main reasons for the recent decrease in their population. To investigate the effect of the development on thermal environments，we compared the water temperature of a natural tidal flat with that of an artificial area. Multipoint observations of the water temperature were conducted using 60 recordable compact thermometers so as to examine the fluctuation and distribution of the water temperature. The result showed that the average temperature of the seawater was 20.20C and that of the river was 13.70C. Further, the average temperature at the natural river mouth was usually less than 20oC. On the other hand, the water temperature hardly reached below 20oC，which is the critical temperature for juvenile Ryukyu-ayu, at the modified river mouth where as mall tidal flat remained without mangroves. We speculated that the mixing of seawater and river water was promoted by the existence of tidal flats and mangroves. In addition，shallow areas provided by tidal f1ats and the blocking of sunlight by mangroves were believed to be important for maintaining the optimum environment for Ryukyu-ayu.