The temporal tendency of winter rain events in the Sugadairakogen Highlands was investigated using 33 years daily records of rainfall/snowfall discrimination at the Sugadaira Montane Research Center, University of Tsukuba, and the characteristics of atmospheric circulation in relation to the precipitation-phase changes were analyzed for 12 precipitation events by simple laser-type disdrometer observations with numerical weather simulations. The frequency of rainy days was 12 % from December to February, and 70 % of the rainy days were accompanied with traveling extratropical cyclones. A long-term increase of the snowfall frequency by extratropical cyclones was observed from November to April. The rainy days did not show a long-term trend. However, the large year-to-year variability of rainy days was significantly correlated with the index of the Pacific Decadal Oscillation. The year with an abrupt increase in the number of rainy days corresponded with the warm winter with less accumulated precipitation amount when the snow cover structure in high elevation areas is likely to be affected by the occurrence of rain. In the five rainfall-only cases and seven rainfall and snowfall cases identified in three winter seasons, rainfall dominant events were accompanied with broad warm-air mass expansion covering Honshu area with various courses of extratropical cyclones. On the other hand, rainfall with snowfall events were accompanied with a cyclone passing along the south coast of Japan or long-ranged cold front, and the precipitation phase changed mostly from rain to snow. In Sugadaira, southerly winds were suppressed before the phase change, and the air temperature stayed around 0 °C. A numerical simulation confirmed that weakening of the wind was due to the barrier effect behind the Echigo mountain range with prevailing east-west component winds by the traveling cyclone. A numerical model successfully simulated the rainfall-only events because the synoptic-scale circulation controlled the broad warm air migration. However, cases of a precipitation shift from rainfall to snowfall were not fully simulated. The causes of the discrepancies between the observation and simulation were discussed from the viewpoint of the low-level air-mass exchanges in the large valleys running in the south-north direction and the occurrence of Foehn in the lee-sides of mountain ranges accompanied with a traveling cyclone.

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 Cost-benefit analysis is generally used for evaluation of social investments, but it is argued that the method for benefit evaluation demands further consideration. Regarding projects related to waterside environment development, cost-benefit analysis is problematic because projects usually involve environmental components for which it is difficult to evaluate the value in monetary terms. In addition, many conflicts among local government and residents have occurred along with waterside environment development projects. Residents' requirements for projects are usually so broad that a project valuation system incorporating a conflict management concept is necessary to achieve consensus.
 Therefore, this study first establishes a multi-criteria valuation system for waterside environments based on residents' impressions about rivers. Secondly, a conflict risk index is proposed to evaluate quantitatively, the diversity of people's sense of values. Thirdly, the methodology of works is explained with a case study of two regions in a river basin of Kamo River, Kyoto. The methodology is applied to questionnaire results for residents in the regions, and a priority of waterside environmental components to be developed is analyzed using multi-criteria analysis. The prioritized components are thought to be superior to others in terms of increasing people's use of the waterside areas as well as reducing conflict risks among residents in promoting the waterside development project.

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 Participatory irrigation management (PIM) has been promoted in developing countries to achieve higher efficiency and sustainability in irrigation projects, while some industrial countries in eastern Asia tend to have public water management systems.Korea particularly has strongly promoted public management since the 1980s. It eventually abolished farmers' irrigation organizations through the establishment of a public corporation (now the Korea Rural Community Corporation, KRC) in 2000, thereby introducing a comprehensive public water management system with no farmer membership fees. This study was conducted to analyze problems that have arisen from the use of this strong public water management system in a small and private farming system. This analysis is based on close observation of the behavior and activities of farmers and KRC staff together with a questionnaire administered to selected farmers. The study clarified that no agreement has been made related to the responsibility for farm ditch management, which has engendered several problems: 1) the KRC has no capacity to solve water distribution disputes in the farm ditches; 2) farm ditches have been insufficiently maintained by the KRC and farmers; and 3) the farmers have little willingness to solve these problems, but expect the KRC to do so.

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