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全国規模の長期温暖化現象と尾瀬に比較的近い観測所の観測結果を比較した．第4次尾瀬総合学術調査で重点的に調べられた湿原の洪水現象の調査結果を元に，近隣の観測所の降雨量データと比較した．湿原における河川氾濫は従来考えられていたよりも少ない降水量，すなわち日降水量が50mmを超えると発生する可能性があり，その頻度が近年増加していた．, Long-term global warming phenomena were compared between nation-wide survey and the data recorded at local meteorological offices closer to the Oze area. Based on the flooding events studied intensively during the 4th Scientific Research of the Ozegahara mire, relationships between water level changes and the precipitations observed at the nearby meteorological stations were examined. The flooding in the mire took place at precipitations lower than the reported value for causing inundation. Precipitation events more than ca. 50 mm per day have been increasing in frequency, probably causing flood in the mire.

尾瀬ヶ原と尾瀬沼における赤雪（アカシボ）の分布を航空写真の解析から明らかにした. 2000年5月25日時点での積雪はアカシボの生じる見本園中央部で30cm, 周辺で100cmであった. 積雪底のpHは5～7であり中央部で中性に近かったが, 積雪コアの融解水のpHは何処も5付近であった. SSは最大で200g m-2, アカシボSSの量子収率は著しく低く, 藻類はアカシボ初期には少ないと思われる. アカシボにはDOCも多い傾向にあり最大で400mgC m-2であった. 同じくNaイオン（600mg m-2）もアカシボ発生付近で高くなっていた. 雪の酸素同位体比（δ18O）は周辺部分（－12‰）よりアカシボの中心で重くなっており（－10‰）, 周辺部の雪解け水が一度泥炭層に潜り込み, 間隙水・地下水が上昇してきたと考えられる. 本研究の現地調査と分析結果から積雪１m程度になると湿原周囲の雪解け水が地下からわき上がり, 細かく分解された泥炭の一部や鉄が一時的に噴出して広がり酸化され, その後日射で周囲より早く解け窪地ができるものと思われる. その後, 藻類や底生生物の増殖・集合を伴いながら雪が解けて行くものと思われる.

In the nature restoration project, it is important to decide the aimed environment. Therefore, it is necessary for develop the multi-temporal database. The topographic maps are useful information in the development of the multi-temporal database, because they have been maintained for a long term. In this study, we estimated the wetland area using multi-temporal topographic maps in Kushiro Wetland and Sarobetsu Mire and evaluated the change of wetland area. Kushiro wetland decreased about 13,000 ha from 1920s. Sarobetsu mire decreased about 4,500 ha from 1920s. These results indicated that it is necessary in effective conservation and restoration planning to comprehend the long-term wetland change and the cause. Furthermore, we discussed the problems on the estimation of wetland area using topographic maps.

Behavior of the fine sediment around vegetation is still unknown because knowledge of complex flow around vegetation is limited. Moreover, only limited research has been done on flow resistance and fine sediment transport inof open channel flow wherewith vegetation that considers a growth type, which includinge emergent plants, submerged plants, and land plants, etc., has been considered are hardly researched. This study considered the growth type of vegetation and analyzed the flow of water with vegetation that considers a growth type of vegetation by using laboratory experiments that includeds various methods such as LDV and numerical simulations employing turbulence model. For emergent plants, it was found that the lateral momentum of transport reachedtakes a peak value at a certain vegetation density which wasis much larger than the density of the actual reed field, and the cause of this wascause related greatly to the shape of the horizontal vortex. WhenFor the case in which the ratio of a vegetation group's length to width wasis nearly 1:.7, the horizontal eddies were generated at the boundary of the vegetation group's region, and the momentum of transport reachedtakes a peak value. A numerical computation employing SDS&2DH turbulence models was introduced to investigate the resistance and the roles of the surface and submerged vegetation layers, and the effect of generated turbulence. Theseis models allowed us tocan predict the mean velocity of the surface and submerged vegetation layers, and provided information on the shapes of vortices, lateral distributions of the depth averaged flow velocity, and turbulence statistics. A phenomenon involving wavy motion of very flexible submerged vegetation (termed honami) was observed, and the displacement of the plants was found to be closely associated with the structure of the turbulent flow, which yieldeds a larger Reynolds stress near the top of the vegetation layer. Finally these experiments and simulations applyied to the development of methods for catching fine sediment method for the wetland conservation.