The vertical distribution of freshwater planarians in the Mt. Teshio district in the Kitami Mountains and in the Okhotsk seaboard district in North Hokkaido is reported. The highest peak, Mt. Teshio-dake (1557.6 metres above sea level), is situated at the southern corner of the Kitami Mountains (Lat. 43°57′N. and Long. 142°56′E.). The Okhotsk seaboard district is the flat-surfaced hilly land. The main river systems of the area surveyed are the Teshio, the Ishikari and the Shokotsu. The Shokotsu River discharges into the Okhotsk Sea ; the other two rivers empty into the Sea of Japan. Surveys were made in the summers of 1963,1964 and 1965. In the area surveyed, six species of freshwater planarians, Phagocata vivida (IJIMA et KABURAKI), Polycelis sapporo (IJIMA et KABURAKI), Polycelis akkeshi ICHIKAWA et KAWAKATSU, Polycelis auriculata IJIMA et KABURAKI, Polycelis schmidti (ZABUSOV) and Dendrocoelopsis lacteus ICHIKAWA et OKUGAWA, were found. Ph. vivida and Pol. auriculata were common in the localities in the Rubeshibe River, one of the tributaries of the upper part of the Ishikari River. Ph. vivida was also collected in some localities in the upper part of the Teshio River. Pol. auriculata was also collected in some localities in the upper parts of the Teshio River and the Shokotsu River. Pol. schmidti was collected in the cold-water streams in the upper parts of the Teshio River and the Shokotsu River and in some springs in the Okhotsk seaboard district. Pol. sapporo was most common in the localities of the seashore and mountainous districts. Pol. akkeshi was collected in some localities in the Mt. Teshio district. Pol. akkeshi was, however, the most dominant species in the Okhotsk seaboard district. Den. lacteus was collected only in the localities in the Okhotsk seaboard district. The altitude range of the distribution and inhabitable water temperature range of the above-mentioned species which were found in the Mt. Teshio and the Okhotsk seaboard districts are as follows : Ph. vivida (alt. 280-840 m, 6.3-12.5℃) ; Pol. sapporo (alt. 1-1000 m, 7.9-18.2℃ ; including the data of Pol. akkeshi) ; Pol. auriculata (alt. 280-1000 m, 6.3-12.5℃) ; Pol. schmidti (alt. 4-840 m, 4.8-11.8℃) ; Den. lacteus (alt. 1-90 m, 10.5-14.5℃). The type of vertical distribution in the area surveyed is SVA-VA (the Ishikari River) or S-SVAC (the Teshio River) or SC-SAC (the Shokotsu River and the Okhotsk seaboard districts).

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The vertical distribution of the freshwater planarians in the Teshio Mountains (the Uryu mountainous district) and its adjacent seaboard district on the Sea of Japan in central and North Hokkaido is reported. The Teshio Mountains are rather low mountains and the highest peak, Mt. Pissiri, is 1031.5 metres above sea level. The seaboard district on the Sea of Japan consists of two topographical units, one is the low land (the district between Wakkanai and Rumoi) and the other is the Mashike mountainous district (the main peak, Mt. Shokanbetsudake, is 1491 m high). The area surveyed is situated in Lat. 43°30′N. to 45°30′N. and Long. 141°20′E. to 142°30′E. The main river systems of the districts are the Ishikari, the Teshio and several short rivers (the Enbetsu, the Kotanbetsu, the Obirashibe and the Shokanbetsu). Surveys were made chiefly in the summers of 1962,1963,1964 and 1965. In the area surveyed, nine species of freshwater planarians, Dugesia japonica ICHIKAWA et KAWAKATSU, Phagocata vivida (IJIMA et KABURAKI), Phagocata iwamai ICHIKAWA et KAWAKATSU, Phagocata albata ICHIKAWA et KAWAKATSU, Polycelis sapporo (IJIMA et KABURAKI), Polycelis schmidti (ZABUSOV), Dendrocoelopsis lacteus ICHIDAWA et OKUGAWA, Dendrocoelopsis ezensis ICHIKAWA et OKUGAWA and Dendrocoelopsis sp. of Otoineppu, were found (including the data of Dr. KAWAKATSU). Pol. sapporo was found everywhere in the streams and springs both in the seashore district and the stations below the altitude of about 460 metres. Pol. schmidti was rather common in the cold-water localities in the Teshio Mountains and at Teshio-cho (alt. 15-740 m). Ph. vivida was collected only in the cold-water spring at On'nenai (the northernmost locality of this species). The other six species were found chiefly in the localities in the plain. The inhabitable water temperature range of the main species of freshwater planarians is as follows : Pol. sapporo (6.2-18.3℃) ; Pol. schmidti (7.0-10.2℃). The type of vertical distribution in the area surveyed is JSC-SC-C. The geographical distribution of Ph. vivida, Pol. auriculata and Pol. schmidti in Hokkaido is also described (modification of the deduction of the Dr. KAWAKATSU's 1965 article). 1. The northern limit of distribution of Ph. vivida : the Oshima Peninsula〜Sapporo〜Mt. Teshio〜the Shiretoko Peninsula. 2. The northern limit of distribution of Polycelis auriculata : the Oshima Peninsula〜Sapporo〜Mt. Teshio〜Kushiro. 3. The southern limit of distribution of Pol. schmidti : Mt. Pisshiri〜Mt. Teshio〜Akan〜the Shiretoko Peninsula.

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In the present paper, the vertical distribution of freshwater planarians in the Mt. Wenshiri district, the Kitami Mountains in North Hokkaido, is reported. The highest peak, Mt. Wenshiri, is 1142 metres above sea level (Lat. 44°13′N. and Long. 142°53′E.). The main river systems of the area surveyed are the Okunayoro, the Okoppe, the Mookoppe and the Shokotsu. The Okunayoro River, the upper part of the Teshio River, discharges into the Sea of Japan ; the other three rivers empty into the Okhotsk Sea (fig. 1). The surveys were made in August 1962 and August 1963. In the district, the four species of freshwater planarians, Polycelis sapporo (IJIMA et KABURAKI), Polycelis akkeshi ICHIKAWA et KAWAKATSU, Polycelis schmidti (ZABUSOV) and Dendrocoelopsis lacteus ICHIKAWA et OKUGAWA, were found. Pol. sapporo, the commonest numerous-eyed white flatworm in Hokkaido in North Japan, was distributed in the localities below the altitude of about 420 metres. It was common in rivers, creeks, brooks and brooklets. Pol. schmidti was, however, common in the cold-water streams and springs within the altitude range from 300 to 560 metres. The animal is the common dark colored Polycelis species in North Hokkaido and is the most stenothermic among the Japanese freshwater planarians (cf. Kawakatsu 1964,1965). Pol. akkeshi, another numerous-eyed white flatworm in Hokkaido, was collected in some localities near Oshorokko (Okoppe River System). Den. lacteus was only found in two localities at Nishiokoppe and Kamiokoppe (alt. 100〜140 m). The inhabitable water temperature range of the above-mentioned four species found in the Mt. Wenshiri district is as follows ; Pol. sapporo (8.0〜16.0℃ ; including the data of Pol. akkeshi) ; Pol. schmidti (7.0〜14.0℃) ; Den. lacteus (7.6〜11.7℃). Pol. sapporo and Pol. schmidti were found together where their inhabitable water temperature overlapped. The habitats of planarians are also described in detail. No planarian was found in any localities of the Sakuru Waste Land, an argillaceous zone along the upper part of the Shokotsu River (fig. 1,table 1). The type of vertical distribution of the district is S-SC-C (S : Pol. sapporo ; C : Pol. schmidti). The result of the present investigation shows that the planarian fauna and the type of vertical distribution in the Kitami Mountains differ from that of the Mt. Daisetsu district in Middle Hokkaido(cf. YAMADA 1962 ; YAMADA & TANJI 1962,1964).

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本研究は、冬期に降水量が十分に得られない流域においての日単位の長期流出解析であり、寒冷地である北海道・東北地方の５つのダム流域（岩尾内ダム,漁川ダム,定山渓ダム,浅瀬石川ダム,玉川ダムの各流域）を対象とした。対象期間は2002年6月から2006年4月までの約4年間である。解析にはGISが活用できるように改良された安藤等の水循環モデルを用いた。冬期は観測資料が十分ではないが、ダム地点の降水量データは良好であったため、それをもとに仮定した標高-降水量関係から流域平均降水量を推定した。GISメッシュは100mとし、降水量の他、積雪・融雪計算をしている。流出特性として一雨雨量-直接流出高の関係や地下水流出の減水定数等を表し、それらの値をパラメータとして用いた。解析の結果、岩尾内流域では冬期の降水量データは全て不良であったためモデルの再現性は十分でなかったが、他の４ダム流域では良好な再現性が示された。

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There has been a discrepancy between the European view of the term “alpine” zone and the Japanese one. European researchers consider orthodoxically the alpine zone as a tree-less area covered with ericaceous dwarf shrubby cushion plants between the timberline at its lower limit and the climatic snow line at its upper limit. Japanese researchers have traditionally reckoned the alpine zone as an area covered with the extension of the Pinus pumila thickets admixing many alpine-boreal elements above the forest limit. Japanese phytosociologists have recently payed attention to such a traditional Japanese view of the alpine zone. The author is much interested in this problematic usage of the term “alpine”; in the present study, an approach is made to this subject through his own research on the ecology of the P. pumila thickets carried out in Mts. Taisetsu, Central Hokkaido.
Compared with the European alpine communities with those of Japan, it is clear that the latter is fundamentally different from the former because of the well-establishment of the P. pumila thickets rich in boreal forest elements and the high productivity of P. pumila itself which is nearly equal to that of the Abies-Picea forest. Thermally, WI of the area occupied by the P. pumila thickets is no less than WI=15 that has been considered to coincide with the northern forest limits. Further, P. purnila thickets differ fundamentally from the conifer krummholz which is highly popular to the European high mountains though the thickets look like the krummholz forms. The latter forms the component of the forest while the former never forms the forest.
The author concluded that the traditional definition of the “alpine” zone in Japan should be abandoned, and that the P. pumila thicket belongs essentially to the upper part of the forest zone in the vertical distribution. Another conclusion is that the so-called alpine zone occupied with the extension of the P. pumila thickets in Japanese high mountains as well as at Mts. Taisetsu does not strictly correspond to the krummholz zone at the upper part of the forest zone in European high mountains
The Japanese alpine zone is a unique and independent vegetational zone, and it is not the fragment of the forest zone such as the conifer krummholz zone in Europe.

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日本産のキンバイソウ属は，温帯上部から亜高山帯にかけて分布するキンバイソウTrollius hondoensis Nakaiを除くと，亜高山帯から高山帯にかけて生育する高山植物である（レブンキンバイソウは礼文島の海岸草原に生えるが，環境的には高山に準ずるとみなされる）．しかし，北海道・道北及び道東地方には低地（普通標高200 m 以下）の渓流に沿って生育するキンバイソウ類がある．このような環境に生育するキンバイソウ属植物は北海道以外には知られていないため，新たにソウヤキンバイソウ節sect. Yezoinsulicola Kadota を提唱した．ソウヤキンバイソウ節はシナノキンバイソウ節sect. Insulaetrollius Dorosz. に比べ，生育地の違いに加えて，①全体大型で，②茎がよく分枝して，③花は普通5個以上つき，④花柄が長さ8–15 cmになる点で異なる．（以降はPDFを参照ください）

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The behavior of the river ice and the frazil ice were important for study of the ice-covered river. However, it was difficult to investigate the river ice and frazil ice thickness and behavior on the ice-covered river. We enabled to measure the ice layer thickness using the snow depth meter, the depth sounder, and SWIP(Shallow Water Ice Profiler). And we could investigate time series behavior of the river ice internal structure that was snowfalls, the river ice and the frazil ice. Especially, we could understand the behavior of the suspended frazil ice that existed in water by using SWIP. As a result, the suspended frazil ice would originate in the weather condition such as the snowfalls and temperature. And at the Break-up, the suspended frazil ice would exist by high concentration from the upper stream transportation by the rise of the water temperature. This study presented the time series measurement technique of thickness and behavior of the river ice and the frazil ice.

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The smoke of γ-BHC was used to estimate the density and the biomass of forest arthropods. The problem of determining the number of quadrats is considered in this paper. A six meter by six meter quadrat consisting of 36 units of 1 m^2 vinyl sheets was set up in a beech stand of the Ashu Experimental Forest of Kyoto University in Kyoto Prefecture in May and July of 1965. On one calm morning five containers of γ-BHC were made to smoke. The arthropods fell and died on the sheets and were collected. The minimum unit area and its size were calculated by the application of the statistical theory to estimate the density and the biomass of the arthropods. As for the density, if 20 units of 1 m^2 were used, the values 20 per cent of fiducial limits to the average on 95 per cent confidence can be obtained. The variance in the biomass, however, was somewhat larger than that in the density, so a larger area is required to get the values of the above mentioned. It was estimated to be 30-50 m^2.

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The most utilized flood runoff model for engineering applications in Japan is based on the storage- discharge function of the type S=kQp. The parameters p and k vary between flood events, causing difficulty in estimating and forecasting the flood runoff hydrographs accurately. The aim of this study is to identify the parameters in the storage-discharge relationship for floods for the Sameura Dam basin, Sagae Dam basin, Taisetsu Dam basin and the Iwaonai Dam basin, located in different regions in Japan and representing different topographical, geological and climatological conditions. In order to optimize the parameters p and k by maximizing the Nash-Sutcliffe efficiency, 10,000 simulations are carried out for each flood event by changing the values of k and p. The results show that the optimum parameters in the storage-discharge function, the sets of p and k, for floods in each study basin are represented by the p- k curve on the log-log graph.

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統合的かつ持続可能な水資源管理を行なう上で，流域水収支を把握することは非常に重要である．水収支を構成する涵養量は，地下水資源開発や3次元地下水流動解析における重要な因子であり，水収支解析においては降水量から蒸発散量および流出量を減じた残差として算出される．近年，レーダーアメダス解析雨量データなどの2次元分布データの整備により，降水量および蒸発散量についてはその空間分布を精度良く推定することが可能となってきている．一方の流出量に関しては，流量観測所の設置が主要河川に限定されるため，観測所が存在しない流域（未観測流域）における流出量推定手法の確立が課題となっている．
本研究では流出と密接に関係している地形に着目し，DEMを用いた地形計測および統計量解析より求められる「流出指標」をもとに，北海道下川地域の未観測流域における流出量の推定を行なった．流出指標と2008年8月に測定した河川流量データとを比較した結果，両者の間には強い正の相関関係が見られた．この結果は流出指標の妥当性を示すとともに，両者の回帰式を用いて未観測流域の流出指標を河川流量に変換することが可能であることを示唆している．

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Field surveys, experiments and numerical calculations were conducted to examine driftwood accumulation in a river channel, with respect to the existence of sandbars. We investigated the areas where driftwood accumulated and captured from river channel is observed in two rivers. It seemed that factors such as the existence of riparian woods, sandbar configurations, and sandbar locations relative to the river flow determined the points of driftwood accumulation. Based on the field survey results, hydraulic model experiments investigated the flow path of driftwood in model river with alternate sandbars. The analysis related to flood flow indicates that when the flow velocity and the water depth of the main current differ greatly from the flow velocity and the water depth of the flow that is away from the main current, the force of the main current acting on driftwood pushes the driftwood outward. And we clarified the relationship between discharge and the locations of driftwood capture, traps were built at different points on a sandbar.

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