一ツ瀬川源流破砕帯小支渓における堆積地の形成と地形条件に関する研究
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The purpose of this paper is to anaiyze topographical control concerning the formation of deposition in mountain streams. An analysis of the deposition with mud-flow by topographical control is carried out with consideration given to the foIIowing: width, incline, bending angle and sinuous angle of stream. Summary of the results are as follows. As regards the width of the stream bed, bed depositions are formed with a large-scale mud-flow in the wide sections, and a smaII-scale mud-flow in the rela tive narrow sections, which are scoured among the terrace (wide deposition) or the vaIIey slope. In the width over th.e limit, the deposition volume is caused by not the width but by the length of the stream. Concerning the sinuous angle of the stream bed, in streams with a large sinuous angle, depositions are broken otT and only large stones are suspended. From these facts, the sinuous section with a large often function as "the joint spot" concerning the formation of depositions. As regards the incline and the bending angle of the stream bed, largescale deposition are formed in the gentle slope on the average, and small-scale depositions are formed in the bending section with a large angle. In the stream which has a wide, bending and sinuous section, there is high frequency the scours and depositions because of the intensive conditions. The more the condition for deposition is intensified, the more the stability(the period of scours and depositions) of the deposition is shorten, because the deposition with mud-flow frequency occur in the identical section. Generally speaking, mud-flow in the stream bed is selectively conditioned by topographical control in responce the energy of movement.はじめに １．研究方法 （１）破砕帯小支渓 （２）方法 （３）渓床堆積物 （４）地形条件 （５）時系列 ２．調査対象地と調査方法 （１）大河内周辺支渓とトウザ谷（森林理水試験地）―砂岩・頁岩・粘板岩渓流― （２）大谷川・大越谷―花崗岩渓流― ３．渓床堆積地の実態 （１）砂岩・頁岩・粘板岩渓流の岩屑堆積地 a．空中写真からみた堆積地分布 b．石礫分布（トウザ谷） c．植生侵入 （２）花崗岩渓流の堆積地 a．堆積地分布 b．巨石分布と横断面形 c．植生浸入 ４．堆積地の形成と地形条件 （１）地形条件による制約 （２）堆積規模と地形条件 ５．要約 引用文献
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