Japanese industry has remarkably increased its demand for water these several years. Our government and monopolistic capitalist forces are going to reduce the water rights of farmers for irrigation in order to meet this demand. Such a situation will bring a drastic reorganization of the systems of water use which have been built up mainly on the basis of water rights for irrigation.
Above-mentioned reorganization will cause various problems on the water use in various rivers. In order to forecast these future problems, we must get a exact image of socio-economic relations among users of river-water all over our country.
In this article, author tried to classify Japanese rivers (except those of Hokkaido) according to the types of socio-economic relations on the use of their water.
Such relations are represented by (1) number and areal scale of main facilities for drawing water for irrigation, (2) adjustment for how to distribute river-water among the facilities, (3) historic origins of water rights belonging to each facility, and (4) rules for drawing water to each facility.
Assorting such items, we can classify the facilities as follows :—
A) Facilities which take part in forming social relations on the use of river-water for irrigation,
1) facilities whose water rights come from administrative recognition and whose manners of water-drawing are regulated in relation to the other agricultural facilities for drawing river-water,
2) facilities whose rights come from contracts with nonagricultural users of river water (such as electric power stations) and whose manners of water-drawing are regulated in relation to the other facil-ities for drawing river-water,
3) facilities whose manners of drawing river-water are regutated according to customs originated premodern era,
4) facilities whose preferential and unrestricted rights for drawing river-water are recognized according to customs,
B) Facilities whose rights and manners of water-drawing are not adjusted with other facilities for irrigation,
5) facilities whose water rights come from administrative recognition,
6) facilities whose water rights come from contracts with nonagricultural users of river-water,
7) facilities drawing water without recognized rights and relation to the others.
Considerating (1) the ratio of the area irrigated by each group classified as above in the whole area irrigated with river-water, (2) the number and areal scale of main facilities for drawing river water and (3) the relations between agricultural water rights and non-agricultural ones, we can classify Japanese rivers into regional types shown in the following table : —
Generally speaking, social relations on the use of river-water have been more developed and fixed in the rivers of (B) region than in the rivers of (A) or (C). In the rivers of (A) region, the water rights for irrigation have been much influenced by electric power development and administrative investment for the improvement of farming land. Authur thinks that such regional defferences have been brought mainly by regionality of Japanese agriculture itself.

View full abstract

The author surveyd the topographies and volcanic ash in the area surrounding Mt. Daisen, San-in disstrict, western Honshu. Up to present, it has been said that the terraces and uplands are scarcely developed in San-in district, but the author recognized the several series of fluvial, marine terraces and pyroclastic uplands, many of which are covered with volcanic ash several meters thick.
The author's purpose in this survey was to make clear the condition of these terraces, uplands and volcanic ash, and to establish the geomorphic development in the area surrounding Mt. Daisen.
The condition of volcanic ash beds are shown in Figs. 1-3, and distribution of terraces and pyroclastic uplands are in Figs. 5-7. The developing order of terraces and pyroclastic uplands were concluded by t-he correlation of volcanic ash beds covering them, some absolute dates of which were decided by Carbon-14.
The geomorphic development derived from the above data is summarized in Table 1.

View full abstract

The River Yoneshiro rising from the southern part of the Towada Volcano flows westward through Hanawa, Odate and Takanosu Basins into Noshiro Plain, and it finally pours into Japan Sea at Noshiro City, Akita Prefecture.
Terrace plains are well developed along the river course. The aim of this report is to make clear the subaqueous sedimentation of pumiceous fragments in the lower terrace deposits. First of all, the writer surveyed the distribution of the terrace plains and investigated their longitudial profil, micro-relief (figs. 1, 2, tab. 1). As to the result of these morphological observation, he presumed the distribution of the river agencies at the stage of the terrace plain formation. Then, he observed sedimentary facies of the terrace deposits, and classified them according to the lithologic kind and size of deposits (phot. 1_??_4) into such five types as pumiceous gravel layers (Ka-, Ge-facies), pumiceous sand layers (Od—), lithic sand layers (Ki—) and lithic gravel layers (Ot—) . And his survey was conducted to discusse the herizontal and vertical distrbution of each other (figs. 3, 4). So, it was worthy of his notice that pumiceous gravel layers (Ka-, Ge-) were always accumulated on pumiceouse sand layers, in reverse the case of lithic layers. Further, he measured the grain size, ratio of mixing of lithology, ratio of suspensive and floating material, bulk density and absorption of pumiceous gravels, and sheir sinking ratio (figs. 5, 6, tabs. 2, 3, 4).
The results of these field survey and laboratory analysis, are summerized as follow:
1. Enumerating these facies in order of the presumed strengeth of the river agencies, they arrange Ot-, Ki-, Od-, Ge-and Ka-facies, so Ot-facies show the strongest of all.
2. Pumiceous fragments are accumulated under the qualitive environments as compared with lithic fragments of same size.
3. In spite of their small grain size, pumiceous sand leyers are formed under stronger river agencies than pumiceus gravel layers. Ka-facies layers are accumlated in the dum up basin, and Ge-facies layers are formed on the top of the natural levees or sand banks.

View full abstract