In this study, the distributions of the direction and velocity of the prevailing winds in Konsen-Genya, Southeastern Hokkaido, were made clear by using results of field observation and available wind data.
First, investigations were carried out on the distribution of prevailing wind directions and wind velocity observed at fourteen agrometeorological stations in Konsen-Genya. Secondly, field observation were made on wind-shaped trees in order to make clear the detailed distribution of the prevailing winds and local wind conditions. The grade of defor-mation and the direction of deformation of wind-shaped larch trees (Larix leptolepis) were measured at about 100 points in August, 1972.
The results obtained in this study are summarized as follows:
In summer:
(1) The southerly winds from the Pacific Ocean blow up to north along the Kushiro river.
(2) The southerly winds from the Pacific Ocean blow up to north in the central part of the Konsen-Genya, and then gradually change the direction northeastwards along the Shibetsu mountains and one branch of the southerly winds flows northwestwards from the Nemuro Bay.
(3) The easterly winds from the Nemuro Bay blow into the lowland along the Shibetsu and the Nishibetsu Rivers. Their easterly border runs on the eastern side of the Kenebetsu, Nishishunbetsu and Chanai regions.
(4) The strongest wind region is found on the coast and the weak wind prevails in the Shibecha, Arekinai and Ota regions.
In winter:
(1) The northerly winds blow from the Sea of Okhotsk to Pacific Ocean on the lowland area along the Kushiro River.
(2) One branch of the northerly winds blows southeastwards between the Nishibetsu moun-tains and the Shibetsu mountains.
(3) The westerly winds blow from the Kenebetsu and Nishishunbetsu regions to the Nemuro Bay.
(4) The strongest wind region is found in the lowland along the Kushiro River as well as in the Shibetsu region. The border of the region with strong prevailing winds estimated from wind-shaped trees in winter runs in the Nishibetsu and Nishishunbetsu regions.
Further, an attempt was made to clarify the relation between the mean wind velocity of the prevailing wind in summer at the thirteen agrometeorological stations and the grade of wind-shaped trees of Larix leptolepis in the Ishikari Plain, the Shari-Abashiri region and Konsen-Genya.
The result is represented by the following equation:
W_s=1.6+0.95 Gs_l
where, W_s: mean wind velocity (m/s) observed at the meteorological stations in summer, and Gs_l: grade of wind-shaped trees of Larix leptolepis in summer. This means that the mean wind velocity in summer (m/s) is approximately equal to the value adding 1.4_??_1.6 to the grade value of wind-shaped larch tree.

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It is well known that among bed forms on the sandy river-bed dunes play important roles in fluvial processes relating to channel geometry, hydraulic variables, . and sediment trans-port. Though many experimental studies concerning bed forms have been carried on, they are not sufficient enough to make clear interrelations between the shape of dunes, flow phe-nomena, and channel characters in a natural river. The purpose of this study is to present the arrangement of the shapes of duns for various stages and the change of dunes with the stream discharge in a natural river, and to discuss these processes in connection with hy-draulic conditions.
Observations of bed forms and flow characteristics were made in the Yoro River at Azu, Chiba . Prefecture (Fig. 1), for the various river stages occurred during September 20 to Octo-ber 18, 1970. Fig. 2 shows a sketch plan and cross-sectional profiles in the study reach having 270m in length. The dimensions and shapes of dunes were investigated by an echo-sounder in the observation reach of a 50-meter length from sections D to I. Measurements of flow char-acteristics were carried out either at the narrowest section G or at the widest one I in the observation reach. These data are summarized in Table 1, and plotted in Figs. 4 and 5 in order to represent the relations of hydraulic variables to discharge.
Based on the indices such as the number of dunes per 10-meter length, dune height, and dune steepness, which is a proportion of dune height to dune length, the dimensions and shapes of dunes were examined from all available charts of echo-sounding profiles (Photo. 2). As shown in Fig. 7, the dune characteristics varies both transversely and longitudinally in the observation reach. The longitudinal variations of them may be related to the cross-sec-tional form of the reach. That is, in the narrower and deeper reach between sections F and G, the dune height and steepness are larger. And these graphs are assumed to describe the arrangement of dune characteristics in response to hydraulic condition at a given discharge.
The change of dunes according to the stage of flow was also investigated during the runoff event which occurred on 30 September 1970 (Table 2). At the falling stage, the values of dune characteristics as a whole were affected by the generation of new dunes on the resi-dual dunes. That is, the mean height of dunes became smaller, but the mean steepness of dunes became larger. While at the rising stage, considering from the relation shown in Fig. 6, the shape of dunes may become flatter because of disappearance of small dunes.
In order to discuss the observed dune characteristics hydraulically, it seems necessary to make clear relationships between the shape of dune and hydraulic variables. Since bed forms are an element of roughness, it may be assumed that the resistance to flow in alluvial chan-nels depends on the shape of dune, especially dune steepness. From Fig. 9 plotted by the data on flow measurements for each dune in Table 3, the following relation is obtained;
f=0.136 (h/λ) ^0.54
where f is friction coefficient and h/A is dune steepness.
The correlation suggests that at a given discharge or flow intensity the difference between the values of friction factor at sections G and I, as illustrated in Fig. 5 D or 8, originates from the variation of . dune steepness occured at these two locations (Fig. 7C), and that with decreasing discharge the increase of friction (Fig. 5D) is also caused by the increase of dune steepness. Fig. 10 plotted by the data on flume experiments and natural rivers shows that the similar rough relation exists independently of grain size.

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According to the definition of Go in the text of the Yoro Law, we can understand that Go of ancient Japan was an administrative unit which was composed of about 50 Go-kos (_??__??_)¹⁾. But, according to another part of the same text, the annotation books of the text, and other ancient documents, we can also understand that Go was an administrative area. Then how was this administrative area, that is, Go-iki (_??__??_) organized?
In the Southern Bittyu Province, Go as a unit of irrigation in the Edo era, the system of which was used at least inn the early Heian era, almost corresponds with Go as an administrative unit written in the ancient documents of the 8th and 9th century. And particularly in the case of Plattori-GO, the Go in the Edo era agrees not only in terms of name, but also approximately in terms of limit of area in ancient times, in early medieval times and in early modern times.
Also in the Eastern Heguri County of Yamato Province, ancient Go-ikis considerably correspond with the irrigation units.
In short, Go-ikis generally correspond with the irrigation units in ancient Japan. This will bring such conclusion as follows; especially in the place where water for agriculture is insufficient, it was the irrigation system that did form the core of “Lebensraum” from which Go-ikis were mainly organized.

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The observed results of CO and NO₂ concentration in and around a tunnel are summarized in Table 1. Dimensions of this tunnel, called Shinobu-yama Tunnel, are about 700 m in length and 56m² in cross-sectional area. From these data, we find that the concentration of NO₂ seems to be related with sunshine as if the photochemical reaction occurs outside of the tunnel but not inside of it, and that the wind direction controls the distribution of pollutants in the tunnel.
The tunnel must be artificially ventilated by fans because of the extremely weak wind and great deal of automobiles, judging from empirical equations (1) or (2) concerning ventilation, where L, C and Q are the length of the tunnel the traffic density and the ventilation volume respectively.
The relationship between the wind in and around the tunnel was clarified using the wind tunnel equipment. Table 2 and Fig. 3 are a part of obtained results. The distribution of pollutants in the tunnel can not be measured but we can estimate it from the air-temperature distribution shown in Fig. 4.

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Recently, the wave of urbanization has been sweeping over the cities and towns in Japan. As a result, in prefectures such as Hyogo, Osaka, Nara, and Kagawa where a number of irrigation reservoirs are being used to supply irrigation water for agricultural lands, a number of them have fallen into disuse, their water area reclaimed, and the land diverted for other purposes such as housing sites, land for factories, public use, and so on.
In Hyogo Prefecture, usage of 139 irrigation reservoirs ceased during the eight fiscal years of 1963 to 1970. These reservoirs were located around 14 cities (Aioi, Akashi, Amagasaki, Himeji, Itami, Kakogawa, Kasai, Kawanishi, Kobe, Mild, Nlshlnomlya, Nishlwakl, Ono, and Takarazuka) and eight towns (Harima, Ichikawa, Inami, Midori, Nandan, Taishi, Tsuna, and Yashiro). Most of these cities and towns are located along the coast of the Inland Sea and are included in the Harima Industrial District having an area of 800km², and the rest are located near the city of Osaka.
200.25 ha of the water area of the irrigation reservoirs has been reclaimed andd has been used for other purposes. 126 reservoirs making up 87 per cent (174. 45 ha) of the reclaimed land have ceased functioning in the 14 cities.
The reclaimed land from former irrigation reservoirs in the 14 cities varied from 0.02 ha (in Kasai) to 3.79 ha (in Kakogawa) per reservoir. 65 reservoirs of the 126 disused reservoirs in the 14 cities have been used to construct housing sites. 44 per cent of the 174.45 ha reclaimed land in the 14 cities has been used for housing, and 18 per cent has been used for factories.
The largest number of abandoned reservoirs was in the cities of Kawanishi (30 reservoirs), Akashi (24 reservoirs), and Kakogawa (22 reservoirs). The number of abandoned reservoirs in these cities amounted to 76. The water area amounted to 77.34 ha in Kakogawa, 43.83 ha in Akashi, and 10.64 ha in Kawanishi. This presented 76 per cent of the total water area disused in the 14 cities.
Kakogawa is located at the center of the Harima Industrial District. Therefore, most of the recalimed land from the larger reservoirs have been used for factories. This area represents 91 per cent of the whole diverted area for factories in the 14 cities.
On the other hand, in Kawanishi, 96 per cent of the disused area has been diverted into housing with no factories. A large number of houses will still have to be built, because the city is located near the large city of Osaka, and the ratio of increase of population in this city continues at the highest level in the Prefecture (46.2 per cent from 1960 to 1965 and 42.2 per cent from 1965 to 1970). This is one of the main reasons why so much of the recalimed land have been used for housing in this city.

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