The effects of upstream weir heights on flow over weir were studied experimentally.
From the experimental results, the flow states are classified into weir flow and sill flow by the rato H₁/ W=7.0, where H₁ is the total head of weir and W is the weir height.
H₁/W<7.0 corresponds to the weir flow. In this case, the discharge coefficient m_H increases with the increase of H₁/W as far as the control section lies on the crest. On the other hand, as the control section shifts to upstream mil decreases its value and a transition to sill flow appears.
H₁/ W>7.0 corresponds to the sill flow. In this case, the flow states do not depend upon H_d/ W (H_d: the design head) and m_H is well explained by the Rouse's formula for sill flow of sharp edged weir.
Moreover, it is found that the state of submarged-flow, or the critical condition between over-flow and submarged-flow is affected by whether it is weir or sill flow.

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The designed current velocity for a sluiceway of a diversion dam should be that is sufficient to flush away the largest gravel in the deposit on the sluiceway. We studied, first in this paper, the forces acting on the single spherical granul pebble on a riverbed, and secondly by excluding the negligible factors in consideration of the flow characteristics on a sluiceway, we obtained a formula of the curreut velocity for a sphere in a state of equilibrium on a riverbed.
We made a study of the scale effect for the model test.
And we made a study of the effect of the gravel shape of pebble on the critical velocity, and found that d= (b+c)/ 2 and √bc are suitable as the diameter for design. Nextexamining the experimental data, we showed the propriety of the equations.
Using the logalithmic velocity distribution formula, we obtained the coefficient k (kf and kr), by which we should multiply the equation when it is used as a formula for the design velocity.
We propose, a design velocity formula and its the simplified form, as follows
_??_
ums=5.2k√d

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1.水田カンガイ地帯の地下水理は,半被圧浸透とみなしうる流動を生じ,これには速水の海岸地下水の理論を発展さしだものをこころみたところ,予備考察ではあるがかなりの適合性をみた。
すなわち,試験田の施設が完全でないため,地下水圧の減衰だけを検討するにとどめた。
このため,理論式(8)の常数mと代表的な減衰とおもわれる4回の測定値とを対比したところ,前者はm=1.02×10^-4(c.g.s.)後者ではm=1.03×10^-4(c.g.s.)となってかなり適用性はよいものとおもわれること。
2.またさきに石原が行ったびわ湖周辺草津市(旧老上村)近郊での実験値があったので,これと対比したところTable 2のように適合性がよいことがわかったこと。などである。
よって今後低湿地での水田地下水の動態をとりあつかうとき,いままでの自由面ないしは被圧状態と考えるほかに,半被圧浸透とみなしたものを用いることが可能とおもわれる。
なお,今後この実験研究は継続してFig.3(a)にしめした四囲の承水溝のうちF点側の一辺のみをさらに深く掘り下げるとともに,他の三辺をしゃ断した施設をつくりF点側の承水溝の水位のみを任意条件のもとに変動さし,種々の地下水圧の変動状態を追究したいと考える。

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In this paper the authers consider the measurements of the centrifugal moisture content from variouspoints, arid point out the relations of the effective moisture content to constitutions and structures of soils, based on some experimental results.
It can be summarized as follows:
1) Drainage does not seem to be conpleted with a truncated cone-crusible in measuring the: moisture contents. Therefore, it is advisable to use a cylindrical crucible for a truncated conecrucible.
2) The moisture content largely depends upon constitutions of soil. Therefore the values of the: moisture content obtained on the constituents of a soil which contain the grains smaller than 2, 0mm can not be substituted in place of that obtained on the original soil of the farm.
3) As the moisture content largely depends upon mixing conditions of soil, grain shapes and soon, the capacity of the centrifuge employed should be so large as to be suitable for measurements for the soil in-situ.
4) The moisture contents have no relations to compactness of soil. Then a centrifuge is available: for the practical purpose to measure the moisture contents.

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Transpiration is vitally essential to plant life. It is therefore necessary to understand transpiration thoroughy in order to make more efficient use of irrigation water.
As transpiration is evaporation from leaf surfaces, it can be expressed approximately as the resultant effects of micrometeorological conditions in a similar manner as evaporation. The growth of paddy rice plant can be taken to show the effect of micrometeorological conditions.
As the author's attention was drawn to the fact that the extent of evaporation of the upper leaves was greater than that of the lower leaves, the vertical distribution of evaporation was obtained and it was found that the shape of this distribution had a large effect on yield of rice plant.

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The district where the water balance and the groundwater flow were investigated, is in the south-eastern part of Ibaraki Prefecture, being located between the Pacific Ocean and the River Tone. It consists of sandy soil having a length of 16 km and a width of 2-4 km, measuting about 50 km² in area. The groundwater level of this district changes very little without relation to dune undulation, and the watershed of the groundwater runs approximately parallel to the coast line.
The water balance of this district was computed each month by using the following formulas:
P=D₂+E+G₂+ΔS (1)
ΔS=H·P_a+M (2)
where
P: precipitation, D₂: runoff,
E: evapo-transpiration, G₂: groundwater flow, ΔS: variation of storage,
H: variation of groundwater level,
p_a: air capacity of soil in the part of changing groundwater level,
M: variation of soil moisture.
P and H were determined by actual measurements, E was obtained from the observed value of evaporimeter (E_p) at Choshi Weather Station near there, and the coefficient E/ E_p was assumed to be 0.8 in June, July and August, and 0.4-0.7 in other months. G₂ per year was obtained by putting M=0 in formula (1), and G₂ in each month was computed assuming that the groundwater level (height above the sea) is proportional to G₂. P_a was obtained from formula (2), where ΔS was computed from formula (1) at intervals of 5 days, and H was actually measured. Scattering of points in plotting, showed M. D₂ was confirmed in the process of this calculation. P_a given as the gradient of points in plotting was 0.20 and coincided with the measured values at several places. In the future, if the irrigation water is introduced in this district, the percolated water is expected to increase. In this case, the rise of groundwater level is calculated at certain intervals of time from the following formulas:
G=H·p_a+G₂ (3)
_??_(4)
where G: supply of groundwater, h₀: groundwater level at the beginning of irrigation (above the sea level), G₀: groundwater flow at the beginning of irrigation. The percolation coefficient K is obtained at the balanced conditions of G and G₂ as follows:
_??_(5)
where ha/2: groundwater level at the central part of the peninsula, a: width of the peninsula H:
H:mean flow depth (h₀+ha/2/2)
By the hydraulic calculation using this K, the rise of groundwater level can be obtained as follows:
_??_(6)
where x: distance from the sea of Kashima-nada, m: air capacity of soil (vapor phase%), t: time.

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As a continuation of the authors' previous report, this paper reports how the gronndwater level around the district concerned changes in accompany with the construction of Kashim a Port.
Having an area of about 70 km2, the district where the dug port will be constructed in a sandy seaside plain with a small part of sand dune. The thickness of aquifer is estimated at about 30m below the sea surface by boring. The port is provided with the main-route, the north-route and the south-route (Fig. 1).
The change of groundwater level after construction of the dng port can be estimated by the hydraulic method. However, the special feature of this report consists in obtaining the basic data by the hydrological method. The permeability coefficient in the large area can be directly obtained by the pumping test. Also it can be calculated from the groundwater flow (which is balanced with the groundwater supplied) and the groundwater table. Such groundwater flow is determined by the water balance method and is checked by the measured values of the groundwater seepage to the drainage canal.
Considering the shape of the port and the topography of the district, the change of groundwater level after the construction of the dug port is given by formula (1) available for a district surrounded by port, sea or river in a U-shaped form, by formula (2) for a district surrounded in a fanshaped form, and by formula (3) and (4) for a district surrounded in a semi-elliptical form. Formulas (1)-(4) are listed below:
_??_(1)
_??_(2)
_??_(3)
_??_(4)
The watershed is obtained if the formula (3) and (4) are equivalent and r= r1. The symbols used in these formulas are designated in Fig.6.
The values of groundwater flow G adopted in fomulas (1)-(4) are based on those obtained by the water balance of the southern part of Kashima (of the previous paper). Fig.7 was obtained by correcting the results estimated by formula (1)-(4) inaccordance with the practical conditions. The lowering of groundwater is shown in Fig. 8.The authers believe that it is very useful to apply the water balance and hydranlic methods together for the estimation of groundwater table after changes of general conditions have occurred.

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