To implement farm land consolidation that takes into consideration mobilization of land for agricultural use and formation of land use order (planning subjects), the planning units of a comprehensive district plan by inhabitants is going to be made clear. Three types of planning units are considered ; an agricultural settlement unit, a Meiji administrative village unit and a type which combines the former two units. The ideas of municipal authorities and typical examples for each planning unit are gathered, and are examined and their effectiveness is compared, and the points mentioned below are made clear.
(1) It's easy to make a comprehensive district plan on an agricultural settlement scale and set the project on foot, if each agricultural settlement leader and municipality are very enthusiastic about it. But it's not enough for accomplishing the above planning subjects. It's impossible to implement the plans at a lot of ordinary agricultural settlements which have lost the substance of traditional village functions.
(2) It's suited to perform the above planning subjects on the Meiji administrative village scale. But improvements from the viewpoint of an agricultural settlement are often forgotten. There are less special Meiji administrative villages which have very enthusiastic district leaders, settlement leaders and administrators than special agricultural settlements.
(3) A combined type on the Meiji administrative village scale and agricultural settlement scale is effective as a planning unit because it is able to perform the above planning subjects even at a lot of ordinary old villages by using the “Kande method” as a planning method.

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To implement farm land consolidation that takes into consideration mobilization of land for agricultural use and formation of land use order (planning subjects), a conflict model of a rural planning system is effective. One of the effective factors is that the “Kande method” is effective as a planning method for a comprehensive district plan.
This paper compares the results of the applied examples of the “Kande method” as a planning method of a conflict model, with which is a “combined farming and residential area method” and makes clear the mechanism of the effectiveness of the “Kande method”.
(1) The reasons why the “Kande method” is effective are because the planning process of the “Kande method” is performed in the following three steps; 1) the inhabitants recognize the problems and possibilities (or potentialities) of a district (the step of making up and examining a written investigation of self survey), 2) basic principles of a plan are established (the step of making up and examining a written plan for a pilot plan), 3) a planning authority builds consensus on a comprehensive district plan (the step of making up and examining a written plan for a master plan).(2) Each member of a planning organization, which is composed of settlement leaders, settlement residents, self-government body and planners, communicate with one another, learn systematically the planning subjects of the district, reform their way of thinking and perform planning subjects of the district.(3) On the other hand, the “mixed farming and residential area method” dosen't have such mechanisms.

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Underdrain pipe is one of effective slope protection works that can be adopted practically. As fine soil particles are suspended in percolating water, a strainer structure of underdrain pipes is necessary to prevent clogging by soil suspension flow. This study deals with effective forms of strainer structure of underdrain pipes for slope protection. Experimental results showed that the underdrain pipe discharge through the funneledstrainers was larger than that through the constant pore radius strainers. Also, the ratio of underdrain pipe discharge through the funneled strainers to that through the constant radius strainers increased with the increase in volume concentration of percolating suspension. Additionally, it was analysed on the basis of rheological properties of soil suspension flow which prevents clogging that the effective strainer structure of underdrain pipes is the funneled strainer in which pore radius is larger in the flow direction.
According to experimental and theoretical results, it was concluded that a strainer with enlarged pore radius toward flow direction is more effective than a strainer with constant pore radius.

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This study was conducted to clarify the application method for continuous subsurface irrigation using low positive pressure as the means of water management for broccoli or egg-plant cultivation, the fact why the water supply is suppressed under the condition of constant pressure in the porous pipes, and to search for the way to avoid problems.
The results obtained are as follows.
1) The continuous subsurface irrigation method by using low positive pressure is very useful for water management of the aforementioned crops.
2) The depression of water supply is thought to be caused by roots entangling to the pipes.
3) The depression of water supply could be avoided by using cheesecloth a little.
Lastly, it is necessary to continue search for other materials to perfectly prevent roots from interfering with the water supply.

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A study was made of the applicability to real-time flood forecasting of a conceptual storage rainfall-runoff model (LST Model) structured as a Kalman filter. Two variations of the model were used. The first (System I) treated the upper layer storage as a state variable in an extended Kalman filter. The second (System II) treated all storage depths as state variables and the system dynamics were linearized statistically preparatory to applying a linear Kalman filter for state estimation. Three alternative future rainfall scenarios were considered:(a) The present rainfall intensity continues, (b) The past 3-hour average rainfall intensity continues, and (c) Rainfall is modeled as an autoregressive process and updated with a Kalman filter.
The two forecasting system models were applied for 12 floods from the 115km² catchment which supplies Osako Dam. Runoff forecast using lead times of 1-hour, 2-hours and 3-hours was made. There are three principal conclusions: 1) The differences between the results of two models were small, 2) The accuracy of 3-hours ahead forecasting depended on the accuracy of predicted rainfall, and 3) The accuracy of flood forecasting using the future rainfall given by the simplest method (a) was almost the same as the complicated one (c), and better than approach (b).

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River discharges with lead time of up to several months during drought years were made with the Long-and Short-Term Runoff Model (LST Model). Fourteen years of hydrologic data from 1975 to 1988 at Eigenji Dam (132km²) were used.
A simple method for modifying daily areal rainfall and evapotranspiration was introduced into the operation of the LST Model instead of the application of a Kalman filter, and the model states were adjusted to be consistent with measured streamflow. The climatological time series from a specific date during drought for a given return period were drawn statistically on the basis of several 10-day cumulated rainfall amounts. Monthly evapotranspiration and simplified daily rainfall patterns which consist of a sequence of rainy days with average intensity and that of no-rain days were assumed. Several 10-day cumulated runoff volumes during drought for a given return period were obtained using those climatological time series and compared with observed volumes.
The results were summarized as follows: The effects of modification of daily data on runoff forecasting is limited within a month at most. The forecasted river discharge volumes for 1-9 ten-days ahead periods in drought years for 5-, 7-and 15-years return periods agree with the observed cumulated runoff volumes.

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Dynamical variations of soil-water content are combined phenomena of present form of water among soil particles and the ongoing rain input. As intensity of rain varies not only by its nature but also by the movement of rain area and intermission, it effects on the variation of soil water content. On the other hand, relatively short periods of variation of the intensity seem to be prevented to infiltrate into the ground because the surface of the ground averages the variation.
In order to clarify the mechanisms of travelling of variation of rain intensity into the ground in terms of the soil water content, experiments of infiltration under the pseudo-random (M-sequence) rain input were conducted using sand and Kanto loam cylindrical soil columns. In addition to these, several types of rain input with intermission were added to sand column to clarify the phenomena of intermission of rain. Apparent specific resistance of each depth of the column and groundwater outflow from bottom were measured. Observed phenomena are:
(1) M-sequence type variations of rain intensity at the surface of the ground travelled to-4m deep of the column in terms of the correlation function between rain input and the inverse value of the apparent specific resistance.
(2) Velocities of travelling of impulse of the correlation function became fast with time when soil water content increased.
(3) Secondary wetting front after intermission of rain reached the primary wetting front and hastened the velocity of the primary wetting front. Redistribution of water in intermission is analyzed schematically. Results are explained by the “Open Unsaturated Capillary Percolation (OUCP) ” model. Finally, relation between the rain infiltration and the occurrence of ground hazards is discussed based on the observations of the series of experiments.

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A dephosphorization experiment adding FeCl₃ simultaneous with inflow of wastewater was conducted in a sequencing batch reactor with intermittent aeration used as a rural sewerage treatment facility, and concluded that phosphorus can be removed without influencing nitrogen removal efficiency.
Removal efficiency of phosphorus depends on the mole ratio of Fe/P.
When Fe/P=0.5, the removal ratio of phosphorus was 70% or more, and the T-P concentration of treated water was 1mg/l or less. When Fe/P=1.0, the removal ratio of phosphorus was 90% or more and the T-P concentration of treated water was 0.5mg/l or less.
Under the same condition of FeCl₃ added, concentration of phosphorus of the treated water was stable, even though there occurred temporary variation of T-P concentration, of influent.

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Trying for efficient agricultural management and improvement in crop intensity, large-sized paddy field is required in flat land. This paper focused on the characteristics of paddy field structures of the Kakurai area and Usui area in Chiba Prefecture, where they have been consolidated into large-sized paddy fields with various improvements based on present standard lot structure. Specifically, we estimated the functions and effects of paddy field structures from the viewpoints of irrigation and drainage, efficiency of agriculture operation, water management and so on.
Through the research, the authors found the following results:
1) In these areas, the plots have being expanded by farm block leveling through soil dressing, adjustment of the contours through land grading and took off levees during and after the farm land consolidation projects, and large-sized plots were found as large as 6.8ha, 2.5ha in 1992. Also, there is few problem even in leveling 6.8 ha plot using a laser guided bulldozer, but there is also an example that 5.2 ha plot is divided into 3 plots with insufficiency of land leveling in the irregular sized and land subsided farm block.
2) There are no problems as regarding irrigation and drainage in the large-sized paddy fields of 6.8ha, 2.1 ha and so on. This is obtained by buried irrigation and drainage canal, dual-purpose underdrainage system, as well as automatic watering.
3) Efficient agriculture management has become true in the large-sized paddy fields due to efficient farm machine operation, labor-saving of water management operation and adding effect of direct seeding culture of paddy rice on well-drained paddy field and so on.

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In 1993 the localized heavy rain attacked Kagoshima City as well as neighboring towns and caused severe damage. Many areas suffered from landslides. As a result, a great number of farmlands and roads were covered with debris flow. To take effective measures to protect farmlands from natural disasters, it is considered to be important to assess the degrees of damage accurately and effectively.
Satellite has been used to monitor a wide area. In this study, therefore, the remote sensing techniques was applied to evaluate its practical use. The data observed on Aug. 12, 1993 by a satellite were used since it was known that stricken areas were scattered widely and that many small landslides occurred here and there on the day.
Aerial photographs taken on the same day were also analyzed at the same time. Usually aerial photographs have been visually examined by human eyes. However this demands technical skill and exertion. Therefore some techniques of image analysis were attempted to identify the stricken areas accurately and speedly. The relation between the difference of Shirasu and Andesite, and the incident of a landslide was also studied.
The results of the analyses based on the satellite data and aerial photographs were compared and practical problems in the analyses were evaluated.

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We investigated the water area reclamation projects, in particular the changes of these projects in Japan after the World War II.
Firstly, we explained the institution of water area reclamation projects.
Secondly, we classified these projects and made the distribution maps of the projects.
From these results, the following was found worthy of being reported:
1) Sea coast reclamation projects are concentrated around Ariake Sea, Yatsushiro Sea, Seto Inland Sea, Ise Bay, Mikawa Bay and Kagoshima Bay where tidal range is remarkable.
2) All projects above mentioned except Kagoshima bay belong to alluvial plains
3) Water area reclamation projects at lakes are almost all distributed around large lakes or brackish water lakes, i. e. Lake Shinji, Nakaumi, Lake Biwa, Lake Hamana, Kasumigaura, Imbanuma, Teganuma, Izunuma, Hachirogata, Lake Jusan.
4) The total number of the sea coast reclamation projects is more than that of the water area reclamation projects. But the total project area and the total reclamation area of the latter are larger than those of the former.
Then, from the view of social conditions, international situations and agricultural administrations, we discussed the historical transition of the projects in detail, and explained the change and decay of the projects.
Lastly, we presented some tables of the project area and the reclamation area produced by each projects and these diverted area.

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The irrigation water requirements of cabbage to obtain maximum yield with minimum water use were investigated based on meteorological conditions and soil moisture dynamics at the coastal areas in California peninsula, Mexico. Six water levels corresponding to 0.9, 1.3, 1.45, 1.7, 1.8 and 1.9 ET_p (ET_p=potential evapotranspiration calculated from the Penman method) were employed as irrigation water under drip conditions. The yield of cabbage at the water levels of 0.9 and 1.3 ET_p was low in comparison with that at 1.45 ET_p. No significant yield differences were realized between 1.45 and 1.9 ET_p levels. The ratio of the yield to the total applied water was maximum at the 1.45 ET_p. Under these conditions, the 1.45 ET_p is demonstrated to be the optimal water requirements of cabbage for saving water and obtaining high yield. It was also demonstrated that the soil moisture depletion in the root zone of cabbage was about 1.5 times the potential evapotranspiration.

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