In order to improve the conventional evaluation index based only on individual changes, including labor applied to evaluate the effect of farmland consolidation projects for rice cultivation, an evaluation method that uses total factor productivity (TFP) as an index to make a comprehensive evaluation of economies of scale based on the data of individual farmers was developed. Field application of this new method realized improvement in rice cultivation efficiency by factors of 1.12 to 1.25 timed for all farmers of farmland consolidation projects, permitting the quantitative evaluation of such projects.

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The workshop approach to planning construction of an assembly hall is introduced to establish a model of a citizen participation type design determination process. Relevant cases were analyzed to identify important points essential to smoothly carry out the process.

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The attitudes of residents of intermediate and mountainous areas toward their local environment varies depending on locational conditions even if they live in the same municipality. To improve local environments, the direction of each development project must be set accounting for differences in the residents’ attitude to their local environment that are a result of these locational conditions.

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In a membrane bioreactor, cake layers deposited on the membrane play a major role in removing bacteriophage (or phage). The method is superior to conventional activated sludge methods by 2 log in phage removal ratio.

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Multi-faceted characteristics of residents’ attitudes before and after implementation of a rural community sewage plant improvement project were analyzed by the TN method (Tohoku National Agricultural Experiment Station method) and DEMATEL method. Analysis revealed that residents held a variety of expectations of the project before its implementation and that their expectations focused on the improvement of conditions for fixed settlement after implementation.

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When the dissolved oxygen concentration during aeration is controlled at a fixed value, It was found that the completion of nitrification and the ORP inflection point occur simultaneously. This phenomenon was applied to develop an automatic control system that carries out efficient aeration to remove organic matter and nitrogen, while saving the volume of aeration.

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The relationship between the rate of flow and natant action for medaka, a kind of cyprinodont that is designated as an endangered species, was investigated, revealing that the fish evacuates into areas with a gentle flow, such as behind waterweed when the rate of flow increases. The majority of a school begins evacuation when the rate is between 18 and 22 cm/s (about 6 to 7 times the total length of a medaka). It was found that the rate of flow at which medaka move safely is below 15 to 20 cm/s.

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The non-agricultural roles of agricultural water facilities are becoming increasingly important as the number of non-agricultural residents within agricultural villages is increasing. The study quantitatively identified the recognition by non-agricultural households of nearby agricultural water facilities, and indicated the need for the participation of non-agricultural residents to the management of the facility and for its publicity.

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Agricultural water has been used not only for irrigation but also domestic uses such as washing clothes and fire fighting. On the basis of a questionnaire survey directed to local water users within rural communities, local water uses are classified as contact type and non-contact type, and decreasing trends in such uses are identified in accordance with the classification. The appropriate water depth of washing places is also quantitatively identified.

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A (Ca²⁺ + Mg²⁺) - bicarbonate - radon concentration diagram can differentiate between a shallow groundwater in flatland such as alluvial lowland, in weathering soil that is distributed in surface layer along the topography of mountains, and a deep groundwater in basement of mountains. The authors revealed that radon in deep groundwater (NaHC0₃ type) has a high electric conductivity but is in equilibrium at an extremely low concentration.

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With rural communities in the Abukuma Mountains chosen as subjects, the authors developed a method to establish a land resources information database containing land information and agricultural activity trends with rural communities as units on the geographic information system (GIS).

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A method was developed to calculate topographic factors for the Universal Soil Loss Equation (USLE) for a field by using the geographic information system (GIS) according to the actual status of the shape of the field in order to evaluate a wide-area evaluation of soil loss. Use of this method allows soil loss to be evaluated in a way that reflects the topographic shape of each field or the situation of growth management at the catchment area level.

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Net radiation flux density of about 40 to 60 W/m² is obtained during the clear-sky night in autumn, and by the following morning, lettuces exposed to the atmosphere are cooled down to a temperature almost the same as that achieved by ordinary precooling. In a simple facility that provides shelter from wind or sunlight, this nocturnal radiative cooling effect may be enhanced. Using the net radiation flux density estimated from the temperature difference between the dry bulb temperature and the globe temperature as an index, it is possible to properly open and close the covering.

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A small irrigation pump could be driven by a savonius windmill at a wind velocity of 3 m/s or more. Energy conversion efficiency is a maximum of 0.05 at a tip speed ratio of 0.25. Torque coefficient decreases at a tip speed ratio of 0.25 or over.

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Using portable instruments consisting of an ultrasonic sensor, a data logger, a set of digital level and a battery, a simple measuring technique of water level that can account for a waving water surface has been developed.

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It is possible to analyze the working frequency at any given point, cut depth, and other factors during land leveling work at a farm land consolidation site based on accurate vehicular swept paths including height information of bulldozers obtained by automatically tracking the bulldozers with an automatic tracking total station.

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Swelling is one of major causes of water immersion failure of a dry clod made of bentonite that is swelling clay, and its failure behavior in diluted solution and dense solution differs. Air pressure is another major cause of water immersion failure of dry clods made of kaolinite that is non-swelling clay.

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The newly developed soil hardening chemical uses magnesium carbonate and phosphate fertilizer as its main raw materials. This chemical can harden organic soil or high water content soil: kinds which have been difficult to harden with cement or lime. The hardened materials are weak alkalines and may be used as soil or phosphate fertilizer when pulverized.

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Simple laboratory permeability test equipment was developed to determine unsaturated hydraulic parameters for filter materials of underdrain. Inverse analysis of the test result determines unsaturated hydraulic parameters for filter materials at the good accuracy, thereby allowing water transfer analysis around the underdrain pipes other than those in saturated condition.

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The general error of PIV (particle image velocimetry) measurement of air velocity in a wind tunnel experiment is an average of about 3 to 5%, which means it is an effective way to measure airflow in greenhouses. PIV can be used to analyze the airflow distribution in the naturally ventilated Venlo greenhouses and open-roof greenhouses.

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CFD (computational fluid dynamics) computed airflow distributions in multi-span greenhouses during natural ventilation due to wind forces are in good agreement with the results of a wind tunnel experiment. CFD results show that a reverse flow occurs in an open-roof greenhouse and the airflow distribution depends on the direction of ventilator openings in a Venlo greenhouse.

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Light quality influences the shape of petunia plants during their growth process. In particular, yellow light (that actually includes some red zone) has made for compact plants. When light intensity is different, yellow light makes the plant shorter than white light, with the difference in the growth increasing as the light intensity is reduced. Yellow light effectively controls spindly growth when its intensity is low.

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Measurement data concerning the relationship of agricultural water and drainage control at paddy field areas with water quality obtained in Area R near Lake Biwa were analyzed to study the water quality preservation and purification capabilities of a wide-area water use block with multiple water intakes

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A three-dimensional model that calculates three-dimensional water temperature and flow by accounting for the density variation due to water temperature was developed. This model can be applied to the analysis of dam lakes and other relatively small water areas with complicated shapes.

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A unitized labyrinth weir was developed for use as the spillway (discharge system during flood) of an agricultural reservoir. This unit guarantees greater reservoir storage efficiency, improved safety, and lower costs than a conventional straight weir, and its introduction is an effective way to repair the many irrigation ponds (small-size dam reservoirs) located throughout the country.

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Once engineers use the interactive user interface of this newly developed system to input the planned routes and design conditions for an irrigation pipeline route, the system displays hydraulic characteristics of each planned route. Then it allows the engineers to evaluate each one by means of two- and three-dimensional maps repeatedly.

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Automatic hydro-mechanical gate designed to automatically close the gate and discharge overflow through the spillway when the water level of a canal rises and to automatically open the gate when the level decreases was developed. Its hydraulic characteristics were identified by laboratory hydraulic experiments.

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A PC-equipped system capable of inputting data and of graphically showing the results such as inundation area for regional drainage analysis was developed. This system allows a field engineer conducting regional drainage analysis to prepare accurate data and to visualize analysis results by simple operations.

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The relationship of the precipitation causing 41 floods that occurred in about 30 years from 1969 to 1997 in the catchment basin of Lake Inbanuma with the maximum water level in Lake Inbanuma that is located in the downstream area along the Tone River where urbanization has advanced rapidly was analyzed to statistically evaluate the capability referred to in the above title based on the relationship of the reduction of agricultural and forest land in the catchment basin (urbanization) with changes in flood run-off characteristics.

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A method to predict run-off sediment from the catchment basin of an irrigation dam reservoir was proposed. This method allows us to easily predict the sediment load that will be run-off from a relatively small catchment basin up to about 100 km², based on the watershed’s area and its climatic category and geological category.

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A system is developed which can monitor the state of infiltration of reservoir water two-dimensionally a fill dam body by resistivity tomography method using embedded electrodes in all parts of the dam body during construction of the dam.

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The newly developed surface cut-off method uses steel panels as impermeable material applied to upstream slopes or bottoms of agricultural reservoirs and provides improved impermeable performance and durability to reduce the total construction cost.

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This is a technique for analyzing temperatures of the section of the fill dam inspection gallery where pipe cooling is performed. A new method of designing an inspection gallery made of steel fiber reinforced concrete was proposed by identifying the deformation behavior of the inspection gallery of a fill dam on which fill load acts. This design method can reduce construction cost.

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A new embankment analysis method that expresses non-linearity of elastic characteristics of fill dam foundation ground was developed. It is especially useful for relatively soft ground such as soft rock or fault zone.

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Field and documentary investigations of the current status of agricultural water facilities were conducted to reveal the factors that cause the degradation of structural and hydraulic functionality. It is necessary to develop measures appropriate to deal with each cause.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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