Most of dehydrated cake which was generated by turbid water treatment of the process for making crushed stone and crushed sand is subjected to landfill disposal. The effective use of dehydrated cake discharged from crushed stone quarry is required to relieve the tightness of the residual capacities of disposal sites and to secure limited natural resources. In this study, a dehydrated cake discharged from crushed stone quarry with excellent caking properties was examined to see if it can be used for soil materials, such as impermeable materials. In addition, physical and mechanical tests were conducted on the dehydrated cake, and then its properties were compared with those of commonly used cohesive soils. It was found that the dehydrated cake had significantly different properties from those of general cohesive soils, and it also did not match the mechanical properties of general compacted soils. Thus, it was concluded that the dehydrated cake cannot be handled based on the commonly used soil standards. In addition, it was found that reducing the water content and adjusting the particle size are effective in increasing the strength of dehydrated cake and that reducing the water content is particularly effective.

To date, basin precipitation was estimated by point observation by rain gauge and data processing. However, the observation has shortfalls to be solved in future such as lesser rain gauges in the mountainous area. Radar AMeDAS precipitation currently utilized new method that would be solved the above problems. The research aims to confirm the accuracy of the Radar AMeDAS by water balance analysis of the Tedori River mountainous basin. As a result of the research, assume the estimation of evaporation and discharge observation is accurate, the water balance analysis was indicated that the under estimate about 607mm shortage (the ratio of water balance difference to basin area rainfall is -17.2%) through the entire year but only about 49mm (the ratio of water balance difference to basin area rainfall is 4.7%) over estimate though the summer (June-Oct.). From the above result, we found that the Radar AMeDAS precipitation is accurate for basin precipitation observation, if except the snow falling in winter.

Adhesive strength tests are performed in the field by mounting a 40 mm square fixture and cutting along the sample edges with a concrete cutter. However, because the cuts form a hash pattern in which the cuts are longer than the side length of the square due to shape of the cutter blade and the shape of the fixture, difficulties arise in terms of workability during testing and repair and appearance after repair. To solve these problems, we therefore propose a method for adhesive strength testing of inorganic repair materials in the field in which a circular fixture and a core drill are used. In this study, adhesive strength tests were performed using a square fixture and a circular fixture, and the superiority of circular fixture over the square fixture was confirmed. These results suggest that the stress distribution differed between the fixtures and that the adhesive strength was larger when using the circular fixture than when using the square fixture for low-strength materials. A circular fixture of 45 mm in diameter provided adhesive strength that had small variation and was equivalent to that obtained with a square fixture, indicating that the circular fixture is suitable for adhesive strength testing.

This study examined the achievement situation and desirable management method of treated wastewater from rural sewerage with submerged biological filters by the ISO guidelines for irrigation use. The study found that the BOD concentrations and SS concentrations of treated wastewater had close relation to influent concentrations, hydraulic loading, and aeration rate in the contact aeration tank. The study also found that the BOD concentrations of treated wastewater in normal operation has mostly satisfied the quality of category C. There was a high probability that the BOD concentrations of treated wastewater achieved the quality of category B under the operating condition in which the aeration rate in the contact aeration tank was around 3 m³∙m^‐3∙h^‐1, and the influent BOD concentrations in the contact aeration was managed with around 30 mg∙L^-1. In order to achieve the quality of category A, it was thought that the operation required an increasing frequency of cleaning of the sedimented sludge and high aeration-rate operation of the contact aeration tank. The number of coliform groups in the treated wastewater could satisfy the quality of category B in the case where residual chlorine was more than 0.1 mg∙L^-1. From the perspective of the irrigation use of treated wastewater, it was considered that monitoring residual chlorine concentration was important.

The deformation of an embankment is permitted to some extent in a level 2 earthquake-resistant inspection of an agricultural fill dam. Newmark's method is used to evaluate the deformation of an assumed sliding mass by calculating the angular acceleration using the driving moment and the resisting moment of a sliding mass around the center of the circular sliding surface in every time step of earthquake acceleration data. However, it is not considered that the driving moment becomes small by the movement of the sliding mass. Hence, a new calculation process that the sliding mass is divided again and the driving moment and the resisting moment are calculated in every time step when the sliding mass moves was added to the Newmark's method in this study. As a result, it becomes clear that the driving moment becomes smaller gradually as sliding displacement becomes larger with the new process, and that the final sliding displacement without the new process becomes larger than that with it as the sliding displacement becomes large.

This research aimed to reveal the relationship between place attachment and cultural practice formed by the use of safflower in Yamagata prefecture. First, by snowballing interview, it shows that people use safflower not only for agricultural products but also for daily use such as household planting and cooking. After interview research, we conducted a questionnaire survey for people living in this area. By factor analysis, place attachment in this area can be divided into five factors. The t-test result shows people who use safflowers for cooking or go to local events frequently foster place attachment. Then we use SEM for further analysis between place attachment and cultural practice. The result shows that safflower cultivation and planting foster place attachment indirectly. However, it is also shown that cultural practice for economic benefit does not contribute for fostering place attachment.

This study aims to compare economic multiplier effects, which consist of output effects, value-added effects and greenhouse gas emissions due to backward linkage effects, of the multifunctional payment schemes and the Agricultural and Rural Development Projects at the local municipality and prefectural levels, with an attention to the diversity of the multifunctional payment schemes. To analyze economic multiplier effects at the local levels, we employed the empirical payment data collected from 3 local organizations receiving the multifunctional payments, as well as a national input-structure survey on the Agricultural and Rural Development project (open channel construction), and conducted an inter-regional input-output analysis combined with the regional share method. Consequently, we demonstrated that: (1) there are significant differences in intermediate input structures and local shares of the expenditures between the two schemes/projects; (2) the multifunctional payment schemes show larger shares of output effects taken by local municipalities and prefectures, and smaller greenhouse gas emissions, in comparison to the Agricultural and Rural Development Projects; and (3) the diversity of the multifunctional payment schemes is manifested in the differences in economic multiplier effects and their local shares.

The Kano spur dike was built as a water control measure in the Edo Era. It is an existing spur dike in a fast-flowing section of the Class 1 Kiso River, which flows through the alluvial fan of Inuyama, and among the spur dikes on Kiso River, this is far and away the largest and it is functioning to this day. This research investigated the historical background of this Kano spur dike based on written literature, documents, etc. from the occurrence of flood damage to the installation of the spur dike. In addition, the value of stone spur dikes as heritage sites for drainage and reclamation engineering was considered using nationwide survey data on spur dikes. This research made it clear that of the stone spur dikes installed at the start of the Edo Era in Japan, this is one of the largest that is still functioning.

Japan's agricultural sector is at a major historical turning point. In response to changes in agricultural technology and the difficulty in sustaining the self-produced farming system created by the Agrarian Reform after the second World War, a new cultivated land development method is necessary. There is a need for new technical frame works for land consolidation. The land consolidation method, which is a historical concept, refers to the process adopted by farmers to adapt cultivated land conditions to adapt cultivated land conditions to suit current requirements. In this study, we examined the book “Land Readjustment of Farm Land” by Kagato Shinzawa and Susumu Koide, which presented a new technical view in the turbulent post-war period to address this issue. The goal of this study is to evaluate future land consolidation technology issues from several perspectives. First, the characteristics of the techniques, methods, and methodologies presented in the book are elucidated. Subsequently, the significance and issues of the technological view suggested in the book are discussed. A new technical framework for land consolidation is then suggested．

Labor saving in irrigation and drainage facility management is an important task because of the advancing labor shortage in rural areas in Japan. We conducted a field study to evaluate the amount of labor demand to operate those facilities by the “A” Land Improvement District (LID). In this study, we carried out field work about facility locations, types of management activities, amount of work, and amount of travel in a paddy irrigation district with irrigation pipelines. At 167 facility sites, the average number of work events was 17 per day, and the average amount of working hours was 1.5 hours per day. Operation of pump stations required the greatest amount of labor both in terms of time and number of work events, accounting for about 50% of the total work at facilities. Water distribution required the greatest amount of work, and was characterized by having many work events with short working hours per event. These results show that reducing the amount of work in the water distribution process would be an effective way to save labor in irrigation and drainage facility management in this LID.

This case study was conducted to clarify the primary factors that contributed to the continuous conversion of agricultural land into residential housing sites in the 12 years following the abolition of the Urbanization Adjustment Area (UAA) zoning by the City Planning Act. The effects of demands concerning agricultural land conversion were examined on both developers and agricultural landowners in the former UAA of Saijo-city in Ehime, Japan, while focusing on the relationships among housing types, location of conversion, and zoning for agricultural sites. Integrated size of the area and the location emerged as important factors that led to continuous conversion after the period needed for both parties to reach agreement on terms and conditions. Agricultural land was particularly converted into built-for-sale houses and apartments for rent very shortly after zoning abolition. The existence of a White Area Zoned for Agricultural Use around the Urbanization Area (UA) prevented wanton development or commercial land sprawl by confining housing just around the UA and helped to preserve the surrounding rural area. Furthermore, intentions of agricultural landowners seemed to take precedence over potential developmental needs when selecting the location of conversion for a general dwelling house.

Groundwater discharge into distributary channels on an alluvial fan is a local hydrological process distinct from the regional water cycle of the whole fan. Radon and chemical composition analyses of water samples from the Tedori River alluvial fan, within a local area of such groundwater discharge, revealed that the discharging groundwater occurs through the flow paths and recharge sources that differ from those of artesian groundwater in the aquifer at the seaward edge of the fan. Cross-correlation analysis of rainfall and riverbed water temperatures identified a 2–3-day episodic process linking rainfall and groundwater runoff in summer. This finding implies that in winter, the persistent wet condition of the surrounding paddy fields would cause continuous groundwater discharge. This small-scale groundwater process may be influenced by water management practices in paddy cultivation.

Variable speed control of irrigation pump for small paddy fields was investigated by hydraulic analysis of modeling pipeline system. The method to create target pressure curve for estimated constant end-pressure control, which is used for water supply systems, is proposed and assessed when applied to paddy irrigation systems. The water distribution and the water power of various variable speed control pump systems were estimated on this model. It was revealed that terminal pressure control measuring pressure at all end points can provide most adequate water supply. Though estimated constant end-pressure control is slightly poor at both water distribution and energy saving than terminal pressure control measuring pressure at all end points, water distribution of that control is better than that of terminal pressure control measuring pressure at limited points. Estimated constant end-pressure control can reduce the water power to 40 % of pump driving at designed operating point. Estimated constant end-pressure control is advantageous when adopting measuring equipment to all end points is difficult.

There has been concern that the increased turbidity in the Atsuma River due to large slope failures caused by the 2018 Hokkaido Eastern Iburi Earthquake may have an effect on the intake of agricultural water in the area. In this study, a series of observations was conducted to determine the condition of turbidity water at four headworks in the Atsuma River mainstream, and a management method of intake for agriculture was considered. The observation results from the non-irrigation season showed a relationship between the maximum suspended solid concentration at all four points and the slope failures area rate for each tributary basin. On the other hand, in the irrigation season, the peaks of suspended solid concentrations were delayed and abrupt increases were reduced due to the effect of residence at headworks. Therefore, the maximum suspended solid concentration gradually decreased as the water traveled through the headworks from upstream to downstream. As a disaster reduction method to prevent the intake of turbidity water or to minimize its effect, we calculated the criterion times for water intake operation, and considered a management method of intake for agriculture that could become a guideline for intake gate operation.

Zinnia was cultivated on light oil-contaminated soil to investigate the growth of the Zinnia plants, the change in soil physical properties over time and the purification of the oil-contaminated soil. Zinnia plant height and dry matter weight increased significantly by the 40th, 80th and 120th days after the start of the test. Soil TPH concentration decreased significantly over time. Also, the amount of soil DHA increased significantly from 80 to 120 days after the start of the test. There was little change in soil dry bulk density or total porosity, but coarse porosity increased over time. Among the microorganisms living in and around the rhizosphere soil of Zinnia, the microorganisms with oil resolution are the ones that are able to detect light oil components. Some of the soil microorganisms in the Zinnia rhizosphere can use light oil compounds as energy sources to enhance their activity and growth. Therefore, it is thought that this contributed to the purification of the light oil-contaminated soil.

A simple automatic control method was envisioned for the autonomous navigation of a radio-controlled mower based on a commercial bush cutter that was developed for aquatic plants in irrigation canals and was verified by a model experiment. The method aimed to zigzag between the right and left canal walls when flowing down from upstream to downstream. The experimental hull model was approximately 33 cm in length and 25 cm in width and had one rudder. An Arduino-compatible control board controlled the servomotor to steer the hull by signals from sensors on the hull. A thread with a weight was attached to the back of the hull. The hull dragged the weight and flowed down. As a result of the model experiment, zigzag navigation was realized by steering the rudder by detecting the right and left canal walls using an infrared photo reflector and/or the distance from the canal wall using an ultrasonic distance sensor.

The objectives of this study are to evaluate the effects of freeze-thaw action on the abrasion resistance of a cementitious surface coating material. We prepared both air entrained (AE) and non-air entrained (nAE) Ordinary Portland Cement mortar beams with water-cement ratios of 40, 50 and 60%. After freezing and thawing tests were conducted on these specimens, they were subjected to the water jet abrasion test to investigate the effects of freeze-thaw action on their abrasion resistance. In the AE specimens after the freeze-thaw tests, the relative dynamic moduli of elasticity were over 90%, and the progress of degradation due to freeze-thaw was small. In the nAE specimens after the freeze-thaw tests, the relative dynamic moduli of elasticity were less than 40% at the maximum at the placement surface, 70-80% at the bottom surface, and 80-90% at the specimen center. Deterioration due to freeze-thaw progressed on the both surface layer. In addition, there was a difference in the progress of deterioration depending on the part of the specimen. The average wear depth of the mortar specimens after water jet abration test becomes smaller as the W/C is smaller and the surface quality is more dense in the initial state before being subjected to freeze-thaw action. The average wear depth of the mortar specimens after the freeze-thaw test increases as the relative elastic moduli of the specimens around surface layer decreases due to the freeze-thaw action. In this test, the abrasion resistance of the mortar containing after the freeze-thaw test was significantly improved by the addition of AE admixtures. This result suggests that the use and management of appropriate AE admixtures are important for securing frost damage resistance of mortar materials in frost damage environment.

Joint filling using single-component sealants is commonly employed in the repair of joints in irrigation channels, owing to its ease of use and economic efficiency. However, sometimes a single-component sealant becomes deformed soon after it is applied due to swelling, rupture, or leakage under the impact of back water pressure. This study focused on sealants for irrigation channels, and hardening confirmation tests and water pressure resistance tests were conducted, with evaluated the impact of deformation on the waterproofing of early-age sealants. The results show that at a low temperature of 0 ℃, each sealants manifested strength about 1 to 2 weeks later than at a temperature of 23 ℃. Additionally, when the acting water pressure exceeded 0.02MPa, balloon-shaped swelling and rupture of the single-component and two-component sealants occurred, reducing waterproofing. The results also revealed that the fast-hardening, three-component sealant is highly resistant to deformation caused by water pressure.

Growth of aquatic plants to physically large sizes can cause a decline in waterway areas and negatively impact scenic views. We determined optimum mechanical treatment month for aquatic plant control, of a colony consisting mainly of Elodea nuttallii, in an irrigation channel located in the Tohoku region of northern Japan. We removed aquatic plants using an engine-powered water jet in early August and mid-September and observed aquatic plant colony heights and surface aquatic plant varieties. We set up 4 test blocks, each of which consisted 48 monitoring stations and analyzed by comparing test blocks. Early August treatments did not show significant effects, since treated colony heights were similar to those of untreated blocks. However, colony heights did not reach the water surface and thus did not cause scenery deterioration. If aquatic plants do not grow rapidly enough to reach the water surface, mid-September treatments could be skipped. Conversely, mid-September treatments could effectively reduce October colony heights.

We investigated a method for utilizing the underdrain cleaning system in paddy fields in Hokkaido as a means of subirrigation for soybean and winter wheat. During the period of greatest soil water uptake by these crops, the set water level was 30 cm below the surface when the soil water potential of the primary root zone fell below -31 kPa, and subirrigation was carried out by using the underdrain system one day after reaching the set water level. The results demonstrated that both growth and grain yield were increased by subirrigation. In addition, we calculated the number of days until the soil water potential in the root zone returned to -31 kPa or less after rainfall or subirrigation using the observation data for soil water potential. Based on these results, we proposed a method by which subirrigation is conducted more than 10 days after 20 mm or more of event-wise precipitation for soybean fields and more than 15 days after 20 mm or more of event-wise precipitation for winter wheat fields.

This study examines determinants of preference and non-preference for the MARUDORI system in farming, which has been touted to have several benefits. We used the Evaluation Grid Method to identify what the users—the citrus farmers who use the MARUDORI system—find attractive about specific features. Results of the interview surveys show that principal determinants of preference are labor load and quality of citrus produced. This suggests that farmers accept the features of the MARUDORI system that help reduce workload and produce good results. Principal determinants of non-preference are related to the problems in installing and operating the system, including lack of instruction and risk of failure. These factors need to be resolved to further the usage of the MARUDORI system.

Material strength characteristics (internal frictional angle φ, cohesion c) of a reservoir embankment for irrigation in Aomori prefecture were assessed using conventional direct shear test (DST) and in-situ vane-cone shear test (VCST). Based on the main physical properties of natural water content (ω), fine fraction content (F_c) and the dry density (γ_d), many reservoir embankments have been constructed using foundation ground material obtained near the reservoir. The shear stress ratio (τ/σ_v) was found to be convergent, around 0.5, with increased vertical stress (σ_v) in DST. Much of the vertical displacement tended to move the compression side. Because many values of τ/σ_v in VCST were scattered, we were able to infer some difficulties within the range of experimental accuracy. Although no correlation was found by φ_d in DST and φ_v in VCST, the values of c_d in DST were higher than c_v in VCST. Furthermore, a certain degree of correlation of φ_d × γ_d to F_c/ω was confirmed.

This paper focuses on the feasibility and issues of collective irrigation using small village reservoirs. A participatory on-farm trial was conducted on supplementary irrigated rice cultivation using a small reservoir near Tamale, the capital of the Northern Province of Ghana. We examined and analyzed the operation, fund management, and organizational activities based on the rules established by the farmers. The results show that farmers can 1) increase their yields through collective irrigation based on the rules, 2) pay the fuel cost for irrigation, 3) highly appreciate the penalties among the rules, and 4) recognize the supplementary irrigated rice cultivation as a cultivation method with a high increase in yield, thus have incentives to use collective irrigation. Some challenges include improving coordination among farmers and equalizing field conditions to realize a more even water supply. Furthermore, educational support and external interventions are needed for the better management of funds and implementation of rules.