The future solid waste management toward carbon neutralization will have to deal with problems on decreasing in the amount of burnable waste accompanying with population decreasing and promotion of 3R in each municipality. This study optimized the size and layout of incineration facilities and relay and transfer stations for municipal burnable waste in Hokkaido in 2050, regarding the total costs or energy. In the cost optimization, the effects of increase in the number of relay and tranfer stations on the cost reduction were large until the number of incineration facilities of 10, and the total cost was the lowest when the numbers of incineration facilities and relay and tranfer stations were 19 and 9, respectively. In the energy optimization, the net energy consumption was the lowest when the numbers of incineration facilities and relay and transfer stations were 1 and 20, respectively. These results are expected to be shared to enhance consensus building to integrate incineration facilities to be renewed until 2050.

 In this study, the impact of climate change and land use change on disaster debris potential was assessed using inundation depth data from flood inundation analysis by socioeconomic scenario, SSP (Shared Socioeconomic Pathway). As a result, it was pointed out that climate change can increase the amount of disaster debris potential from 1.10 to 1.30 in 2031 to 2050 and from 1.06 to 1.43 in 2081 to 2100, compared to the 1981 to 2000 base climate. The effect of population distribution on the amount of disaster debris potential was analyzed, and it was indicated that the amount of disaster debris potential due to climate change decreases due to population decrease, however, the disaster risk in terms of the amount of disaster debris per capita can increase.

 We investigated the effect of earthquake-resistant housing on reducing the amount of disaster waste generation in prefectures, cities, wards, towns and villages in the Kansai region following the Nankai Trough mega-earthquake. For this purpose, we set and analyzed the current scenario based on the current seismic retrofitting rate, the seismic retrofitting plan scenario based on the target seismic retrofitting rate of the seismic retrofit promotion plan, and the complete seismic retrofitting scenario with a seismic retrofitting rate of 100%. Results show that, compared to the current scenario, the amounts of disaster waste reduction in the seismic retrofitting plan scenario and the complete seismic retrofitting scenario were estimated to be about 6.6 million tons and about 10.6 million tons, respectively. In the complete earthquake resistance scenario, Osaka prefecture had the largest amount of reduction at 3.4 million tons, followed by Wakayama prefecture at 2.1 million tons, and Hyogo prefecture at 1.9 million tons. The reason why disaster waste can be reduced by about 40-50% in Osaka and Wakayama prefectures is because they have many municipalities where seismic reinforcement has not progressed in areas where the expected seismic intensity is 6+.

 The joint collection and recycling of waste plastic packaging and other waste plastic products is expected to increase the amount of recycled plastic materials; however, it may pose harmful influences on plastic recycling system, such as the decrease in plastic waste quality. This research investigated the influences that the joint collection may pose on mechanical recycling facilities as well as on municipalities and the countermeasures based on interview surveys. Although the joint collection may increase the amount of collected plastic waste for recycling, it may lead various harmful influences to plastic recycling processes, particularly by stopping the recycling processes and increasing the amount of residues. Additional counter-measures are practiced to prevent the harmful influences, such as by excluding the harmful plastic products from collection and strengthening the recycling processes. It is essential to assess the benefits of joint collection and the additional countermeasures by multiple indicators including the amount of recycled plastic and recycling costs.

 This study focused on resource collection stations in Tachiarai-town, Fukuoka prefecture, Japan. The survey asked residents about "how to redeem points", "how long it takes to get from their homes to the pickup location", "when they use the pickup location", and "what features they want in a pickup location". Using the results of the questionnaire survey, a choice conjoint analysis was performed to quantitatively evaluate the utility value of each item. As a result, “time required from home to the collection site” was given the highest importance. Principal component analysis and cluster analysis were conducted to divide the respondents into four clusters and quantitatively analyze the trends of each cluster. The results clearly indicated that the geographical and temporal characteristics of the stations and the multifunctionality of the stations in combination with other uses (local community activities, shopping, etc.) are factors that promote the use of resource collection stations.

 The purpose of this study was to determine the effects of pesticide usage on aquatic biota by comparing the biomass of aquatic organisms in fields practicing reduced pesticide farming and conventional farming in lotus root fields in Naruto City, Tokushima Prefecture. Surveys were conducted four times each from May toAugust 2023 using bottle sampling and scoop-net sampling systems.The analysis results showed no significant differences in the biomass of zooplankton and organisms sampled by scoop-net and bottle sampling systems between farming systems. However, significant differences were observed in the biomass of Fejervarya limnocharis and Procambrus clakii between farming systems or season in reduced pesticide farming.This suggests that reduced pesticide farming may have a positive effect on certain species, but no overall recovery effect was observed in the community. Since reduced pesticide farming has been practiced for only five years, it is suggested that the lack of recovery in biodiversity may be due to the relatively short duration of the practice.

 This study aims to understand appropriate methods of nature restoration as the Nature-Positive strategy for abandoned farmlands, which has been increasing in reservoir areas. Therefore, we conducted case study surveys in various types of 14 sites that were restored as nature restoration for abandoned farmlands and attempted to categorize types of nature restoration considering both environmental and human activity factors. The results indicated that the sites of nature restoration were categorized into nine types considering dry to wet conditions and human activities to natural succession. We also discussed to would enhance habitat function and habitat environment of each type by using these methods. In addition, assessment criteria for applying these types were developed and analyzed based on interviews with the people related to the sites. It was understood that 6 assessment criteria should be considered to apply the 9 types of nature restoration.

 The invasive alien diatom Cymbella janischii can cause nuisance blooms in invaded rivers, concerning about its impact on the ecosystem, including damage to fish populationsand, not only spoil the scenery of the river. In this study, we used Maxent software to formulate a model for predicting the distribution of target diatoms in the upper reaches of the Chikugo River based on geographical factors, such as vegetation map, slope, and land use area. The probability of C. janischii occurrence was found to increase with the degree of slope and amount of surrounding land used for buildings. The surface geology was most affected by sand and gravel, followed by andesite; however, this may be due to bias and should be treated with caution. Further field surveys are required to improve the accuracy of the results.

 The purpose of this study is to develop a method of valuing the effectiveness and efficiency of infection prevention measures though the willingness to pay (WTP) analyses targeting the tourists' anxiety from the mortality risk by new Colona virus infections. The WTP research is designed to assume hypothetical tourisms from Tokyo to Hokkaido by the travel costs 36,000 yen (36k) and 45,000 yen (45k), and hypothetical policy effects of from 20% to 80% mortality risk reductions. The maximum and minimum median WTPs are 4,719 yen and 1,266 yen for the cases of travel cost 36k with 80% reduction and of travel cost 45k with 20% reduction, respectively. The measurement results suggest that "alcohol disinfection" and "avoiding enclosed spaces" are considered as effective and efficient policies for reducing tourist anxiety in both the 36k and 45k cases, while "washing hands and gargling" is effective and efficient in the 45k case.

 This study conducted an interview survey of college students participating in environmental volunteer activities. The purpose of this study is to identify factors that contribute to participation and persistence in environmental volunteer activities by using text mining. Nine factors were set as structural hypotheses for the activity: "recreation”, "altruism”, "realization of ideal”, "image”, "purposelessness”, "acquisition of knowledge and skills”, "social”, "career”, and "burden”. As a result of the text analysis, the eight of nine factors were extracted as participation factors, with the exception of "career”. In addition, "parental influence" was extracted as a new factor that is not set in the structural hypothesis. It was suggested that the facilitating factors for the continuation of the activity were "human relations" and "strong altruism”, while the inhibiting factor was "lack of image before the activity”.

 This study targeted Okoppe Town, Hokkaido, and proposed and implemented a method to create a "Regional Resource Circulation Map" that expresses resource circulation within the region through direct interviews with local companies. We were able to visualize the structure of the resource items that enter each industry, where they come from within the town or outside the town, and where the resources go from that industry. Additionally, we were able to visualize not only the micro-level movement of resources in each industry, but also the macro-level resource circulation structure of the town as a whole. Furthermore, network analysis such as centrality index and cluster detection which is one of the objective evaluation indicator revealed that the current regional resource circulation structure of Okoppe Town is characterized by a well-developed dairy-related value chain, and that multiple resource circulations are occurring centered on BGP.

 In recent years, many studies have been conducted on the proper disposal of waste plastics discharged from the agricultural sector. However, there have not been enough studies on the number of plastic materials used and discharged, focusing on the detailed classification of plastic materials by agricultural product category. In this study, we attempted to estimate the material flow of plastics used in agricultural products by classifying them into three categories: fruit vegetables, leafy vegetables, root vegetables, and cereals.

 The results showed that the amount of plastic used per unit cropland area was 850 g/m²/year for fruit vegetables, 330 g/m²/year for leafy greens, 0.97 g/m²/year for root crops, and 2.5 g/m²/year for cereal crops. Emissions per unit cropland area were 350 g/m²/year for fruit vegetables, 63 g/m²/year for leafy stems, 0.97g/m²/year for root crops, and 0.64 g/m²/year for cereal crops.

 Climate citizens' assembly, in which randomly selected citizens as a proxy for the relevant population attend and deliberate on a climate issue, has gained attention, recently. Although they were randomly selected from those who expressed an intention to participate, those who expressed an intention to participate in the first place are likely to be biased against the population. In this paper, the relationship between the attributes and attitudes of citizens toward global warming and their willing or unwilling to participate in local climate assembly was discussed through an online questionnaire survey in Japan. How differences in conferencing methods, such as in-person and online, affect willingness to participate was also examined. Willingness to participate is generally higher in the higher age category, more respondents answered “can not participate” rather than “do not want to participate” in younger age category. Willingness to participate is higher for in-person assembly than for online assembly, particularly in the higher age category mainly due to the unfamiliarity with online conferencing. Respondents were classified into four segments according to their awareness and attitude toward global warming, then willingness to participate was clearly different in each segment. However even in “skeptics” group, there was a certain number of respondents who expressed their willing to participate in the assembly.

 In this study, we conducted a scenario-selective Planungszelle on decarbonization measures for detached houses for the citizens of Kitakyushu, Japan. We quantitatively evaluated the participants' scenario selection process through information provision and discussion based on the questionnaire survey data conducted during the discussion and the conversation data during the discussion. The results showed that the participants as a whole selected scenarios based on the cost performance of the countermeasure equipment before the discussion. In contrast, they selected scenarios based on the social burden in the discussion after providing information on the social burden of subsidies for introducing the equipment. The "proactive group" and the "negative group" selected scenarios mainly based on cost performance. However, the difference was that the former group emphasized reducing social burden, and the latter emphasized cost reduction. The "global warming skeptics" and "global warming indifferent" chose scenarios that maintained the status quo after the discussion due to concerns about the maturity and reliability of decarbonization technologies presented in this study.

 In order to realize the transition to a decarbonized society, behavioral changes on the part of consumers and systems to encourage such changes are required. Climate assemblies, which are small groups of randomly selected citizens who learn, deliberate, and make recommendations about climate policy issues, would help identify widely acceptable decarbonization systems. Referring to four domestic and two British examples of municipal climate assemblies, a detailed design was developed and implemented for Tsukuba City, aiming for the best local climate assembly in Japan at present. By promising in advance that the recommendations would be reflected in policy, and by increasing the amount of reward, we were able to attract a large number of potential participants to make up a mini-public. In addition, by providing opportunities to widely receive diverse opinions and by simultaneously considering changes in actions and systems, we believe that we were able to obtain recommendations that fully reflect the views of the citizens. The recommendations will be organized into a roadmap that indicates the timing of implementation and will be reflected in the action plan for global warming countermeasures.

 In recent years, the use of electric vehicles and car-sharing has been promoted as a means to reduce the environmental impact of the transportation sector. In this study, a case study was conducted in six municipalities in the southeastern part of Saitama Prefecture to evaluate the CO₂ emissions and business feasibility of introducing electric vehicle sharing using a questionnaire-based intention survey. The analysis revealed that the introduction of electric vehicle sharing could lead to a reduction in CO₂ emissions of up to approximately 4.3%, and considering the feasibility, up to approximately 3.2%. Additionally, it became evident that areas with low population density have lower business feasibility.

 Sustainable aviation fuels (SAF) are expected to be introduced to achieve carbon neutrality, but SAF derived from waste residues alone is not sufficient to meet the demand. Microalgae-derived SAF is expected to be a promising source, but its life-cycle greenhouse gas (GHG) emissions are unknown. In this study, the lifecycle GHG emissions of microalgae-derived bio-kerosene (the main component of aviation fuel) were evaluated for the first time. The results showed that recovery by flocculation and extraction using hexane as a solvent after crushing reduced GHG emissions. GHG emissions would be 447.06 kgCO_2e/MJ if CO₂ were produced from fossil fuels, but 140.13 kgCO_2e/MJ if GHG-free CO₂ were available from large-scale emission sources. Furthermore, under the 2030 power supply mix, GHG emissions were found to be 42.63 kgCO_2e/MJ, half the GHG emissions of kerosene from petroleum sources.

 Under the circumstances where factors that hinder production activities, such as a shortage of labor-intensive workers, are becoming apparent, the agriculture, forestry, and fisheries industries are required to decarbonize. Against this backdrop, the "Strategy for Sustainable Food Systems, MIDORI" has been formulated, which aims to achieve both productivity improvement and sustainability in the food, agriculture, forestry, and fisheries industries. This strategy calls for a complete transition to a fossil fuel-free horticulture by 2050. As a short-term transition strategy until the corresponding technological innovation, it is important to select eco-efficient covering materials. In this study, we analyzed the effects of different combinations of outer and inner cover materials on GHG (Greenhouse Gases) emissions and business feasibility of environmentally controlled horticulture, and evaluated the combinations with high eco-efficiency. As a result, it was found that the combination of Ethylene Tetra Fluoro Ethylene (ETFE), which is an expensive covering material with high transparency and little change in light transmittance over time, as an outer covering material and polyvinyl chloride as an inner covering material had the highest eco-efficiency.

 Reactive nitrogen, it is presumed that, has been over the planetary boundaries, thus nitrogen flows (NF) with human activities should be estimated appropriately for the sustainable management. Numerous studies, especially in Europe, have already quantitatively analyzed NF and the sectoral flows mainly for agriculture have been identified, while results on wastewater treatment sector remain limited. In addition, though Japan is one of the few Asian countries that has accumulated scientific knowledge on national NF by some researchers, NF of the only sewage treatment plant (STP) have been estimated for a domestic wastewater. However, Japan has been operating various domestic wastewater treatment systems (DWTS), as well as STP, in such a way as to match regional characteristics, but there is no reliable analysis on NF by DWTS including STP yet even though treatment capacities may be different. Therefore, this study evaluates national nitrogen inflow by DWTS between 2005 and 2019 by compiling the nitrogen inflow estimates for 1, 731 municipalities in Japan. The municipal nitrogen inflow is calculated by multiplying number of users by DWTS, namely sewage treatment, onsite treatment (called as “Johkaso”), community plant, the others and pit toilet, by per capita nitrogen intake as food, for a municipality, using statistical data. As the results, total nitrogen inflow in Japan was almost flat (504–540 GgN/year), in the target years, and NF into STP were constantly dominant (333–411 GgN/year). Furthermore, in the past 15 years NF into pit toilet and the others decreased, while NF into STP and Johkaso increased, instead. It is found that the NF into STP is 20–30% lower than that of the past study due to differences of system boundaries. Meanwhile, NF into STP using plant-based data differ by region, which are presumably caused by differences of practical usage of and other inflows into STP.

 The river water in the Tama River includes river water from the Tone and Arakawa Rivers as recycled sewage water. The ratio of river water was estimated to be 17.2% on average per year and 43.1% on the maximum day in 2018. When the flow of the Tama River was insufficient, the ratio of river water was estimated to be 24.0% on average during the year and 44.7% on maximum day. Then, the percentages corresponding to abundant (95-day flow), normal (185-day flow), low (275-day flow), and drought (355-day flow) conditions were estimated to be 18.6%, 26.3%, 29.9%, and 41.9%, respectively. Recycled water in the river water of the Tama River, which originates from the Tone and Arakawa Rivers, is important for maintaining the river water volume, and this condition is maintained by the water cycle of man-made systems such as water supply and sewage systems. From the point of view of the water cycle, it is necessary to clarify the position of the water cycle of man-made systems in the Basic Law on the Water Cycle and its Plan. Furthermore, it is argued that the water cycle perspective should be taken into consideration when discussing the water environment in terms of ensuring the normal function flow, ensuring stable water supply in times of disaster, and investigating the Water Environment Soundness Index.

 In this study, we developed a discrete water pipeline dagame estimation method that can be used for pipe network analysis considering damage to water pipelines based on data on the damage mode of pipelines in past earthquake disasters in Japan. the existing pipeline damage data were classified into leakage and deviation, and the occurrence ratio of each type of pipeline was clarified in the development of the damage mode estimation model. Based on a statistical study of the existing pipelines, water pipeline damage fragility curves were developed using the maximum likelihood estimation method for each pipe type. As a result, a discrete water pipeline damage estimation model was established, which can be used for pipe network analysis considering water pipeline damage.

 Reservoirs, which have various roles other than being a water source, are closed spaces that are greatly affected by the quality of water from incoming rivers and rainwater from the surrounding forest soil. The forest's water source recharge function plays various roles such as storage of water resources, flood mitigation, and purification of water quality, and forest management is essential to obtain high-quality raw water for water supply. In this study, the relationship between vegetation data, dissolved ions in the inflow river, and the constituent elements of forest soil was analyzed by comparing them with the state of the forest to clarify the relationship between them. Furthermore, principal component analysis was conducted using data on dissolved ions in the inflow rivers of the Ogochi Reservoir to compare water quality from one inflow river to another to clarify the characteristics and properties of the catchment area of each inflow river, and to propose a water source forest management method for better raw water supply.

 Understanding the stock and flow on construction sector in flood hazard areas is important for assessing future flood damage and considering land use regulations in flood hazard areas. This study estimated material stock and flow on construction sector at the individual building level and revealed the trends in flood hazard areas. As a result, the building stock in flood hazard areas increased from 2003 to 2020, accounting for approximately 42% of the total national building stock. Especially, the stock of non-durable low-rise wooden buildings in hazard areas with flooding depth of over 3 meters had reached over 195 million tons nationwide by 2020. It was evident that the stock turnover rate is similar both inside and outside flood hazard areas, indicating that buildings have been constructed without considering flood risk.

 In recent years, exacerbation of river disasters due to climate change has become a significant issue, and adaptation, including not only river channel maintenance but also watershed management, has been advocated. Paddy field dams have been recognized as excellent flood control elements, and methods for properly evaluating their effectiveness are being sought. This study examined the impact of both the total area of paddy fields and the condition of waterway networks on storage characteristics through laboratory experiments. Three types of paddy field models with different areas were used in the experiments to investigate the effects of the presence of paddy field dams and the complexity of waterway networks on runoff control. The results showed that while the outflow from paddy fields is effectively suppressed by paddy field dams, the storage capacity of waterway networks decreases. Additionally, it was demonstrated that the more complex the waterway network, the greater the increase in storage capacity within the network.

 The purpose of this paper is to clarify the mechanism of the germination and propagation of "Waku-waku" feeling, which means feeling of anticipation or excitement, through "Collaborative Nature Restoration". We conducted a questionnaire survey of both active and passive participants in "Collaborative Nature Restoration" activities, and performed a covariance structure analysis, with the aim of clarifying the mechanism by which “Waku-waku” feeling is generated and spread through "Collaborative Nature Restoration." The results showed that the "fun of gaining knowledge" from learning about rivers had a large influence on the generation of “Waku-waku” feeling among active participants, while the "fun of creation" from doing hand-made work had a large influence on the generation of excitement among passive participants. It was also revealed that the generation of “Waku-waku” naturally leads to the spread of “Waku-waku”. This suggests that in order to make active participants “Waku-waku”, events that allow them to gain new knowledge should be created, and in order to make passive participants “Waku-waku”, programs centered on hand-made work should be created to make "Collaborative Nature Restoration" activities better.

 Nocturnal drainages which have a potential to lower air temperature of their outflow points, are thought to occur when air masses of relatively low potential temperature formed in relatively large river drainage areas, concentrate and flow down along the rivers. The author call such nocturnal drainages “cold air flows”. In Osaka Plain, relatively large-scale cold air flow is expected to occur along Yodo River. In this study, numerical simulations were carried out using the WRF to examine flow structures of the cold air flows that form along Kizugawa River, which is thought to be the mainstream of the Yodo River cold air flow. It was found that westward cold air flows form along the main stream of Kizugawa River from the Ueno Basin to the Kyoto Basin, that after their outflow into the Kyoto Basin, the flows extend to the Osaka Plain via the so-called three river confluence point or over the northern part of Ikoma Mountains, and that the flows can locally lower air temperature in the Osaka Plain by 2K or more.

 This paper conducted an analysis of the service life of ductile cast iron pipes wrapped in polyethylene sleeves. In a previous study, focused on the pitting corrosion that occurs on the outer sur-face of ductile cast iron pipes due to aging, and attempted to analyze the prediction of water pipe deterioration. Using the pitting corrosion depth prediction formula, we calculated the service life of pipes that are not wrapped in polyethylene sleeves. However, for pipes wrapped in polyethylene sleeve, there remained problems in applying the pitting corrosion depth prediction formula, such as large variations in data. Therefore, adding the latest data, reexamined the pitting corrosion depth prediction formula, and conducted multiple analyzes using physical property test results, etc., and attempted to reexamine the service life with polyethylene sleeves encasement . As a result, analysis of measured data confirmed that polyethylene sleeves encasement can extend the service life by at least 20 to 40 years.

 The Imazu tideland is located at the estuary of the Zuibaiji River in Fukuoka City, which is an important habitat for rare species, such as Corbicula japonica, Batillaria multiformis, and Periophthalmus modestus. To prepare for future restoration and management of the tideland environment, we attempted to understand the status of benthic organisms by conventional morphological observation of the inflow river and to detect them from environmental DNA. Comparative analysis using the non-metric multidimensional scaling method revealed differences in biota between tidal flats and transitional areas to rivers. Although the number of species detected in the environmental DNA was small, we were able to obtain information on the presence and genetic diversity of Stosicia annulata, which could not be confirmed by morphological observation, as well as information on hybridization with the alien species Corbicula fluminea, thus confirming the effectiveness of the environmental DNA survey.