Language：Japanese   Publishing type：Research paper (scientific journal)  

CHANGES IN MOUNTAIN CHANNEL TOPOGRAPHY AND RIVERBED MATERIALS AFTER THE 2017 NORTHERN KYUSHU FLOODS, JAPAN

Authorship：Last author   Language：Japanese   Publishing type：Research paper (scientific journal)  

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Language：Others   Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

An open levee system is a traditional flood mitigation system for reducing the expansion of inland flooding and decreasing the peak flow. However, there have been few quantitative studies on its feasibility. Furthermore, the differences in applicability depending on the topography and the construction of continuous levees have not been fully examined. We studied its feasibility based on simulations in the Kuji River area, where the vast Typhoon Hagibis occurred. Morphological models representing the past (the 1940s) and the present (2019), obtained by modifying the highly accurate digital elevation models (DEM) via the tracing of aerial photos, were applied to a 2D unsteady flow simulation model to reveal the effects of the levee system on river hydrography and overland flood behavior. The results indicated that inundation flow through an open area decreased both inundation duration and depth, while the reduction of peak discharge is relatively insignificant at approximately 10%. The sub levees are not adequate under the current conditions and floodwater volume, and their effectiveness depends on the surrounding conditions, such as the development of continuous levees.

DOI： 10.3390/w14091343

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Language：English   Publishing type：Research paper (other academic)   Publisher：IOP Publishing  

Abstract

The diverse socio-cultural conditions in Indonesia can make it difficult to develop sustainable micro-hydro power (MHP) generation in rural areas. However, the existing framework of sustainable development indicators to assess MHP sustainability does not include indicators for locations with traditional characteristics. This study aimed to develop indicators related to the specific cultural features for evaluating the sustainability of MHP generation. The identification of indicators was accomplished through field investigations and literature studies. Thirty-one experts in the Delphi method validated the indicators. The results revealed three indicators related to specific traditional characteristics and importance to the sustainability of MHP generation, i.e., electricity-supported cultural activities, customary rules of environmental protection, and directive of a traditional leader. These indicators can be elaborated with the existing framework and expected to increase sustainability assessment efforts for MHP generation in remote locations.

DOI： 10.1088/1755-1315/994/1/012003

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Other Link： https://iopscience.iop.org/article/10.1088/1755-1315/994/1/012003/pdf

Language：Japanese   Publisher：Japan Society of Civil Engineers  

<p>洪水氾濫による人的被害軽減のため，機械学習を活用した洪水氾濫予測に関する研究が進められている．筆者らはランダムフォレストを用いて地形と浸水の関係性から洪水氾濫域を推定する手法を提案し，高精度で鬼怒川内の氾濫を推定した．本研究では，同手法を用いて，地形条件の異なる複数の地域でモデル構築を行い，各地域での適用性を明らかとすることを目的とした．結果として，全対象地域における氾濫を高精度で推定可能であり，対象地域の地形的特徴によって氾濫推定の際に重要となる説明変数が異なることを明らかとした．さらに，本手法における汎化の試みとして，未学習地域への推定を行い，説明変数の寄与率に類似性がある場合は，ある程度良好な推定結果が得られることを明らかにした．</p>

DOI： 10.11532/river.28.0_43

CiNii Research

Language：Japanese   Publisher：Japan Society of Civil Engineers  

<p>低頻度の大洪水時の河道変化については，稀な事象を対象とするため研究事例が少ない．特に大規模に改変された河道が，その後の時間の経過と共にどのように変化していくかの報告は見られない．本研究では，2017年九州北部豪雨災害を受けた，地質の異なる3つの山地河川を対象に，UAV等により地形測量・解析と河床材料調査を実施し，低頻度大洪水後の数年間における河道地形と河床材料の変化を明らかにした．結果として，低頻度大洪水時の河道変化の状況および，その後数年間における地形や河床材料の変化の様相は河川によって大きく異なり，河床材料や岩盤の特徴を規定する地質の影響が示唆された．花崗岩類の白木谷川支川などは，大洪水の後も継続的に河道が大きく変化しており，大洪水前の河床高に近づけば変化が収束する訳ではなく，災害前と異なる河床高に変化していくことなどが確認された．</p>

DOI： 10.11532/river.28.0_19

CiNii Research

Language：English  

DOI： https://doi.org/10.3390/en14206727

Language：Others   Publishing type：Research paper (scientific journal)  

The sustainable development of micro-hydropower (MHP) plants is a challenge for rural electrification in developing countries, especially in Indonesia, which has diverse ethnic groups, cultures, and traditions in several isolated locations due to its complex terrain. The uniqueness of a social situation in a location can affect the sustainable electrification development. This study aimed to assess the sustainable development of MHP plants in the Kasepuhan Ciptagelar, which has unique traditions and cultural characteristics. The assessment was conducted using the sustainable development indicator (SDI) method, the Ilskog method, which can include social, economic, environmental, technical, and institutional dimensions. Data were collected through field investigations and qualitative dialogs to understand the culture and ways of thinking. The results of the Ilskog method analysis revealed that the environmental dimensions had the highest scores, whereas economic dimensions had the lowest scores, indicating that the cultural background of the Kasepuhan Ciptagelar impacted the SDI scores. This was attributable to the decision of Kasepuhan’s traditional leader, which strengthened the community commitment to renewable energy use. However, the cultural background adversely impacted monetary income to sustain MHP plants. This study proposed that community innovation and microcredit availability could improve productive activities, resulting in better economic conditions to sustain MHP plants.

DOI： 10.3390/en14206456

Language：Others   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s10113-021-01820-z

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Energy is the prerequisite for social and economic development of a community and country. In Japan, national government is promoting small hydropower (SHP) through a renewable energy policy by providing a high FIT price of 34 yen ( approximately equal to or the image of 0.32 US$/kWh) on energy generated from an SHP of less than 200 kW. Until now, the energy generation was controlled by national government agencies, but now independent power generation businesses are growing at the local community level in rural Japan. For the future growth of SHP, it is necessary to make electricity generation at the local community level. Therefore, these local communities will install and manage their renewable electricity by themselves. It will help to make the community self-sustainable and independent from the national government, and at the same time, it will also lead them to achieve the Sustainable Developments Goals (SDGs) target from community-based action. This paper aimed to discuss an SHP development business model in which local community will become the business owner of the SHP. It means "of the community, by the community and for the community". The community identifies their renewable energy potential and needs, they borrow money from the financial organization or banks, install the power plant and do necessary maintenance and management by themselves. The revenue earned by selling electricity is used to repay the loan, and the rest is used for community development directly (such as local roads construction, agriculture land improvements, community hall maintenance, waterways maintenance, welfare, etc.). This paper also discussed a community-based 50 kW SHP installed in Miyazaki prefecture of Japan as a case study. This SHP is one of the best examples of a community ownership model (Community-based business model). A detailed explanation from planning to investment has been discussed. The local community is getting approximately 112,000 USD per year by selling the electricity, and 162-ton CO2 is estimated to decrease yearly, which will support the achievement of SDGs. Finally, installing this kind of SHP in remote areas will provide managerial skills to the local community directly, plant operation knowledge, and education to local students. Local communities learn the problem-solving skills, which lead them to solve the local problem on a community level by themselves.

DOI： 10.3390/en14113349

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.egyr.2020.11.230

Language：Japanese   Publishing type：Research paper (scientific journal)  

EVALUATION OF FLOOD CONTROL FUNCTION OF IRRIGATION PONDS IN THE ROKKAKU RIVER WATERSHED

Language：English   Publishing type：Research paper (scientific journal)  

Although many significant policies and legislation have been put forth by the Chinese government aiming toward “ecological civilization” for the aquatic environment, in practice, the situation is still undesirable. A pioneering multi-year study has since been conducted on the East Tiaoxi River (a major tributary of the renowned Yangtze River), focusing on fish distribution, influencing factors and habitat requirements, and river health as well. This revealed certain key species, hotspot protection areas, negative impacts of local anthropogenic activities, and inappropriate perceptions and practices of conservation and restoration. We found that not all fish species were equally conserved and that the supposedly ecological engineering measures were initiated without regard for ecological integrity. Our exemplary study appreciates scientific basis and truly ecological notion, and urgently advocates comprehensive and continuous basin-scale scientific investigation of fish biodiversity, and “ecological river”-oriented conservation and restoration action for the Yangtze River Basin and broader areas of China.

DOI： 10.3390/w12113043

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Operation and maintenance of micro-hydropower plants in a remote area of Indonesia: electricity demand-supply conditions and plant operational statuses

In Indonesia, electrification of remote villages has been promoted using renewable energy, such as micro-hydropower generation. Nevertheless, no follow-up survey of operations or maintenance of micro-hydropower plants (MHPPs) has been reported after their introduction to the villages. Therefore, the operational status of MHPPs remains unclear. To clarify details of the operational status of MHPPs managed mainly by local residents in the remote village, we investigated the history of the micro-hydropower project, along with the outline, operation, and maintenance of the MHPPs in Ciptagelar village located in mountainous West Java. The four MHPPs in the village were frequently damaged or broken because of human error and natural disasters. They sometimes stopped for long periods. Our calculation of the MHPP operation and maintenance costs and data related to electricity charges revealed that electricity fees collected from residents can cover standard maintenance costs, but are insufficient to allay disaster recovery costs. Output of the MHPPs estimated from flow regimes of the intake river showed an uneven distribution of the available power. These results suggest that a micro-grid system can be effective because it can effectively use surplus electricity and increase the resilience of MHPPs to natural disasters.

DOI： 10.3178/jjshwr.33.212

Language：Japanese  

Language：English   Publishing type：Research paper (scientific journal)  

© 2020 Elsevier B.V. The continuous warming observed in recent decades as a result of climate change is posing significant threats to the environment, particularly for freshwater ecosystems. Therefore, it is highly important to predict the impact of this phenomenon on habitat suitability. However, such prediction requires the use of an integrated framework in which different parameters can be incorporated. While 1D modelling has been commonly used in river habit suitability simulations, most 1D mathematical models either do not provide enough information for the area along the rivers or do not consider the impact of river basin management on the river flow characteristics. This study seeks to develop such an integrated framework is in which water temperature and hydrologic-hydraulic parameters are jointly applied to simulate habitat suitability. The modeling setup is based on a combination of the Soil and Water Assessment Tool (SWAT) and international river interface cooperative (iRIC) models, and, due to the importance of the water temperature, the water temperature module in SWAT was modified. To examine the effectiveness of this method, Kikuchi basin is selected as the case study, and two different general circulation models, namely HadGEM2-ES and MICRO5, under two representative concentration pathways are applied to evaluate river habitat suitability under climate change conditions. The results showed a reduction in the river flows, water depths and velocities that have slightly positive effects on the habitat suitability of the Kikuchi river. However, this reduction causes some parts of the river to become dry, so that some of the habitats may disappear as a result of climate change. Moreover, it is shown that the downstream section of the Kikuchi river is more vulnerable to climate change. Therefore, migration of fishes to its upstream section is predicted. Finally, the proposed methodology is strongly recommended for use in modeling of other regions suffering water scarcity.

DOI： 10.1016/j.jhydrol.2020.124936

Language：English  

Language：Others  

Socio-economic Development of Local Community through SHP Development: A Case Study of Oohito 50kW SHP in Hinokage town, Miyazaki Prefecture, Japan

Language：English   Publishing type：Research paper (scientific journal)  

Influence of Microtopography and Alluvial Lowland Characteristics on Location and Development of Residential Areas in the Kuji River Basin of Japan

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1080/24705357.2019.1663713

Language：Others   Publishing type：Research paper (scientific journal)  

© 2019 by the authors. Dam removal is typically intended for river restoration or as a countermeasure for aging dams. The influence of dam removal has mainly been studied in large rivers. This study is intended to investigate the influence of the sediment supplied after opening a check dam drain in a small steep stream to contribute to the establishment of sediment release technology form check dam by accumulating the basic knowledge about the influence of sediment release. Deposited sediment in the impoundment was rapidly discharged immediately after opening the drain outlet, and a moderate sediment discharge followed. The water course of the sediments deposited by repeated channel widening and riverbed degradation tended to stop longitudinal topographic changes from downstream. In addition, the turbidity during a flood was high in the first year and tended to decrease in the second year. As for the ecosystem response, changes in the benthic macroinvertebrate community were confirmed in downstream sites, and net-spinning species especially deceased immediately after the sediment supply began. Our monitoring results suggest that the increasing turbidity was suppressed during the flood because sediment release was conducted from the small-scale facility. As a result, a negative impact on the aquatic ecosystem seemed to be reduced.

DOI： 10.3390/w11040716

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Others  

Combined Small Hydropower Technologies in Asia: Indonesian Turbine, Japanese Electrical Control and Indian Calculating Model
Edited by: Japan council for Renewable Energy

Language：Others   Publishing type：Research paper (scientific journal)  

Investigating the influence of various stormwater runoff control facilities on runoff control efficiency in a small catchment area
© 2018 by the authors. Licensee MDPI, Basel, Switzerland. Urbanization causes an increase in the flood discharge because of the infiltration capacity. Furthermore, extreme precipitation events have been an increasing concern for many regions worldwide. This study aimed to investigate the influence of different outflow control facilities on runoff reduction in a small watershed. We focused on the soil-improvement technology and rainwater tanks as outflow control facilities and conducted a runoff calculation using a rainfall event of a magnitude that is likely to occur once in a hundred years. The calculation showed that the soil-improvement technology reduced runoff during long-term continuous rainfall, whereas in a concentrated short-term rainfall event, a significant difference in the runoff reduction effect between rainfall tanks of various volumes was observed. Since effective countermeasures for runoff reduction differ depending on the rainfall distribution pattern, we suggested both facilities for storing initial rainfall and initiating countermeasures for penetration improvement over the long term.

DOI： 10.3390/su10020407

Language：Japanese  

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.2208/jscejhe.74.5_I_1255

Language：Japanese  

DOI： https://doi.org/10.3178/jjshwr.31.262

DOI： https://doi.org/10.3825/ece.19.165

Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： https://doi.org/10.1016/j.egypro.2017.11.044

Language：Japanese  

DOI： https://doi.org/10.2208/jscejhe.72.49

Language：English  

Language：English  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Others   Publishing type：Research paper (scientific journal)  

Effect of waterfalls on fluvial fish distribution and landlocked Rhinogobius brunneus populations on Yakushima Island, Japan
© 2014, The Ichthyological Society of Japan. The distribution of fluvial fish was surveyed at 55 sites on Yakushima Island, Japan, which has precipitous mountains and waterfalls (below- or no-waterfall sites: 31; above-waterfall sites: 24). Eleven diadromous and one river resident (introduced Oncorhynchus masou masou) species were found, but absolutely no fish were detected at the 18 above-waterfall sites. Statistical analyses revealed that the presence of waterfalls (> 5 m in height) below the sites had a significant negative effect on fish distribution, suggesting that waterfalls prevent migration of diadromous fishes. We found Rhinogobius brunneus populations above high waterfalls such as Nunobiki Falls (50 m) and Ohko Falls (88 m). Otolith Sr:Ca ratios and mitochondrial DNA (cyt-b region) were examined to determine the migratory history and genetic properties of these populations; the Sr:Ca ratios indicated that the populations had a landlocked life cycle, whereas the genetic endemism/isolation of landlocked populations was unexpectedly absent. There is no clear explanation for this phenomenon, but fairly infrequent individuals of nonlandlocked type might have migrated beyond the waterfalls with their sucker-like organ and mated with landlocked populations, disrupting the genetic isolation of landlocked populations.

DOI： 10.1007/s10228-014-0400-4

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.4236/oje.2014.47031

Language：Others   Publishing type：Research paper (scientific journal)  

Navigation disturbance and its impact on fish assemblage in the East Tiaoxi River, China
We provide the first evidence for navigation impact on resident river fish in China. The survey was conducted in the East Tiaoxi River that discharges into Lake Taihu near Shanghai, on which cargo ship traffic has dramatically increased in the recent economic development period. Water turbidity, ship traffic and other environmental factors were evaluated at 29 sites on the river. In a multiple regression model with the stepwise method, turbidity was significantly correlated with ship traffic (R 2 = 0.53). Another survey was conducted at 46 sites in the same area of the river, in which environmental factors were evaluated and fish individuals were electrofished. A generalised linear model with the stepwise method was applied to predict ecological indicators of the fish assemblage (species richness, individual density and Shannon's diversity index) based on environmental factors. The results showed that the indicators were negatively correlated with turbidity and presence of artificial shore embankment structures. Another analysis further showed that the negative effect of turbid water was especially considerable for fish of smaller size. In conclusion, cargo ship traffic has a negative impact on fish assemblage, especially on smaller individuals, in the East Tiaoxi River. A higher profile for conservation actions and consideration of environmental impacts of such traffic should be given increasing focus for this and other similar East Asian water courses. © 2011 International Consortium of Landscape and Ecological Engineering and Springer.

DOI： 10.1007/s11355-011-0181-0

Language：Others   Publishing type：Research paper (scientific journal)  

Index of biological integrity (IBI) based on fish to assess the river health in the East Tiaoxi River was established in this study. Two IBI systems and assessment criteria were established due to sampling sites being from two different eco-regions. The sampling sites from the tributaries in the upper reaches of East Tiaoxi were in the eco-zone of evergreen broad-leaf forest between Zhejiang Province and Fujian Province, and IBI in the tributaries was established including species richness (M1), percentage of species in the Balitoridae to species richness (M5), percentage of endemic species to species richness (M6), Shannon-Wiener's diversity index (M7), percentage of invertivores to abundance (M13), percentage of herbivores to abundance (M14) and percentage of intolerant species to abundance (M16). The sampling sites from the middle-lower reaches of East Tiaoxi River were in the Eco-zone of agriculture area in urban and suburban in the Yangtze River Delta, and IBI in the middle-lower reaches was established including species richness (M1), percentage of species in the Gobiidae to species richness (M4), percentage of endemic species to species richness (M6), Shannon-Wiener's diversity index (M7), percentage of species inhabit in the up layer to species richness (M8), percentage of species inhabit in the middle-up layer to species richness (M9), percentage of herbivores to abundance (M14), percentage of species spawn in shells to species richness (M21), abundance (M22) and percentage of DELT to abundance (M23). The status of river health was categorized into five levels, such as 'healthy', 'fair', 'poor', 'very poor' and 'no fish'. Two IBIs were applied to assess the 45 observation sites in the East Tiaoxi River in 2010 and 2011. The results showed that the river's health was mainly at the status of 'fair' and 'poor'. By contrast in 2011, the observation sites of 'healthy' and 'fair' decreased by 1 and 2 sites than those in 2010, respectively. Meanwhile, the observation sites of 'poor', 'very poor' and 'no fish' increased by 1 site than those in 2010, respectively.

Language：Others   Publishing type：Research paper (scientific journal)  

Distribution pattern, threats and conservation of fish biodiversity in the East Tiaoxi, China
East Tiaoxi River is one of the largest inflowing rivers into Taihu Lake, and the fish fauna in the river is poorly understood. In the present study, an extensive survey of fish was conducted in October and November 2009, May and September 2010 and May 2011 covering a total of 55 sites along the whole river. A total of 84 freshwater fish species belonging to 8 orders, 18 families and 52 genera have been recorded. Among these are 35 species endemic to China, and 3 newly recorded exotic species. The fish composition varies greatly from headwaters to downstream. Based on cluster analysis with presence-absence data, the East Tiaoxi River is divided into four regions, specifically, the upper reach, middle-up reach, middle reach and lower reach. It is observed that species richness and the proportion of omnivorous species increased from upstream to downstream while the proportion of invertivorous species decreased consequently. Habitat alteration, overfishing, pollution and inland navigation adversely affect the fish diversity and ecosystem functioning in the East Tiaoxi River. To protect fish diversity more effectively in the area, the conservation of fish biodiversity in the North Tiaoxi River and Middle Tiaoxi River should be considered as a priority. Meanwhile, shallow zones or backwater areas should be created in the middle-lower reaches. Furthermore, river restoration, in terms of habitat creation, should be considered to protect the structure and diversity of fish communities, halt the progressive deterioration of freshwater ecosystems and sustain a valuable ecological resource for humans. © 2012 Springer Science+Business Media B.V.

DOI： 10.1007/s10641-012-0036-z

Language：Others   Publishing type：Research paper (scientific journal)  

Fishes of the east Tiaoxi river in Zhejiang Province, China
We conducted fish sampling at 90 sites in the East Tiaoxi River, Yangtze River basin, China. Seventy-seven species belonging to 19 families were recorded, and photographs of live specimens are provided for all species. Three exotic species were recorded: Cirrhinus cirrhosus, C. molitorella, Gambusia affinis. The top 3 species-rich families were Cyprinidae (46 %), Cobitidae (5 %) and Gobiidae (5 %). The species composition in the East Tiaoxi River is similar to that of the Yangtze River Basin; however, the East Tiaoxi River has quite a diverse fish fauna for a small river system. © 2013 by Verlag Dr. Friedrich Pfeil, München, Germany.

Language：Japanese  

Language：Others   Publishing type：Research paper (scientific journal)  

Spatial and temporal variation of fish assemblages and their associations to habitat variables in a mountain stream of north Tiaoxi River, China
The spatial and temporal variations of the fish assemblages in mountain streams of China are poorly understood. The relationships between the fish assemblage and selected habitat features were examined in the North Tiaoxi River, one of headwaters of Taihu Lake. A total of 3,348 individuals belonging to 5 orders, 11 families, 25 genera and 34 species were collected including 33 native species and one invasive species. Among those, about 20 species were endemic to China. Non-metric Multidimensional Scaling (NMDS) was applied to compare fish assemblage structures from upstream to downstream during four seasons. Species assemblages differed along the stream continuum, but there was little apparent change associated with the seasons. Species richness and Shannon-Weaver index (H′) tended to increase along the stream continuum from the upstream to downstream and the proportion of invertivorous fish tended to significantly decrease along the continuum with a parallel significant increase in the percentage of omnivores. Fish assemblages were significantly related to both water quality and habitat structure variables. Canonical Correspondence Analysis ordinations (CCA) revealed that 6 of the 14 selected environmental variables had significant relationships with the fish assemblage such as distance to source, stream width, altitude, pH, water depth, and water velocity and different sampling sites were associated with different environmental variables in different seasons. The main differences in fish assemblage structure and diversity within the whole watercourse are probably related to large-scale factors such distance to source, altitude and stream width. Differences of instream characteristics are likely to be caused by natural variability of the ecosystems but also, in some case, by anthropogenic influence like human settlements, agriculture and river embankment and pollution from small factory. © 2011 Springer Science+Business Media B.V.

DOI： 10.1007/s10641-011-9928-6

Language：Japanese  

Present Condition of River Environments and Biodiversity in Lake Taihu Basin : Freshwater Fishes and Anthropogenic Impacts in the East Tiaoxi River

Language：Others   Publishing type：Research paper (scientific journal)  

Distribution pattern of loaches (teleostei: Cobitoidea) in the river east Tiaoxi, China
The distribution patterns of loaches (Teleostei: Cobitoidea) were revealed in the River East Tiaoxi in China. Eight loach species (Cobitis sinensis, C. dolichorhynchus, C. laterimaculata, Misgurnus anguillicaudatus, Paramisgurnus dabryanus, Leptobotia tchangi, Vanmanenia pingchowensis and V. stenosoma) were found in field surveys at 90 sites. A macroscale analysis of the geographical distribution showed that related species were segregated in accordance with longitudinal alterations along the river course. M. anguillicaudatus was widely distributed from the middle reaches to upstream of the river whereas the related species, P. dabryanus, was distributed only downstream. Three spined loaches, namely C. dolichorhynchus, C. sinensis, and C. laterimaculata, were distributed in the middle reaches, the middle to upstream reaches, and the upstream section of the river, respectively. The distribution of V. pingchowensis was further upper stream than that of V. stenosoma in the upstream section. More detailed microscale analysis revealed that L. tchangi and the two Vanmanenia species, V. stenosoma and V. pingchowensis were mostly found in the 'Riffle' (lotic) habitats, whereas the two spined loaches, C. laterimaculata and C. sinensis preferred the 'Pool' (lentic) habitats. These results demonstrated that related loach species preferred similar habitat units in the River East Tiaoxi system.

Language：Japanese  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)  

Language：Japanese  

Assessment of River Environment in the East Tiaoxi Basin, China Using GPS-Logger, Google Eearch and Landsat Images
In Taihu Lake Basin in China, due to the rapid development of economy and society, degradation of aquatic environment has been one of the most urgent issues. On the other hand, the region still holds a lot of rivers and lakes with good environmental condition, which Japan and other advanced countries have already lost. For the first step to conserve such remaining environments, the past and present environmental status of the East Tiaoxi River (one of the most significant rivers in Taihu Lake Basin) was surveyed using GPS-logger, Google Earth and Landsat images. At first, NDBI, NDVI, BA was calculated from the multi-temporal Landsat images. The past Landsat images showed that, since 2000, urban areas and open-cast mining have been drastically expanded in the region. Classification of bank type was conducted using high resolution satellite images of Google Earth and digital photographs taken at main stream of East Tiaoxi; As a result, it was suggested that the carrying vessels for mineral substance considerably disturb the river environment.

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