Tone River Basin Research Articles

The habitat status of native and invasive aquatic animals in an inter-levee floodplain water body in a stream, the Tone River basin

The habitat status of native and invasive aquatic animals in an inter-levee floodplain water body in a stream, the Tone River basin

Using the sectoral and statistical demand to availability index to assess freshwater scarcity risk and effect of water resource management

A more objective assessment of the freshwater scarcity risk at a watershed basis scale contributes to the achievement of the Sustainable Development Goals (SDGs), in which water plays a key role in issues like safe and affordable drinking water, water-related disasters, forest management, biodiversity and ecosystems. Within the SDGs, water scarcity is assessed primarily by using the ratio of withdrawal to availability (WTA). This index has been developed to evaluate the average annual conditions on a broad scale, such as country or large basin. However, there are insufficient cases for assessing specific and detailed risk conditions by using this original WTA concept, due to seasonal and interannual variations of the river discharge and withdrawal volumes. For example, infrastructure (e.g. large dams) and its operation, can drastically change the available water and demand volumes at temporal scales finer than annual. Because recently many daily and monthly records of river discharge and water use have become publicly available, it is possible to conduct water scarcity risk assessments on a monthly basis. By employing these datasets, in this study, we propose to compare volumes of available water and demand by using a Sectoral and Statistical Demand to Availability (SS-DTA) index. The novelty of this index is marked not only by the use of monthly volumes of available and required water but also by how environmental water requirements are included and the statistical relevance of the evaluation. Usually, to determine the available water resources, existing methods deduct from the river discharge the volumes that are required to preserve the surrounding ecosystems. Our proposed method considers the environmental flow requirements as one of the water-demand sectors allowing a simultaneous evaluation of water use that is not possible with existing methods. We applied this method to three representative river basins, two located in Japan (the Tone and the Arakawa River basins) and the Brantas River basin in Indonesia. The results showed the variations of water scarcity risk level through the river operation in each river basin. In the Tone River basin, it was succeeded in a drought year to decrease its risk level from 1 to 0, and to transport sufficient volume of water to the Arakawa River basin through an artificial channel to meet the demands at the same time. In the Brantas River basin, the river operation changed the SS-DTA score from 3 to 2, which means the water scarcity risk level was alleviated, while the main impact of the operation was found in high-water season to decrease the flood risk. Because the number, type, and priority of water demands can be adjusted based on the local situation and all the timeseries data of each demand sector are visualized in parallel, the result includes not only the whole risk level of the river basin but also the practical and specific degree of the risk with demand sector information.

Recovery of the Forests in Tone River Basin Reduce Peak Flow of the Basic Design Discharge

Recovery of the Forests in Tone River Basin Reduce Peak Flow of the Basic Design Discharge

How Inter-Basin Transfer of Water Alters Basin Water Stress Used for Water Footprint Characterization

Water footprint assessments contribute to a better understanding of potential environmental impacts related to water and have become essential in water management. The methodologies for characterizing such assessments, however, usually fail to reflect temporal and spatial variations at local scales. In this paper, we employ four widely-used characterization factors, which were originally developed with global estimates of water demand and availability, to evaluate the impact that inter-basin transfer (IBT) of water has on water risk assessments and, consequently, on the evaluation of the soundness of water cycle. The study was conducted for two major river basins in Japan, where diversion channels were built to move water from the Tone river basin to the Arakawa river basin. Considering IBT, the available water in the Arakawa river basin increases a 45%, reducing the characterization factors a 44% on average and denoting their tendency to overestimate the risk in this basin, while the Tone river basin increased the characterization factors a 28% on average by IBT. Moreover, with a simple example we show how ambiguity in the definition of some characterization factors may cause significant changes in the result of the assessments. Finally, we concluded that local water footprint characterization can be more helpful in local assessment of water resources if the results are unanimous, Targetable, Replicable, Ameliorable, Comparable, and Engageable (uTRACE).

Nitrogen Deposition from Atmosphere and Nitrogen Concentration of Rivers in Upper Region of Tone River Basin

Nitrogen Deposition from Atmosphere and Nitrogen Concentration of Rivers in Upper Region of Tone River Basin

Spatiotemporal Evaluation of the Gauge-Adjusted Global Satellite Mapping of Precipitation at the Basin Scale

This study evaluated the accuracy of gauge-adjusted Global Satellite Mapping of Precipitation (GSMaP_Gauge version V5.222.1, hereafter G_Gauge) data in Japan’s Tone River basin during 2006-2009. Specifically, the accuracy of a gauge non-adjusted product, GSMaP Moving Vector with Kalman Filter (GSMaP_MVK, hereafter G_MVK), was also evaluated. Both products were also evaluated against ground observation data from rain gauge-radar combined product Radar-Automated Meteorological Data Acquisition System (Radar-AMeDAS) in terms of temporal and spatial variability. Temporal analyses showed that G_Gauge had better accuracy than G_MVK at sub-daily time scales (1, 3, 6, 9, 12, and 24 h) within any range of precipitation intensity and better detection capabilities of rainfall event. Linear regressions with Radar-AMeDAS showed better performance for G_Gauge than G_MVK at any time scales in terms of Pearson’s correlation coefficient and the slope of regression. At an hourly scale, in particular, Pearson’s correlation coefficient for G_Gauge (0.84) was higher than that for G_MVK (0.72) as well as the slope of linear regression (0.87 and 0.65, respectively). The probability of detection (POD) improved from 0.48 (G_MVK) to 0.70 (G_Gauge) when gauge-adjusted data were used. However, spatial analysis detected that G_Gauge still underestimated the precipitation intensity in high-elevation regions and slightly overestimated it in low elevation regions. The POD and false alarm ratio had a linear relationship with log-transformed elevation data, and the relationships were stronger in the winter seasons than in the summer seasons. At any spatial and temporal scale, the evaluation of these products should consider seasonal changes (especially in winter) and the topographic effects. For further improvements of G_Gauge, we suggest including higher resolution gauge-based network data than the Climate Prediction Center unified gauge-based analysis of global daily precipitation, which is used for G_Gauge.

Are both agricultural intensification and farmland abandonment threats to biodiversity? A test with bird communities in paddy-dominated landscapes

Land-use changes, including agricultural intensification and farmland abandonment, influence biodiversity in agricultural landscapes. However, few studies have focused on how the two major land-use changes affect different types of species at landscape scales. This study examined the relationships between the richness and abundance of five bird groups (agricultural wetland species, agricultural land species, grassland species, edge species, and woodland species) as well as the total species richness and abundance, and intensification or abandonment in 28 square, 100-ha grid cells in paddy-dominated landscapes in the Tone River basin of central Japan. Rice-field intensification and abandonment were not completely segregated spatially: intensification occurred in both plain and hilly areas surrounded by forests, while abandonment tended to occur in hilly areas. The effects of intensification and abandonment differed among species groups and between seasons. The richness or abundance of agricultural wetland species in summer were negatively associated with both intensification and abandonment. While the abundance of agricultural land species in winter and grassland species in both seasons were positively associated with intensification and abandonment, respectively. The total species richness and abundance did not show clear association with intensification and abandonment due to a variety of responses of the five bird groups. Based on prefectural Red Data Books, agricultural wetland species, followed by grassland species, were more threatened than other three groups in both summer and winter. This study found that (1) the diversity of habitats (including consolidated and abandoned farmlands) provides buffer areas for the different bird groups on different times of the year and (2) agricultural wetland species that use flooded rice fields in summer, such as egrets and shorebirds, are particularly threatened by both intensification and abandonment.

Formaldehyde formation from tertiary amine derivatives during chlorination

In May 2012, formaldehyde (FA) precursor contamination in the Tone River Basin led to the suspension of water supply to approximately 360,000 homes, which affected approximately 870,000 people in the Tokyo Metropolitan Area. The discharge of industrial effluents containing hexamethylenetetramine (HMT), a tertiary amine and FA precursor, without proper treatment resulted in the formation of FA during chlorination at water purification plants. Tertiary amines are known to be the precursors of aldehydes upon chlorination. In this study, FA formation from 29 separate amine derivatives during chlorination was investigated to determine any other potential causes of this water quality accident. The FA formation yield also included FA formation by the autolysis of the target compounds as well as the chlorination of the autolysis products. The FA molar formation yield of HMT was the highest after 24h of chlorination (440%). Among the various tertiary amine derivatives containing N-methyl groups, tertiary amines and hydrazines were found to be strong FA precursors because the FA molar formation yields per N-methyl group ranged from 25% to 45% (with a mean of 38%) and from 35% to 45% (with a mean of 41%), respectively. Guanidines and sulfamides containing N-methyl groups were also FA precursors but they exhibited lower FA molar formation yields per N-methyl group. The FA molar formation yields of the remaining compounds were <4%. The FA formation yield of HMT was extremely high even on a per weight basis (95wt.%). The FA weight formation yields of some tertiary amines and hydrazines were greater than 20wt.%.

A COMBINED DYNAMICAL/STATISTICAL DOWNSCALING APPROACH FOR ASSESSING FUTURE OF WATER RESOURCES IN THE TONE RIVER BASIN, JAPAN

Dynamical downscaling is a promising tool to assess the future fate of water in a catchment. To overcome strong biases in Coupled Ocean-Atmosphere General Circulation Models (CGCMs), the Pseudo Global Warming Downscaling (PGW-DS), which combines climatology differences (future-past) of CGCM ensembles and Reanalysis Dataset (RD) was proposed as a reliable and efficient method, but biases originated from downscaling of RD was not addressed. Hence, this study evaluated the results from a long-term, high-resolution Downscaled Precipitation (DP) derived from a RD over the Tone river basin. DP showed strong bias over mountainous regions owing to resolution enhancement. DP and CGCM precipitations were merged with Statistical Bias Correction methods (SBC) to obtain a comprehensive outlook on biases and the most appropriate SBC. Characteristics of biases were quite different in DP and CGCM, which performed very poor for extreme rainfall intensities and thus required an explicit treatment. Seasonal inconsistency in extreme events of CGCMs affected the corrected rainfall and discharges significantly. Conversely, a simple cumulative gamma method was successful for DP to represent climatology, extreme statistics of rainfall and discharges owing to the use of RD, which generated lesser bias compared to CGCMs. The proposed method will be applied to PGW-DS to obtain reliable information of future changes of water in the basin.

Estimation of a possible maximum flood event in the Tone River basin, Japan caused by a tropical cyclone

AbstractThe damage to society caused by tropical cyclones depends largely on the storm track relative to geography. A procedure is proposed to generate different typhoon tracks deviating from the original track of a given reference case. In this procedure, the position of a typhoon is artificially shifted at a certain time before landing in a physically consistent way by applying potential vorticity inversion methodology. After shifting the typhoon position, the subsequent progress is again simulated by a mesoscale weather model. The procedure is applied to a strong typhoon that emerged in a global warming experiment using an atmospheric general circulation model. Various realizations of typhoon landfall cases are generated. Using the output of a suite of realization of different tracks, the worst case scenario is discussed in terms of the river discharge in the Tone River basin, Japan. Copyright © 2013 John Wiley &amp; Sons, Ltd.

Risk Management Framework Related to the Accidental Formaldehyde Contamination in Water Supplies along the Tone River Basin

Risk Management Framework Related to the Accidental Formaldehyde Contamination in Water Supplies along the Tone River Basin

Estimating nitrate travel time to groundwater in agricultural areas in the Tone River basin from deep soil properties and layer characteristics

Estimating nitrate travel time to groundwater in agricultural areas in the Tone River basin from deep soil properties and layer characteristics

Discussion on the Accidental Formaldehyde Contamination in Water Supplies along the Tone River Basin and Public Perception on the Suspension of Water Supply

Discussion on the Accidental Formaldehyde Contamination in Water Supplies along the Tone River Basin and Public Perception on the Suspension of Water Supply

CLIMATE CHANGE IMPACT ON RIVER FLOW OF THE TONE RIVER BASIN, JAPAN

Future river flow changes in the Tone River basin, Japan, were investigated using a fine resolution distributed hydrologic model and the MRI-AM20km projection output, which is simulated under the A1B climate change scenario. Multiple dam reservoir operations and current water usage information were also considered for realistic river flow simulations. The future water usage and reservoir operation was assumed to be the same as under current conditions. Analysis results show that the river flow change downstream of the basin seems to be insignificant compared to the area upstream of the basin; however, more frequent water shortage days are expected in the future, especially at the Tone-Ozeki station. Revised dam reservoir operation rules should be prepared unless the current water demand changes properly in the future.

A Study of Effect of Channel Storage and Design Flood Discharge with Branch River Junction in the Upper Tone River Basin

近年，ダムによらない治水対策が課題となり，河川計画の検証が期待されている．1980年に利根川の治水計画は当時の技術水準のもとに集中型モデルとして貯留関数法が使われた．1947年9月に来襲したカスリーン台風の当時は基準点より上流にはダムは存在していない．著者は既往研究において戦後のダム設置のもとにどのように治水安全度が年々向上してきたのか，同モデルを使い検証してきた．利根川は工事実施基本計画から45年が過ぎ，降雨および洪水データの蓄積や流出モデルの開発が進み，実際の洪水流出現象からより正確な検証が求められるようになった．本研究では，利根川上流域の支川合流に伴う河道貯留効果による低減効果について着目し，貯留関数法，Kinematic wave法により洪水流出解析を行い，同時に計画高水流量の考察を行った．

Source of N-nitrosodimethylamine in river waters of the upper Tone River basin in Japan

The presence of N-nitrosodimethylamine (NDMA) in the Hirose River and its tributaries, located in the upper Tone River basin, in the Kanto region of Japan, was investigated. NDMA was detected at high levels in the Arato River, one of the tributaries of the Hirose River, at high concentrations (up to 2,100 ng/L). Due to the confluence of the Arato River, NDMA concentration in the Hirose River increased (up to 61 ng/L). The NDMA in the Arato River was due to industrial discharge from a livestock processing plant located near the river. There were three discharges at the plant, with NDMA concentrations of 78, 11, and 33,000 ng/L. The industrial discharges from the livestock processing plant did not contain significant amounts of NDMA precursors on chloramination. On the other hand, sewage effluent was shown to contain NDMA precursors. The amounts of NDMA precursors in the sewage effluent that were rapidly transformed into NDMA were considered to be lower than those slowly transformed into NDMA.

First record of the North American invasive crayfish Pacifastacus leniusculus from the Kanto region, Tone River basin, central Japan: a range expansion to a warm water area

First record of the North American invasive crayfish Pacifastacus leniusculus from the Kanto region, Tone River basin, central Japan: a range expansion to a warm water area

Hydrologic Evaluation on the AGCM20 Output Using Observed River Discharge Data

The controlled simulation output of a super-high resolution atmospheric model (AGCM20) was evaluated from a hydrologic point of view, using a distributed hydrologic model and observed river discharge data. The AGCM20 output for the current climate condition should be able to provide a current river flow pattern when it is converted into river discharge information using a reasonably well-prepared hydrologic model. For this evaluation, a distributed hydrologic model was composed for various basin scales ranging from 60 km2 to 8,772 km2 in the Tone River Basin, Japan, and calibrated in advance, using observed data of each sub-basin. Most sub-basins in the study area provide more than 25 years of observed discharge data, and the evaluations were conducted by comparing seasonal patterns of simulated and observed discharges. The result shows that the GCM output provides excellent discharge output when the basin scale is more than 5,000 km2, while its utilization into a smaller basin remains limited. The proposed hydrologic evaluation method provides direct and comprehensive understanding to hydrologists in addition to the conventional evaluation method.

Assessment of a distributed biosphere hydrological model against streamflow and MODIS land surface temperature in the upper Tone River Basin

Land surface temperature (LST) is a key parameter in land–atmosphere interactions. The recently released Moderate Resolution Imaging Spectroradiometers (MODIS) LST Version 5 products have provided good tools to evaluate water and energy budget modelling for river basins. In this study, a distributed biosphere hydrological model (WEB-DHM; so-called water and energy budget-based distributed hydrological model) that couples a biosphere scheme (SiB2) with a geomorphology-based hydrological model (GBHM), is applied to the upper Tone River Basin where flux observations are not available. The model facilitates a better understanding of the water and energy cycles in this region. After being calibrated with discharge data, WEB-DHM is assessed against observed streamflows at four major gauges and MODIS LST. Results show that long-term streamflows including annual largest floods are well reproduced. As well, both daytime and nighttime LSTs simulated by WEB-DHM agree well with MODIS observations for both basin-averaged values and spatial patterns. The validated model is then used to analyze water and energy cycles of the upper Tone River Basin. It was found that from May to October, with relatively large leaf area index (LAI) values, the simulated daily maximum LST is close to soil surface temperature (Tg) since Tg is much greater than canopy temperature (Tc) in their peak values; while the daily minimum LST appears similar to Tc. For other months with relatively small LAI values, the diurnal cycles of LST closely follow Tg.

Bromate, chlorate, chlorite and perchlorate in sodium hypochlorite solution used in water supply

A survey was conducted to reveal the concentrations of bromate, chlorite, chlorate and perchlorate as impurities in sodium hypochlorite solutions and those of chlorate and perchlorate in raw and processed waters including a metropolitan area. High concentrations of bromate (max. 414 mg l−1) and chlorate (max. 260,000 mg l−1) were found in purchased sodium hypochlorite solutions for drinking water disinfection that had been stored for a long time, more than two years at a maximum. In the survey of chlorate and perchlorate in raw and processed waters in the Tone River Basin, the highest concentration of chlorate in raw water was 78 μg l−1 and that of perchlorate was 40 μg l−1. Chlorate and perchlorate concentrations in 32 purchased sodium hypochlorite solutions and six on-site-generated hypochlorite solutions were also analysed. In the purchased sodium hypochlorite solutions, perchlorate concentrations ranged from 0.170 to 33.0 mg l−1. In hypochlorite solutions whose measured FAC (free available chlorine) concentration was lower than the manufacturer-specified FAC concentrations, the chlorate and perchlorate concentrations were higher than those in relatively fresh sodium hypochlorite solutions. In on-site-generated hypochlorite solutions, the maximum concentrations of chlorate and perchlorate were 1,700 mg l−1 (140 mg g−1 of measured FAC) and 0.660 mg l−1 (0.053 mg g−1 of measured FAC), respectively.