Journal articles: 'River discharges' – Grafiati (2024)

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The municipality of Rotterdam and two regional drinking-water companies jointly started an action programme in an attempt to reduce the sources of pollution in consultation with the dischargers. Rotterdam aims to reach written agreements with each relevant discharger in which the discharger is committed to reduce his discharge in order to improve the Meuse water quality. In exchange Rotterdam relinquishes legal claims upon the discharger. Results of the measured discharges are presented. The 8 major dischargers of Br, Cd, NH4 and P each contribute up to 79% of the total contaminant discharge into the Meuse.

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Abstract. Climate changes have a high impact on river discharges and therefore on floods. There are a few different methods we can use to predict discharge changes in the future. In this paper we used the complex HBV model for the Vipava River and simple correlation between discharge and precipitation data for the Soča River. The discharge prediction is based on the E-OBS precipitation data for three future time periods (2011–2040, 2041–2070 and 2071–2100). Estimated discharges for those three future periods are presented for both rivers. But a special situation occurs at the confluence where the two rivers with rather different catchments unite, and this requires an additional probability analysis.

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This study demonstrates the dependence between the forest burning rates and abnormal decrease in Siberian river discharges under the conditions of the permafrost zone. Our study area is in Central Siberia and Eastern Siberia/Yakutia. Four rivers (Podkamennaya Tunguska, Lower Tunguska, Aldan, and Viluy) were selected for the study. We analyzed the long-term and seasonal variation of river discharges (archive of The Global Runoff Data Centre for 1939–2015) together with the forest burning dynamics within the river basins (archive of Sukachev Institute of Forest for 1996–2015). We compared the discharges per year with the 77-year average value. Abnormally low levels of discharge constituted 58–78% of the averaged annual rate. An analysis of available chronologies of extreme fire events and relative burned areas (RBAs) showed a high correlation with intra-seasonal data on the runoff minima. The most significant response of river discharges to the wildfire effect was shown for the late summer/autumn season after extreme wildfires during the summer period. The deficit of the runoff was not explained by a low precipitation. Late summer and autumn anomalies of discharge were typical (r = −0.57…−0.77, p < 0.05) for rivers of Central Siberia in seasons of extreme forest burning. The correlation was lower for rivers of Eastern Siberia/Yakutia.

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Research into global water resources is challenged by the lack of ground-based hydrometric stations and limited data sharing. It is difficult to collect good quality, long-term information about river discharges in ungauged regions. Herein, an approach was developed to determine the river discharges of 24 rivers in ungauged regions on the Tibetan Plateau on a long-term scale. This method involved coupling the Manning–Strickler formula, and data from an unmanned aerial vehicle (UAV) and the Gaofen-2, SPOT-5, and Sentinel-2 satellites. We also compared the discharges calculated by using the three satellites’ data. Fundamental information about the rivers was extracted from the UAV data. Comparison of the discharges calculated from the in-situ measurements and the UAV data gave an R2 value of 0.84, an average NSE of 0.79, and an RMSE of 0.11 m3/s. The river discharges calculated with the GF-2 remote sensing data and the in-situ experiments for the same months were compared and the R2, RMSE, and the NSE were 0.80, 1.8 m3/s, and 0.78, respectively. Comparing the discharges calculated over the long term from the measured in-situ data and the SPOT-5 and Sentinel-2 data gave R2 values of 0.93 and 0.92, and RMSE values of 2.56 m3/s and 3.16 m3/s, respectively. The results showed that the GF-2 and UAV were useful for calculating the discharges for low-flow rivers, while the SPOT-5 or the Sentinel-2 satellite gave good results for high-flow river discharges in the long-term. Our results demonstrate that the discharges in ungauged tributaries can be reliably estimated in the long-term with this method. This method extended the previous research, which described river discharge only in one period and provided more support to the monitoring and management of the tributaries in ungauged regions.

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Wavelet analysis of the Baltic region river runoff longh-term trends and fluctuations The study of changes in river discharge and flood regime can provide important information on climate change and its impacts. Wavelet analysis offers new possibilities to study changes of river discharge patterns in regard to periodical processes on a background of climate change. In this study wavelet analysis was used to study long-term changes of river discharge in the Baltic region. Periodic oscillations of discharge intensity, and low- and high-water flow years are common for the major rivers in the Eastern Baltic region. Main frequencies of river discharge were estimated to be 14, 28, 37 years for the studied rivers. Wavelet analysis allowed to identify similarities between the river discharge regime, and thus, the factors influencing it. Years of maximal and minimal discharges for major rivers were identified and the impact of large-scale atmospheric circulation processes on the river discharge was studied.

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Under the influence of global climate change, the discharges of major global rivers directed into the ocean have undergone significant changes. To study the trends and causes in discharge variation, we selected 40 large rivers and analyzed their annual discharges near their estuaries from 1960 to 2010. The method of runoff variation attribution analysis based on the Budyko hypothesis for large-scale basins was developed, in which influencing factors of human activities and glacial melting factors were added to the formula. The contribution rate of climate factors and human activities to changes in discharge were quantitatively identified. Climatic factors include precipitation, evapotranspiration and glacial melting. Human activity factors include underlying surface and artificial water transfer. The contribution rate is determined by the elastic coefficient, which is obtained by the ratio of change rate of each factor and the change rate of runoff. The results indicated that the discharges predominantly showed downward trends with a few upward trends. Rivers in North America and Africa showed downward trends, and those in Europe principally showed upward trends. Climate was the main influencing factor of discharges changes, and only approximately 25% of river discharges were greatly affected by human activities. River discharges in 75% of the basins which mainly contains subtropical monsoon humid climate and savanna climate zones showed upward trends. In the four basins which are mainly contains tropical rainforest climate and tropical monsoon climate, they all showed downward trends. The trend of discharges in the temperate monsoon climate, temperate continental climate, and temperate maritime climate cannot be accurately judged because of irregular variation. The discharges in the mid-high latitudinal zones predominantly showed upward trends, while those in the mid-low latitudinal zones with the influence of human activities showed downward trends.

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The flood travel time (FTT) along the Longmen-Tongguan Reach, part of the stem channel of the Middle Yellow River, is shorter than 30 h, and estimating the FTT of different discharges propagating from Wubu Hydrology Station to Tongguan Hydrology Station is necessary. However, the propagation of floods in this river network, the main channel of the Wubu-Tongguan Reach and related tributaries, has rarely been analyzed due to the lack of geometry data. Thus, a one-dimensional (1D) dynamic model was selected to simulate the FTT along the WT reach. Firstly, the 1986 flood event was selected to calibrate the physical parameters in the hydraulic model. Secondly, the FTT with different discharges (500–9000 m3/s) were estimated with calibrated parameters. Thirdly, an empirical formula based on simulated results was fitted. This empirical formula could be used to describe the relation between discharges, distances to Tongguan Hydrology Station, and the FTT. Analyses showed that the discharges with minimum FTT were different for different tributaries. For the river reach between Wubu Hydrology Station and the Wuding River, the discharge and corresponding minimum FTT were 6000 m3/s and approximately 30.4–34 h, respectively. For the river reach between the Zhouchuan and Qingjian Rivers, the discharge and FTT were 3000–3500 m3/s and 21–26.8 h, respectively. The formula can be used to estimate the FTT of flood events, which would be cost-saving and time-saving for river management. Sensitivity analyses indicated that the FTT were sensitive to the Tongguan elevation and Manning’s roughness coefficient in the main channel.

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Abstract. An efficient method that accounts for personal safety, accuracy and reliability for measuring flood discharge of mountain rivers is proposed. It is composed of new measurement method, tools, and techniques. Measuring flood discharge from mountain rivers by using conventional method is costly, time-consuming, and dangerous. Thus previous discharge measurements for mountainous areas were typically based on estimated precipitation, which alone cannot generate accurate measurements. This study applies a novel flood discharge measurement system composed of an Acoustic Doppler Profiler and crane system to accurately and quickly measure velocity distributions and water depths. Moreover a novel and efficient method for measuring discharge, which is based on the relationship between mean and maximum velocities and the relationship between cross-sectional area and gauge height is applied to estimate flood discharge. Flood discharge from mountain rivers can be estimated easily and rapidly by measuring maximum velocity in the river crosssection and the gauge height. The measured flood discharges can be utilized to create a reliable stage-discharge relationship for continuous estimations of discharge using records of water stage. The proposed method was applied to the Nanshih River, Taiwan. Results of measured discharges and estimated discharges only slightly differed from each other, demonstrating the efficiency and accuracy of the proposed method.

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Abstract The aim of this study is to detect changes in flow regime of rivers in Poland. On the basis of daily discharges recorded in 1951-2010 at 159 gauging stations located on 94 rivers regularities in the variability of the river flow characteristics in the multi-year period and in the annual cycle were identified and also their spatial uniformity was examined. In order to identify changes in the characteristics of river regime, similarities of empirical distribution functions of the 5-day sets (pentads) of discharges were analyzed and the percent shares of similar and dissimilar distributions of the 5-day discharge frequencies in the successive 20-year sub-periods were compared with the average values of discharges recorded in 1951-2010. Three alternative methods of river classification were employed and in the classification procedure use was made of the Ward’s hierarchical clustering method. This resulted in identification of groups of rivers different in terms of the degree of transformation of their hydrological regimes in the multi-year and annual patterns.

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River discharge is crucial to water resources development and ecological protection. However, in some arid areas of northwest China, it is still difficult to measure discharge accurately. In this study, unmanned aerial vehicle (UAV) imagery has been used to estimate river discharge at two river sections in the upper reaches of the Shiyang River in the eastern part of the Qilian Mountains based on the Manning formula. The estimated discharges at those two sections are 1.16 m3/s and 3.11 m3/s, respectively. Taking the discharges measured by an acoustic Doppler current profiler (ADCP) as the reference, the relative error of the estimates is below 5%, which is accurate enough for water resources management in mountain basin regions. Multiple high-resolution satellite images were also used to calculate water discharges at the two sections, which were in good agreement with the discharges estimated from UAVs. This study demonstrates the feasibility of using UAVs to estimate river discharge, which is of great significance for future regional-scale water resource assessments.

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Abstract The hydrological series of the minimum annual discharges of the Instruch River (hydrological gauging station Ulyanovo, Kaliningrad region) was studied. The values of the minimum discharge rates were processed in the Mathcad environment. The characteristics of the minimum discharges (average and minimum annual, minimum 5-, 10- and 30-day discharges) of the Instruch River in 1901-1912 and 2008-2020 are determined. A comparative analysis of the characteristics of the minimum annual discharges of the river Instruch for the indicated periods.

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The upcoming Surface Water and Ocean Topography (SWOT) mission will measure rivers wider than 50–100 m using a 21-day orbit, providing river reach derived discharges that can inform applications like flood forecasting and large-scale hydrologic modelling. However, these discharges will not be uniform in time or coincident with those of neighboring reaches. It is often assumed discharge upstream and downstream of a river location are highly correlated in natural conditions and can be transferred using a scaling factor like the drainage area ratio between locations. Here, the applicability of the drainage area ratio method to integrate, in space and time, SWOT-derived discharges throughout the observable river network of the Mississippi River basin is assessed. In some cases, area ratios ranging from 0.01 to 100 can be used, but cumulative urban area and/or the number of dams/reservoirs between locations decrease the method’s applicability. Though the mean number of SWOT observations for a given reach increases by 83% and the number of peak events captured increases by 100%, expanded SWOT sampled time series distributions often underperform compared to the original SWOT sampled time series for significance tests and quantile results. Alternate expansion methods may be more viable for future work.

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Abstract. Quantitative evaluations of the impacts of climate change on water resources are primarily constrained by uncertainty in climate projections from GCMs. In this study we assess uncertainty in the impacts of climate change on river discharge in two catchments of the Yangtze and Yellow River Basins that feature contrasting climate regimes (humid and semi-arid). Specifically we quantify uncertainty associated with GCM structure from a subset of CMIP3 AR4 GCMs (HadCM3, HadGEM1, CCSM3.0, IPSL, ECHAM5, CSIRO, CGCM3.1), SRES emissions scenarios (A1B, A2, B1, B2) and prescribed increases in global mean air temperature (1 °C to 6 °C). Climate projections, applied to semi-distributed hydrological models (SWAT 2005) in both catchments, indicate trends toward warmer and wetter conditions. For prescribed warming scenarios of 1 °C to 6 °C, linear increases in mean annual river discharge, relative to baseline (1961–1990), for the River Xiangxi and River Huangfuchuan are +9% and 11% per +1 °C respectively. Intra-annual changes include increases in flood (Q05) discharges for both rivers as well as a shift in the timing of flood discharges from summer to autumn and a rise (24 to 93%) in dry season (Q95) discharge for the River Xiangxi. Differences in projections of mean annual river discharge between SRES emission scenarios using HadCM3 are comparatively minor for the River Xiangxi (13 to 17% rise from baseline) but substantial (73 to 121%) for the River Huangfuchuan. With one minor exception of a slight (−2%) decrease in river discharge projected using HadGEM1 for the River Xiangxi, mean annual river discharge is projected to increase in both catchments under both the SRES A1B emission scenario and 2° rise in global mean air temperature using all AR4 GCMs on the CMIP3 subset. For the River Xiangxi, there is substantial uncertainty associated with GCM structure in the magnitude of the rise in flood (Q05) discharges (−1 to 41% under SRES A1B and −3 to 41% under 2° global warming) and dry season (Q95) discharges (2 to 55% under SRES A1B and 2 to 39% under 2° global warming). For the River Huangfuchuan, all GCMs project a rise in the Q05 flow but there is substantial uncertainty in the magnitude of this rise (7 to 70% under SRES A1B and 2 to 57% under 2° global warming). Differences in the projected hydrological changes are associated with GCM structure in both catchments exceed uncertainty in emission scenarios. Critically, estimated uncertainty in projections of mean annual flows is less than that calculated for extreme (Q05, Q95) flows. The common approach of reporting of climate change impacts on river in terms of mean annual flows masks the magnitude of uncertainty in flows that are of most importance to water management.

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Abstract. Quantitative evaluations of the impacts of climate change on water resources are primarily constrained by uncertainty in climate projections from GCMs. In this study we assess uncertainty in the impacts of climate change on river discharge in two catchments of the River Yangtze and Yellow Basins that feature contrasting climate regimes (humid and semi-arid). Specifically we quantify uncertainty associated with GCM structure from a subset of CMIP3 AR4 GCMs (HadCM3, HadGEM1, CCSM3.0, IPSL, ECHAM5, CSIRO, CGCM3.1), SRES emissions scenarios (A1B, A2, B1, B2) and prescribed increases in global mean air temperature (1 °C to 6 °C). Climate projections, applied to semi-distributed hydrological models (SWAT 2005) in both catchments, indicate trends toward warmer and wetter conditions. For prescribed warming scenarios of 1 °C to 6 °C, linear increases in mean annual river discharge, relative to baseline (1961–1990), for the River Xiangxi and River Huangfuchuan are +9% and 11% per +1 °C, respectively. Intra-annual changes include increases in flood (Q05) discharges for both rivers as well as a shift in the timing of flood discharges from summer to autumn and a rise (24 to 93%) in dry season (Q95) discharge for the River Xiangxi. Differences in projections of mean annual river discharge between SRES emission scenarios using HadCM3 are comparatively minor for the River Xiangxi (13% to 17% rise from baseline) but substantial (73% to 121%) for the River Huangfuchuan. With one minor exception of a slight (−2%) decrease in river discharge projected using HadGEM1 for the River Xiangxi, mean annual river discharge is projected to increase in both catchments under both the SRES A1B emission scenario and 2° rise in global mean air temperature using all AR4 GCMs on the CMIP3 subset. For the River Xiangxi, there is great uncertainty associated with GCM structure in the magnitude of the rise in flood (Q05) discharges (−1% to 41% under SRES A1B and −3% to 41% under 2° global warming) and dry season (Q95) discharges (2% to 55% under SRES A1B and 2% to 39% under 2° global warming). For the River Huangfuchuan, all GCMs project a rise in the Q05 flow but there is substantial uncertainty in the magnitude of this rise (7% to 70% under SRES A1B and 2% to 57% under 2° global warming). Greatest differences in the projected hydrologic changes are associated with GCMs in both catchments than emission scenarios and climate sensitivity. Critically, estimated uncertainty in projections of mean annual flows is less than that calculated for extreme (Q05, Q95) flows. This research suggest that the common approach of reporting of climate change impacts on river in terms of mean annual flows may mask the magnitude of uncertainty in flows of most importance to water managers.

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Abstract Well-known responses of regional precipitation in the southeastern United States to variation in the state of the El Niño-Southern Oscillation (ENSO) can yield similar regional responses of river discharge. Effects of ENSO on gaged river flows were examined in the lower Cape Fear River basin in southeastern North Carolina. Linear regression of monthly flows against sea surface temperatures (SST) in Niño Region 1 + 2 in the eastern equatorial Pacific identified significant effects of SST on flows, in several winter and spring months in the Black, Northeast Cape Fear, and main stem Cape Fear rivers. Major warm-phase ENSO events, as in 1997–1998, yielded almost a doubling of river discharges in the watershed, while typical cold phase events drove approximately 50% reductions in flows. River discharges have important effects on water supply for human needs, delivery of water to estuaries, and fluxes of water-borne materials to coastal waters. ENSO effects on the Cape Fear River watershed therefore have implications for adjacent estuarine and coastal ocean ecosystems at certain times.

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The pollution burden of river discharges in the Mediterranean far exceeds all other sources, e.g. land based sources. The main contributors are the Rhone, Po and Ebro. Contributions from the River Nile are expected to be much less than those from rivers in the European continent. Recent Nile management schemes and irrigation projects in Egypt are posing direct impacts on the Mediterranean. This includes the erosion of the Nile Delta and off-shore pollution due to wastewater discharges. In view of the prevailing circulation patterns in the Mediterranean, these impacts are dominant in the South Levantin region. Cutrent practices of river management do not necessarily include the protection of marine resources. Similarly, sea protection programs do not include pollution from sources in the river basin. Marine management programs are largely concerned with pollution loads at the points of river discharge. In the case of a land-locked sea, such as the Mediterranean, it is particularly important to integrate river basin management schemes in the sea protection program. Under a suitable management plan, it could be possible to determine main sources of sea pollution within the river basin. This should serve as the basis for the implementation of control measures, since the problem is not exclusively within the river basin.

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Abstract. Large-scale hydrological modelling of flood hazards requires adequate extreme discharge data. In practise, models based on physics are applied alongside those utilizing only statistical analysis. The former require enormous computational power, while the latter are mostly limited in accuracy and spatial coverage. In this paper we introduce an alternate, statistical approach based on Bayesian networks (BNs), a graphical model for dependent random variables. We use a non-parametric BN to describe the joint distribution of extreme discharges in European rivers and variables representing the geographical characteristics of their catchments. Annual maxima of daily discharges from more than 1800 river gauges (stations with catchment areas ranging from 1.4 to 807 000 km2) were collected, together with information on terrain, land use and local climate. The (conditional) correlations between the variables are modelled through copulas, with the dependency structure defined in the network. The results show that using this method, mean annual maxima and return periods of discharges could be estimated with an accuracy similar to existing studies using physical models for Europe and better than a comparable global statistical model. Performance of the model varies slightly between regions of Europe, but is consistent between different time periods, and remains the same in a split-sample validation. Though discharge prediction under climate change is not the main scope of this paper, the BN was applied to a large domain covering all sizes of rivers in the continent both for present and future climate, as an example. Results show substantial variation in the influence of climate change on river discharges. The model can be used to provide quick estimates of extreme discharges at any location for the purpose of obtaining input information for hydraulic modelling.

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A new multibranch Integrated Catchment (INCA) model INCA-Metals has been developed to simulate the impact of tannery discharges on river systems. The model accounts for the key chemical reaction kinetic processes operating as well as sedimentation, resuspension, dilution, mixing and redistribution of pollutants in rivers downstream of tannery discharge points and for mine discharges or acid rock drainage sites. The model is dynamic and simulates the daily behaviour of hydrology and eight metals, including cadmium, mercury, copper, zinc, lead, arsenic, manganese and chromium, as well as cyanide and ammonia. The model is semi-distributed and can simulate catchments, tributaries and instream river behaviour. The model can also account for diffuse pollution from rural runoff as well as point sources from effluent and trade discharges. The model has been applied to the new Savar tannery complex on the Dhaleshwari River system in Bangladesh to assess the impacts on pollution levels in the river system and to evaluate a set of treatment scenarios for pollution control, particularly in the dry season. It is shown that the new effluent treatment plant at Savar needs to significantly improve its operation and treatment capability in order to alleviate metal pollution in the downstream Dhaleshwari River System and also protect the Meghna River System that falls in the Bay of Bengal.

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Water resources are increasingly under stress in Central Asia because downstream countries are highly dependent on upstream countries. Water is essential for irrigation and is becoming scarcer due to climate change and human activities. Based on 20 hydrological stations, this study firstly analyzed the annual and seasonal spatial–temporal changes of the river discharges, precipitation, and temperature in the Syr Darya River Basin and then the possible relationships between these factors were detected. Finally, the potential reasons for the river discharge variations have been discussed. The results show that the river discharges in the upper stream of the basin had significantly risen from 1930 to 2006, mainly due to the increase in temperature (approximately 0.3 °C per decade), which accelerated the melting of glaciers, while it decreased in the middle and lower regions due to the rising irrigation. In the middle of the basin, the expansion of the construction land (128.83 km2/year) and agricultural land (66.68 km2/year) from 1992 to 2015 has significantly augmented the water consumption. The operations of reservoirs and irrigation canals significantly intercepted the river discharge from the upper streams, causing a sharp decline in the river discharges in the middle and lower reaches of the Syr Darya River in 1973. The outcomes obtained from this study allowed us to understand the changes in the river discharges and provided essential information for effective water resource management in the Syr Darya River Basin.

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Rivers are natural channels on the surface of the earth to drain water, apart from that, of course, interactions between discharges, other factors such as human activities along rivers give different characteristics of river formation. the largest portion comes from land clearing activities around the Langkolome river body located in Wambona Village, South Wakorumba District, Muna Regency. Based on the results of the calculation of the flood discharge of the Langkolome River in Wambona Village from 10 years of rainfall data, namely Q10 = 128,773 m3/sec, Q25 = 244,067 m3/sec. The capacity of the Langkolome river which has an impact on flooding Q = 158,063 m3/s. The maximum rainfall is greater than the capacity of the river, so this causes flooding in the Langkolome River, Wambona Village, Muna Regency

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AbstractThe Greenland ice sheet is experiencing dramatic melt that is likely to continue with rapid Arctic warming. However, the proportion of meltwater stored before reaching the global ocean remains difficult to quantify. We use NASA MODIS surface reflectance data to estimate river discharge from two West Greenland rivers – the Watson River near Kangerlussuaq and the Naujat Kuat River near Nuuk – over the summers of 2000–12. By comparison with in situ river discharge observations, ‘inundation–discharge’ relations were constructed for both rivers. MODIS-based total annual discharges agree well with total discharge estimated from in situ observations (86% of summer discharge in 2009 to 96% in 2011 at the Watson River, and 106% of total discharge in 2011 to 104% in 2012 at the Naujat Kuat River). We find, however, that a time-lapse camera, deployed at the Watson River in summer 2012, better captures the variations in observed discharge, benefiting from fewer data gaps due to clouds. The MODIS-derived estimates indicate that summer discharge has not significantly increased over the last decade, despite a strong warming trend. Also, meltwater runoff estimates derived from the regional climate model RACMO2/GR for the drainage basins are higher than our reconstructions of river discharge. These results provide indirect evidence for a considerable component of water storage within the glacio-hydrological system.

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. Runoff during the autumn-winter low-water period is of great importance in the life of river ecosystems. In this work, the goal is to construct a mathematical model of the curves of daily water discharge during the autumn-winter low-water period (September-April) on the Anadyr River near the village Snezhny (catchment area 106 000 km2 ). Anadyr River is the largest waterway of the Chukotka. The river is used by public utilities, river transport in summer and road transport in winter. Pacific salmon spawn in this river every year. The conditions for the survival of salmon eggs in winter are influenced by the water content of the rivers. The basin under consideration is located in a zone of subarctic climate and continuous permafrost. Therefore, the autumn-winter low-water period on the Anadyr River lasts from September to April during this period, 4–6 % of the annual runoff occurs. Based on the average annual monthly water discharges for September-April, the averaged runoff depletion curve was calculated in relative ordinates, which is approximated by an exponential function. Based on this curve, you can predict daily water discharges from September 15th to April 15th of the following year. Verification calculations for the years of winters with different water content showed that the mathematical model works satisfactorily. Based on the data on the runoff of other hydrological stations in the Anadyr catchment, the study can be continued to derive a basin formula, which can be used to predict the daily water discharges of the autumn-winter low-water period on any unexplored river.

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The impact of climate change on local discharge variability is investigated in the Kone River basin located in Central Vietnam. In this study, historical and predicted river discharge trends are discussed. The predicted discharge is simulated using the BTOPMC model based on the A1B scenario as a scientific basis for socioeconomic development and integrated water resource management in the Kone River basin, during the period 2011–2034. During the period 1979–2007, annual discharge in the Kone River basin trended upwards slightly. However, both maximum and minimum discharges declined. The results of the predicted discharge under the A1B scenario suggest that river flow will increase slightly in the Kone River basin in the future. Both annual and flood season discharges will tend to increase during the period 2011–2034. In contrast, discharge during the low flow season will tend to decrease over the same period. For the period 2011–2034, the discharge volume in the Kone River will increase by 3%, in comparison with the period 1980–1999. Water volume will decrease by about 18.6% during the flood season and increase by approximately 90.0% during the low flow season relative to the period 1980–1999.

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The spatial and temporal dynamics of physical habitat in rivers is driven by the interaction between channel morphology and discharge. However, little is known about how altered discharge affects the dynamics of habitat patches such as slackwaters. This study investigated the influence of discharge on the availability, stability, quality, and diversity of slackwaters in a southeastern Australian lowland river. The area, spatial configuration, permanence, and within-patch characteristics of slackwaters of two reaches in a regulated section and two reaches in a largely unregulated section of the river were compared. There was less slackwater area and it was less permanent at higher discharges and in the two regulated reaches than at lower discharges and in the largely unregulated reaches. Individual slackwaters were more hom*ogenous in relation to within-patch characteristics in the regulated than in the largely unregulated reaches. However, variability in the spatial configuration of slackwaters and within-patch characteristics and diversity at the reach scale were not related to discharge. We suggest that channel morphology, rather than discharge, is the main driver of these characteristics.

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The building of large dams in the Upper Paraná River basin altered the discharge regime at the Porto São José River section. The discharge regime has been altered since 1972, but the changes intensified after the Porto Primavera damming, in late 1998. Considering that discharge control affects the relationship between channel and floodplain, this work aimed to evaluate the intensity of the discharge control that resulted from the operation of the Porto Primavera Dam. To achieve this objective, statistical analyses were carried out based on the Porto São José Fluviometric Station historical series of river level readings and discharge, between 1964 and 2007. Results showed that the average discharge increased from 1964 to 1981 and diminished after river damming. The increase of average discharge rates was followed by an increase of the duration of higher discharges at different levels of geomorphologic and limnological importance, and the reduction of average discharge during the last observed period was followed by a disproportionate decrease in the duration of the abovementioned discharges. Moreover, it is clear that the relationship between fluviometric level and fluvial discharge changed, which implies that a certain river level reading represents a higher discharge than necessary before river damming.

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The study assessed the impact of effluent discharges on the quality of Otamiri River in Imo state, Nigeria. Six water samples were collected at discharge points where the industries discharge their effluents and abattoir. Samples that were collected upstream and downstream were analyzed in the field and in the lab using standard procedures. The source of pollution is attributable to industrial and abattoir activities whose effluent discharges impact the quality of Otamiri River. Therefore, without any treatments, the River cannot be used for any residential purposes in its current condition. It is advised that the river be periodically monitored and that cost-effective manufacturing technology, such as on-site waste separation and reduction, effluent recycling techniques, be introduced.

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The article discusses the possibility of using dynamic models in the form of first- and second-order differential equations for forecasting water discharges in rivers of Uzbekistan. The models were tested on two small mountain catchments, which differ in the conditions for the formation of river runoff. Verification forecasts of average daily water discharges for five years are made. It was found that water discharges of the Akdarya River are predicted effectively with a daily lead time using both a first-order model and a second-order model. The listed models do not give satisfactory results when forecasting water discharges of the Zeravshan River at the Navoi city. In this case, it is necessary to modernize the models to suit the conditions of river runoff formation with an accurate account of the anthropogenic load, which is significant for the catchments of Uzbekistan.

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Abstract. This study focuses on the impact of discharges of small rivers on the delivery and fate of fluvial water and suspended matter at the northeastern part of the Black Sea under different local precipitation conditions. Several dozens of mountainous rivers flow into the sea at the study region, and most of them, except for several of the largest, have little annual runoff and affect adjacent coastal waters to a limited extent under average climatic conditions. However, the discharges of these small rivers are characterized by a quick response to precipitation events and can significantly increase during and shortly after heavy rains, which are frequent in the considered area. The delivery and fate of fluvial water and terrigenous sediments at the study region, under average climatic and rain-induced flooding conditions, were explored and compared using in situ data, satellite imagery, and numerical modeling. It was shown that the point-source spread of continental discharge dominated by several large rivers under average climatic conditions can change to the line-source discharge from numerous small rivers situated along the coast in response to heavy rains. The intense line-source runoff of water and suspended sediments forms a geostrophic alongshore current of turbid and freshened water, which induces the intense transport of suspended and dissolved constituents discharged with river waters in a northwestern direction. This process significantly influences water quality and causes active sediment load at large segments of the narrow shelf at the northeastern part of the Black Sea compared to average climatic discharge conditions.

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Abstract. This paper presents an attempt of simulating daily fluctuations of river discharge at global scale. Total Runoff Integrating Pathways (TRIP) is a global river routing model which can help to isolate the river basins, inter-basin transport of water through river channels, as well as collect and route runoff to the river mouths for all the major rivers. In the previous version of TRIP (TRIP 1.0), a simple approach of constant river flow velocity is used. In general, that approach is sufficient to model mean long-term discharges. However, to model short-term fluctuations, more sophisticated approach is required. In this study, we implement a variable streamflow velocity method to TRIP (TRIP 2.0) and validate the new approach over the world's 20 major rivers. Two numerical experiments, one with the TRIP 1.0 and another with TRIP 2.0 are performed. Input runoff is taken from the multi-model product provided by the second Global Soil Wetness Project. For the rivers which have clear daily fluctuations of river discharge, TRIP 2.0 shows advantages over TRIP 1.0, suggesting that TRIP 2.0 can be used to model flood events.

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The paper examines changes in air temperature, precipitation, and river discharges on seasonal and annual scale over the Sava River watershed in Bosnia & Herzegovina during the period 1961–2016. Based upon data gathered from 11 meteorological stations and 3 hydrological stations, hydroclimatic variables trends were established by utilizing the nonparametric Mann-Kendall test and the nonparametric Sen’s slope estimator. The results show significant positive seasonal and annual trends (expect for autumn, during which upward trends were insignificant) in air temperature, whereas both positive and negative insignificant seasonal and annual precipitation trends are shown where determined for the entire watershed. Most prominent upward trends in air temperature were found in summer and afterwards in winter and spring, indicating a pronounced warming tendency over the Sava River watershed. Trends in river discharge displayed a negative tendency in all seasons. Nevertheless, a majority of estimated trends of river discharges were weak and statistically insignificant. Throughout the year, river discharges showed significant positive correlation with precipitation, whilst connection with air temperature was mostly significant and negative. The study results suggest that climate is an important factor affecting river regimes, as well as that changes in river discharges are reflecting recent abrupt changes in climatic variables.

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Aim of the study: i. Comparison of characteristic discharges (mean and mean of annual minimum, i.e. mean low discharge) of small lowland river between two periods (1963-1990 and 1991-2020) estimated on the base of field measurements. ii. Comparison of specific discharges of two small catchments of various size in the period 1991-2020. iii. Evaluation of local indirect methods for estimation of mean and mean low discharge applied for the two small catchments. Material and methods: Since 1962, hydrological investigations have been conducted in a small lowland catchment of the Zagożdżonka River. The catchment area is characterized by agro-forested land use, and is located in the south part of the Masovia region, Poland. Continued monitoring of water stages and discharge measurement at the river gauge Płachty Stare were conducted for estimating daily and characteristic discharges for two periods: 1963-1990 and 1991-2020. Other methods were also used for both of the hydrological characteristics. They were based on maps of specific discharges from the Hydrological Atlas of Poland. Results and conclusions: Mean discharge of the Zagożdżonka River at the gauge Płachty Stare between the two periods decreased by 24%. Mean low flow decreased by 43%. Higher evapotranspiration, caused by climate change, i.e. temperature increase and higher ratio of forested area in the catchment, is indicated as the main reason of the changes. Mean specific discharge from the smaller catchment (at Wygoda gauge) was 36% less than from the larger catchment. The application of the indirect methods for estimation of mean and mean low discharges for the larger catchment seems to give satisfactory results.

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In this study, we estimated discharge from Upper Kabul River basin in the Hindu Kush Mountain (Paghman range) in Afghanistan. The Upper Kabul River basin covers an area of 1633.8km2 with a maximum elevation of 4522 m and minimum elevation of 1877 m. The Kabul River is one of the main rivers in Afghanistan and sustains a significant flow of water in summer months due to the melting of snow. In this study, daily discharge from Upper Kabul River basin, west of Kabul basin, for 2009 and 2011 is estimated by using Snowmelt Runoff Model (SRM) (Version 1.12, 2009), originally developed my J. Martinec in 1975. Daily precipitation, air temperature, discharge and snow cover data are used in the model as input variables. We calibrated the model for 2009 and validated in 2011. The observed and calculated annual average discharges in 2009 are 5.7m3/s and 5.6m3/s, respectively; and in 2011 are 1.33m3/s and 1.31m3/s, respectively. The model results are in good agreement with the measured daily discharges. With an increase of 1°C in temperature and 10% precipitation, the increase in discharge in winter, summer and annually relative to 2009 discharge are 39%, 18.5% and 17.9%, respectively. Similarly, with an increase of 2°C in temperature and 20% in precipitation, modeled discharge increases by 51.2%, 40.8% and 47.3%, respectively. The results obtained suggest that the SRM can be used efficiently for estimating discharge in the snow fed sub-catchment of the Upper Kabul River basin and other mountain basins in Afghanistan.Journal of Hydrology and Meteorology, Vol. 9(1) 2015, p.85-94

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In accordance with the water management zoning of the territory of Ukraine, the Poltva river basin belongs to the Vistula river basin region. The evaluation methodology of the channel and floodplain river complex state was proposed by Himko R. V. (2005). According to this methodology, the parameters (23 indicators), characterizing river state by points scale (5 quality classes), were defined. The research included three steps. During the preparatory stage cartographic materials were investigated and the coastal protection zones were highlighted. The fieldwork stage included: visual assessment of water quality and of the state of channels; identification of sources of pollution and clogging of waters and coastal areas; study of features of anthropogenic load within floodplains. In the third stage, generalization and evaluation works were carried out. Wastewater discharges from enterprises and coastal settlements affect the water quality of the study area. Lviv has the greatest economic impact on the Poltva river due to its channelling within the city and due to large volumes of wastewater discharges (121.4 million m3 in 2017). The water quality of the Poltva River tributaries depends on sewage discharges from small industrial and public utilities, as well as on unauthorized sewage discharges in villages. Significant parts of the river channels are regulated. Drainage systems, that occupy much of the study area, as well as ponds and small reservoirs, directly affect on the hydrological regime of the rivers. The level of land-use of coastal territories is characterized by their urbanization level and their level of plowing. The urbanization of the upper reaches of the Poltva river valley is a determining factor that has influenced the sanitary status of its channel. Outside the Lviv city, many coastal areas (within the coastal protection zones) are plowed. Overgrowing of waters and obstruction of channels by water and coastal plant remains lead to a significant deterioration of sanitary conditions of the rivers, hence to secondary contamination of its waters. Geoecological state of the Poltva river channel and floodplain complex was designated as «unsatisfactory» (4th grade from 5 classes), of Yarychivka and Gologirka river complexes – as «satisfactory» (3rd grade), of other rivers – as «rather good» (2nd grade). The rivers of the Poltva watershed are under significant economic influence. To improve the geoecological state of river channels and floodplains, a complex of water protection measures is required: reduction of insufficiently treated wastewater discharges of Lviv city; cleaning of watercourses; monitoring of compliance with water protection rules etc.

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The U.S. Geological Survey is actively investigating remote sensing of surface velocity and river discharge (discharge) from satellite-, high altitude-, small, unmanned aircraft systems- (sUAS or drone), and permanent (fixed) deployments. This initiative is important in ungaged basins and river reaches that lack the infrastructure to deploy conventional streamgaging equipment. By coupling alternative discharge algorithms with sensors capable of measuring surface velocity, streamgage networks can be established in regions where data collection was previously impractical or impossible. To differentiate from satellite or high-altitude platforms, near-field remote sensing is conducted from sUAS or fixed platforms. QCam is a Doppler (velocity) radar mounted and integrated on a 3DR© Solo sUAS. It measures the along-track surface velocity by spot dwelling in a river cross section at a vertical where the maximum surface velocity is recorded. The surface velocity is translated to a mean-channel (mean) velocity using the probability concept (PC), and discharge is computed using the PC-derived mean velocity and cross-sectional area. Factors including surface-scatterer quality, flight altitude, propwash, wind drift, and sample duration may affect the radar-returns and the subsequent computation of mean velocity and river discharge. To evaluate the extensibility of the method, five science flights were conducted on four rivers of varying size and dynamics and included the Arkansas River, Colorado (CO), USA (two events); Salcha River near Salchaket, Alaska (AK), USA; South Platte River, CO, USA; and the Tanana River, AK, USA. QCam surface velocities and river discharges were compared to conventional streamgaging methods, which represented truth. QCam surface velocities for the Arkansas River, Salcha River, South Platte River, and Tanana River were 1.02 meters per second (m/s) and 1.43 m/s; 1.58 m/s; 0.90 m/s; and 2.17 m/s, respectively. QCam discharges (and percent differences) were 9.48 (0.3%) and 20.3 cubic meters per second (m3/s) (2.5%); 62.1 m3/s (−10.4%); 3.42 m3/s (7.3%), and 1579 m3/s (−18.8%). QCam results compare favorably with conventional streamgaging and are a viable near-field remote sensing technology that can be operationalized to deliver real-time surface velocity, mean velocity, and river discharge, if cross-sectional area is available.

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This paper presents the application of the object-oriented framework SMILE to the management of flows and water quality in the Upper Mersey river catchment. The design river flows are those exceeded for 95% of the time, and are estimated applying alternative methods. The influence of compensation reservoirs, surface-water abstractions, and continuous discharges on low river flows is quantified. The annual licensed abstraction volumes are further reviewed. The monitored river water quality is classified using the River Ecosystem scheme. The compliance of the sewage treatment works and trade effluents with their discharge-consent limits is also assessed. The impact of effluents on the variation of river water quality is evaluated through Monte Carlo simulations at the discharge points. The points where the downstream water quality fails to comply with proposed River Quality Objectives are identified. The consent limits of the corresponding discharges are assessed, and changes to the BOD and total ammonia limits are suggested.

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Worldwide abatement of untreated sewage discharge into surface water is a challenging task. Sewage discharging into surface waters has a detrimental impact on water quality. This paper presents a MATLAB (R2018b) framework designed to identify sewage flow discharges into rivers from an inverse problem-solving perspective. The computational tool integrates a hydrodynamic model using the Hydrologic Engineering Center’s River Analysis System (HEC-RAS 5.0.0) and an open-source toolbox for Differential Evolution Adaptive Metropolis (DREAM) as the inverse problem method. The proposed framework can effectively infer discharge sources in scenarios of highly transient flow based on hydraulic data at pre-set monitoring sites. To validate its capabilities, one hypothetical case and two real cases of sewage flow discharges entering a river were used to test the developed modeling framework. The results based on three performance metrics showed that this mathematical tool can be extended to simulate complex hydrodynamic flow patterns. This accomplishment underscores its potential as a valuable asset for environmental monitoring and water quality restoration efforts.

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This study aims to simulate the watershed of the Mindanao River Basin (MRB) to enhance water resource management for potential hydropower applications to meet the power demand in Mindanao with an average growth of 3.8% annually. The soil and water assessment tool (SWAT) model was used with inputs for geospatial datasets and weather records at four meteorological stations from DOST-PAGASA. To overcome the lack of precipitation data in the MRB, the precipitation records were investigated by comparing the records with the global gridded precipitation datasets from the NCDC-CPC and the GPCC. Then, the SWAT simulated discharges with the three precipitation data were calibrated with river discharge records at three stations in the Nituan, Libungan and Pulangi rivers. Due to limited records for the river discharges, the model results were, then, validated using the proxy basin principle along the same rivers in the Nituan, Libungan, and Pulangi areas. The R2 values from the validation are 0.61, 0.50 and 0.33, respectively, with the DOST-PAGASA precipitation; 0.64, 0.46 and 0.40, respectively, with the NCDC-CPC precipitation; and 0.57, 0.48 and 0.21, respectively, with the GPCC precipitation. The relatively low model performances in Libungan and Pulangi rivers are mainly due to the lack of datasets on the dam and water withdrawal in the MRB. Therefore, this study also addresses the issue of data quality for precipitation and data scarcity for river discharge, dam, and water withdrawal for water resource management in the MRB and show how to overcome the data quality and scarcity.

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Neck cutoff is a sudden phenomenon that occurs during the evolution of meandering rivers, but its process and mechanism remain unclear. In this investigation, the neck-narrowing process before cutoff, the formation of a new river, and the appropriate conditions for cutoff under constant and variable discharges were studied using experimental methods in a laboratory flume. The results indicated that bank erosion upstream and downstream of the neck was the main factor that triggered cutoff, regardless of whether the discharge changed. The sinuosity of the model river was approximately 7, the ratio of the neck width to the average river width reached approximately 0.43, and the experimental material was nonuniform natural sand. Under the conditions that the unit width discharge ranged from 0.0039 to 0.0069 m2/s and the longitudinal gradient was 1‰, neck cutoff could occur after sufficient bank erosion. When neck cutoff was imminent, the sinuosity of the channel increased and the channel rotated downstream. After neck cutoff, the formation of a new river experienced three stages, namely, the short-term longitudinal scouring stage, the long-term horizontal widening stage, and the long-term transverse widening and normal slow development stage. The discharge resulting in neck scouring was the effective discharge contributing to the cutoff, and this discharge directly affected the cutoff time and position. We attempted to explain the factors leading to neck cutoff from an energy consumption perspective. Neck cutoff was a sudden phenomenon that occurred when the energy consumption of a meandering river increased to its maximum value upon entry to the recession stage from the relative equilibrium stage. To a certain extent, this study is significant in understanding river evolution and neck cutoff.

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Due to unavailability of sufficient discharge data for many rivers, hydrologists have used indirect methods for deriving flood discharge amount, that is, application of channel geometry and hydrological models, for the estimation of peak discharge in the selected ungauged river basin(s) in their research/project works. This paper has studied the estimation of peak flood discharge of the Kunur River Basin, a major tributary of the Ajay River in the lower Gangetic plain. To achieve this objective, field measurements, GIS technique, and several channel geometry equations are adopted. Three important geomorphic based hydrological models—manning’s equation, kinematic wave parameter (KWP), and SCS curve number (CN) method—have been used for computing peak discharge during the flood season, based on daily rainfall data of September, 2000. Peak discharges, calculated by different given models, are 239.44 m3/s, 204.08 m3/s, and 146.52 m3/s, respectively. The hydrograph has demonstrated the sudden increase with heavy rainfall from the 18th to the 22nd of September, 2000. As a result, a havoc flood condition was generated in the confluence zone of Ajay and Kunur Rivers. This hydrograph might be not only successful application for flood forecasting but also for management of the lower Ajay River Basin as well as the downstream area of Kunur Basin.

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As part of the Remedial Action Plan (RAP) programs for the St. Lawrence and Spanish Rivers in Ontario, Canada, tainting evaluations were conducted using members of the Public Advisory Committees (PACs) and the RAP teams. Triangle test sensory evaluations were conducted on caged rainbow trout (Salmo gairdneri) exposed insitu upstream and downstream of the pulp and paper mill diffuser outfalls In the St. Lawrence River only, evaluations were conducted on indigenous yellow perch (Perca flavescens) caught upstream and downstream of the mill discharge . In both locations, the odour of the flesh from the caged trout exposed above the diffuser outfall was not judged significantly different from caged trout exposed downstream of the discharge. However, the indigenous perch caught downstream of the mill in the St. Lawrence River were judged by the panelists to have a significantly more objectionable odour than those caught upstream of the discharge. While the effluent tainting potential appears to have been eliminated in the Spanish River, further studies are required to determine the source and magnitude of tainting concerns in the St. Lawrence River. The sensory test and results reported here provide useful tools for evaluating the tainting potential of pulp mill discharges and for assessing perceived consumer quality of the fish exposed to these effluents.

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Abstract The article summarises the results of observations conducted in the periods 1989-1992, 1998-2000, and 2001- 2003 in the catchment of the Roztocze section of the Wieprz River with an area of 404 km2. The presented results of the study on fluvial transport document the response of an upland river to variable hydro-climatic conditions. Fluvial transport rate in periods extreme in hydrological terms was compared. In the conditions of low water stages (1989- 1992) and mean annual discharges lower than the mean multiannual by 19%, the Wieprz River discharged an average of 13300 tonnes of solutions and 485 tonnes of suspensions annually. The unitary indices amounted to 32.7 and 1.2 t/ km2/year, respectively. In the years 1998-2000, in the conditions of high water stages and mean annual discharges higher than the multiannual by 41%, the Wieprz River discharged approximately 22,800 tonnes of solutions and 981 tonnes of suspensions annually. The unitary indices increased proportionately to 56.2 t/km2/year and 2.4 t/km2/year, respectively. In the years 2001-2003, in the conditions of variable water stages and discharges higher than the multiannual by 12%, the Wieprz River discharged an average of approximately 17,500 tonnes of solutions and 441 tonnes of suspensions annually. The unitary indices reached the values of 43.3 t/km2/year and 1.1 t/km2/year, respectively.

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This study marks a significant step toward the future development of river discharges forecasted in real time for flash flood early warning system (EWS) disaster prevention frameworks in the Chugoku region of Japan, and presumably worldwide. To reduce the disaster impacts with EWSs, accurate integrated hydrometeorological real-time models for predicting extreme river water levels and discharges are needed, but they are not satisfactorily accurate due to large uncertainties. This study evaluates two calibration methods with 7 and 5 parameters using the hydrological Cell Distributed Runoff Model version 3.1.1 (CDRM), calibrated by the University of Arizona’s Shuffled Complex Evolution optimization method (SCE-UA). We hypothesize that the proposed ensemble hydrological parameter calibration approach can forecast similar future events in real time. This approach was applied to seven major rivers in the region to obtain hindcasts of the river discharges during the Heavy Rainfall Event of July 2018 (HRE18). This study introduces a new historical extreme rainfall event classification selection methodology that enables ensemble-averaged validation results of all river discharges. The reproducibility metrics obtained for all rivers cumulatively are extremely high, with Nash–Sutcliffe efficiency values of 0.98. This shows that the proposed approach enables accurate predictions of the river discharges for the HRE18 and, similarly, real-time forecasts for future extreme rainfall-induced events in the Japanese region. Although our methodology can be directly reapplied only in regions where observed rainfall data are readily available, we suggest that our approach can analogously be applied worldwide, which indicates a broad scientific contribution and multidisciplinary applications.

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Abstract. Pre-regulation channel sinuosities of the meandering rivers of the Pannonian Basin are analysed in order to define a mathematical model to estimate the influence of the bankfull discharge and the channel slope on them. As a primary database, data triplets of slope, discharge and sinuosity values were extracted from historical and modern datasets and pre-regulation historical topographic maps. Channel slope values were systematically modified to estimate figures valid before the river regulation works. The bankfull discharges were estimated from the average discharges using a robust yet complex method. The "classical" graphs of Leopold and Wolman (1957), Ackers and Charlton (1970b) and Schumm and Khan (1972) were compiled to a set up a theoretical surface, whose parameters are estimated by the real values of the above database, containing characteristics of the Pannonian Basin rivers. As a result it occurred that there is a two-dimensional function of the bankfull discharges, which provides a good estimation of the most probable sinuosity values of the rivers with the given slope and discharge characteristics. The average RMS error of this estimation is around 15% on this dataset and believed to be the effect of the non-analysed changes in the sediment discharge and size distribution.

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Abstract. This study proposes a more efficient method of flood discharge measurement in mountain rivers that accounts for personal safety, accuracy, and reliability. Because it is based on the relationships between mean and maximum velocities and between cross-sectional area and gauge height, the proposed method utilizes a flood discharge measurement system composed of an acoustic Doppler profiler and crane system to measure velocity distributions, cross-sectional area, and water depths. The flood discharge measurement system can be used to accurately and quickly measure flood data that is difficult to be collected by the conventional instruments. The measured data is then used to calibrate the parameters of the proposed method for estimating mean velocity and cross-sectional area. Then these observed discharge and gauge height can be used to establish the water stage–discharge rating curve. Therefor continuous and real-time estimations of flood discharge of a mountain river can become possible. The measurement method and system is applied to the Nanshih River at the Lansheng Bridge. Once the method is established, flood discharge of the Nanshih River could be efficiently estimated using maximum velocity and the water stage. Results of measured and estimated discharges of the Nanshih River at the Lansheng Bridge differed only slightly from each other, demonstrating the efficiency and accuracy of the proposed method.

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The river Toplica springs on the east slopes of Kopaonik. It is the biggest left tributary of the Juzna Morava, in which it empties at the town of Korvingrad. It is 130 km long and the surface of its river-basin amounts to 2180 km?. This study estimates the probability of average, minimum and maximum discharge occurrence on the hydrological profile Pepeljevac on the Toplica River in the period 1951-2014. Pearson type III distribution was used for quantifying average, minimum and maximum annual discharge. Results of the study point out to significant fluctuations in the river Toplica discharge upstream the hydrological profile Pepeljevac, which is the base for further study and improvement water management planning in the basin. On the basis of probability of average annual discharges occurrence, a classification of years by water richness was done. Mann-Kendal test examined the trend of Toplica discharge, while Pettit, SNTH, Buishand and von Neumann tests analyzed hom*ogeneity of the data on the observed profile. Analysis of average annual discharges shows that years moderately rich in water are the most numerous (29) with somewhat higher participation of rich in water (16) than dry (14) years. Coefficients of variation of maximum and minimum annual discharges for the Toplica river point out to significant fluctuations upstream the hydrological profile Pepeljevac. These results are the base for further study and improvement of water management planning in the basin.

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Siak River is one of the primary rivers in Riau province, so that this river holds and flows water runoff from the left and right areas along the river flow. As a result of changes in sediment transport discharges resulted in degradation in the riverbed of Siak, resulting in the collapse of the bridge. Concerns due to the collapse of several bridges over the Siak River and seeing the condition of the Siak Bridge I need to calculate how much the sediment river sediment transport is around the Siak bridge pillar. The method used to analyze the data uses the Yang's method and hydraulic concept, based on the results of the analysis and calculation of sedimentation transport due to maximum discharge, the largest sediment transport is 3,753,25924 kg / day.

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Abstract Allocations of water discharges between dry and flood seasons along the Yangtze River have significantly hom*ogenized during the past decades, mainly due to precipitation change, regulation of key hydraulic works on the mainstream like the Three Gorges Reservoir (TGR), and the construction of numerous dams scattered in sub-basins. To reveal the specific roles of these three major factors in changing the seasonal discharges of the whole Yangtze River, this paper analyzes daily discharges during 1961–2014 at 16 hydrological stations from the far upper reach (the Jinshajiang Reach) to the estuary. We found that precipitation has only hom*ogenized in areas 427 km downstream of the TGR, contributing 9.5–23.6% to the hom*ogenized discharges. Even though the TGR is the largest hydraulic works in the world, it only contributes 17.5–27.2% to the downstream hom*ogenization of seasonal discharge. By comparison, dams in sub-regions are a major contributor (61.1–100%) in the hom*ogenized reach either upper or lower to the TGR. Of all the sub-basins, dams in Hanjiang River basin have the most significant effect (16.9%) on changing the allocations of seasonal discharges to the sea, followed by Wujiang (11.5%), Jialingjiang (10.1%), Yalongjiang (9.4%), Qingjiang (8.4%), and Daduhe-Minjiang (4.7%) river basins.

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The flow regime conditions of the Danube River are continually changing. These changes are the result of natural processes and anthropogenic activities. The territory of the Danube River Basin is one of the most flood-endangered regions in Europe and assessing the design discharges along the Danube channel is complicated by the different estimation methods that are applied in particular countries. For this reason, it is necessary to harmonize flood design value assessment methods. The long-term maximum annual discharge series of the Danube River and other rivers in the Danube basin were analyzed and used to estimate the flood design values. We used the Log-Pearson type III distribution, which is one of the most widely used theoretical probability distributions to estimate extremes. This distribution can be flexibly applied to extreme values depending on the skew coefficient. We also analyzed the effect of the inclusion and exclusion of the historical extremes in the processed dataset. The results show that the inclusion of historical floods and the regionalization of the Log-Pearson type III distribution skew parameter can change the design discharges.

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Perfluorinated compounds (PFCs) have been used for many years, and are distributed all over the world. This study focused on occurrences of PFCs, especially perfluorooctane sulfonate (PFOS) and perfluorooctonoic acid (PFOA) in Thai rivers and industrial estate discharges, while comparing results with rivers of other Asian countries (Japan, China, and Malaysia). Surveys were conducted in Chao Phraya River, Bangpakong River and three industrial estates. A solid phase extraction (SPE) and HPLC-ESI-MS/MS were used for the analysis of these chemicals. The average concentrations of PFOS and PFOA were 1.9 and 4.7 ng/L, respectively in Chao Phraya River, while lower concentrations were detected in Bangpakong River with the averages of 0.7 ng/L for both PFOS and PFOA. Higher concentrations were detected in all industrial estate discharges with the averages of 64.3 ng/L for PFOA and 17.9 ng/L for PFOS., Total loadings from three industrial estates were 1.93 g/d for PFOS and 11.81 g/d for PFOA. The concentraion levels in Thai rivers were less than rivers in Japan, China, and Malaysia. However, PFCs loading rate of Chao Phraya River was much higher than Yodo River (Japan), due to the higher flow rate. The other six PFCs were found above the Limit of Quantification (LOQ) in most samples. PFHxS and PFNA were also highly detected in some river samples.

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Abstract. River plumes have a direct influence on coastal environments, impacting coastal planktonic and benthic communities, including fishery resources. In general, the main drivers of river plume dynamics are the river discharge and the alongshore wind stress, whereas the tides and topography play a secondary role. In central Chile, rivers flowing into the eastern Pacific have a relatively short path on land, with a high slope and a mixed snow–rain regime. This study aims to understand the interannual variability in the plumes of the Maipo and Rapel rivers in the coastal/shelf area off central Chile and their influence on local ocean dynamics. We used the Coastal and Regional Ocean Community (CROCO) model, with 1 km horizontal resolution and 20 sigma levels, to simulate the ocean dynamics for the period 2003–2011. The results show that the plume's area coverage and coastal ocean salinity are strongly correlated with the river discharges. The predominant northeastward winds control the plumes' orientation toward the northwest. However, episodes of southeastward winds in winter can reverse the plumes' direction, promoting their attachment to the coast and southward transport. Results also show a salification trend linked to the severe droughts hitting central Chile during the studied period. This salification determines a change in local dynamics which could be more frequent in future scenarios of climate change with a significant lack of rain and river discharges along central Chile.