River Runoff Research Articles

Prediction of Zarrinehrud River Run-Off in the Climate Change Condition using Artificial Neural Networks

Prediction of Zarrinehrud River Run-Off in the Climate Change Condition using Artificial Neural Networks

Mapping the Mean Annual River Runoff in the Ukrainian Carpathian Region

The paper presents the spatial distribution of the mean annual river runoff in the Ukrainian Carpathians in the form of a map. The methodological approaches concerning the river runoff mapping and the technological stages of map creation by applying the geographic information system (GIS) analytical functions are considered. The accuracy assessment of the calculation of the mean annual river runoff water based on the data from the hydrometric stations for the whole observation period was performed. The mapping reliability of the mean annual runoff and their territorial variability over the main basins in the Ukrainian Carpathians are analysed.

Spatial Differentiation of the Maximum River Runoff Synchronicity in the Warta River Catchment, Poland

Based on daily flows recorded in the period 1971–2010, the synchronous occurrence of the annual (AMAXq), winter (WMAXq), and summer (SMAXq) maximum specific runoffs in 39 sub-catchments of the Warta River catchment (WRC) in Poland was analyzed. First, trends in the flows were detected using the non-parametric Mann–Kendall (M-K) test. Then, the degree of the synchronous and asynchronous occurrences of the maximum specific runoffs (MAXq) in respective sub-catchments in relation to the Gorzów Wielkopolski gauge closing the WRC was calculated. Finally, the reasons for the detected spatial and temporal differences were discussed. The study revealed a noticeable variability of the analyzed parameters. The highest synchronicity of AMAXq and WMAXq in relation to the closing Gorzów Wielkopolski gauge was revealed in the man-made Kościański and Mosiński canals and in the sub-catchments of the Noteć, Wełna, and lower Prosna rivers. While compared to AMAXq and WMAXq, the summer maxima showed relatively lower degrees of synchronicity, an increase in the synchronous occurrence of SMAXq in the southern part of WRC, and a decrease in its central part were identified. It was concluded that the stronger synchronicity of WMAXq resulted from the nival regime of the investigated rivers. Consequently, the annual maxima were most often associated with the winter half-year. The detected differences of synchronicity of the annual and seasonal runoffs are conditioned by climate, more specifically by the course of winter and resulting from it snow cover thickness, and also the amount and intensity of rainfall in summer.

Modeling of Godavari River Run-Off Process Using Artificial Neural Networks

Modeling of Godavari River Run-Off Process Using Artificial Neural Networks

Testing a Hydrological Model to Evaluate Climate Change Impact on River Runoff

For two hydrological models, the ECOMAG and SWAP, the hypothesis is checked that a model which has successfully passed the test based on observational data is more efficient for assessing future hydrological consequences of climate change than the models which did not pass the test. The efficiency is evaluated using two criteria: the robustness of a model and the uncertainty of simulation results. Three versions of each model constructed for the basins of the Lena and Mackenzie rivers are examined: the model whose parameters are set a priori (without calibration), the model which was calibrated against runoff hydrographs at the outlet, and the model which was calibrated against runoff hydrographs at several gaging stations of the river network. The estimates of possible changes in the river runoff by the end of the 21st century are obtained using data of global climate models. It is shown that the hydrological model which successfully passed the proposed testing procedure is more effective for assessing climate change impact on the river runoff.

The Impacts of Reservoirs on Runoff in the Upper Yellow River, China

River runoff is an important link in the water cycle that can be adversely affected by the construction of reservoirs. Based on the runoff data from 1950 to 2009 at eight stations in the upper Yellow River, this study investigated on the impacts of the combined operation of Longyangxia Reservoir and Liujiaxia Reservoir on river runoff. The measured series of runoff data for the period after the commencement of combined operation of two reservoirs were restored by adjusting for water balance. The intra-annual characteristics of observed and restored runoff at Lanzhou station and Xiaheyan station were analyzed using Mann-Kendall test and wavelet analysis. There was a significantly downward trend in both runoff series, with abrupt changes in 1986 in the observed data and in 1989 in the restored data. Periodic oscillations in the observed and restored runoff series occurred at temporal scales of 3–5-year, 6–9-year, 14–19-year, and 22–27-year. The observed runoff series at Lanzhou station and Xiaheyan station had periodicities of 25-year, 16-year, 8-year, and 4-year. The restored runoff series at Lanzhou station had periodicities of 23-year, 8-year, and 4-year, and at Xiaheyan station had periodicities of 24-year, 4-year, and 8-year. The results show that the combined operation of Longyangxia Reservoir and Liujiaxia Reservoir contributed to the decreasing trend of river runoff, and leaded to runoff abrupt changes and alterations in the periodic variation.

Role of River Runoff and Sea Ice Brine Rejection in Controlling Stratification Throughout Winter in Southeast Hudson Bay

The Hudson Bay system is undergoing climate-driven changes in sea ice and freshwater inflow and has seen an increase in winter river inflow since the 1960s due in part to flow regulation for hydropower production. Southeast Hudson Bay and adjacent James Bay are at the forefront of these changes, with more than 1-month shortening of the season of sea ice cover as defined using satellite data, increases in winter inflow from the regulated La Grande River complex, and changes in coastal ice and polynya behavior described by Belcher Islands’ Inuit. In summer, there is a fresh coastal domain in southeast Hudson Bay fueled by river runoff and sea ice melt. To investigate winter oceanographic conditions and potential interactions between runoff and ice melt or brine in southeast Hudson Bay, we initiated the first winter study of the shallow waters surrounding the Belchers, collecting conductivity-temperature-depth (CTD) profiles and conductivity-temperature (CT) time series using under-ice moorings, and collecting water samples and ice cores during four campaigns between January 2014 and March 2015. Tandem measurements of salinity and δ18O were made for the water and ice samples to discriminate between freshwater sources (river runoff and sea ice melt). We find that southeast Hudson Bay, and particularly the nearshore domain southeast of the Belchers, is distinguished in winter by the presence of river water and strong surface stratification, which runs counter to expectations for a system in which local freshwater remains frozen on land until spring freshet (May–June) and sea ice growth is adding brine to surface waters. The amount of river water around the Belcher Islands increased significantly from fall through to late winter according to δ18O records of ice. The accumulation of river water in surface waters during the winter is directly associated with an accumulation of brine, which considerably exceeds the capacity of local ice formation to produce brine. We therefore infer that brine is advected into the study area together with river water, and that interplay between these properties establishes and maintains the level of surface stratification throughout winter. With reference to a NEMO ocean model simulation of winter circulation in the study area, we propose a conceptual model in which winter river inflow into James Bay drives the northward transport of both river water and brine captured near the surface, with reductions in brine-driven deep convection in the area’s flaw leads. While past changes in winter oceanographic conditions and sea ice cannot be reconstructed from the few available scientific data, the presence of significant runoff in winter in southeast Hudson Bay implies heightened sensitivity to delayed freeze-up under a warmer climate, which will have the effect of reducing brine early in the winter, also promoting increased stratification and river plume transport.

Rainfall-runoff simulation and flood dynamic monitoring based on CHIRPS and MODIS-ET

ABSTRACTIn this study, satellite meteorological products were used as important data sources to achieve rainfall-runoff simulation and flood dynamic monitoring in the Songhua River basin (below the Sancha estuary) in northeastern China. Satellite precipitation products CHIRPS (the Climate Hazards Group Infrared Precipitation with Stations) and satellite evapotranspiration products MODIS-ET (the Moderate Resolution Imaging Spectroradiometer-Evapotranspiration) were collected for the study area during 2010–2015. The accuracy of satellite meteorological products was validated by ground observation data in the same period. Then, combined with satellite meteorological products, a daily-scale rainfall-runoff model suitable for the study area was established. The daily river runoff (RR) and surface runoff depth (SRD) of the study area were obtained through this model. It is found that the overall performance of satellite meteorological products is good through verification. The annual average deviation of MODIS-ET and observation data is less than 1 mm. In tertiary basins of the study area, the correlation coefficient (CC) between CHIRPS and observation data is in the range from 0.59 to 0.71, and the root-mean-square error (RMSE) varies from 3.75 to 4.50 mm. The rainfall-runoff model based on satellite meteorological products can well simulate the variation characteristics of observed RR: the CC reach 0.83, and the Nash–Sutcliffe efficiency coefficient (NSE) reach 0.72. The established model was used to analyse a flood event in 2013. And the simulation results showed the changing process of the RR accurately. The dynamic changing process of the SRD was monitored by the established model during the flooding period. The model can be used to reflect the spatial distribution of potential inundation areas. This study validates the performance and deviation of CHIRPS and MODIS-ET, and proves that these satellite meteorological products have good applicability in rainfall-runoff simulation and flood dynamic monitoring. The output results, daily RR and SRD data with 0.05° grid unit, can provide the decision support for hydrological information monitoring and flood forecasting.

Influence of the Chernaya River Runoff during High and Low Water on the Ecological State of the Apex of the Sevastopol Bay Water Area

Influence of the Chernaya River Runoff during High and Low Water on the Ecological State of the Apex of the Sevastopol Bay Water Area

Independence of Future Changes of River Runoff in Europe from the Pathway to Global Warming

The outcomes of the 2015 Paris Agreement triggered a number of climate impact assessments, such as for floods and droughts, to focus on future time frames corresponding to the years of reaching specific levels of global warming. Yet, the links between the timing of the warming levels and the corresponding greenhouse gas concentration pathways to reach them remain poorly understood. To address this gap, we compared projected changes of annual mean, extreme high, and extreme low river discharges in Europe at 1.5 °C and 2 °C under Representative Concentration Pathways RCP8.5 and RCP4.5 from an ensemble of regional climate model (RCM) simulations. The statistical significance of the difference between the two scenarios for both warming levels was then evaluated. The results show that in the majority of Europe (>95% of the surface area for the annual mean discharge, >98% for high and low extremes), the changes projected in the two pathways were statistically indistinguishable. These results suggest that in studies of changes at global warming levels, the projections of the two pathways can be merged into a single ensemble without major loss of information. With regard to the uncertainty of the unified ensemble, the findings show that the projected changes of annual mean, extreme high, and extreme low river discharge were statistically significant in large portions of Europe.

When isotopes fail: importance of satellite telemetry and multi-site validation when estimating the foraging grounds of migratory species

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 633:197-206 (2020) - DOI: https://doi.org/10.3354/meps13179 When isotopes fail: importance of satellite telemetry and multi-site validation when estimating the foraging grounds of migratory species O. I. Coffee1,*, D. T. Booth1, J. A. Thia1, C. J. Limpus2 1The University of Queensland, School of Biological Sciences, St Lucia, Queensland 4072, Australia 2Queensland Government, Department of Environment and Science, Aquatic Threatened Species Unit, Dutton Park, Queensland 4102, Australia *Corresponding author: owen.coffee@uq.net.au ABSTRACT: A combination of δ13C and δ15N isotope ratios, capture-mark-recapture and satellite telemetry data were used to investigate the foraging locations supporting nesting loggerhead turtles Caretta caretta on the Woongarra coastline, southeast Queensland, Australia. Known foraging grounds were available for a subset of these turtles and supplemented with samples taken from foraging turtles to determine whether foraging regions could be identified in untracked nesting turtles using the stable isotopic values of their sampled tissue. Despite the large distances between known foraging regions, no latitudinal gradient was observed in the isotopic values of these turtles. In addition, the isotopic values of foraging individuals from a single site encompassed the range of all loggerhead turtles sampled over the 2000 km north-south distribution along the east coast of Australia. This study demonstrates that assumptions common to δ13C and δ15N stable isotope inference in migratory species are not adhered to globally. Contrasting the successes of stable isotope analysis in the northern hemisphere, these results indicate that factors in the southwest Pacific such as differing prevailing oceanic currents, temperature regimes and river run-offs may prevent the establishment of region-specific unique isoscapes needed for identifying the foraging region of turtles using their isotopic values. Therefore, we caution against the use of δ13C and δ15N stable isotopic values as suitable indicators of foraging regions for loggerhead turtles in Australia. These findings potentially highlight the need to re-evaluate when and where the use of isotopic analysis is appropriate for identifying foraging locations in marine turtle species. KEY WORDS: Loggerhead turtles · Caretta caretta · Carbon isotope · Nitrogen isotope · Migration connectivity Full text in pdf format PreviousNextCite this article as: Coffee OI, Booth DT, Thia JA, Limpus CJ (2020) When isotopes fail: importance of satellite telemetry and multi-site validation when estimating the foraging grounds of migratory species. Mar Ecol Prog Ser 633:197-206. https://doi.org/10.3354/meps13179 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 633. Online publication date: January 09, 2020 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2020 Inter-Research.

Continuous measurements of riverine chemical constituents reveal the environmental effect of the 2014–2015 Bárðarbunga eruption in Iceland

The 2014–2015 Bárðarbunga eruption caused one of the most intense and widespread volcanic derived air pollution events in centuries. The volcanic plume was tracked all the way to central Europe. Volcanic gas and aerosol dissolved in precipitation and accumulated as aerosol and snow on land in Iceland. Here we report on the continuous monitoring of discharge and dissolved constituents of a direct runoff river located 85 km from the eruption site during the entire snowmelt period in 2015. Osmotic samplers collected continuous water samples so short-lived flood peaks would not be missed. Comparison between results from this 2015 study and data from 1998 to 2013 from the same river showed that average pH was 0.2 units lower in 2015 and the Cl and SO4 average concentration were 36% and 38% higher than prior to the eruption, respectively. Integrated riverine fluxes of H+ and SO4 were two to three times higher during summer 2015 than in the control years, and the Cl flux was 37% higher. The measured excess H+ flux was however only a small fraction of the calculated excess H+ flux stemming from excess SO4 and Cl fluxes in 2015 which can be explained by ion-exchange in the catchment soil, water-rock interaction consuming protons within the catchment, and by elevated sea spray derived Cl and SO4 due to relatively high wind speed during the 2014–2015 winter. In addition, the small H+ increase in the river water can be the cause of the less than expected excess SO4 riverine flux, normalised to the total measured volcanogenic SO2 and HCl emission fluxes (11 Tg/0.1 Tg), which underscores the slow oxidation of SO2 to SO4 in relatively dry weather conditions and reduced sunlight during winter in Iceland. Despite being sensitive to riverine pH and aluminium changes, freshwater ecosystem was not threatened by the eruption, since it did not cause large pH changes and the dissolved aluminium concentration was always low during the study period. This study provided the means to quantify the integrated chemical fluxes and the impact of volcanic emissions on a riverine system in the vicinity of the eruption site and the implication of increased chemical fluxes of solutes of volcanic origin on the system.

Dynamics of Changes in Long-Term Average Annual River Runoff in the Lake Sevan Basin

In the work, long-term fluctuations in the annual runoff of rivers flowing into lake Sevan were identified, analyzed and evaluated. As the source material, daily data of long-term actual instrumental observations of the annual runoff of rivers flowing into the lake, as well as air temperature and atmospheric precipitation of the lake basin for the entire observation period were used.

Phosphorus deficiency induced by aluminum in a marine nitrogen-fixing cyanobacterium Crocosphaera watsonii WH0003

Large amounts of aluminum (Al) enter the ocean through atmospheric dust deposition and river runoffs. However, few studies have reported the effects of Al on marine phytoplankton, especially nitrogen-fixing cyanobacteria. By using the isotope tracer method and quantitative reverse transcription PCR (RT-qPCR), we examined the physiological effect of Al (0.2, 2 and 20μM) on the unicellular marine nitrogen-fixing cyanobacterium Crocosphaera watsonii in Aquil* medium. We show that Al has an inhibitory physiological effect on C.watsonii, including changes in growth rate, nitrogen fixation rate, carbon fixation rate, cell size, fast rise chlorophyll fluorescence kinetics, cellular photosynthetic pigment and C/N/P content, the same as that of the phosphorus deficient treatment. The ratio of cellular elements C:N:P showed that phosphorus was deficient in the cell of C.watsonii after Al treatment (2 and 20μM). In addition, Al stimulated the expression of phosphorus-related genes pstS, phoH, phoU, ppK and ppX in C.watsonii. All these results suggest that Al-treated C.watsonii is phosphorus-limited, and that the phosphorus deficiency induced by Al may be one mechanism behind aluminum's toxicity.

Distribution and characterization of microplastic particles and textile microfibers in Adriatic food webs: General insights for biomonitoring strategies

This study provided a comprehensive characterization on ingestion of different typologies of microplastics in several fish and invertebrate species from the Adriatic Sea, considered as a preferential area of plastic accumulation in the Mediterranean. Almost 500 organisms were sampled in the three sectors of Northern, Central and Southern Adriatic, testing the hypothesis that area of collection, habitat and feeding strategy might influence the occurrence of plastic particles in biota. In this study, the overall characterization considered separately plastic microparticles (MPs) from textile microfibers (MFs) which also included natural and semi-synthetic ones. Ingestion of MPs was a widespread phenomenon, but their number (typically 1 or 2) did not reveal any significant relationship with biometric values, geographical areas or ecological features of the species. Conversely, the frequency of ingestion, ranging from 13 to 35% of organisms containing MPs, appeared a more reliable index to highlight such differences, revealing higher values in species from Central and Southern basins compared to the Northern one, as well as in benthopelagic compared to benthic or pelagic organisms. Geographical differences also occurred in terms of size and typology of ingested particles, suggesting the importance of local river runoffs and surface currents dynamics. Textile microfibers (MFs) were also abundant in Adriatic food webs occurring in all the analyzed species with average numbers (3–10) and frequencies (40–70%) higher than those reported for MPs; further, an elevated percentage of MFs (>80%) was of natural or semi-synthetic origin.Overall, this study provided general insights toward the harmonization of a common biomonitoring strategy, as in the context of MSFD, including the suggestion of a frequency-based index and of a multi-species approach to increase the ecological relevance of assessment, as well as the comparability between different areas and trophic webs.

Osnovnye zakonomernosti dolgovremennoy evolyutsii khalinnoy stratifikatsii Chernogo morya

Purpose. At present the process of formation of haline stratification in the Black Sea is poorly studied. The current state of the basin is considered to be close to equilibrium. However, having been analyzed, the long-term observations testify to a tendency towards desalination of the sea surface layer and salination of the deep waters. The goal of the study is to obtain a complete pattern of the haline stratification formation in the basin and the characteristic time scales of its long-term climatic evolution. Methods and Results. Numerical calculations of the Black Sea circulation which is formed being influenced by water exchange through the Bosporus, river runoff, precipitation and evaporation, are compared with the laboratory simulation results obtained previously using the NEMO model. It is shown that the time period of formation of the upper and lower Bosporus currents is of a characteristic time scale 20 years. Relatively short period of adaptation of the Bosporus water exchange to the external conditions testifies that on the climatic scale, the strait should be in a quasi-equilibrium state. The results of the numerical experiments also show that, against the background of the initially preset constant salinity of the Black Sea, the vertical haline stratification is formed rather rapidly due to the fact that the upper forty-meter layer is desalinated by the river runoffs. This leads to formation of a halocline in the 10–40 m layer. In the deeper layers, salinity increases slowly owing to the Marmora Sea water inflow. Each of the calculations shows that intense desalination of the surface layer lasts 70–80 years, whereupon its salinity grows slowly. Conclusions. As a result, the characteristic adaptation period of the basin stratification to the changes in the external factors constitutes 70–100 years. After the equilibrium regime is settled, slow quasi-stationary evolution of the basin fields takes place. Analysis of the obtained results enabled us to deduce the equations for describing slow evolution of the haline stratification.

Statistical Modeling of the Global River Runoff Using GCMs: Comparison with the Observational Data and Reanalysis Results

Specific methods are proposed to assimilate the results of the “historical” experiments on 28 climate models. The results of the analysis confirm the hypothesis regarding a stationary character of changes in the global river runoff during “instrumental” period (approximately 150 years). Part of the models (about one third) reproduces the non-stationary changes in the global runoff with respect to the mean. At the same time, the number of such models indicating increased runoff is exactly equal to the number of models that indicate a decrease in runoff. The models generally reproduce well the coefficient of variation of global river runoff in comparison with the observational data, as well as the small value of the coefficient of asymmetry. The model of the Gaussian white noise is optimal for the description of the majority of the annual time series of global river runoff generated by the GCMs.

Integrated model projections of climate change impacts on water-level dynamics in the large Poyang Lake (China)

Abstract This study outlines a framework for examining potential impacts of future climate change in Poyang Lake water levels using linked models. The catchment hydrological model (WATLAC) was used to simulate river runoffs from a baseline period (1986–2005) and near-future (2020–2035) climate scenarios based on eight global climate models (GCMs). Outputs from the hydrological model combined with the Yangtze River's effects were fed into a lake water-level model, developing in the back-propagation neural network. Model projections indicate that spring–summer water levels of Poyang Lake are expected to increase by 5–25%, and autumn–winter water levels are likely to be lower and decrease by 5–30%, relative to the baseline period. This amounts to higher lake water levels by as much as 2 m in flood seasons and lower water levels in dry seasons in the range of 0.1–1.3 m, indicating that the lake may be wet-get-wetter and dry-get-drier. The probability of occurrence for both the extreme high and low water levels may exhibit obviously increasing trends by up to 5% more than at present, indicating an increased risk in the severity of lake floods and droughts. Projected changes also include possible shifts in the timing and magnitude of the lake water levels.

HCHs and DDTs in the Bohai Sea: Contamination, distribution and sources

Concentrations, distributions, and potential sources of DDTs and HCHs in seawater, sediments, soils, and atmosphere were collected to review their pollution statuses in the Bohai Sea and its coastal areas. In comparison to various sediment and seawater quality standards, DDTs and HCHs in sediments and seawater were at low levels in the entire Bohai Sea and might not cause adverse biological effects. However, DDTs and HCHs levels in various sea areas were closely associated with local pesticides production and application as well as hydrodynamic. DDTs and HCHs showed an obvious spatial distribution pattern. High levels were found in the Bohai Bay, Haihe River and Yellow River estuary. DDTs and HCHs concentrations in river and estuary sediments were higher than sea sediments and a seaward decreasing trend was observed. Although HCHs and DDTs residues in the Bohai Sea primarily originated from river runoffs (pesticide factory wastewater, historical applications and residues of technical HCH and DDT, etc.), additional sources of lindane and dicofol existed. Runoff from the demolished old pesticide factories might be another source. Further researches are highly recommended on pollution hotpots of DDTs and HCHs and investigate their migration and transformation at sediment-water interface and pollution history from sediment depth profiles.

Hydro Power Energy Generation of Run-off River Type by using Plural Flow Duration Curve

This research intends to present a new method about the discharge modeling for mini-hydro power so it can be obtained the maximum energy. The methodology consists of modelling by the plural Flow Duration Curve (FDC). By using this method, it is hoped that the hidden discharge potency on a river can be appear and optimally used. The detail methodology is as follow: to analyze the available dependable discharge in the Konang watershed, to know the condition of Konang watershed based on the ratio pf Qmax/Qmin, to determine the suitable turbine type for the mini-hydro power of run off river in the Konang river, and to analyze the power and energy based on the single and plural Flow Duration Curve (FDC). The result can be applied on the design of run off river mini-hydro power in the Konang river, Trenggalek regency-Indonesia, By the treatment, it is hoped to be able to produce the significant decreasing of mini-hydro power energy.