Les flux de sels nutritifs dans l'estuaire de la Seine (France); rôle et importance du bouchon vaseux au cours du mélange estuarien

1983 ◽  
Vol 40 (S1) ◽  
pp. s180-s187 ◽  
Author(s):  
Jean-François Guillaud
Keyword(s):  
River Flow ◽  
Particulate Phosphorus ◽  
Dissolved Nutrients ◽  
Seine River ◽  
Flushing Time ◽  
Dissolved Inorganic Nutrients ◽  
Phosphate Loading ◽  
High Turbidity ◽  
Nitrogen Nutrients ◽  
High River Flow

Dissolved nutrient loadings from the Seine River as it enters the Seine Estuary were examined for the period 1976–79; these are directly related to river flow, except for more constant phosphate loading. Mean annual inputs of dissolved inorganic nutrients attain 37 600 t/yr for silica, 10 300 t/yr for phosphorus and 66 000 t/yr for nitrogen. Nutrients samples were also collected along the estuary during March 1978 and March and September 1979; results show that in the estuary the dissolved nutrients are generally mixed in a conservative way; a few exceptions can be noticed — addition of silicate to the bottom water during high river flow periods and production of ammonia and nitrites during the summer months. Results also indicate that particulate phosphorus and particulate organic nitrogen can be trapped within the area of the turbidity maximum but this process affects only a small fraction of the total inputs of nutrients from the river. Finally it is suggested that high turbidity levels and rapid flushing time are two significant factors limiting the primary production and the removal of dissolved nutrients within the estuary.

scholarly journals Anomalies and trends of high river flow under temperate climatic conditions in north-eastern Romania

2020 ◽  
Author(s):  
Ionuț Minea ◽  
Oana Elena Chelariu
Keyword(s):  
Water Resource Management ◽  
River Flow ◽  
Climatic Conditions ◽  
High Flow ◽  
Data Sets ◽  
Pi Index ◽  
Starting Point ◽  
North Eastern ◽  
Management Plans ◽  
High River Flow

Abstract Regional water resource management plans include various scenarios related to the anomalies and trends of hydro-climatic parameters. Two methods are used for the identification of the anomalies and trends associated with high flow (annual and seasonal) of the rivers in Eastern Romania, namely the quantile perturbation method (QPM) and the partial trend method (PMT). These methods were selected due to the fact that they are suitable for data sets which do not rely on restrictive statistical assumption as common parametric and nonparametric trend tests do. For six of the nine stations analyzed, the decreasing trend in high extremes for annual high flow based on the PTM is the same as the annual trend obtained with the QPM. Using the PI index (associated with PTM) for the estimation of trend intensity, values between −2.280 and −9.015 m3/s were calculated for the decreasing trend of the annual high flow and between +1,633 m3/s (in autumn) and −9.940 m3/s (in summer) for the seasonal high flow. The results obtained on the anomalies and trends of high river flow may represent a starting point in the analysis of the evolution of water resources and their effective management.

Invasion and upstream migration by glass-eels of Anguilla australis australis Richardson and A. reinhardtii Steindachner in Tasmanian Freshwater Streams

1984 ◽  
Vol 35 (1) ◽  
pp. 47 ◽  
Author(s):  
RD Sloane
Keyword(s):  
Fresh Water ◽  
River Flow ◽  
Condition Factor ◽  
Late Summer ◽  
Upstream Migration ◽  
Larval Life ◽  
Freshwater Streams ◽  
Anguilla Australis ◽  
Glass Eels ◽  
High River Flow

The recruitment of glass-eels into fresh water was investigated by hand-netting and electrofishing at the lowest permanent freshwater riffle on several streams in eastern Tasmania. Measurements of the forward extent of the dorsal fin distinguished the short-finned eel, A. a. australis, from the long-finned eel, A. reinhardtii; this separation was verified by vertebral counts and A. a, australis glass-eels were found to be larger than A. reinhardtii. A. a. australis glass-eels were collected at the first riffle during all seasons of the year except mid-summer. Numbers in the catch declined during mid-winter, probably as a result of an effective seaward movement of the freshwater-estuarine interface during periods of high river flow; A. a. australis glass-eels were still found to be abundant near estuary mouths at such times. A. reinhardtii glass-eels exhibited a more restricted movement into fresh water during late summer and autumn with no collections recorded after mid-winter. For both species, the stage of pigmentation was found to advance as the season progressed, and length, weight and condition factor declined with advancing pigmentation. The otoliths of invading glass-eels of both species appeared similar with a single summer ring, suggesting a larval life of 1-1½ years. The restricted invasion period of A. reinhardtii and the similar size throughout the species range suggests a short and precise larval life. The length of larval life of A. a. australis is probably quite variable, resulting in a more substantial and prolonged influx of glass-eels into Tasmanian waters.

Expected Future Runoff of the Upper Jordan River Simulated with a CORDEX Climate Data Ensemble

2016 ◽  
Vol 17 (3) ◽  
pp. 865-879 ◽  
Author(s):  
Gerhard Smiatek ◽  
Harald Kunstmann
Keyword(s):  
Complex Terrain ◽  
River Flow ◽  
Regional Climate ◽  
Climate Data ◽  
Jordan River ◽  
Discharge Rates ◽  
Ensemble Mean ◽  
The Future ◽  
The Mean ◽  
High River Flow

Abstract Data from five different RCMs run in two experiments from the Coordinated Regional Climate Downscaling Experiment (CORDEX) are applied together with the Water Flow and Balance Simulation Model (WaSiM) to assess the future availability of water in the upper Jordan River. Simulation results for 1976–2000 show that the modeling system was able to reasonably reproduce the observed discharge rates in the partially karstic complex terrain without bias correction of the precipitation input. For the future climate in the area, the applied CORDEX models indicate an increasing annual mean temperature for 2031–60 by 1.8 K above the 1971–2000 mean and by 2.6 K for 2071–2100. The simulated ensemble mean precipitation is predicted to decrease by 16.3% in the first period and 22.1% at the end of the century. In relation to the mean for 1976–2000, the discharge of the upper Jordan River is simulated to decrease by 7.4% until 2060 and by 17.5% until 2100, together with a reduction of high river flow years.

scholarly journals Heavy Metals and Related Human Health Risk Assessment for River Waters in the Issyk−Kul Basin, Kyrgyzstan, Central Asia

2020 ◽  
Vol 17 (10) ◽  
pp. 3506 ◽  
Author(s):  
Wen Liu ◽  
Long Ma ◽  
Yaoming Li ◽  
Jilili Abuduwaili ◽  
Salamat Abdyzhapar uulu
Keyword(s):  
Public Health ◽  
Heavy Metals ◽  
Central Asia ◽  
Human Health ◽  
River Flow ◽  
Major Ions ◽  
Human Health Risk ◽  
The Sustainable Development ◽  
River Waters ◽  
High River Flow

The water resources of Central Asia play an important role in maintaining the fragile balance of ecosystems and the sustainable development of human society. However, the lack of research on the heavy metals in river waters has a far−reaching influence on public health and the sustainable development in Central Asia. In order to reveal the possible sources of the heavy metals and to assess the associated human health risks, thirty−eight water samples were collected from the rivers of the Issyk−Kul Basin during the period with low river flow (May) and the period with high river flow (July and August), and the hydrochemical compositions and major ions of heavy metals were analyzed. No changes in hydrochemical facies were observed between the two periods and the river water type was calcium bicarbonate. Carbonate dissolution and silicate weathering controlled the variation of cations and anions in river waters from the Issyk−Kul Basin. There were some differences in the sources of heavy metals in water bodies between the two periods. During the period with low river flow, heavy metals (Cr) were closely clustered with major ions, indicating that they were mainly affected by water–rock interactions. During the period with high river flow, all heavy metals studied in this paper had different sources of major ions, and the heavy metals maybe influenced by human activities. From the human health risk assessment, the hazard quotients for all samples were less than 1, reflecting that there was no noncarcinogenic risk in the river waters of the Issyk−Kul Basin during the two sampling periods. However, the water samples with carcinogenic risk of arsenic exceeding the threshold (10−4) accounted for 21.1% of the total, indicating that there were some certain carcinogenic hazards for human health via water drinking with direct oral ingestion. The results are of certain significance for the utilization and protection of water resources in the basin as well as the protection of public health.

Identifying resuspended sediment in an estuary using the 228Th/232Th activity ratio: the fate of lagoon sediment in the Bega River estuary, Australia

2000 ◽  
Vol 51 (7) ◽  
pp. 659 ◽  
Author(s):  
Gary J. Hancock
Keyword(s):  
Suspended Sediment ◽  
River Flow ◽  
Activity Ratio ◽  
Sediment Resuspension ◽  
River Estuary ◽  
Low Flow ◽  
Eastern Australia ◽  
Lagoon Sediment ◽  
Thorium Series ◽  
High River Flow

Thorium-series nuclides (228Th and 232Th) have been used to identify resuspended sediment in the Bega River estuary, south-eastern Australia. A non-conservative increase in concentration of suspended sediment of water in the vicinity of mid-estuary back-flow lagoons was associated with a decrease in the 228Th/232Th activity ratio (AR) of the suspended sediment. The lagoon sediment is characterized by a low estuarine 228Th/232Th signature, distinguishing it from freshwater suspended sediment recently delivered to the estuary, and identifying it as the likely source of the additional suspended sediment. Sediment-core 210Pb profiles show that the lagoons are accumulating sediment, presumably during high river-flow events. However this study indicates that during intervening periods of low flow, 40% of sediment deposited in the lagoons is subsequently resuspended and exported to the lower estuary, and possibly to the ocean. The utility of the 228Th/232Th AR to quantify sediment resuspension in estuaries is likely to be estuary-dependent, and is controlled by the extent of scavenging of dissolved 228Th by suspended particles.

Export of nutrients and suspended sediment during a cyclone-mediated flood event in the Herbert River catchment, Australia

1997 ◽  
Vol 48 (1) ◽  
pp. 79 ◽  
Author(s):  
A. W. Mitchell ◽  
R. G. V. Bramley ◽  
A. K. L. Johnson
Keyword(s):  
Agricultural Land ◽  
Suspended Sediments ◽  
Flood Event ◽  
Particulate Phosphorus ◽  
Nutrient Concentrations ◽  
Data Sets ◽  
Particulate Nitrogen ◽  
Flood Peak ◽  
Dissolved Inorganic Nutrients ◽  
Parallel Data

Changes in the river chemistry of the Herbert River (northern Queensland) during a flood event that followed Cyclone Sadie in January 1994 are presented. Parallel data sets collected by AIMS and CSIRO were generally well correlated. Around the flood peak, concentrations of dissolved inorganic nutrients declined to a minimum, whereas particulate nutrient concentrations increased to a maximum (particulate nitrogen, 1200 µg N L-1; particulate phosphorus, 225 µg P L-1). Concentrations of dissolved organic nutrients varied erratically. Concentrations of silicate and potassium, pH and electrical conductivity varied inversely with discharge. Good correlations were observed between the concentrations of particulates and concurrent discharge, with differing relationships existing during the rising and falling stages of the flood. It is estimated that this flood event resulted in the export of at least 600 t of N, 65 t of P and 100000 t of suspended sediments over a period of six and a half days, with most transport (85%) occurring within the first two days. Particulate fractions of N (50%) and P (80%) constituted the bulk of the nutrient flux. This study illustrates the potential for high nutrient exports during brief flood events from intensively farmed agricultural land within tropical catchments.

Nitrogen nutrients in a subtropical river: temporal variation and analysis at different spatial scales

2017 ◽  
Vol 68 (10) ◽  
pp. 1935 ◽  
Author(s):  
Rodrigo Moncayo-Estrada ◽  
Carlos Escalera-Gallardo ◽  
Miriam Arroyo-Damián ◽  
Oswaldo Campos-Campos ◽  
José T. Silva-García
Keyword(s):  
River Flow ◽  
Spatial Scales ◽  
Water Discharge ◽  
Regression Tree ◽  
Hierarchical Cluster ◽  
Road Density ◽  
Regression Tree Analysis ◽  
Poor Water Quality ◽  
Nitrogen Nutrients ◽  
High Concentrations

Herein we provide a framework for evaluating the spatiotemporal variation of nitrate and ammonium and their relationships with environmental and anthropogenic variables at different scales. Bimonthly samples were collected from 28 sites in the Duero River, Mexico, from May to December 2013. The river flow changed and lost connectivity during the dry season because more water was diverted for irrigation. Four sites had the highest nitrate and ammonium values (7.6 and 22.1mgL–1 respectively), which were related to direct waste water discharge. The remaining 24 sites were analysed using a multivariate approach. Using hierarchical cluster analysis, seasonal trends were identified with two groupings during July and five in December. Sites were grouped into those with constant discharge and nitrates affected by springs and those with poor water quality (high concentrations of ammonium). Non-metric multidimensional scaling simultaneously revealed the variation in time and space, organised sites into an environmental ammonium gradient and differentiated between seasons according to nitrate levels. Regression tree analysis established a relationship between nutrients and independent variables. At the landscape level, the agricultural area affected nitrate (75%) and urban area affected ammonium (45%); at the basin level, road density influenced both parameters (10.68km per 25km2).

scholarly journals Trace metals in the water and margin sediments of the Rio Doce Basin in Linhares municipality, ES, Brazil

2020 ◽  
Vol 2 (1) ◽  
pp. 1-11
Author(s):  
Polyana Silverio Massario ◽  
Cláudia Carvalhinho Windmöller ◽  
Juliano Souza Ribeiro ◽  
Jose Maria Rodrigues Luz ◽  
Mauro Cesar Dias
Keyword(s):  
Trace Metals ◽  
River Flow ◽  
Wet Season ◽  
Environmental Disaster ◽  
Level Ii ◽  
Guideline Values ◽  
Minas Gerais State ◽  
Freshwater Source ◽  
High River Flow ◽  
Mn Concentrations

The Rio Doce Basin (DRB) is the largest freshwater source in Espírito Santo (ES) state, Brazil. In November 2015, the disruption of the iron tailings dam in the Mariana municipality, Minas Gerais state, Brazil, severely affected this river. In this study, we showed the trace metals concentrations in the water and margin sediments of the DRB during the dry and wet seasons. This new data was obtained in 2011, prior to the environmental disaster caused by disruption of the dams. We observed Cr, Ni and Pb contaminations in the sediments. The concentrations of these elements in the high river flow (wet season) were higher than the guideline values (GV) of level II and geoacumulation Index (Igeo). However, Fe and Mn concentrations were well above the GV in the wet season. The levels of these two elements were lower than the values found in the region's Haplic Cambisol. Furthermore, the comparison between our data and those of the technical reports released after the dams rupture shows that iron ore mine tailings greatly alter the trace metals concentration in water and sediments. However, we have observed a trend of resilience that requires more systematic and careful studies in DRB.

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