scholarly journals Turbidity in the fluvial Gironde Estuary (southwest France) based on 10-year continuous monitoring: sensitivity to hydrological conditions

2015 ◽  
Vol 19 (6) ◽  
pp. 2805-2819 ◽  
Author(s):  
I. Jalón-Rojas ◽  
S. Schmidt ◽  
A. Sottolichio
Keyword(s):  
River Flow ◽  
Hysteresis Loops ◽  
Annual Runoff ◽  
Transitional Period ◽  
Estuarine System ◽  
Upstream Migration ◽  
Hydrological Conditions ◽  
Frequency Monitoring ◽  
Turbidity Level ◽  
River Floods

Abstract. Climate change and human activities impact the volume and timing of freshwater input to estuaries. These modifications in fluvial discharges are expected to influence estuarine suspended sediment dynamics, and in particular the turbidity maximum zone (TMZ). Located in southwest France, the Gironde fluvial-estuarine system has an ideal context to address this issue. It is characterized by a very pronounced TMZ, a decrease in mean annual runoff in the last decade, and it is quite unique in having a long-term and high-frequency monitoring of turbidity. The effect of tide and river flow on turbidity in the fluvial estuary is detailed, focusing on dynamics related to changes in hydrological conditions (river floods, periods of low discharge, interannual changes). Turbidity shows hysteresis loops at different timescales: during river floods and over the transitional period between the installation and expulsion of the TMZ. These hysteresis patterns, that reveal the origin of sediment, locally resuspended or transported from the watershed, may be a tool to evaluate the presence of remained mud. Statistics on turbidity data bound the range of river flow that promotes the upstream migration of TMZ in the fluvial stations. Whereas the duration of the low discharge period mainly determines the TMZ persistence, the freshwater volume during high discharge periods explains the TMZ concentration at the following dry period. The evolution of these two hydrological indicators of TMZ persistence and turbidity level since 1960 confirms the effect of discharge decrease on the intensification of the TMZ in tidal rivers; both provide a tool to evaluate future scenarios.

scholarly journals Turbidity in the fluvial Gironde Estuary (S–W France) based on 10 year continuous monitoring: sensitivity to hydrological conditions

2015 ◽  
Vol 12 (3) ◽  
pp. 2843-2883 ◽  
Author(s):  
I. Jalón-Rojas ◽  
S. Schmidt ◽  
A. Sottolichio
Keyword(s):  
Continuous Monitoring ◽  
River Flow ◽  
Hysteresis Loops ◽  
Annual Runoff ◽  
Transitional Period ◽  
Hydrological Conditions ◽  
Frequency Monitoring ◽  
Turbidity Level ◽  
River Floods

Abstract. Climate change and human activities impact the volume and timing of freshwater input to estuaries. These modifications in fluvial discharges are expected to influence estuarine suspended sediment dynamics, and in particular the turbidity maximum zone (TMZ). Located in the southwest France, the Gironde fluvial-estuarine systems has an ideal context to address this issue. It is characterized by a very pronounced TMZ, a decrease in mean annual runoff in the last decade, and it is quite unique in having a long-term and high-frequency monitoring of turbidity. The effect of tide and river flow on turbidity in the fluvial estuary is detailed, focusing on dynamics related to changes in hydrological conditions (river floods, periods of low-water, inter-annual changes). Turbidity shows hysteresis loops at different time scales: during river floods and over the transitional period between the installation and expulsion of the TMZ. These hysteresis patterns, that reveal the origin of sediment, locally resuspended or transported from the watershed, may be a tool to evaluate the presence of remained mud. Statistics on turbidity data bound the range of river flow that promotes the TMZ installation in the fluvial stations. Hydrological indicators of the persistence and turbidity level of the TMZ are also defined. The long-term evolution of these indicators confirms the influence of discharge decrease on the intensification of the TMZ in tidal rivers, and provides a tool to evaluate future scenarios.

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.

scholarly journals Deliberation of Hilly Areas for Water Harvesting Application in Western Crete, Greece.

2016 ◽  
Vol 18 (3) ◽  
pp. 621-629 ◽  
Keyword(s):  
Overland Flow ◽  
Annual Runoff ◽  
Annual Rainfall ◽  
Water Harvesting ◽  
Hydrological Conditions ◽  
Monthly Average ◽  
Dry Seasons ◽  
Harvesting Techniques ◽  
The Mean ◽  
Water Problems

<div> <p>The meteorological, physical and hydrological conditions prevailing in a hilly area, namely the region around Malaxa (Western Crete), are analyzed and investigated in relation to water harvesting applications. The literature relating to water harvesting techniques and applications is reviewed and the conclusions that have been drawn by other investigators concerning methods of water harvesting techniques and applications are outlined and discussed. Specific reasons for choosing this particular study area was given and the types and installation of equipment used are also described. The results indicate that despite the fact that the mean annual rainfall can be considered as high (940 mm), its distribution is very uneven and only 6% of it falls from May to September. This fact creates serious water problems in the area during the dry seasons. Also, mean annual and monthly average temperatures have values which contribute to the evapotranspiration of high amount of precipitation and may form frost and overland flow respectively, during some days. Furthermore, the annual runoff is estimated to be 248 mm and a part of this can be overland flow while the other part can be a throughflow. The occurrence of overland flow is also proved by the comparison of the infiltration and the intensities of rainfall with the return periods of 5 and 10 years. Additionally, the quantification of overland flow is made by collecting and analyzing it from experimental plots. By this method, we clarified that the quantity of overland flow is affected by the inclination of the ground, the density of vegetation and the compaction of the soil. These results, although all of them are not wholly conclusive, can present an advance for understanding the use of meteorological, physical and hydrological conditions for water harvesting applications in an area.</p> </div> <p>&nbsp;</p>

scholarly journals Timing of Landsat Overpasses Effectively Captures Flow Conditions of Large Rivers

2020 ◽  
Vol 12 (9) ◽  
pp. 1510 ◽  
Author(s):  
George H. Allen ◽  
Xiao Yang ◽  
John Gardner ◽  
Joel Holliman ◽  
Cédric H. David ◽  
...  
Keyword(s):  
Frequency Distribution ◽  
River Flow ◽  
The United States ◽  
Large Rivers ◽  
United States Geological Survey ◽  
Hydrological Conditions ◽  
Hydrological Extremes ◽  
Wide Range ◽  
Significant Difference ◽  
Flow Frequency

Satellites provide a temporally discontinuous record of hydrological conditions along Earth’s rivers (e.g., river width, height, water quality). The degree to which archived satellite data effectively capture the overall population of river flow frequency is unknown. Here, we use the entire archives of Landsat 5, 7, and 8 to determine when a cloud-free image is available over the United States Geological Survey (USGS) river gauges located on Landsat-observable rivers. We compare the flow frequency distribution derived from the daily gauge record to the flow frequency distribution derived from ideally sampling gauged discharge based on the timing of cloud-free Landsat overpasses. Examining the patterns of flow frequency across multiple gauges, we find that there is not a statistically significant difference between the flow frequency distribution associated with observations contained within the Landsat archive and the flow frequency distribution derived from the daily gauge data (α = 0.05), except for hydrological extremes like maximum and minimum flow. At individual gauges, we find that Landsat observations span a wide range of hydrological conditions (97% of total flow variability observed in 90% of the study gauges) but the degree to which the Landsat sample can represent flow frequency distribution varies from location to location and depends on sample size. The results of this study indicate that the Landsat archive is, on average, representative of the temporal frequencies of hydrological conditions present along Earth’s large rivers with broad utility for hydrological, ecologic and biogeochemical evaluations of river systems.

scholarly journals Impact of Anthropogenic Facilities on the Morphodynamic Evolution of an Estuarine System: The Case of Oum Er-Rbia Estuary (Azemmour, Morocco)

2019 ◽  
Vol 7 (8) ◽  
pp. 248 ◽  
Author(s):  
Mustapha El Jakani ◽  
Said Ettazarini ◽  
Hassan Rhinane ◽  
Mohammed Raji ◽  
Mohamed Radid ◽  
...  
Keyword(s):  
River Flow ◽  
Field Work ◽  
Google Earth ◽  
Aerial Photographs ◽  
Estuarine System ◽  
Watershed Area ◽  
Morphologic Evolution ◽  
Gis Environment ◽  
Morphodynamic Evolution ◽  
Sand Deposition

The Oum Er-Rbia estuary is located on the Atlantic littoral of Morocco. It undergoes severe clogging due to the sand deposition in its outlet. The current study examined the indicators of the morphodynamic evolution in the littoral system including the Oum Er-Rbia estuary and the neighboring beaches over 1970–2017. The methodology adopted was based on the analysis and the interpretation of aerial photographs and Google Earth images under a GIS environment and field work. The morphodynamic evolution was discussed by taking into account the evolution of hydraulic facilities installed in the watershed area, especially the construction of dams, as well as the dredging works in the Oum Er-Rbia estuary. The results highlight the morphologic evolution estimated in terms of surface units observed in the estuary and the neighboring beaches. The evolution of the littoral system was mainly influenced by the closest dam location and by the dredging works, in addition to the regulation of the river flow by the installation of hydraulic facilities upstream.

scholarly journals Monitoring water quality in estuarine environments: lessons from the MAGEST monitoring programme in the Gironde fluvial-estuarine system

2010 ◽  
Vol 7 (6) ◽  
pp. 9411-9436
Author(s):  
H. Etcheber ◽  
S. Schmidt ◽  
A. Sottolichio ◽  
E. Maneux ◽  
G. Chabaux ◽  
...  
Keyword(s):  
Water Quality ◽  
Environmental Changes ◽  
Monitoring Programme ◽  
Reference Database ◽  
Estuarine System ◽  
Gironde Estuary ◽  
Future Evolution ◽  
External Forcings ◽  
Frequency Monitoring

Abstract. The Gironde estuary, one of the largest European ones, presents temporary low dissolved oxygen content in its fluvial section close to the Bordeaux urban area. In a context of population growth and of long-term environmental changes, the development of a high-frequency monitoring programme of the fluvial-estuarine system of the Gironde, called MAGEST (MArel Gironde ESTuary), had appeared essential to address current and future water-quality issues/evaluations. The objectives of the MAGEST survey programme are to establish a reference database to improve the knowledge of the Gironde estuary functioning, encompassing the aspects of hydrology, sediment dynamics and biogeochemistry. Through examples of results from intratidal to seasonal time scales, we demonstrate how such a time-series is of valuable interest to extract the main trends of its functioning and of the water quality in relation to external forcings (climatology, urban wastes, land use, ...) and to predict the future evolution of the Gironde estuary with global and environmental changes.

scholarly journals Impact of urbanized landscapes on the river flow in Europe

2019 ◽  
pp. 78-87
Author(s):  
N. I. Koronkevich ◽  
K. S. Melnik
Keyword(s):  
River Basin ◽  
Russian Federation ◽  
River Runoff ◽  
River Flow ◽  
River Basins ◽  
Annual Runoff ◽  
The Russian Federation ◽  
Urbanized Areas ◽  
The Impact ◽  
Moscow River

Global urban landscapes were growing rapidly during last decades. The impact of this growth on annual river runoff of foreign European and Russian river basins was shown in this article. Calculations for Moscow river basin were taken as a basis for computations. The performed calculations show, that 1% of urbanization area increase also enhances total river runoff at 1%. At the same time 1% growth of watertight territories (included in urbanized landscapes) leads to an increase in runoff by 2–3%. The growth of urbanized areas led to a smaller increase in runoff (2–3 times) in the past (in comparison with current period) due to a less established system of diversion from urbanized landscapes. Calculations were made for Spree, Thames, Seine river basins in comparison Moscow River basin. Impact of capitals landscapes (Berlin, London, Paris, and Moscow) on river runoff was estimated initially, and then the influence of other urbanized areas located in river basins. As a result, the general influence of all urbanized territories was defined. According to results of conducted calculations, modern urbanized areas led to an increase of annual river runoff by more than 9% in Spree river basin, more than 20% of the Thames, over 11% of the Seine and 10% in the basin of Moscow River in comparison with changes during the period of norm calculation (from the end of 19th century till the beginning of the 1960s of the 20th century). According to the results of conducted calculations, modern total annual runoff increase is 2.2–4.5% for Europe and 0.2–0.3% for the Russian Federation in comparison with changes during the period of norm calculation, and in relation to the runoff from the most populated their parts is 3.5-6.9% and 1-2%, respectively. In addition, it can be expressed in km3 with following values: 44.9–89.8 (for foreign Europe) and 7.2–14.3 (for the Russian Federation). For the whole Europe (including European territory of Russia), the runoff increases by 50–100 km3 (or by 2–4%) per year. Actually, this is not so much in percentage terms, though in terms of volume – these values are close to annual runoff of such river as Neva.

Rio de la Plata estuarine system: Relationship between river flow and frontal variability

2008 ◽  
Vol 41 (11) ◽  
pp. 1876-1881 ◽  
Author(s):  
G.J. Nagy ◽  
D.N. Severov ◽  
V.A. Pshennikov ◽  
M. De los Santos ◽  
J.J. Lagomarsino ◽  
...  
Keyword(s):  
River Flow ◽  
Estuarine System ◽  
Rio De La Plata ◽  
Río De La Plata ◽  
La Plata

APPLICATION OF RAINFALL-RUNOFF MODEL: CLIMATE CHANGE IMPACTS ON RESERVOIR INFLOW

2020 ◽  
Author(s):  
Kateřina Knoppová ◽  
◽  
Daniel Marton ◽  
Petr Štěpánek ◽  
◽  
...  
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Drinking Water ◽  
Czech Republic ◽  
River Flow ◽  
Hydrological Modelling ◽  
Rainfall Runoff ◽  
The Czech Republic ◽  
Hydrological Conditions ◽  
Reservoir Inflow

The impacts of climate change are beginning to be felt in the Czech Republic. In recent years, we were challenging a dry period, which threatens to continue affecting Czech economy, agriculture and personal comfort of local people. The need to adapt to climate change is obvious. The groundwater resources are in continuous decline, consequently, the surface water supplies are increasing in importance. How would the quantity of available water change in the future? How much water would we be able to store within the year to manage it during the dry seasons? Rainfall-runoff models enable us to simulate future changes in hydrological conditions based on climate projections. One of such tools is Runoff Prophet, the conceptual lumped model being developed at the Institute of Landscape Water Management at Brno University of Technology. It is used to simulate time series of monthly river flow in a catchment outlet without the need to describe the morphological characteristics of the catchment. Runoff Prophet produced good results of calibration and proved its suitability for conceptual hydrological modelling in variable hydrological conditions of the Czech Republic. The aim of the paper was to assess the possible impact of climate change on future inflow into Vír I. Reservoir, one of the drinking water resources for Brno, a city of 380 000 inhabitants. The recently developed software Runoff Prophet was used to simulate future river flow time series. The model was calibrated on the catchment of gauging station Dalečín on Svratka River as the reservoir inflow. Prognoses of future river flow were performed using climate scenarios prepared by Global Change Research Institute of Czech Academy of Sciences. These scenarios (RCP types) are based on the outcomes from different regional climate models of Euro-CORDEX initiative. Characteristics of possible future air temperature and precipitation in the basin were evaluated in terms of its impact on reservoir management. The results of hydrological modelling gave the perspective of expected changes in Vír I. inflow yield. The options of using Vír I. Reservoir as a drinking water supply for Brno in coming decades were assessed.

Annual runoff change in the headstream of Yangtze River and its relation to precipitation and air temperature

2012 ◽  
Vol 44 (5) ◽  
pp. 850-874 ◽  
Author(s):  
Lihua Xiong ◽  
Kunxia Yu ◽  
Honggang Zhang ◽  
Liping Zhang
Keyword(s):  
Air Temperature ◽  
Yangtze River ◽  
River Flow ◽  
Annual Runoff ◽  
Climatic Conditions ◽  
The Yangtze River ◽  
Runoff Generation ◽  
Runoff Change ◽  
Runoff Series ◽  
Seasonal Analysis

We analyse the change trends of the annual and seasonal runoff series of the hydrological station Batang on the headstream of the Yangtze River over the period 1960–2007. The relations between runoff series and precipitation and temperature conditions are investigated, and the influence of the refreezing process of meltwater of the glaciers on the Yangtze River flow is examined with the proposed accumulated temperature deficit (ATD) index. It is found that annual runoff at the Batang station is not stable during the period 1960–2007. From 1960 to 1980, there was a rather strong decrease of 14.4 m3 s−1 year−1 on average in spite of the statistically significant increase in air temperature and rather stable precipitation. It is argued that the annual rate of glacier runoff generation is possibly controlled by the ATD rather than by the direct air temperature. Seasonal analysis indicates that ATD might be of greater influence in autumn and winter in affecting runoff than in spring and summer. The research in this paper may be helpful in understanding how the hydro-climatic conditions affect runoff generation in the cold regions.

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