Influence of river discharge patterns on the hydrodynamics and potential contaminant dispersion in the Douro estuary (Portugal)

2010 ◽  
Vol 44 (10) ◽  
pp. 3133-3146 ◽  
Author(s):  
Isabel C. Azevedo ◽  
Adriano A. Bordalo ◽  
Pedro M. Duarte
Keyword(s):  
River Discharge ◽  
Contaminant Dispersion ◽  
Discharge Patterns ◽  
Potential Contaminant

scholarly journals Multi-variate infilling of missing daily discharge data on the Niger basin

2021 ◽  
Author(s):  
Ganiyu Titilope Oyerinde ◽  
Agnide E. Lawin ◽  
Oluwafemi E. Adeyeri
Keyword(s):  
Missing Data ◽  
River Discharge ◽  
Missing Values ◽  
Spatial Scales ◽  
Gap Filling ◽  
Discharge Data ◽  
Flow Duration ◽  
Daily Discharge ◽  
Flow Duration Curves ◽  
Discharge Patterns

Abstract The Niger basin have experienced historical drought episodes and floods in recent times. Reliable hydrological modelling has been hampered by missing values in daily river discharge data. We assessed the potential of using the Multivariate Imputation by Chained Equations (MICE) to estimate both continuous and discontinuous daily missing data across different spatial scales in the Niger basin. The study was conducted on 22 discharge stations that have missing data ranging from 2% to 70%. Four efficiency metrics were used to determine the effectiveness of MICE. The Flow Duration Curves (FDC) of observed and filled data were compared to determine how MICE captured the discharge patterns. Mann-Kendall, Modified Mann-Kendall, Pettit and Sen's Slope were used to assess the complete discharge trends using the gap-filled data. Results shows that MICE near perfectly filled the missing discharge data with Nash-Sutcliffe Efficiency (NSE) range of 0.94–0.99 for the calibration (1992–1994) period. Good fits were obtained between FDC of observed and gap-filled data in all considered stations. All the catchments showed significantly increasing discharge trend since 1990s after gap filling. Consequently, the use of MICE in handling missing data challenges across spatial scales in the Niger basin was proposed.

scholarly journals Trace elements in mussel shells from the Brazos River, Texas: environmental and biological control

2019 ◽  
Author(s):  
Alexander A. VanPlantinga ◽  
Ethan L. Grossman
Keyword(s):  
River Discharge ◽  
Distribution Patterns ◽  
Low Flow ◽  
Clumped Isotopes ◽  
Metabolic Rates ◽  
Brazos River ◽  
Growth Increments ◽  
Shell Chemistry ◽  
Mussel Shells ◽  
Discharge Patterns

Abstract. In sclerochronology, understanding the drivers of shell chemistry is necessary in order to use shells to reconstruct environmental conditions. We measured the Mg, Ca, Sr, Ba, and Mn contents in water samples and in the shells of two freshwater mussels (Amblema plicata and Cyrtonaias tampicoensis) from the Brazos River, Texas to test their reliability as environmental archives. Shells were analyzed along growth increments using age models established with stable and clumped isotopes. Shells were also examined with cathodoluminescence (CL) microscopy to map Mn / Ca distribution patterns. Sr / Ca correlated with Mn / Ca, while Mg / Ca and Ba / Ca showed no clear trends. Mn / Ca correlated inversely with the log of river discharge. Because dissolved and inorganic particulate sources of manganese are low during low flow, peak Mn / Ca values may come from elevated feeding or metabolic rates. Shell Mn / Ca values were used to reconstruct river discharge patterns, which, to our knowledge, has previously only been performed with shell chemistry using oxygen isotopes.

River discharge variability as the link between climate and fluvial fan formation

Geology ◽  
2020 ◽  
Vol 48 (10) ◽  
pp. 952-956 ◽  
Author(s):  
Mark R. Hansford ◽  
Piret Plink-Björklund
Keyword(s):  
River Discharge ◽  
Climate Changes ◽  
Sedimentary Record ◽  
Data Set ◽  
High Discharge ◽  
Climate Conditions ◽  
Streamflow Variability ◽  
Quantitative Analyses ◽  
Discharge Patterns ◽  
Favorable Conditions

Abstract There are two contrasting hypotheses on whether fluvial fans need specific climate conditions to form. Deduction of climatic and tectonic signals from landscapes and the sedimentary record is a key aim in geology and geomorphology. It is thus of great interest to obtain recognition criteria for specific climate changes in the sedimentary record in general, and fluvial fans in particular, because they may form the bulk of the continental fluvial record. The hypothesis that links fluvial fan occurrence to climate specifically indicates precipitation variability as a key control, because it promotes streamflow variability, channel instability, and avulsions, which are the key processes involved in fluvial fan formation. Here, we tested this hypothesis by quantitative analyses of discharge patterns from 68 fan-forming rivers that have a global distribution. Using an ensemble of dimensionless metrics, we show that 75% of the fan-forming rivers in this data set have a high discharge variability. We further analyzed down-fan changes in discharge variability and discuss the nature of discharge variability in different hydroclimates as a function of intra- and interannual precipitation fluctuations. We also examined the fan-forming rivers with moderate to low discharge variability and concluded that although river discharge variability strongly promotes fluvial fan formation, fluvial fans may also be formed by rivers with a moderate or low discharge variability if other favorable conditions that promote avulsions occur.

Kajian Debit Sungai di DAS Wae Ruhu, Kota Ambon

2018 ◽  
Vol 1 (1) ◽  
pp. 18-23
Author(s):  
Matheus Souisa ◽  
Paulus R. Atihuta ◽  
Josephus R. Kelibulin
Keyword(s):  
River Discharge ◽  
River Flow ◽  
Secondary Data ◽  
Data Retrieval ◽  
Sediment Discharge ◽  
Flood Prevention ◽  
Retrieval Processes ◽  
Water Catchment ◽  
Steep Slopes ◽  
Station Point

Ambon City is a region consisting of hilly areas and steep slopes with diverse river characteristics. Research has been carried out in the Wae Ruhu watershed in Ambon City which starts from upstream (water catchment) to downstream. This study aims to determine the magnitude of river discharge and sediment discharge in the Wae Ruhu watershed. This research was conducted in several stages including, secondary data collection, research location survey, preparation of research tools and materials as well as field data retrieval processes which included tracking coordinates at each station point and entire watershed, calculation of river flow velocity, river geometry measurements, and sampling sediment. The results showed that the average river discharge in the Wae watershed in the year 2018 was 1.24 m3 / s, and the average sediment discharge was 6.27 kg / s. From the results of this study and the field observations proposed for flood prevention and the rate of sediment movement are the construction of cliffs with sheet pile and gabions.

Rainforest conversion in Central Sulawesi, Indonesia: recent development and consequences for river discharge and water resources

Erdkunde ◽  
2007 ◽  
Vol 61 (3) ◽  
pp. 284-293 ◽  
Author(s):  
Constanze Leemhuis ◽  
Stefan Erasmi ◽  
André Twele ◽  
Heinrich Kreilein ◽  
Alexander Oltchev ◽  
...  
Keyword(s):  
Water Resources ◽  
River Discharge ◽  
Central Sulawesi
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