Temporal Variability of Sediments, Dissolved Solids and Dissolved Organic Matter Fluxes in the Congo River at Brazzaville/Kinshasa

N’kaya, Guy D. Moukandi; Orange, Didier; Padou, Sandra Murielle Bayonne; Datok, Pankyes; Laraque, Alain

doi:10.3390/geosciences10090341

Cited by 12 publications

(6 citation statements)

References 36 publications

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“…For BZV/KIN, this paper presents the mean results of the study of Moukandi N'Kaya et al (2020) [56], about the comparison of the only two longer multiannual monthly chronicles of available data (1987-1993 versus 2006-2017) issued respectively from two French-Congolese projects, i.e., 8 years (1987-1993) of PEGI and 12 years of SO-HYBAM (during 2006-2017 period), the latter still operating. The parameters studied are TSS, TDS, DOC, pH and EC.…”

Section: Hydrosedimentological and Biogeochemical Studiesmentioning

confidence: 99%

“…Moukandi et al (2020) [56] show that in comparison with the PEGI data, SO-HYBAM data presents a slight increase (+7.5%) of interannual mean TSS concentrations, from 25.3 to 27.2 mg L −1 , a lower TDS concentration in the current period, i.e., −15% with a drop from 36.5 to 31.1 mg L −1 and a DOC concentration increase (+28%) from 9.9 to 12.8 mg L −1 . These variations appear to be essentially due to the increase in flows (nearly 4.5%), from 38,000 to 39,660 m 3 s −1 (inter-annual average), respectively for the two study periods.…”

Section: Main Features Concentrations and Fluxes Of The Congo Rivermentioning

confidence: 99%

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Recent Budget of Hydroclimatology and Hydrosedimentology of the Congo River in Central Africa

Laraque¹,

N’kaya

Orange

et al. 2020

Water

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Although the Congo Basin is still one of the least studied river basins in the world, this paper attempts to provide a multidisciplinary but non-exhaustive synthesis on the general hydrology of the Congo River by highlighting some points of interest and some particular results obtained over a century of surveys and scientific studies. The Congo River is especially marked by its hydrological regularity only interrupted by the wet decade of 1960, which is its major anomaly over nearly 120 years of daily observations. Its interannual flow is 40,500 m3 s−1. This great flow regularity should not hide important spatial variations. As an example, we can cite the Ubangi basin, which is the most northern and the most affected by a reduction in flow, which has been a cause for concern since 1970 and constitutes a serious hindrance for river navigation. With regard to material fluxes, nearly 88 × 106 tonnes of material are exported annually from the Congo Basin to the Atlantic Ocean, composed of 33.6 × 106 tonnes of TSS, 38.1 × 106 tonnes of TDS and 16.2 × 106 tonnes of DOC. In this ancient flat basin, the absence of mountains chains and the extent of its coverage by dense rainforest explains that chemical weathering (10.6 t km−2 year−1 of TDS) slightly predominates physical erosion (9.3 t km−2 year−1 of TSS), followed by organic production (4.5 t km−2 year−1 of DOC). As the interannual mean discharges are similar, it can be assumed that these interannual averages of material fluxes, calculated over the longest period (2006–2017) of monthly monitoring of its sedimentology and bio-physical-chemistry, are therefore representative of the flow record available since 1902 (with the exception of the wet decade of 1960). Spatial heterogeneity within the Congo Basin has made it possible to establish an original hydrological classification of right bank tributaries, which takes into account vegetation cover and lithology to explain their hydrological regimes. Those of the Batéké plateau present a hydroclimatic paradox with hydrological regimes that are among the most stable on the planet, but also with some of the most pristine waters as a result of the intense drainage of an immense sandy-sandstone aquifer. This aquifer contributes to the regularity of the Congo River flows, as does the buffer role of the mysterious “Cuvette Centrale”. As the study of this last one sector can only be done indirectly, this paper presents its first hydrological regime calculated by inter-gauging station water balance. Without neglecting the indispensable in situ work, the contributions of remote sensing and numerical modelling should be increasingly used to try to circumvent the dramatic lack of field data that persists in this basin.

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Section: Hydrosedimentological and Biogeochemical Studiesmentioning

confidence: 99%

Section: Main Features Concentrations and Fluxes Of The Congo Rivermentioning

confidence: 99%

Recent Budget of Hydroclimatology and Hydrosedimentology of the Congo River in Central Africa

Laraque¹,

N’kaya

Orange

et al. 2020

Water

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“…In order to provide context for the observations among the streams in this study, we can examine the same compositional parameters determined in previous studies of much larger rivers such as the Orinoco and Congo (Coynel et al., 2006; Laraque et al., 2013; Moukandi N'kaya et al., 2020). The Orinoco and Congo rivers are large systems characterized by relatively constant hydrographs, similar mean annual discharges, comparable watershed area and similar climate.…”

Section: Discussionmentioning

confidence: 99%

“…The four parameters calculated from the daily concentration data include the fraction of TSS as a percentage of total dissolved and particulate load (Frac TSS = 100 × [TSS/(TSS + TDS)]), the fraction of POC calculated as a percentage of total organic carbon (Frac POC = 100 × [POC/(POC + DOC)]), the mass abundance of POC as a percentage of TSS (%POC = 100 × (POC/TSS)), and the mass abundance of DOC as a percentage of TDS (%DOC = 100 × (DOC/TDS)). These parameters have been used in previous studies to evaluate temporal (seasonal and inter‐annual) trends in the compositions of fluvial material export (e.g., Coynel et al., 2006; Moukandi N'akya et al., 2020) and compare the nature and dynamics of suspended and dissolved loads across different river systems (e.g., Laraque et al., 2013). In this paper, we use these parameters to investigate patterns in the compositions of the particulate and dissolved loads as a function of discharge conditions among streams with distinct watershed and hydrological characteristics.…”

Section: Methodsmentioning

confidence: 99%

Mobilization and Export of Particulate and Dissolved Solids and Organic Carbon From Contrasting Mountainous River Watersheds in California and Oregon

et al. 2023

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“…If one considers that Kadei is the upper branch of the Sangha River, the river has a total length of 1333 km and is the second main right-bank tributary of the Congo River after Oubangui River [9]. The Congo River is the longest river in Africa after the Nil, and the largest river in Africa in terms of water discharge and basin size (respectively 40,500 m 3 /s and 3.7 × 10 6 km 2 ), second only to the Amazon River at the global level [10] [11]. The Dja is the main tributary of the Sangha River [9].…”

Section: Presentation Of the Study Areamentioning

confidence: 99%

Study of the Impact of Climate Change on Water Resources in the Sangha Watershed at Ouesso Hydrological Station, Republic of the Congo-Brazzaville (1961-2020)

Moukoko,

Mvoundou,

Mangouende

et al. 2023

JWARP

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The Sangha River basin is the largest sub-basin of the Congo River basin, which drains the northern part of the Republic of the Congo-Brazzaville. It is the most important economic zone in this part of the country, with a strong timber industry, agriculture and hydroelectricity. The catchment also boasts the country's third-largest river port, located in the town of Ouesso. Unfortunately, increasingly frequent low-water levels in recent years have led to a decline in river navigation and economic activities. So, the aim of this study is to show the effects of climate change over the last six decades in the Sangha watershed at Ouesso hydrological station, located in the north of the Republic of the Congo-Brazzaville, and elucidate its impact on water resources. To achieve this, several statistical and hydrological methods were used. The application of change-point or shift detection tests to flow series from 1961 to 2020 revealed variability in the hydrological cycle, characterized by two major phases of homogeneous flows: a wet surplus phase and a dry deficit phase. The results show one shift in flood flows in 1971 (Buishand test), one shift in yearly average flows or modules in 1971 (Pettitt test and Buishand test), and one shift in low-water flows in 1976, with all two tests. These disruptions were accompanied by a drop in flow of around 15.63%, 21.70% and 35.67%, on average, for floods, modules, and low-water, respectively, a drop in rainfall of around 9.6% and a rise in temperature of around 0.76˚C. These flows show an overall downward trend. The calculated recession coefficients show that, over the entire study period, a recession occurred in March 1985.

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Temporal Variability of Sediments, Dissolved Solids and Dissolved Organic Matter Fluxes in the Congo River at Brazzaville/Kinshasa

Cited by 12 publications

References 36 publications

Recent Budget of Hydroclimatology and Hydrosedimentology of the Congo River in Central Africa

Recent Budget of Hydroclimatology and Hydrosedimentology of the Congo River in Central Africa

Mobilization and Export of Particulate and Dissolved Solids and Organic Carbon From Contrasting Mountainous River Watersheds in California and Oregon

Study of the Impact of Climate Change on Water Resources in the Sangha Watershed at Ouesso Hydrological Station, Republic of the Congo-Brazzaville (1961-2020)

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