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Estimation of suspended sediment rate by double correlation method in Mouillah basin, North-West of Algeria

Belarbi Fadila, Boulchelkia Hamid, Remini Boualem

Journal of Water and Land Development

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2020

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no. 46

29--37

EN

The study deals with the assessment of the solid transport in the wadi Mouillah watershed (Tafna, Algeria). Sediment transport is a complex phenomenon. The quantity of sediment transported is very important, and it fills in the reservoirs. The scale is out of proportion in semiarid areas. Algeria is one of the most affected countries by this phenomenon. A simple method, based on average discharges, easy to implement, has been developed for estimating the sediment yield using double correlation method (a first one between liquid discharge – solid concentration and a second one between solid flow – concentration). It is based on hydrometric data (liquid flow, concentrations and sediment discharges) with applications analysis on seasonal and annual scales for data’s of Sidi Belkheir station at the outlet of the wadi Mouillah watershed (North-West of Algeria). The obtained results by the application of this method are very encouraging because of the quite significant correlation coefficients found (≥59% for the first correlation and ≥88% for the second correlation). The water-shed of Mouillah produces between 43 730 and 56 410 Mg·y–1 as suspended sediment load against 48.56∙103 to 53.3∙103 m3·y–1 of liquid intake.

2

Development of a relationship between hydrometric and hydrographic observations to predict reservoir capacity loss

Jabbar Y. C., Yadav S. M.

Acta Geophysica

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2019

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Vol. 67, no. 5

1451--1469

EN

Accuracy of reservoir capacity loss estimation on daily timescale is dependent on the certainty of sediment load prediction, density estimate and capacity observed by consecutive hydrographic surveys. Data-scarce and uncertain data conditions restrict the development of a relationship between hydrographic surveys and hydrometric observations. The present study has been carried for Ukai Reservoir, India. A novel sediment rating curve ftting approach by optimization technique has been proposed in order to accurately predict sediment load from low-frequency sampled discharge and sediment concentration observations. The study demonstrates the validation of the bulk density estimate using statistical hypothesis testing and identifes the correctness of the hydrographic survey results. Application of the developed hydrometric and hydrographic relationship indicated that about 50% of the capacity loss of a year might occur during a single extreme event. The proposed approach can serve as a decision support system to monitor and manage sedimentation for the reservoir having uncertain data conditions.

3

A performance evaluation of neuro‑fuzzy and regression methods in estimation of sediment load of selective rivers

Varvani J., Khaleghi M. R.

Acta Geophysica

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2019

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Vol. 67, no. 1

205--214

EN

Sediment rating curves (SRCs) have been recognized as the most popular method for estimating sediment in the hydrology of river sediments and in watersheds. In this regard, in order to compare and correct estimation methods of river sediment load, estimated rates of several univariate types of SRCs and a multivariate type of SRCs (MSRCs) were studied using the neuro-fuzzy and tree regression models in five selective hydrometric stations of different climatic zones of Iran and with various indexes of the accuracy (AI) and the precision (PI). The results of the data analysis showed that the mean of the AI of neuro-fuzzy and tree regression models in selective stations is 151 and 536%, respectively, which shows the low efficiency compared with SRCs. Also according to the results, the best rate of the AI of the MSRCs belongs to the Glink station with the rate of 1.12. Also, the average value of the AI of MSRCs is 1.15 which is an acceptable amount of the other considered various methods.

4

Sediment load estimation in the Mellegue catchment, Algeria

Selmi K., Khanchoul K.

Journal of Water and Land Development

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2016

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no. 31

129--137

EN

Soil erosion by water and the impact of sediment transport on lakes and streams, can seriously degrade soil and create problems for both agricultural land and water quality. The present study has been carried out to assess suspended sediment yield in Mellegue catchment, northeast of Algeria. Regression analysis was used to establish a relationship between the instantaneous water discharge (Q) and the instantaneous suspended sediment concentration (C) based on all recorded data and seasonal ratings for the period 1970–2003. The regression technique used in this paper involved a division of data into discharge – based classes, the mean concentrations and discharges of which are used to develop power regressions, according to single and season ratings, through logtransformation. Sediment loads estimated by stratified rating curves reduced underestimations to a range from 2 to 4%. The mean annual sediment yield during the 34 years of the study period was 589.23 t∙km–2∙y–1. Sediment transport is dominated by fall rainstorms accounting for 41% of the annual load. The big supply of sediment during this season confirms the intense geomorphic work by fall storms caused by high intensity rainfall and low vegetation cover.

PL

Erozja wodna gleby i wpływ transportu osadów na rzeki i jeziora może znacząco degradować gleby i stwarzać problemy zarówno na obszarach rolniczych, jak i dla jakości wód. Przedstawione badania prowadzono celem oceny zawiesiny wytworzonej w zlewni rzeki Mellegue w północno-wschodniej Algierii. Analizę regresji użyto do ustalenia zależności pomiędzy chwilowym odpływem wody Q a chwilowym stężeniem zawiesiny C na podstawie wszystkich zebranych danych i przedziałów sezonowych dla lat 1970–2003. Regresje zastosowane w tych badaniach uwzględniały podział danych na klasy bazujący na wielkości odpływu. Średnie stężenia i wielkości odpływu w poszczególnych klasach wykorzystano do skonstruowania funkcji wykładniczej poprzez transformację logarytmiczną. Ładunki osadu ustalone na podstawie stratyfikowanych krzywych natężenia przepływu wykazywały niedoszacowanie w zakresie 2–4%. Średni roczny ładunek wytworzonych osadów dla okresu 34 lat badań wynosił 589.23 t∙km–2. Transport osadów był spowodowany jesiennymi ulewnymi opadami, które odpowiadały za 41% rocznych ładunków. Duża dostawa osadów w tym okresie potwierdza intensywną aktywność geomorfologiczną jesiennych sztormów wywołaną silnymi opadami i ubogą pokrywą roślinną.