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1

Soil erosion rate and hazard level at the Sianjo-anjo Reservoir watershed in Indonesia

Gusma Felia, Azmeri Azmeri, Jemi Faris Z., Rahmatan Hafnati

Journal of Water and Land Development

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2023

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no. 57

181--187

EN

The Sianjo-anjo reservoir is used to meet the need for downstream clean water. Land activity at the Sianjo-anjo reservoir watershed can potentially increase the rate of erosion and the silting of rivers and reservoirs due to sedimentation. Reservoir siltation is a crucial challenge for reservoir management because it can reduce its function and affect its service life. However, sediment yield is often overlooked in reservoir planning and environmental assessment. This study aims to predict the rate of land erosion and sediment yield, and create an erosion hazard map of the Sianjo-anjo reservoir watershed. The study used a Geographic Information System, GIS-based Universal Soil Loss Equation (USLE) method and discovered that the erosion rate of the Sianjo-anjo reservoir watershed was between 35.23 Mg∙ha-1∙y-1 until 455.08 Mg∙ha-1∙y-1, with 95.85% classified as the low level, 0.03% as moderate, and 4.12% as high. Meanwhile, the sediment yield from the Sianjo-anjo reservoir watershed was 218,812.802 Mg∙y-1. USLE is vital to identify areas susceptible to erosion and crucial for reservoir sustainability. Furthermore, it is necessary to plan good sediment management. Long-term land conservation is required to maintain storage capacity and ensure effective operation of the reservoir.

2

Sediment yield modeling in Awash Melkasa dam watershed, upper Awash River basin, Ethiopia

Daba Bayisa Itana, Demissie Tamene Adugna, Tufa Fayera Gudu

Acta Geophysica

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2023

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Vol. 71, no. 5

2287--2306

EN

Soil erosion may be a main problem within the Ethiopian highlands. The Awash River basin is one among the Ethiopian highlands suffering from a high rate of surface erosion. Sediment inflow rates of reservoirs and spatial distribution of sediment yield (SY) are required at the sub-basin level to develop alternative watershed management practices. Hence, this study aimed toward estimating SY within the upper Awash River by using the soil and water assessment tool. The spatial, weather, hydrological, reservoir input, and water withdrawal data were collected and analyzed. The model had adjusted and verified for both flow and sediment. The graphical comparison and statistical indicators, coefficient of determination (R2), Nash–Sutcliffe efficiency (NSE), root-mean-square error standard deviation ratio (RSR) and percent bias (PBIAS) had used to evaluate the model's performance. Monthly streamflow and SY estimates were found to be reliable (R2 = 0.78–0.83, NSE = 0.75–0.82, RSR = 0.43–0.5 and PBIAS = 0.1–8.8) based on the model calibration and validation results. After calibration, the simulated average annual SY estimated was 22,109.5 t yr-1at the outlet, with an average spatial distribution of 6.52 t ha-1 yr-1. The model prediction outcomes showed that about 26.16% of the Awash Melkasa watershed, located in southwestern direction, is an erosion-prone area with a mean annual SY ranging from 10 to 18.54 t ha-1 yr-1execiding tolerable soil loss. These sub-basins need prior mitigation measures to reduce soil losses from the catchment.

3

Development of a numerical model for sediment yield for the upper Brahmaputra River basin using optimization technique

Sil Briti Sundar, Pathan Shehnaj Ahmed

Acta Geophysica

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2023

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Vol. 71, no. 5

2423--2438

EN

At a watershed scale, soil erosion occurs at a spatially variable rate, posing a significant danger to long-term resource management. The most serious issue has long been regarded as soil erosion. As a result, estimating soil loss and identifying the critical area for implementing optimum management techniques are essential to the programme's success. A numerical model called the sediment-rainfall-watershed area model (SRWA) is built using a spatially distributed RUSLE-based SDR hybridized model to estimate sediment yields in the upper Brahmaputra River watershed. The developed model has been calibrated and validated from 2001 to 2007 and 2008 to 2014, respectively. For the entire period, the statistical performance of the proposed SRWA model and the SDR-RUSLE-based model reveals a correlation coefficient of 0.93 and a Nash–Sutcliffe efficiency coefficient of 0.84. This demonstrates that the SRWA model may assess sediment yield at any upper Brahmaputra basin watershed/sub-watershed outlet.

4

Surface erosion hazard and sediment yield for Keuliling Reservoir in Indonesia

Azmeri Azmeri, Nurbaiti Nurbaiti, Mawaddah Nurul, Yunita Halida, Jemi Faris Zahran, Sundary Devi

Journal of Water and Land Development

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2022

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no. 52

108--118

EN

The construction of the Keuliling Reservoir aims to accommodate and utilise water for agricultural purposes. In this research, soil erosion modelling using the USLE method showed that the level of erosion hazard for each Keuliling Reservoir sub-watershed was classified into low-moderate. Land erosion occurred in the area around the reservoir inundation is the most significant contribution to the magnitude of erosion (38.62Mg∙ha-1y-1. Based on the point of sediment sampling in the Keuliling reservoir, the sediment volume was 1.43 Mg∙m-3. So, the volumetric sediment input from the Keuliling reservoir watershed is 20.918,32 m3∙y-1. The degradation of reservoir function due to sedimentation can affect reservoir services. The ability to estimate the rate of watershed surface erosion and sediment deposition in the reservoir is vital for reservoir sustainability. Besides the land erosion in the Keuliling Reservoir, there are also other potential sources of erosion that can reduce the capacity of the reservoir, i.e. the rate of sedimentation from a reservoir cliff landslide. The USLE estimation results show that the soil erosion analysis provides important and systematic information about nature, intensity and spatial distribution in the watershed and sediment volume in the Keuliling Reservoir. This finding allows the identification of the most vulnerable areas and the type of erosion dominant for long-term land management.

5

Application of the Erosion Potential Method in Vithkuqi Watersheds (Southeastern Albania)

Marko Oltion, Gjipalaj Joana, Shkodrani Neritan

Journal of Ecological Engineering

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2022

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Vol. 23, nr 4

17--24

EN

Soil erosion is one of the most important phenomena affecting land composition and settlement. Among all natural causes of soil erosion such as rainfall intensity, temperature and wind, the human activity; massive deforestation and intensive agriculture, including the latest climate changes are considered as very important factors, especially nowadays. Thus, calculating the soil erosion coefficient appears very important in order to prevent the phenomena. Many methods are used to calculate such coefficient but in the presented research, the Erosion Potential Method was chosen. In this study, eight watersheds in southeastern Albania were evaluated. Results show that erosion is present in all considered watersheds. In one case (Panariti watershed) the erosion coefficient was very high; excessive, while in others it varies from heavy to very slight erosion. In conclusion, it can be stated that the Erosion Potential Method can be applied in the Albanian contest, same as in other neighbor countries. The results from Panariti, Roshani and Gianci should be further investigated due to the high quantity of soil eroded.

6

Evaluating lateral riverbank erosion with sediment yield through integrated model in lower Gangetic floodplain, India

Ghosh Arnab, Roy Malabika Biswas, Roy Pankaj Kumar

Acta Geophysica

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2022

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Vol. 70, no 4

1769--1795

EN

One of the natural disasters caused by river meandering is riverbank erosion, which creates social, economic, and environmental problems in the riparian zone and serves as a source of increasing sedimentation levels in the river. Riverbank erosion and bank failure create a complex cyclical process, such as riverbank retreat, which cannot be easily measured and predicted by any model. The meandering flow along the Bhagirathi-Hooghly river has created riverbank erosion and riverbank retreat conditions in several areas, through which measuring bank stability and erosion is quite complex. As a result, the BSTEM model, integrating with HEC-RAS, has been used in this article to measure riverbank erosion and retreat accurately. Riverbank erosion and retreat data for 2019–2020 have been simulated based on data observed from 2016 to 2018 for accurate measurement. In addition, the total sediment yielded from the river bank has been calibrated and simulated with the help of sediment transport formulation in HEC-RAS, which indicates a gradual increase in river erosion at present (2019–2020). This model is expected to help formulate government policy on protecting riverbank erosion and river restoration in the future.

7

Evaluating annual and seasonal patterns of suspended sediment loads in a semi-arid watershed, central Algeria

Rabah Mosbah, Bouchelkia Hamid, Belarbi Fadila, Millares Agustin

Journal of Water and Land Development

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2021

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no. 50

158--172

EN

Soil loss is a major problem for watersheds management in semi-arid environments. The objective of the present study is to analyze the annual and seasonal patterns of suspended loads and quantify the specific sediment yields in a semi-arid environment of the Mazafran Watershed in central Algeria. The obtained information of water discharge and suspended sediment load, recorded during 19 years, was confronted with precipitation data in order to establish the relationships between theforcing agents and erosive processes. The specific sediment yield was estimated by assessing rating curve data under two types of identified responses. The obtained results allowedconfirming the seasonality on suspended sediment transport in the studied basin, which accounts for 56% of the total suspended sediment load estimated in winter. The mean annual suspended sediment is estimated at 17.52 Mg∙ha–1·y–1. The results highlighted that the type 2 event dominates the production of sediment in the study area in comparison with type 1 event. The analysis of the variability of rainfall erosivity index showed that there is a strong correlation between the annual precipitation and modified Fournier index (MFI), and a weak correlation with the monthly precipitation concentration index (PCI). Moreover, the spatial distribution of the modified Fournier index at the basin scale showed the highest precipitation aggressiveness in the Southern part of the study region for both type of events, whereas the precipitation aggressiveness low to moderate in the remaining part of the study region.

8

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.

9

Impact of urbanization on the sediment yield in tropical watershed using temporal land-use changes and a GIS-based model

Bello A.-A. D., Hashim N. B., Haniffah R. M.

Journal of Water and Land Development

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2017

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no. 34

33--45

EN

Abundant rainfall areas promote sediment yield at both sub-watershed and watershed scale due to soil erosion and increase siltation of river channel, but it can be curtailed through planned urbanization. The urbanization of Skudai watershed is analysed from historical and future perspective. A GIS-based model (Hydrological Simulation Programme-FORTRAN-HSPF) is used to modelled sediment flow using basin-wide simulation, and the output result is utilized in evaluating sediment yield reduction due to increased urbanization by swapping multiple temporal land-use of decadent time-steps. The analysis indicates that sediment yield reduces with increase urban built-up and decrease forest and agricultural land. An estimated 12 400 tons of sediment will be reduced for every 27% increase in built-up areas under high rainfall condition and 1 490 tons at low rainfall. The sensitivity analysis of land-use classes shows that built-up, forest and barren are more sensitive to sediment yield reduction compared to wetland and agricultural land at both high and low rainfall. The result of the study suggests that increased urbanization reduced sediment yield in proportion to the rainfall condition and can be used as an alternative approach for soil conservation at watershed scale independent of climate condition.

PL

Duże opady atmosferyczne sprzyjają przemieszczaniu się osadów w skali zlewni w wyniku erozji gleby, powodując zamulanie koryta rzecznego. Procesy te można ograniczyć przez planową urbanizację. Urbanizację zlewni Skudai analizowano w perspektywie historycznej (przedziały 10-letnie) i w kontekście przyszłych zmian. Do modelowania przepływu osadu użyto programu symulacji hydrologicznej Fortran (HSPF), a wyniki modelowania wykorzystano do oceny zmniejszenia ilości osadu związanej z urbanizacją. Analiza wskazuje, że ładunek osadów maleje ze zwiększeniem udziału zabudowy miejskiej oraz z ograniczeniem powierzchni lasów i gruntów rolniczych. W warunkach intensywnych opadów ładunek osadu może zmaleć o 12 400 t, gdy udział terenów zabudowanych zwiększy się o 27%. W warunkach małych opadów ładunek zmniejszy się o 1 490 t. Analiza wrażliwości klas użytkowania ziemi wykazała, że obszary zabudowane, lasy i ugory są bardziej wrażliwe na zmniejszenie ładunku osadu niż obszary podmokłe i grunty rolnicze, zarówno w warunkach dużego jak i małego natężenia opadów. Wyniki badań sugerują, że zwiększony udział terenów zabudowanych ogranicza ładunek osadów proporcjonalnie do ilości opadów, w związku z czym planowa urbanizacja może być wykorzystana jako alternatywne podejście do ochrony gleb w skali zlewni, niezależnie od warunków klimatycznych.

10

Scale effects on sediment yield from badland areas in Mediterranean environments

Martínez-Murillo J. F., Nadal-Romero E., Vanmaercke M., Poesen J.

Landform Analysis

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2011

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Vol. 17

105-109

EN

This study investigates area-specific Sediment Yield (SY) in Mediterranean badland areas at different spatial scales using a SY-database compiled from scientific literature. Relationships between the plot and catchment characteristics and the corresponding SY-data are analyzed. Results indicate that in Mediterranean environments SY is larger than in other environments,especially in badlands where a high variability of SY is observed depending on the spatial scale. In intensively gullied badlands,a complex plot or drainage area (A) -SY relationship is observed: for A ranging between 10-5 and 10 ha,SY is very high (mean SY equals 475 t ha-1 yr-1),whereas for A greater than 10 ha,SY decreases with increasing A (mean SY less than 100 t ha-1 yr-1).