Siltation Of Dams Research Articles

Assessing soil erosion risk through geospatial analysis and magnetic susceptibility: A study in the Oued Ghiss dam watershed, Central Rif, Morocco

In northern Morocco, water erosion presents a critical risk for soil degradation and dam sedimentation, attributable to extreme climatic conditions, variegated topography, lithological vulnerabilities, and anthropogenic pressures. This study quantitatively and spatially evaluates soil erosion susceptibility within the catchment area of the Oued Ghiss dam in Central Rif, Morocco. Utilizing the Revised Universal Soil Loss Equation (RUSLE) integrated with Geographic Information Systems (GIS) and calibrated through magnetic susceptibility metrics, the study provides a detailed analysis of erosion factors. The model was applied using GIS to spatially analyze data on rainfall, soil type, topography, land cover, and management practices, with magnetic susceptibility measurements used to calibrate the model by identifying stable and erosion-prone areas. The resultant soil loss map reveals a mean erosion rate of 24 t/ha/year. Specifically, 37.28 % of the catchment area exhibits an erosion rate under 5 t/ha/year, 40.16 % between 5 and 10 t/ha/year, 22.77 % between 10 and 20 t/ha/year, and 0.86 % surpasses 20 t/ha/year. Magnetic susceptibility measurements across various soil profiles indicated that stable soils showed increased susceptibility towards the surface, while eroded soils displayed decreased susceptibility, with significant correlations found between magnetic susceptibility variations and the final risk map. This innovative calibration of the RUSLE model through magnetic susceptibility improves erosion vulnerability assessments and results in a more detailed soil loss map. The findings provide critical information for policymakers to develop targeted management plans for erosion-prone areas, particularly benefiting the Ghiss dam watershed, where these insights will aid in preventing dam siltation and enhancing water resource management. This confirms magnetic susceptibility's reliability in assessing soil erosion vulnerability and improving numerical models.

Geomorphic evolution of a tropical river basin in the Deccan Volcanic Province: a critical water supply source to Mumbai metropolitan region (MMR), India

ABSTRACT Reservoir siltation lowers a dam’s effective storage capacity, which is mostly determined by the sediment discharge from soil erosion in the watersheds. The morphometric parameters are significant in determining erosional susceptibility of watersheds. In the present study, morpho-hypsometric aspects of the Surya sub-basin, a major tributary of Vaitarna river, has been considered. This river system and associated dams provide the major source of drinking water supply to the Mumbai Metropolitan Region (MMR). A major part of the river flows through the Deccan Volcanic Province (comprising basalts) and Quaternary alluvial deposits. The seven sub-watersheds (SWs) of Surya sub-basin were analysed using the morphological parameters (linear, areal, and basin shape aspects), along with ratio factors and hypsometric integral (HI) values. The HI values for the SWs range from 0.11 (SW-1) to 0.51 (SW-6) with a HI value of 0.21 for the whole Surya sub-basin. The relatively high HI values of SW-6 (0.51) and SW-7 (0.31) indicate that these SWs are relatively prone to high erosion and sediment discharge resulting in dam siltation, and will be a great threat to livelihood of millions of people in the MMR. Therefore, prioritizing these SWs for proper engineering measures could reduce erosion and improve recharge.

Evaluation of the impact of erosion control measures on dam siltation and upstream erosion using radioisotope technique 7Be and MUSLE model in the watershed upstream of Allal El Fassi dam, Morocco

Water erosion poses a significant threat to the sustainability of natural resources and hydro-agricultural infrastructure, particularly in the Mediterranean region, including Morocco. The Allal El Fassi watershed faced such challenges and underwent anti-erosion measures between 2008 and 2014. This study aims to evaluate the effectiveness of these measures in mitigating dam siltation within the watershed. The methodologies employed include the utilization of the MUSLE model, optimized with bathymetric surveys of the dam, to estimate the amount of sediment reaching the dam and derive the P-factor associated with the implemented anti-erosion measures. Additionally, the radioisotope technique was utilized to assess erosion rates at managed and unmanaged sites within the watershed. The results obtained using the MUSLE model and bathymetric data revealed a noteworthy reduction in mean annual soil loss within the timeframe of 2002–2010 to 2010–2013, resulting in a 13.9% decrease in sediment reaching the dam. Furthermore, variations in the P-factor of erosion control measures were observed, ranging from 0.31 to 0.52 during the respective periods. Utilizing the radionuclide 7Be, erosion rates ranging from 6.8 to 25.3 t.ha−1 were determined for the studied plots, facilitating the calculation of P-factors for specific erosion control measures. Significantly, gabion check dams displayed a P-factor of 0.47, dry stone barriers had a P-factor of 0.41, fruit trees with basins showed a P-factor of 0.51, and enclosures exhibited a P-factor of 0.67. These findings suggest a causal relationship between the implementation of erosion control measures and the reduction in sedimentation rates at the Allal El Fassi Dam, highlighting the interdependence between the two phenomena.

Erosion and Dam Siltation in an Arzangarzan Earthen Dam in Budgam District of Jammu and Kashmir

Abstract: Many check dams were built in the Budgam district of Jammu and Kashmir during the 1970s, however after a few years, their entire infill was caused by significant siltation rates. This effort aimed to evaluate the mechanisms producing soil particles and their accumulation in the Arzangarzan dam. To measure the amount of sediments and the overall rate of erosion, a bathymetric survey was conducted

Correlation Between Water Erosion and Hydraulics of Slope–Gully Systems According to Check Dam Siltation Depth

Correlation Between Water Erosion and Hydraulics of Slope–Gully Systems According to Check Dam Siltation Depth

Overcoming systemic and institutional challenges in policy implementation in South Africa's water sector

The water sector in South Africa is faced with numerous challenges, among which include; increased flooding and prolonged droughts caused by increased climate variability, rapid population growth, unsustainable water demands and withdrawals by various water users, deficiencies in institutional management and infrastructural maintenance, lack of political will with accompanying high levels of corruption and steady deteriorations in all sub-sectors of the economy. Other significant challenges include provision of water in rural communities, water pollution especially from poorly operated wastewater treatments works, acid mine drainage, nutrients from agriculture, siltation of dams. A combination of these factors has led to high levels of water scarcity and an immense burden on the water supply. However, it must be noted that in 1994, South Africa (SA) embarked on developing numerous policies and strategies to address water challenges. While some levels of success have been achieved in terms of policy formulation, there is, however, a lack of comprehensive coordination and synergy that cut across the broad objectives of these policies in meeting environmental, social and economic targets and aspirations. Additionally, the implementation of the policies and programmes is stalled by structural, systemic and institutional factors, coupled with new challenges arising from climatic variabilities. Using a combination of qualitative and quantitative methods together with rapid appraisal of existing literature, we explore systemic and institutional factors impeding the implementation of policies and strategies designed to drive South Africa's water sector as envisaged within the National Development Plan of 2012. We argue that the water sector is faced with multifarious and interweaving challenges such as inadequate human capital, changes in climatic conditions, limited financial resources, infrastructural deficiencies largely linked to poor urban planning and rapid growth of informal settlements, rampant corruption and mismanagement, lack of stakeholders' involvement and compartmentalisation of institutions. This paper, therefore, recommends a community-based approach that enforces transparency and the participation of civil society, cross-sectoral cooperation and a broad range of stakeholders and decentralisation of policy implementation strategies.

Multidimensional valorization of sediments trapped by dams for sustainable and integrated water resources management

This article introduces an innovative demarche to sustainable and integrated water resource management by proposing a new strategy for valorizing sediments retained by dams, explicitly focusing on the Moroccan context. The novel demarche presented encompasses five critical dimensions related to sediment valorization: quality, quantity, space, time, and regulation. To achieve this, we have designed an optimal valorization approach complemented by a specific valorization guide tailored to the nuances of Moroccan laws and standards. Our methodology includes a detailed quantitative analysis of retained sediments, a qualitative assessment of their physical and chemical properties, and a spatiotemporal analysis of dam siltation. The optimal valorization approach aims to maximize the use of retained sediments by identifying suitable applications. Simultaneously, the specific guide provides a methodological and regulatory framework aligned with the region's legal requirements. The quantitative analysis evaluates measures taken to quantify sediments retained by dams, while the qualitative analysis assesses their physical and chemical characteristics and suitability for various applications. The spatiotemporal analysis offers a dynamic perspective on dam siltation, emphasizing the most affected areas and the evolution of trends over time. Anchored in the Moroccan context, this research provides crucial insights into the sustainable management of water resources through the integrated valorization of sediments trapped by dams. The presented results have significant implications for watershed management and the optimization of dam operations and reservoirs. Furthermore, they pave the way for similar approaches in regions grappling with reservoir sedimentation issues.

Spatiotemporal Siltation Patterns in Moroccan Dam Reservoirs: A Geographic Information System Approach

Siltation of dams appears as an urgent global concern, especially in arid and semi-arid regions concerned by the challenges of managing their limited water resources. These challenges worsen by the increase in water demand driven by population growth, aggravated by the adverse effects of climate change, in particular the siltation of dam reservoirs. This article focuses on the spatiotemporal analysis of the accumulation of sediments in Moroccan dam reservoirs. The methodology involves the collection, verification, correction, and interpolation of bathymetric data, which are organized and visualized in temporal and spatial dimensions using a dedicated Geographic Information System (GIS). The spatial distribution maps generated facilitate the identification of the area most severely impacted by the siltation of dams. The analysis emphasizes that siltation affects all Moroccan watersheds, with a particular emphasis on the Moulouya watershed due to the characteristics of its soil and its arid climate, further aggravated by heavy rainfall and deforestation. This integrated approach, combining bathymetric data with GIS technologies, improves our understanding of dam siltation in Morocco. The results provide valuable information for decision-makers and water resource managers, providing essential information for strategic planning and the implementation of measures to mitigate the impact of siltation.

Effects of sediment on mechanical behavior of polypropylene fiber concrete before and after exposure to high temperature

The phenomenon of siltation of dams causes in Algeria a vital problem which annually loses a considerable volume of water storage.The objective of this study the valorization of calcined sediment from the Fergoug dam (western Algeria) in normal concrete exposed at 800 °C. Moreover, the sediments were calcination-treated at 750°C for 5 hours tomakeitactive. The different mixtures were prepared with 0%, 8%, 12% and 16% of sediment by partial substitution of cement , as well as of polypropylene fiber volume of 0.05% and 0.1%. All mixes were investigated on compressive strength and flexural strength at 90 days with different heating cooling cycles from the room temperature to 800 °C in electric muffle furnace. The experimental result indicates that the inclusion 8 and 12% of calcined sediment with fiber significantly enhances properties of normal concrete before and after heating, respectively.

Earthen Dam Siltation: A Review of Various Methods to Calculate Reservoir Sedimentation

Abstract: The shortage of rainfall and its increasing variability leads to moisture stress particularly in dry and rain-fed areas. Reservoirs, created by dams, are constructed to store water for use in non-monsoon months. However, these benefits are not fully explored due to water storage loss due to siltation. The sediment management at dams and reservoirs have given rise to acute complications owing to its impact on water availability, reliability of infrastructure and impact on downstream users. The methods to calculate the volume of siltation trapped by earthen dams play an important role in addressing these issues. The current article also summarizes the various methods that can be adopted to calculate sedimentation in reservoirs of dams.

Study of the relationship between the siltation rate of Algerian dams and the runoff coefficient

Abstract The accumulation of silt in water dams is a natural phenomenon and an acute problem, and every year, about 4,000 tons of soil per square kilometer goes to the dams or the sea through valleys, causing the dams to become saturated with silt or sanding the ports, coinciding with the shrinking of agricultural areas. In general, the siltation of water dams results from a complex process characterized by four successive stages, namely, runoff, erosion, transport, and sedimentation. In this field, many specialists have presented their approach to the problem of sediment transport and erosion, which can affect silt in the area, and therefore, it is important to know the rate of silt before completing the dams. In addition, many factors affect the siltation of dams, such as runoff. In this regard, this article deals with a meta-study of the relationship between the silt rate in Algerian dams and the surface runoff factor. This is to obtain a database that can be used by research professors as well as experts supervising the construction of dams in Algeria.

Geomorphological and Sedimentological Indicators of Contemporary Erosion Processes: An Example of the Eastern Rhodopes Mountains (Bulgaria)

Erosion processes, triggered by water, occur and propagate on sloping surfaces and have a significant negative impact on the soil quality and vegetation, as well as cause a change of the topographic surface. In the long term, they can lead to an increase in sediment transport, siltation of dams, and higher flood hazard. The development of water erosion reflects on the slope profile and the specific landforms like rills and gullies. In this regard, the geomorphological features of the areas can be considered indicators of the spatial distribution of erosion and accumulation. The sediment properties give information about the conditions of the transport and the intensity of the hydrogeomorphic processes. The current study aims to analyse the short-term changes in erosion and deposition by application of morphometry and grain size analysis. Topographic wetness index (TWI) and cross-section profiles of two small gullies were analysed based on high-resolution digital terrain models (DTMs), generated from unmanned aerial system (UAS) data. Remote sensing was combined with field geomorphological research and sediment sampling. The results of the research show about average 2 cm change in erosion and deposition for the period October 2021 – November 2022. Despite TWI and cross-section profiles depending on the DTMs resolution, they are reliable indicators for erosion and deposition. The grain size analysis supports the morphometric analysis. Coarse to very fine sands are predominant in most cases of sediment sampling. The sorting coefficient shows very poorly to moderately sorted deposits which indicates transport in a more dynamic environment and temporary flow.

Synthesis and characterization of cement clinker based on Tunisian dam sediments

Siltation is a permanent threat to the operation of dams since it reduces its storage capacity. In Tunisia, the annual siltation of dams is estimated at 22 Mm3 / year. Sediments currently cover 20% of the total capacity of the reservoirs, which could be a national water security issue in the years to come. Considering that sediments contain the oxides, SiO2. Al2O3. Fe2O3 and CaO, as main chemical constituents, a partial replacement of the raw materials in the cement production is suggested. This work concerns dam sediments from different regions in Tunisia. Characterisation results show that studied sediments are suitable for a beneficial reuse in the clinker production. However, according to the chemical composition, the incorporation rate of sediments in the raw mix varies from one sediment to another but still relatively important, ranging between 9 and 27 wt%. The characterization of produced clinkers show that mineralogy depends on minor oxides contents, especially SO3. MgO and equivalent Na2O. It has been proven that it is possible to substitute natural materials with 27.4 %SS sediment. The obtained clinker is characterized by the presence of M1 C3S and orthorhombic C3A. The high free lime content associated to incomplete alite formation can be surmounted by increasing slightly the clinkerization temperature.

Assessing the intra-annual variability of agricultural soil losses: a RUSLE application in Nord-Pas-de-Calais, France

The control of water erosion is an important economic and societal challenge. Reduction of the agronomic potential of the parcels, muddy flows, siltation of dams are harmful consequences that mobilize farmers, water managers, local authorities and scientific researchers. This study focuses on mapping and quantifying seasonal soil losses in the territory of the former Nord-Pas-de- Calais administrative region, using the Revised Universal Soil Loss Equation (RUSLE) which incorporates five factors: rainfall erosivity, soil erodibility, topography, land use and erosion control practices. The seasonal (3-months) time scale is chosen to better account for the parameters governing the soil water erosion, especially rainfall and vegetation cover, that show great asynchronous intra-annual variability. Also, high resolution data concerning agricultural plots allows to evaluate which type of culture are the more subject to soil losses. In Nord-Pas-de-Calais, water erosion occurs almost ubiquitously, but the areas characterized by steep slopes are the most at risk (Artois Hills and Flanders), with loss rates up to 54 t∙ha–1∙y–1. The majority of erosion occurs during fall (46% of the computed annual losses of 1.69∙Mt), on plots left bare after harvest (especially corn and beets crops). The study also demonstrates that extending the intercrop technique over the region, and therefore maintaining a fall and winter cover, could reduce the soil losses by 37%.

An Estimation of Soil Erosion Rate Hot Spots by Integrated USLE and GIS Methods: a Case Study of the Ghiss Dam and Basin in Northeastern Morocco

Soil erosion is a major factor leading to dams’ siltation and reducing their storage capacity. This study mapped the hot spots of soil erosion areas to predict the soil erosion/siltation in the Ghiss basin/dam (northeastern Morocco). In this context, various data has been prepared in the geographical information system for the estimation of soil erosion by integrating the universal soil loss equation (USLE). The result of this study revealed that soil loss rate ranges between0 and 19 t∙ha−1∙yr−1. Therefore, the hot spots in the soil erosion area are to be found upstream, potentially leading to dam siltation over time. To avoid Ghiss dam siltation, we suggest terrace farming and reforestation in the soil erosion area hot spots.

Assessment of Spatial Soil Erosion Using RUSLE Model Integration with GIS and RS Tools: The Case of Gilgel Gibe-I Catchment, South West Ethiopia

Water-induced soil erosion is one of the serious environmental, agricultural, and socioeconomic problems in Ethiopian highlands. Accurate information on the rates of soil erosion helps environment protection and socio-economic development efforts of the nation. The objective of this research was to estimate annual soil loss, sediment yield, and map erosion risk areas of Gilgel Gibe-I (GG-I) catchment via integrating Revised Universal Soil Loss Equation (RULSE) model with Geographical Information System (GIS) and Remote Sensing (RS) technologies. The model inputs variables; rainfall erosivity (R), soil erodibility (K), topographic (LS), land cover (C) and land management (P) were derived from meteorological stations, Ethio-soil map, and satellite image of the catchment. The annual soil loss (t^-1ha^-1yr) was estimated using pixel-by-pixel ArcGIS map overlays to ensure the accuracy of RULSE output. The model output revealed on average 12.52 (t^-1ha^-1yr) soils was lost from GG-I catchment through sheet and rill erosion. The rates of soil loss were varying in the catchment, 59.8% of the catchment exposed to low rate (<5 t^-1ha^-1yr), 12.2% to moderate rate (5-12 t^-1ha^-1yr), 11.7% to high rate (12-30 t^-1ha^-1yr), and 6.6% to severe (>30 t^-1ha^-1yr). The annual sediment yield capacity of the catchment was 2.54 t^-1ha and delivery ration estimated 0.203% transported to outlet of the catchment-GGI hydropower dam. To combat the problems of GG-I hydropower dam siltation, land degradation, and low agricultural productivity an integrated natural resource management intervention is required throughout the catchment particularly in high and severe erosion risk areas.

Tracking long-term cascade check dam siltation: implications for debris flow control and landslide stability

Tracking long-term cascade check dam siltation: implications for debris flow control and landslide stability

A method for the economic estimation of dam siltation: a case study in Mexico

A method for the economic estimation of dam siltation: a case study in Mexico

Management of water scarcity in arid areas: a case study (Ziz Watershed)

The 2030 Agenda for Sustainable Development aims to reach 17 Sustainable Development Goals (SDGs). The SDGs 6 deals with water security, which refers mainly to ensure availability and sus-tainable management of water. The present study aims to enhance reservoir performance under climate change to deal with water scarcity. For this purpose, we proposed a new methodology where precipitation and evaporation data provided through temporal downscaling are leveraged by a real-time management algorithm coupled with the Hydrologic Modeling System (HEC-HMS). The real-time dam management algorithm is based on water balance equation and rule curves. It provides information about (1) dam storage, (2) dam release, (3) dam evaporation, (4) dam diversion, (5) spilled water volume, (6) emergency spilled water volume, (7) dam inflow, (8) irrigation demand, (9) irrigation shortage, (10) dam siltation, (11) dam hydropower produc-tion, (12) hydropower energy income. The developed approach has been applied to the Hassan Addakhil multipurpose reservoir in Morocco. The result shows that the dam reliability and resili-ence have increased from 40% to 70% and from 16% to 66%, respectively, while the vulnerability remained constant. Additionally, this study has pointed out that the installation of a hydropower plant is an opportunity to produce clean electrical energy and generate an income enough to cov-er different costs related to dam management and maintenance. Therefore, the real-time man-agement tool developed in the framework of this project can significantly enhance reservoir per-formance.

Reusing calcined sediments from Chorfa II dam as partial replacement of cement for sustainable mortar production

Dam siltation is an alarming problem that significantly affects the dam's lifetime and water storage capacity. In Algeria, the removal of dredged sediment has become a significant environmental impact and an economic issue. In this context, the utilization of calcined sediments as an artificial pozzolanic material could reduce greenhouse gas emissions in the cement industry. This paper addresses the objective of valorizing calcined sediments in sustainable mortar production on fresh and hardened states of grouts and mortars. Moreover, three dry curing methods were used to accelerate improving the strength of the different mortars at a rate of 5, 15, and 25% by weight of Portland cement (CEM I 42.5 N). The first method was applied at 10 °C, and the other two at 20 °C and 40 °C. X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) analysis showed a real advantage of heat treatment at 750 °C of sediments to acquire pozzolanic behavior. A substitution rate of 25% affected the fluidity of cement grouts with calcined sediments at 60 min with a loss of fluidity, even with a high dosage of plasticizer. Indeed, the best mechanical results of the mortars were observed at cure temperatures of 20 °C and 40 °C. With an acceleration of the pozzolanic activity at 90 days for a cure at 40 °C and 180 days at 20 °C, the development of compressive strength is relatively higher than that of the control mortar. In conclusion, the carbon footprint of the final mortars showed that a high substitution rate reduces CO2 emissions, representing a reduction of 3%, 10%, and 17% respectively for the formulation of mortars based on 5%, 15%, and 25% calcined sediment.