Sameh Ahmed Kantoush

Kyoto University | Kyodai · Disaster Prevention Research Institute

Hydraulic infrastructures, such as reservoirs and water diversion channels, cause altered streamflow worldwide. Therefore, this study aimed to assess the coupled impacts of reservoir operations and water transfer on downstream streamflow over 42 years (1979–2020) for a tropical river in Vietnam, the Vu Gia Thu Bon (VGTB). We also quantified variati...

Sediment depletion in the Vietnamese Mekong Delta (VMD) has brought threats to riverbed and riverbank dynamics. The main objective of this research is to make a relationship between turbidity and suspended sediment concentration (SSCs) and to assess temporal-spatial variations of SSCs in the VMD. In this regard, the SSCs were measured and monitored...

Several cities are exceptionally vulnerable to flood impacts due to increasing urbanization, population growth, and climate change. Quantifying flood vulnerability is useful for identifying the system's weakness, monitoring its evolution, and supporting targeted flood risk adaptation policies. One of the vital aims of assessing urban flood vulnerab...

The concepts notes were developed to facilitate discussion among various stakeholders gathered from around the world to share information on their ongoing research activities and current research projects, find collaborative activity partners, showcase research achievements, and challenge further improvements to disaster risk reduction and resilien...

Soil erosion, sediment yield, and sediment transport associated with flash flooding in arid regions result in reservoir storage losses, decreased infiltration, high evaporation rates, and degradation of downstream channels. However, the lack of observational data from wadi systems and an empirical formula to compute sediment yield has hindered rese...

The Vu Gia Thu Bon basin constitutes the primary water supply in Central Vietnam. While climate change disturbs stream discharges and affects flood extremes, upstream dam development may intensify or mitigate such impacts. Therefore, this study provides a quantitative evaluation of long-term alterations in the flow regimes of the VGTB rivers from 1...

Siltation is a major threat to the original storage capacity and lifespan of a reservoir. Pressure flushing is an effective measure against siltation through the partial drawdown of the reservoir water level with limited flushed cone volumes in front of the bottom outlet. In this study, a novel configuration with submerged vanes has been proposed a...

Understanding the complexity of the siltation process and sediment resuspension in shallow reservoirs is vital for maintaining the reservoir functionality and implementing sustainable sediment management strategies. The geometry of reservoirs plays an indispensable role in the appearance of various flow structures inside the basin and, consequently...

Flow, suspended sediment transport and associated morphological changes in the Vietnamese Mekong Delta (VMD) are studied using field survey data and a two-dimensional (2D) depth-averaged hydromorphodynamic numerical model. The results show that approximately 61–81 % of the suspended sediment load in the Hau River during the flood seasons is diverte...

Sedimentation in front of a dam is the main obstacle against reservoir sustainability. Due to the limited availability of suitable new dam sites, the ramifications of inefficient sediment management are associated with socio-economic concerns and environmental issues. Most of the existing sediment management techniques are unfavorable for arid and...

Increasing flood risk due to rapid urbanization and climate change calls for improved integration between flood risk management and spatial planning processes to enhance the resilience of cities, including in Egypt. Although much work has been conducted on flood impact in Egypt, the gap in integrating flood risk assessment with spatial planning pra...

Flood risk mapping forms the basis for disaster risk management and the associated decision-making systems. This process' effectiveness depends on the quality of the input data of both hazard and vulnerability maps and the method utilized. Worldwide, although there are thousands of studies in Flood Vulnerability Assessment (FVA), however, compariso...

Because recurring floods in the Philippines have become more damaging throughout time, risk assessments, quantifying, and visualizing flood damages as accurately as possible become imperative. To deal with an up-to-date database and a practical assessment tool, a satellite imagery-based method was used which aimed to map flood inundation and estima...

Severe flash floods have hit Jordan in recent years, e.g., in 2018 and 2020, leading to fatalities and infrastructure damages. Moreover, even though Jordan is one of the water scarcest countries of the world, extreme rainfall events might occur more frequently under climate change (IPCC Sixth Assessment Report 2021), causing flash floods in wadi sy...

Medjerda is a key transboundary watershed (Algeria and Tunisia) in the Maghreb region. The analysis of rainfall regime in this basin is of paramount importance for water resources management and for regional economic development notably in relation with agriculture. This study examines the rainfall trends over the Medjerda watershed on a multi-temp...

Accurate measurements of sediment flushing cone geometry (SFCG) are essential for determining sediment removal efficiency in reservoirs. SFCG measurements are related to the point-to-point height that affects bathymetry accuracy, and they are used to develop a digital elevation model (DEM). Conventional bathymetry monitoring techniques require a lo...

Key Points  ML methods can reliably reconstruct missing daily discharge values.  The MARS and RF models outperform other ML and RC methods.  Data pre-processing reduces the simulation time and effort. Abstract In this study, six machine learning (ML) models, namely, random forest (RF), Gaussian process regression (GPR), support vector regression...

This chapter focuses on using remote sensing data to monitor floods and ‎develop risk maps. It covers a wide range of issues, reviews remote sensing ‎data types and processing techniques, and discusses the limitations and ‎challenges of using remote sensing images in flood monitoring, especially ‎in the MENA region. Furthermore, the chapter present...

Study region The El-Kharga Oasis in the Western Desert of Egypt is selected as the study area due to its hyberarid climate condition and water scarcity. In this region, the fossil groundwater is the main water source; therefore, preserving groundwater quality and quantity is mandatory. Study focus This study evaluated groundwater suitability for i...

The river beds of the Mekong Delta are some of the most intensively sand mined places in the world. However, sand mining budgets remain limited to rough and indirect estimates. Here, we provide a first systematic, field-based estimation of the Mekong Delta’s sand mining budget. This budget overcomes the limitations of relying on officially declared...

The increasing flood risk due to rapid urbanization, climate change, and mismanagement has called for integration between flood risk management and spatial planning processes, which are increasingly used to enhance cities' resilience against the growing flood risk. In Egypt, Flood Risk Management (FRM) faces crucial challenges; the deficiency of fl...

Reservoirs have been installed as long-term assets to guarantee water and energy security for decades, if not centuries. However, the effect of siltation undermines reservoirs' sustainability because it significantly reduces the reservoirs' original capacity. Extreme events such as typhoons, floods and droughts are posited to have extreme impacts o...

In this paper, we address the impact of agricultural expansion on hydrological patterns of water and sediment budget in one of the largest floodplains along the Cambodian Mekong since the 1980s, using field (water level, discharge, sediment, rainfall, and groundwater level) and remote sensing (land use, surface suspended sediment) data, and numeric...

Medjerda is a key transboundary watershed in the Maghreb region, crossing from the Algerian mountains through northern Tunisia. Therefore, the analysis of the rainfall regime in this basin is of paramount importance for water resources management and regional economic development, notably concerning agriculture. This study examines the rainfall tre...

Investigation of vegetation cover is crucial to the study of terrestrial ecological environments as it has a close relationship with hydroclimatological variables and plays a dominant role in preserving the characteristics of a region. In Iran, the current study selected the watersheds of two rivers, Nazloo-Chay and Aji-Chay, to systematically inve...

Riverine ponds, which are formed and sustained through sediment erosion and deposition, are key habitats for enhancing biodiversity in river reaches. The objective of this study was to understand the roles of traditional river-training wooden structures called “seigyu” on the formation of ponds on nonvegetated bars. Here, the spatial and temporal p...

Sustainable management of wadi flash flood (WFF) risks is desperately needed to secure development in wadi systems. Due to rapid flow generation with sudden high flood peaks, spatiotemporal variability of rainfall occurrence, and poorly sited rapid development, most Middle East and North Africa (MENA) region have no comprehensive proper protection...

Recently, Wadi flash floods (WFFs) have happened frequently in arid environments, resulting in great damage the society and the environment. In Oman, severe WFFs have occurred repeatedly within the last 10 years causing a huge impact on human lives and properties. This paper aims at introducing the framework of an international collaboration projec...

Groundwater contamination and the environmental impact of groundwater uprising due to overpumping are critical issues in Egypt. The main purpose of this study is to evaluate the groundwater quality and the environmental impacts of groundwater uprising in the Fares area of Aswan, Egypt. The environmental impacts of the uprising groundwater level wer...

Climate change, drought, and anthropogenic effects are among the main drivers causing alterations in natural resources one of which is the lake level (LL) of large saline lakes, which are mainly located in arid and semi-arid regions. As an urgent need to manage natural resources, this study focuses on determining the significant reasons for the shr...

Pre-release is the effective measure against large-scale floods that have frequently occurred in recent years, whereas its implementation period based on ‘Pre-release guidelineis’ is limited. In addition, there are few considerations of pre-release in tandem series of dams including hydropower ones. This study investigated the effect on the maximum...

The Vietnamese Mekong Delta (VMD) has been suffered from coastal erosion, morphological changes, and sediment reduction caused by climate change, sand mining, and river damming. Therefore, the main objectives of this work are to study sediment dynamics and morphological changes to address past and present challenges and subsequently suggest adaptiv...

The long-term spatiotemporal assessment of groundwater resources through robust clustering techniques can be used to promote remediation measures for groundwater depletion and contamination. To fully understand the variability of groundwater quantity and quality due to anthropogenic activities and climate changes, a new ensemble clustering framewor...

The ambition of this symposium was to review and create knowledge and praxis in bedload management, support the implementation of restoration measures in Switzerland and strengthen the international network among scientists and practitioners. Switzerland has the legal goal and the financial tools to restore its rivers from the impacts of sediment...

Pressurized flushing is one of the techniques for evacuating sediments from reservoirs. In this study, the impact of submerged vanes on performance of pressurized flushing were investigated. For this purpose, submerged vanes with convergent, divergent and combined arrangements in three distances from the bottom outlet (Lv), three middle distances (...

Reservoir sedimentation is one of the main challenges by which the reservoir behind the dam is filled with sediments transferred through the river flow. Pressure flushing method is an effective way to drain the deposited sediments of the reservoirs through the bottom outlet. So far, several structural methods have been proposed to increase the effi...

Reservoir sedimentation is a long-term process that causes various risks such as the reduction of storage capacity, hydropower generation, and flood control functions throughout a reservoir’s lifespan. For reservoirs facing loss of function with severe deposition, sediment flushing is an approach for the preservation of long-term storage. In this r...

Flash floods in wadi systems are a very important environmental issue, and their monitoring is necessary for many applications, including water resource management, irrigation and flood control. However, monitoring networks are very rare and lack spatial distribution features. In this study, image-based techniques were used to quantify and monitor...

This chapter highlights some substantial questions inquired by researchers to comprehend the flood risks (FRs) that occur in their cities as follows: (1) What is the impact of flooding on urban areas? (2) what effect does urbanization have on FR? (3) What are the existing nonstructural and structural mitigation measures for urban flooding? and (4)...

The behaviors and impacts of flash floods (FF) are different based on the climatic regions. To understand such difference, two case studies were selected for the analysis: Wadi Uday, Oman and Sume Basin, Paraiba, Brazil. The rainfall-runoff inundation model (RRI) was used to simulate the discharge and flood inundation of the recent flood events to...

This study presents two machine learning models, namely, the light gradient boosting machine (LightGBM) and categorical boosting (CatBoost), for the first time for predicting flash flood susceptibility (FFS) in the Wadi System (Hurghada, Egypt). A flood inventory map with 445 flash flood sites was produced and randomly divided into two groups for t...

The river beds of the Mekong Delta are some of the most intensively sand mined places in the world, however sand mining budgets are limited to rough and indirect estimates. Here, we provide a systematic, semi-physically based estimation of the Mekong Delta’s sand mining budget. We provide a quantified budget that overcomes limitations resulting fro...

Vietnam Mekong Delta (VMD), the country’s most important food basket, is constantly threatened by drought-infused salinity intrusion (SI). The SI disaster of 2020 is recognized as the worst in recent decades, hence inspiring this perspective article. The authors’ viewpoints on the disaster’s impacts and causes are presented. The arguments presented...

The Unazuki Reservoir is located on the Kurobe River, which is influenced by a catchment with one of the highest sediment yields in Japan. Due to a sufficiently available discharge during flood events, annual sediment flushing with full water-level drawdown (i.e., free-flow sediment flushing) is conducted to preserve the effective storage capacity...

When a high need for new residences coincides with an insufficient area of obtainable land within cities, urban sprawl occurs. Although densification is a well-known policy for controlling urban sprawl, one of the main challenges faced by researchers is that of determining urban densification potentials and priorities at the city scale. This paper...

To improve knowledge of this matter, the potential application of two gridded meteorological products (GMPs), the China Meteorological Assimilation Driving Datasets for the SWAT model (CMADS) and Climate Forecast System Reanalysis (CFSR), are compared for the first time with data from ground-based meteorological stations over 6 years, from 2008 to...

The buildup of sediment deposits in reservoirs is a longstanding problem with serious consequences on their functionality and the eco-environment of their river systems. In the last two decades, hydraulic dredging has been opted for as a more viable engineering solution to restore reservoirs’ sustainability. This study proposes a novel ejector-pump...

Wadis, an Arabic term referring to a wadi, in the Eastern Desert of Egypt have undergone rapid unsustainable development in areas vulnerable to flash flooding and water scarcity. To reduce the risk of damage and loss of life from flash floods to a wadi’s new residents, the priority is to develop mitigation strategies with distributed (watershed sca...

Hydropower generation is one of the key purposes that dams were built for. World-wide the sustainability of hydropower operation is deprived and threatened by the alarming rate of reservoir sedimentation. The situation is even worst for the cases where the sediment delta has propagated and reached the dam site. Various sediment management practices...

This chapter focuses on group discussion sessions targeting the Priority Areas of the Sendai Framework for Disaster Risk Reduction 2015–2030. Day one group discussion session efforts were on Priority Area One—Understanding Disaster Risks; and Day two emphasis was on Priority Areas 2, 3 and 4.

The hydrogeomorphology of the Vietnamese Mekong Delta (VMD) has been significantly altered by natural and anthropogenic drivers. In this study, the spatiotemporal changes of the flow regime were examined by analysing the long‐term daily, monthly, annual, and extreme discharges and water levels from 1980 to 2018, supported by further investigation o...

Sediment Replenishment (SR) is a common restoration measures implemented in Japanese rivers, which aims to recover the degraded river’s morphology and aquatic ecosystem caused by sediment deficit. In this paper, we developed an integral assessment approach to evaluate the effectiveness of SR strategy on flow regime, river bed, and ecological change...

One of the main problems in reservoirs is sedimentation which reduces the operating life of dams if a proper plan and analysis method are not in place. The techniques to manage sediment in reservoirs include several sustainable management techniques that route sediment through or around the reservoir. One of the main economical methods in arid and...

North-Central Vietnam has suffered annually from complex and far-reaching floods resulting from heavy rain. As of 15th November 2020, the floods had resulted in over 233 fatalities, 66 people missing, and damaged almost 35.2 trillion VND (~US$ 1.52 billion) in this area. The analysis and forecast of floods caused by heavy rain have been an urgent i...

Flood risk mapping forms the basis for disaster risk management and the associated decision-making systems. The effectiveness of this process is highly dependent on the quality of the input data of both hazard and vulnerability maps and the method utilized. On the one hand, for higher-quality hazard maps, the use of 2D models is generally suggested...

Study region: The Mekong basin, where climate change and anthropogenic interventions (e.g., dams, sand mining, and sluice gates) have intensified in the recent decades affecting the pristine flow regime and salinity intrusion. Study focus: This paper aims at quantifying the flow regime alterations in the entire Mekong from 1980 to 2015 and linking...

River bank (RB) erosion is a global issue affecting livelihoods and properties of millions of people. However, it has not received enough attention in the Vietnamese Mekong Delta (VMD), i.e., the world's third largest delta, compared to salinity intrusion and flooding. There have been several studies examining RB and coastal erosion in the VMD usin...

River bank (RB) erosion is a global issue affecting livelihoods and properties of millions of people. However, it has not received enough attention in the Vietnamese Mekong Delta (VMD), i.e., the world’s third largest delta, compared to salinity intrusion and flooding. There have been several studies examining RB and coastal erosion in the VMD usin...