River Overflow Research Articles

Indicators for Disaster Vulnerability to the Overflowing of the Niger River in Adjoining Settlements in the Confluence City of Lokoja, Nigeria

River overflow is one of the main causes of flooding and erosion. In Nigeria, flooding affects (loss and damage to properties and distortion of sources of livelihood) and displaces more people than any other disaster (loss and damage to properties and distortion of sources of livelihood). The 2012 overflowing of the River Niger and the subsequent flooding of Lokoja historically represent the most devastating natural disaster in the city. The study was based on the Geographic Information System’s (GIS) Multi Criteria Analysis (MCA) and examined the risk and vulnerability of Lokoja’s settlements adjoining the Niger River to flooding. The criterion considered were elevation, land cover, slope, curvature, flow accumulation, the Normalised Difference Water Index (NDWI) and the drainage density of the study area. The data used for this study was obtained from a secondary source United States Geological Survey (USGS). The relationship between the NDWI and the precipitation in Lokoja showed that the NDWI and precipitation were inversely related. This implied that an increase in precipitation was consequential to the intensity of the water index in the study area. This study successfully showed the capability of remote sensing and the GIS to assess both pre- and post-disaster (flooding) vulnerability. It also revealed that high precipitation and increasing physical development due to urbanisation in lowlands increased the vulnerability of an area to flooding. The recommendation forwarded was the need for improved river basin management and flood disaster prevention.

Hybrid Surrogate Model for Timely Prediction of Flash Flood Inundation Maps Caused by Rapid River Overflow

Timely generation of accurate and reliable forecasts of flash flood events is of paramount importance for flood early warning systems in urban areas. Although physically based models are able to provide realistic reproductions of fast-developing inundation maps in high resolutions, the high computational demand of such hydraulic models makes them difficult to be implemented as part of real-time forecasting systems. This paper evaluates the use of a hybrid machine learning approach as a surrogate of a quasi-2D urban flood inundation model developed in PCSWMM for an urban catchment located in Toronto (Ontario, Canada). The capability to replicate the behavior of the hydraulic model was evaluated through multiple performance metrics considering error, bias, correlation, and contingency table analysis. Results indicate that the surrogate system can provide useful forecasts for decision makers by rapidly generating future flood inundation maps comparable to the simulations of physically based models. The experimental tool developed can issue reliable alerts of upcoming inundation depths on traffic locations within one to two hours of lead time, which is sufficient for the adoption of important preventive actions. These promising outcomes were achieved in a deterministic setup and use only past records of precipitation and discharge as input during runtime.

Rancang Bangun Monitoring Early Warning System Bencana Banjir Berdasarkan Ketinggian Aliran Sungai Mengunakan Modem SIM900 dan Internet of Things

The rainfall in the Cilacap region is high, about 80-100mm in October-March. The high rainfall that causes the overflow of river water is unpredictable. The high water discharge is not realized until the river water overflows and causes flooding. Therefore, a river water level monitoring system is needed to detect river overflows early. This tool uses a solar cell as a power supply. The monitoring system is divided into two points of river water level monitoring system with a distance between points for the laboratory scale stage, which is 100 meters. Sensors that measure the height of river flow are ultrasonic sensors. The sensor results are processed by microcontroller and SIM 900 L module to be sent to the database . When the water level is in the Alert level 3, the buzzer will sound as a warning. The ultrasonic sensor test results have a very small error. Sensor 1 has an average error of 0.00023% and ultrasonic sensor 2 has an error of 0.00016%. The system is able to transmit river water level data that can be accessed through the website .

Google Earth Engine-Based Identification of Flood Extent and Flood-Affected Paddy Rice Fields Using Sentinel-2 MSI and Sentinel-1 SAR Data in Bihar State, India

Flood is the major cause of fatalities associated with natural disasters in the world. In India especially in the state of Bihar, where about half of the area (North Bihar) gets flooded every year due to the overflow of major rivers during the rainy season. Which severely affects human lives, properties, agricultural production, farmers and their livelihood. Usually, the basins of the Kosi and Gandak rivers are known for their worst affects in Bihar. Synthetic aperture radar (SAR) is widely used for robust monitoring of flood events due to its ability to image the surface of the earth in all weather conditions. However, limited studies are available on flood patterns of Bihar and their impact on agriculture. Here, we investigated the flood extents and affected paddy rice fields for Bihar during the months of June–October (2020) using all accessible Sentinel-1 SAR and Sentinel-2 MSI images with additional supporting datasets available on the Google Earth Engine. The study showed that a large portion of Bihar (7019 km2) was submerged during monsoon season. The floodwater remains in the agricultural fields for 50 to 65 days causing severe damage to the Kharif crops, mainly rice. The extreme effect of flood was seen in agricultural lands (11.23% of the total area) and populations (15.56% of the total population) in Bihar. Satellite-based identification of flood progression and affected rice fields can be helpful for decision-makers at the time of disaster to prioritize relief and rescue operations.

Hydrology and Estimation of Real Erosion in the Patria Nueva Micro-Basin for Five Return Periods

This paper will discuss the actual erosion estimation of the Patria Nueva micro basin in tons/ha/year (E), located in Tuxtla Gutiérrez Chiapas, Mexico. We used the universal soil loss equation (USLE), considered one of the best theoretical tools for planning and soil preservation in the USA and other countries. The actual erosion rates were estimated for 5, 20, 50, 100, and 500 years return periods (Rp), with elevated results due to high degrees of anthropogenic alteration of the micro-basin, especially in the last 50 years. High erosion rates generate the following problems: loss of soil, which is unfavorable for plant life, due to the soil being a non-renewable resource, the undermine can never renovate, the hydraulic area in the main channel reduces during the rainy season (when the river overflows). The sediment accumulates at the lower part of the micro-basin along with waste, garbage, and mud.

MODELING AND PREDICTING THE MONO RIVER OVERFLOW UPSTREAM OF THE NANGBETO DAM IN WEST AFRICA USING MULTIPLICATIVE DETERMINIST MODEL

The variation and non-control of the overflow of the Mono River adversely affects the performance of the Nangbetohydropower plant to the point thatitcan no longermeet the increasinglyincreaseddemand for electricity. This studypresents the development of an operational model for forecastingdaily river flows for the plants water retention. The overflow of the Mono River at the upstreamhydroelectric dam from 1991 to 2019 wasanalyzed and modeled by the deterministicprocesswith R software in order to makepredictions. First, the flow serieswasanalyzed by the ARIMA model (18, 1, 2) then by a multiplicative model afterremoving the seasonal trends fromtheseseries by the movingaveragemethod. The calculatederror of the results of said model revealsthat the deterministic model integrates the input generationprocesseswith an error of the order of . Finally, an annual flow forecasting program has been developed as a planning tool for the operation of the dam, in order to meet production needs and to plan water releases.

ANALISIS TINGGI MUKA AIR PADA KAWASAN SUNGAI CILIWUNG MT. HARYONO – PINTU AIR MANGGARAI DENGAN PROGRAM HEC-RAS 5.0.3

Flooding in DKI Jakarta Province has become a routine that occurs every year. One of the causes of flooding in Jakarta is the overflow of the Ciliwung river. On February 20, 2021, flooding occurred around the MT herd. Haryono – Manggarai sluice as a result of overflowing water from the Ciliwung river. This study aims to identify the water level in the Ciliwung MT river area. Haryono – Manggarai Sluice using the HSS Nakayasu method and hydraulics analysis using the HEC-RAS 4.1.0 application. Based on the results of the analysis and studies that have been carried out in the Ciliwung MT river area. Haryono – Manggarai Sluice, the design flood discharge is obtained as follows: flood discharge 2 years return period = 198.08 m3/second, 5 year return period = 287.87 m3/second, 10 year return period = 351.12 m3/second, 25 year return period = 427.94 m3/sec, 50 year return period = 490.28 m3/sec, and 100 year return period = 563.44 m3/sec. The results of these calculations were analyzed using the HEC-RAS 4.1.0 program so that it can be seen that several points have the elevation of the water level exceeding the elevation of the river bank being targeted.

Analysis of human physical vulnerability using static equilibrium techniques of a Hazard flood for the determination of unsafe areas in the city of Catacaos – Piura, Peru

Heavy rains and El Niño phenomenon are recurring natural phenomena at a national level. These can cause floods due to the overflowing of rivers, which, when close to cities, can cause both human and material losses. The district of Catacaos, located in the city of Piura, was the one with the highest number of injuries due to the flood caused by El Niño phenomenon in 2017. This phenomenon causes a large amounts of rainfalls due to the presence of abnormally warm waters along the northern coast of Peru [1]. It is for this reason that the need arose to carry out an analysis of the physical vulnerability due to instability of people through static equilibrium, in said district, in order to present maps of unsafe areas in the face of this phenomenon. In this investigation, flood hazard maps are generated simulating the one presented in 2017, using 2D hydraulic modeling. For the generation of vulnerability curves, the instability analysis is performed by moment and drag force. Finally, maps with unsafe areas are made using ArcGis software. Where the results obtained indicate that 29.37% of the city was flooded. Likewise, the vulnerability maps generated show us that women and men over 18 years of age in the city of Catacaos would be vulnerable to dragging and overturning in the face of floods in 16.54% and 13.21%, respectively, of the total studied area. This information will be useful for the development of future evacuation plans during floods, carried out by national entities.

XP-SWMM을 이용한 고현천 유역의 홍수피해 저감을 위한 홍수방어계획 수립

Due to the rapid progress of urbanization, the area of impermeable water is increasing, and the flooding accompanied by torrential rain caused by the climate crisis is rapidly flowing into the stream, increasing the frequency of river disasters. In this study, the rainfall data and topography data were analyzed for Gohyeoncheon, Geoje City, where many property damage and flood damage were frequent due to intensive rainfall in 2009, 2016, and 2017. As a result of the simulation, a river overflow occurred in the city center of Gohyeon-dong, where the population was concentrated. Therefore, this study proposed a flood sharing plan to establish a sub-dividing flood volume for the drainage basin and install flood control facilities for the excess amount. Furthermore, a dual drainage system modeling analysis using XP-SWMM was conducted to analyze the immersion area and examine the applicability of forced exclusion facilities. It is believed that the optimal flood defense measures proposed in this study can be used as basic data when establishing policies to prepare for flooding of rivers and domestic disasters.

EVALUATION OF THE CAUSES OF FLOOD AND MITIGATION STRATEGIES IN KADUNA SOUTH LOCAL GOVERNMENT AREA, NIGERIA

Flood disaster has become a significant natural concern to so many rural and urban dwellers in different part of the world, with devastating effects that cannot be overemphasized. Previous studies have discussed causative factors and preventive measures of flooding. However, significant underpinning factors such flood incidence, hazard proximity and delineation of flood vulnerable areas which determine flooding severity and wide scale coverage are often obscured. The situation creates a knowledge gap which this study intends to fill by evaluating the causes of flood in Kaduna South Local Government Area and proffer mitigation strategies. The descriptive survey research design was employed in the study and a total 418 structured questionnaire was shared among residents and professionals in the built environment. Data was presented on tables and analyzed using the relative importance index ranking method so as to determine the severity of the factors that causes flooding and the mitigation measures that are appropriate to tackle the problem. The result of the study showed that 34.36% of the residents have experience flood at least 3 times in single rainy season, while 11.04% and 2.76% of the residents have experience flood at least 6 and 9 times respectively in a single season. Hazard proximity reveals 19.94% of residential buildings located are within 0.1-0.5 km and 13.49% are located within 0.5-1.0 km away from the flood source. Consequently, river overflow with a severity index of 0.31 is the highest cause of flooding in the study area, followed by poor drainage systems and heavy rainfall with Severity index of 0.29 and 0.28 respectively. The study also suggested mitigation measures as good drainage network and stop building on flood plains jointly rank first with a significance index of 0.30, building embankments and implement government policies on flood with 0.28 and 0.27 respectively. Therefore, the authority of Kaduna State Urban Planning and Development should ensure widening and desilting of drainages, the demolition of illegal structures built across the drainage channels and the implementation of government policies on flood.

Interactions between pluvial and fluvial floods in floodplains in Lower Wortley, Leeds, UK

ABSTRACT Heavy precipitation with unplanned land use can alter the catchment response time; thus, natural processes of floods can be affected. As a result, floods from multiple sources can be observed concurrently or consecutively at the same location. However, the location-dependent interactions between floods and the consequences of flood combinations have not been studied sufficiently. This research examined the interactions and the consequences of combined floods occurring on the settlements on floodplains along urban streams in an ungauged and urbanized catchment. The flood extents, merging from the river overflow and the rainfall-induced runoff, were simulated directly for Lower Wortley, Leeds, UK. The study demonstrates that an assessment of the floods occurring from multiple sources at the same location is necessary to improve flood risk management approaches, because the merger floods could significantly increase the impact of any single flood, and so the flood defences become deficient.

МНОГОЛЕТНЯЯ ИЗМЕНЧИВОСТЬ ИОННОГО СТОКА КРУПНЫХ РЕК АРКТИЧЕСКОЙ ЗОНЫ РОССИИ

Studies of river ion runoff and its temporal variability are important. It affects coastal waters and is interrelated with climatic changes in the Arctic region. Long-term data on the chemical runoff of macrocomponents (chlorides, sulfates, hydrocarbonates, calcium and magnesium ions) at the outlet sections of large Arctic rivers in Russia - Pechora, Usa, Yenisei, Ob, Pur, Taz, Lena, Yana and Kolyma are given. The values of volumes and modules of chemical runoff were calculated on the basis of long-term (1980-2018) hydrological and hydrochemical information from the state observation system of Roshydrom-et. It is shown that the change in the absolute values of the chemical runoff is consistent with the water inflow. Greatest contribution to the ionic runoff is made by hydrocarbonates. The intra-annual change in the water inflow and the macrocomponents runoff occurs synchronously. There is a decisive role of water runoff in the formation of chemical runoff from the catchments of large Arctic rivers. Comparison of the chemical runoff modulus indicator made it possible to classify them into low, medium or high ionic runoff rivers. It was found that the maximum runoff of macrocomponents occurs from the catchment of the Usa river. It is may be due to active processes of chemical denudation and climate change.

Anthropogenic flash floods and climate change in rural Zimbabwe: Impacts and options for adaptation

Zimbabwe has been affected by numerous floods-related disasters in the recent past. These disasters often left rural communities in difficult socioeconomic situations. Floods are among the major water-related hazards and natural disasters worldwide. They are associated with excess rainfall, resulting in river overflow due to climate change . Developing countries constitute a large number of losses caused by water hazards. Thereby, in these countries, the vulnerabilities of households that depend on rain fed agriculture and livestock production for their livelihoods increases. This review paper seeks to establish the association between anthropogenic flash floods and climate change and unearth the impacts; vulnerabilities and adaptation options associated with anthropogenic flash floods in rural Zimbabwe. The study found that numerous anthropogenic activities perpetuate an increase in flood risk. These include littering, river or dam regulation measures, intensified land use and emissions of greenhouse gases, which subsequently result in global climate change. The impacts of flash floods established in the study include drought, food insecurity, displacements, malnutrition and severe effects on subsistence economy. The study concluded that even though most rural communities in Zimbabwe are vulnerable to the effects of floods, they have devised numerous diverse adaptation strategies to cope with the changes in the environment.

Mitigasi Bencana di Situs Cidanghyang, Pandeglang: Pencegahan Terhadap Potensi Kerusakan

The existence of the inscription is seen as the main indicator of Indonesia's entry into historical times. The seven Sanskrit inscriptions from Tarumanegara are written evidence of the establishment of a Hindu kingdom in western Java at the beginning of the fifth century AD under the rule of King Purnawarman. One of the inscribed stone relics known as the Munjul inscription, located far from the royal capital around the Citarum estuary between Jakarta and Bekasi, which testifies to the vastness of the territory and the influence of Tarumanegara rule. Carved on the top of andesite rock in situ at the Ci Danghyang meander, a tributary of the Ci Liman river that flows into the Sunda Strait, the Munjul inscription is in a vulnerable position to natural disasters, especially the unpredictable river overflows. Considering the importance of the Cidanghyang inscription as a cultural heritage that has been registered as RNCB 20161025 01 001351, this study aims to reveal the natural phenomenon resent condition that has the potential to change, damage, and even eliminate objects and the surrounding environment. By identifying the impact of river overflow in recent years, it is hoped that this research can obtain field information about potential direct and indirect threats to cultural heritage. The results of these observations can provide a rational basis for formulating disaster mitigation policies on the Ci Danghyang river which has a direct impact on the inscription site as a preventive step in the framework of a cultural resource management system.

RELIABILITY OF 2D HYDRODYNAMIC MODEL ON FLOOD INUNDATION ANALYSIS

This paper presents a flood inundation analysis to determine the possibility of flooding in urban areas. Many studies have conducted flood simulations to generate inundation problems due to river overflow. Urban flood problems commonly occur because of rainfall in subcatchments that do not enter the channel effectively. Therefore, it is necessary to analyze the inundation that occurs owing to overland flow. This study investigates the usefulness of rain-on-grid boundary conditions compared to flow hydrographs to represent the overland flow. The 2D shallow water equation was applied using the HEC RAS 2D model to select suitable boundary conditions to describe watershed problems. The rain-on-grid boundary condition gives a direct rainfall–runoff calculation in the simulation. The flow hydrograph was calculated separately using the rainfallrunoff analysis based on the storm-water-management model. Although rain-on-grid represents the real physical condition, it is difficult for the 2D hydrodynamic model to assess the drainage channel. However, the flow hydrograph boundary condition shows good results compared qualitatively with historical data based on on-site observations obtained from the Department of Public Works, Highways, and Drainage Management. Furthermore, this research provides the capability of flow hydrographs and rain-on-grid boundary conditions for flood simulation in urban areas. The results can be used to conduct an appropriate future simulation of urban drainage planning

Analisis Geomorfologi Terhadap Bencana Banjir di Nagari Taram Kecamatan Harau

The purpose this research is to analyze the flood disaster in Nagari Taram Kecamatan Harau using a geomorphological approach. Data colllection techiques wiith map analysis, interview field observation as supporting data. The analysis technique used is descriptive quntitative with map overlay and scoring. The result showed that (1) the type of flood that occurred in Nagari Taram was the river overflow with the type of inundation for days. Flood disaster occues once a year in Nagari Taram. (2) The index of flood hazard in Nagari Taram is categorized as medium with an area of 2760.2 Ha. (3) Nagari Taram is a lowland and hilly area that has a varied topography, namely flat, hilly, undulating and has an altitude of 500 mdpl-1500 mdpl. The slopes in Nagari Taram are dominated by flat slopes ranging from 0-8% with an area of 1464.4 Ha. Keywords : geomorphological, Flood Disaster

Not All Rivers Are Created Equal: The Importance of Spring-Fed Rivers under a Changing Climate

In the Western United States, volcanic spring-fed rivers are anticipated to become increasingly more important for salmonids and other native fishes, as these rivers will retain coldwater habitats as the climate warms. Despite this, little is known about the hydro-biogeochemical interactions within these ecosystems. A review of existing literature on spring-fed rivers, coupled with a decade of research on volcanic spring-fed rivers of northern California, finds that these systems are exceptionally productive and exhibit stable environmental conditions. These unique conditions stem from hydrogeologic processes typical of young volcanic terrains. Aquatic macrophytes, common to some nutrient-rich spring-fed systems, play a disproportionate role in hydrologic and geomorphic processes by facilitating ecological interactions and velocity conditions that improve juvenile salmonid growth. We find that volcanic spring-fed rivers are also resilient to climate change, due not only to their ability to dampen water temperature changes through deep groundwater flow but also because of their nutrient-driven high ecosystem productivity, which may enable coldwater species to metabolically compensate for marginal increases in water temperature. Understanding the fundamental geomorphic and ecological differences between these rare ecosystems and their numerically dominant runoff rivers is essential for developing long-term conservation strategies for coldwater species under a rapidly changing climate.

DEVELOPMENT OF AGRIBUSINESS PLACES ON PALU RIVERSIDES

Agribusiness may potentially develop on Palu Riversides. This research aims to formulate a sustainable agricultural spatial innovation for the Development of Agribusiness Places on Palu Riversides. The methods used for this study were field observation, satellite image map observation, and literature review. The results showed that the implementation of sustainable agriculture through the development of agribusiness places in urban areas could take advantage of the open spaces designated as green open space zone on the Palu Riversides, namely the River Green Area which is outside the riparian zone, the river overflow runoff area. To achieve this objective, it requires ability to innovate in spatial planning so that an urban agricultural area that is neatly arranged into an agribusiness places can also be developed into one of the city landmark.

Establishment of plant residues and inorganic fertilizer application for growth and yield of Vigna unguiculata (L.) in flood-affected cropland of Koshi Tappu Region, Eastern Nepal

Flood increases due to an increase in river overflow which affects on abiotic and biotic factors. The preliminary study of flood-affected crops was carried out in flood-affected cropland of Koshi Tappu Region of Eastern Nepal. For the experiment the plant residues of Eichhornia crassipes and Sesbania rostrata and inorganic fertilizer were selected to examine the growth and yield in Vigna unguiculata. The appropriate treatments for the production of V. unguiculata were analyzed. Before applying treatments, soil was collected and analyzed for physicochemical, microbial biomass and available nitrogen. Soil texture, soil moisture, water holding capacity and bulk density (BD) were calculated. The parameters such as soil pH organic carbon, organic matter and total nitrogen were determined. Soil microbe increases the significance of organic carbon and soil nitrogen is correlated for growth and yield. The results showed that the combined urea and plant residue increases the highest yield. And the Eichhornia compost represents the highest leaf area index and biomass. The total pod production was found in the Echhhornia compost. The dry weight per single pod in Eichhornia fresh was 7.82 g and in Sesbania fresh was 7.42 g. It proves that the land pattern is significant for the soil organic compounds. The experiment showed that the use of plant residues enhanced the increase of physicochemical properties of soil by adding the nutrients. The combined Urea + Eichhornia supports the best growth and development of the plant. DOI: http://dx.doi.org/10.5281/zenodo.4338159

A Participatory Assessment of the Impact of Flooding in Some Communities in Lokoja, Kogi State, Nigeria

The frequency and consequences of extreme flood events have increased in recent times, having huge impact on the socio-economic well-being of nations with the most significant impact being felt at the community level. Flooding is the most common environmental hazard in Nigeria, particularly Lokoja, with the frequency, intensity, and extent likely to increase due to the effects of global warming leading to climate change such as sea level rise, more intensive precipitation levels, and higher river discharges. While destructive impacts of flood events continue to increase, flood managers in Nigeria have continued to implement a top-down approach towards mitigating these impacts, without involving affected communities in planning and implementation of mitigation strategies. This study therefore employed a participatory approach to determine the causes and impact of flooding in the study area. Participatory research tools such as key informant interviews, focus group discussions, and questionnaire surveys using the purposive sampling method were deployed to elicit data on the perception of the communities about the causes and impact of flood events. Descriptive statistical analysis was performed to elucidate the major causes and areas of impact while qualitative analysis was carried out to corroborate the results and to make for a robust outcome. The Chi Square Test analysis was performed to empirically establish a relationship between the impacts and flooding. Results show that major causes of flooding are the release of water from dams (83% in Adankolo, 97% in Gadumo, and 100% in Ganaja), overflow of rivers, and heavy rainfall while flooding affects economic concerns, property and basic amenities. The Chi Square Test analysis determined empirically that a relationship exists between several areas of impact and flood occurrence. The research concludes that participatory flood research approach can provide flood managers and decision makers a bottom-up approach for effective and robust flood mitigation strategies.