scholarly journals Innovative Monitoring Techniques for Wadi Flash Flood by Using Image-Based Analysis

2021 ◽  
pp. 251-266
Author(s):  
Mahmood M. Al-Mamari ◽  
Sameh A. Kantoush ◽  
Tetsuya Sumi
Keyword(s):  
Water Resource Management ◽  
Flood Control ◽  
Large Scale ◽  
High Efficiency ◽  
Flash Flood ◽  
Flash Floods ◽  
Scale Particle ◽  
Bridge Crossing ◽  
Sectional Profile ◽  
Elevation Model

AbstractFlash 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 flash floods in wadi channels by using two different methods. In the first section, we employed photogrammetry processing technique to quantify post-peak flood discharges by using a drone survey to build a digital elevation model (DEM) with a high resolution and calibrated and validated the model with a field survey (levelling measurements). This technique used drone-collected images to construct a DEM for extracting a cross-sectional profile and elevation points to calculate the peak discharge using the slope-area method with the Manning equation. In the second section, we combined the previous technique with the large-scale particle image velocimetry (LSPIV) technique to measure flash flood discharge by installing a fixed camera on a road bridge crossing a wadi channel and using a digitally extracted cross section from the DEM in the analysis. The results of those techniques show a high efficiency that is equivalent to that of conventional methods.

scholarly journals Real-Time Measurement of Flash-Flood in a Wadi Area by LSPIV and STIV

Hydrology ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. 27 ◽  
Author(s):  
Mahmood Al-mamari ◽  
Sameh Kantoush ◽  
Sohei Kobayashi ◽  
Tetsuya Sumi ◽  
Mohamed Saber
Keyword(s):  
Large Scale ◽  
Flash Flood ◽  
Early Warning Systems ◽  
Flash Floods ◽  
Surface Flow ◽  
Unidirectional Flow ◽  
Real Time Measurement ◽  
Positive Performance ◽  
Image Velocimetry ◽  
Scale Particle

Flash floods in wadi systems discharge large volumes of water to either the sea or the desert areas after high-intensity rainfall events. Recently, wadi flash floods have frequently occurred in arid regions and caused damage to roads, houses, and properties. Therefore, monitoring and quantifying these events by accurately measuring wadi discharge has become important for the installation of mitigation structures and early warning systems. In this study, image-based methods were used to measure surface flow velocities during a wadi flash flood in 2018 to test the usefulness of large-scale particle image velocimetry (LSPIV) and space–time image velocimetry (STIV) techniques for the estimation of wadi discharge. The results, which indicated the positive performance of the image-based methods, strengthened our hypothesis that the application of LSPIV and STIV techniques is appropriate for the analysis of wadi flash flood velocities. STIV is suitable for unidirectional flow velocity and LSPIV is reliable and stable for two-dimensional measurement along the wadi channel, the direction of flow pattern which varies with time.

Food Submergence Calculation and Analysis Using Digital Elevation Model and Geographical Information System

2014 ◽  
Vol 571-572 ◽  
pp. 792-795
Author(s):  
Xiao Qing Zhang ◽  
Kun Hua Wu
Keyword(s):  
Information System ◽  
Digital Elevation Model ◽  
Flood Control ◽  
Large Scale ◽  
Geographical Information ◽  
Economic Losses ◽  
Model Data ◽  
Digital Elevation ◽  
Elevation Model ◽  
Digital Elevation Model Data

Floods usually cause large-scale loss of human life and wide spread damage to properties. Determining flood zone is the core of flood damage assessment and flood control decision. The aim of this paper is to delineate the flood inundation area and estimate economic losses arising from flood using the digital elevation model data and geographic information system techniques. Flood extent estimation showed that digital elevation model data is very precious to model inundation, however, in order to be spatially explicit flood model, high resolution DEM is necessary. Finally, Analyses for the submergence area calculation accuracy.

scholarly journals Flash Flood warning in context: combining local knowledge and large-scale hydro-meteorological patterns

2021 ◽  
Author(s):  
Agathe Bucherie ◽  
Micha Werner ◽  
Marc van den Homberg ◽  
Simon Tembo
Keyword(s):  
Local Knowledge ◽  
Large Scale ◽  
Flash Flood ◽  
Scientific Information ◽  
Flash Floods ◽  
Scientific Data ◽  
Warning Signs ◽  
Local Context ◽  
Detailed Knowledge ◽  
Global Datasets

Abstract. The small spatial and temporal scales at which flash floods occur make predicting events challenging, particularly in data-poor environments where high-resolution weather models may not be available. Additionally, the uptake of warnings may be hampered by difficulties in translating the scientific information to the local context and experiences. Here we use social science methods to characterise local knowledge of flash flooding among vulnerable communities along the flat Lake Malawi shoreline in the district of Karonga, northern Malawi. This is then used to guide a scientific analysis of the factors that contribute to flash floods in the area using contemporary global datasets; including geomorphology, soil and land-use characteristics, and hydro- meteorological conditions. Our results show that communities interviewed have detailed knowledge of the impacts and drivers of flash floods (deforestation, sedimentation), early warning signs (changes in clouds, wind direction and rainfall patterns), and distinct hydro-meteorological processes that lead to flash flood events at the beginning and end of the wet season. Our analysis shows that the scientific data corroborates this knowledge, and that combining local and scientific knowledge provides improved understanding of flash flood processes within the local context. We highlight the potential in linking large-scale global datasets with local knowledge to improve the usability of flash flood warnings.

scholarly journals Application of an Automated Discharge Imaging System and LSPIV during Typhoon Events in Taiwan

2018 ◽  
Author(s):  
Wei-Che Huang ◽  
Chih-Chieh Young ◽  
Wen-Cheng Liu
Keyword(s):  
Large Scale ◽  
Imaging System ◽  
Flash Flood ◽  
Acoustic Doppler Current Profiler ◽  
Surface Velocity ◽  
Cross Section Area ◽  
Section Area ◽  
Image Velocimetry ◽  
Current Profiler ◽  
Scale Particle

An automated discharge imaging system (ADIS), a non-intrusive and safe approach, was developed for measuring river flows during flash flood events. ADIS consists of dual cameras to capture complete surface images in the near and far fields. Surface velocities are accurately measured using the Large Scale Particle Image Velocimetry (LSPIV) technique. The stream discharges are then obtained from the depth-averaged velocity (based upon an empirical velocity-index relationship) and cross-section area. The ADIS was deployed at the Yu-Feng gauging station in Shimen Reservoir upper catchment, northern Taiwan. For a rigorous validation, surface velocity measurements were conducted using ADIS/LSPIV and other instruments. In terms of the averaged surface velocity, all measured results were in good agreement with small differences, i.e., 0.004 to 0.39 m/s and 0.023 to 0.345 m/s when compared to those from acoustic Doppler current profiler (ADCP) and surface velocity radar (SVR), respectively. The ADIS/LSPIV was further applied to measure surface velocities and discharges during typhoon events (i.e., Chan-Hom, Soudelor, Goni, and Dujuan) in 2015. The measured water level and surface velocity both showed rapid increases due to flash floods. The estimated discharges from ADIS/LSPIV and ADCP were compared, presenting good consistency with correlation coefficient R = 0.996 and normalized root mean square error NRMSE = 7.96%. The results of sensitivity analysis indicate that components till (τ) and roll (θ) of the camera are most sensitive parameter to affect the surface velocity using ADIS/LSPIV. Overall, the ADIS based upon LSPIV technique effectively measures surface velocities for reliable estimations of river discharges during typhoon events.

scholarly journals An Operational Forecasting System for Flash Floods in Mountainous Areas in Taiwan

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2100 ◽  
Author(s):  
Yung-Ming Chen ◽  
Che-Hsin Liu ◽  
Hung-Ju Shih ◽  
Chih-Hsin Chang ◽  
Wei-Bo Chen ◽  
...  
Keyword(s):  
Flash Flood ◽  
Flash Floods ◽  
Water Levels ◽  
Airborne Lidar ◽  
Mountainous Areas ◽  
Flood Prediction ◽  
Mountainous Regions ◽  
Operational Forecasting ◽  
Forecasting System ◽  
Elevation Model

Flash floods are different from common floods because they occur rapidly over short time scales, and they are considered to be one of the most devastating natural hazards worldwide. Mountainous areas with high population densities are particularly threatened by flash floods because steep slopes generate high flow velocities. Therefore, there is a great need to develop an operational forecasting system (OFS) for better flash flood prediction and warning in mountainous regions. This study developed an OFS through the integration of meteorological, hydrological, and hydrodynamic models. Airborne light detection and ranging (LiDAR) data were used to generate a digital elevation model (DEM). The OFS employs high-density and high-accuracy airborne LiDAR DEM data to simulate rapid water level rises and flooding as the result of intense rainfall within relatively small watersheds. The water levels and flood extent derived from the OFS are in agreement with the measured and surveyed data. The OFS has been adopted by the National Science and Technology Center for Disaster Reduction (NCDR) for forecasting flash floods every six hours in a mountainous floodplain in Taiwan. The 1D and 2D visualization of the OFS is performed via the National Center for Atmospheric Research Command Language (NCL).

Determinants of Perception and Impact of Climate Change Induced Events on Livelihood of People in the Haor Area of Kishoreganj, Bangladesh

2021 ◽  
Vol 7 (4) ◽  
pp. 1-17
Author(s):  
Md. Azizul Baten ◽  
Md. Kabir Hossain
Keyword(s):  
Climate Change ◽  
Crop Production ◽  
Flood Control ◽  
Large Scale ◽  
Flash Flood ◽  
Sampling Technique ◽  
Cluster Sampling ◽  
Impact Of Climate Change ◽  
The People ◽  
The Impact

Bangladesh is prone to the danger of different natural calamities and is going to be most affected due to climate change-induced events in the upcoming decades. This study attempted to assess the farmers’ awareness, perception and the impact of climate change on the livelihood of people living in the Haor area of Kishoregang, Bangladesh. A total of 230 respondents were interviewed in the study area (Khatkhal union) using the cluster sampling technique. Only 52.2% of farmers are found to be aware of climate change, 61.7% unaware and 47.8% did not know the consequences of rapid climate change. Climate change and the unavailability of flood control embankments are considered as the main reasons for flash floods. Due to the devastating flash flood that occurred in early April 2017; most of the farmers lost more than two-thirds of their standing crops. Flash flood has a large scale impact on soil degradation. As a consequence of these effects, crop production was observed to be reduced the following year. People from Khoishore village are affected by riverbank erosion while the people from Dalargaon village and Hasimpur village are severely affected by Riverbed fill up. Above 93%, people of three villages opined that there is a severe climate change impact on pisciculture, biodiversity and cultivable land.

The Potential of Photoelectrochemical Carbon Sinks

2018 ◽  
Author(s):  
Matthias May ◽  
Kira Rehfeld
Keyword(s):  
Global Warming ◽  
High Temperature ◽  
Greenhouse Gas ◽  
Large Scale ◽  
High Efficiency ◽  
Carbon Sink ◽  
Solar Fuels ◽  
Negative Emissions ◽  
Viable Approach ◽  
Low Sensitivity

Greenhouse gas emissions must be cut to limit global warming to 1.5-2C above preindustrial levels. Yet the rate of decarbonisation is currently too low to achieve this. Policy-relevant scenarios therefore rely on the permanent removal of CO<sub>2</sub> from the atmosphere. However, none of the envisaged technologies has demonstrated scalability to the decarbonization targets for the year 2050. In this analysis, we show that artificial photosynthesis for CO<sub>2</sub> reduction may deliver an efficient large-scale carbon sink. This technology is mainly developed towards solar fuels and its potential for negative emissions has been largely overlooked. With high efficiency and low sensitivity to high temperature and illumination conditions, it could, if developed towards a mature technology, present a viable approach to fill the gap in the negative emissions budget.<br>

The Potential of Photoelectrochemical Carbon Sinks

2018 ◽  
Author(s):  
Matthias May ◽  
Kira Rehfeld
Keyword(s):  
Global Warming ◽  
High Temperature ◽  
Greenhouse Gas ◽  
Large Scale ◽  
High Efficiency ◽  
Carbon Sink ◽  
Solar Fuels ◽  
Negative Emissions ◽  
Viable Approach ◽  
Low Sensitivity

Greenhouse gas emissions must be cut to limit global warming to 1.5-2C above preindustrial levels. Yet the rate of decarbonisation is currently too low to achieve this. Policy-relevant scenarios therefore rely on the permanent removal of CO<sub>2</sub> from the atmosphere. However, none of the envisaged technologies has demonstrated scalability to the decarbonization targets for the year 2050. In this analysis, we show that artificial photosynthesis for CO<sub>2</sub> reduction may deliver an efficient large-scale carbon sink. This technology is mainly developed towards solar fuels and its potential for negative emissions has been largely overlooked. With high efficiency and low sensitivity to high temperature and illumination conditions, it could, if developed towards a mature technology, present a viable approach to fill the gap in the negative emissions budget.<br>

Peculiarities of the phytosanitary state of pome fruits in industrial horticulture

2020 ◽  
Vol 60 (1) ◽  
pp. 159-168
Author(s):  
V. V. Antonenko ◽  
A. V. Zubkov ◽  
S. N. Kruchina
Keyword(s):  
Mechanism Of Action ◽  
Large Scale ◽  
High Efficiency ◽  
Fruit Trees ◽  
Fruit Crops ◽  
Planting Material ◽  
Relative Safety ◽  
Pome Fruits ◽  
Weed Plants ◽  
Spread Of Infection

Data were obtained on the basis of the results of research carried out on the territory of the educational and experimental farm of the Timiryazev State Agrarian University, in Moscow during 2018-2019. As a result of the surveys, the most dangerous diseases and pests of pome crops on the territory of this farm were established. The most resistant apple and pear varieties to major diseases have been identified. Peculiarities of development of alternariosis on pear are described, the harmfulness of the disease on pear and apple seedlings is noted. A possible role in the transfer of alternariosis infection from garden-protective plantations and weed vegetation to fruit trees was noted. A possible role has been established in the transport of septoriosis, powdery dew infection from dicotyledonous weeds plants. The peculiarities of the spread of infection under the influence of wind direction are noted. The results and peculiarities of the application of various methods of scaring birds in the orchard are presented. As a result of route surveys the most harmful weed plants have been identified. The possibility of using herbicides of different mechanism of action in fruit gardens for weed control has been studied. High efficiency and relative safety of application of herbicides of contact action in nursery fields, operational orchards and for control of piglets on fruit trees are shown. Recommendations are given for the use of soil and systemic herbicides of soil in seedlings beds, the first and second fields of the nursery, as well as in the process of production of large-scale planting material and operational orchards of fruit crops. The safety of the herbicides in question is established when used in accordance with the recommended methods of use.

Sign in / Sign up

Export Citation Format

Share Document