scholarly journals Classification of Karst Springs For Flash Flood-Prone Areas in Western Turkey

2016 ◽  
Author(s):  
M. Demiroglu

Abstract. Flash floods are the result of very intensive rainfall events and karst plays an important role in flash floods. A study, using a hydrogeochemical approach, assessing data from several springs of different carbonate rocks in Western Turkey was made to classify karst aquifers' response to heavy rain events. Physicochemical measurements in wet and dry seasons and discharge rates were compared in order to explain aquifer characteristics. The groundwaters have pH values ranging from 6.3 to 8.9, temperatures (T) vary from 7 to 35 °C, and electrical conductivity (EC) values go from 140 to 998 μS cm/S. The groups that have high EC, high T, and low dissolved oxygen (DO) values represent the deep circulating waters. Low EC, low T and high DO values represent the shallow circulating waters. Low variations of the measurements in both the wet and dry seasons reveal that fracture permeability is predominantly controlled by diffused groundwater flow with low or high storage and conduit permeability with high storage. High variations of the measurements show conduit permeability with low storage but high transfer capability is predominantly controlled by turbulent groundwater flow which effective in flash floods.

2016 ◽  
Vol 16 (6) ◽  
pp. 1473-1486 ◽  
Author(s):  
Muhterem Demiroglu

Abstract. Flash floods are caused by heavy rainfall that has become more frequent. They are more prominent in low-storage karst regions, although karst terrain often acts as a natural flood control particularly when it is bare and dominated by conduits. A study using a hydrogeochemical approach and assessing data from several springs in different carbonate rock in western Turkey has made it possible to classify karst aquifers based on their response to heavy rainfall events. According to this aim, physico-chemical measurements in wet and dry seasons and discharge rates in springs are compared in order to explain aquifer characteristics. Groundwater samples have a pH ranging from 6.3 to 8.9, temperature (T) varying from 7 to 35 °C and electrical conductivity (EC) ranging from 140 to 998 µs cm−1. Groundwater samples with high EC, high T and low dissolved oxygen (DO) represent the deep circulating water, while low EC, low T and high DO are linked to the shallow circulating water. Lower variability between wet and dry seasons reveals that fracture permeability is predominantly controlled by diffuse groundwater flow with low or high storage, and conduit permeability with high storage. However, variability of the physico-chemical characteristics is higher in a conduit permeability with low storage. These types of aquifers with high transfer capability, predominantly controlled by turbulent groundwater flow, affect flash floods.


2020 ◽  
Author(s):  
Takahiro Sayama ◽  
Masafumi Yamada ◽  
Yoshito Sugawara ◽  
Dai Yamazaki

Abstract The heavy rain event of July 2018 and Typhoon Hagibis in October 2019 caused severe flash flood disasters in numerous parts of western and eastern Japan. Flash floods need to be predicted over a wide range with long forecasting lead time for effective evacuation. The predictability of flash floods caused by the two extreme events are investigated by using a high-resolution (~150 m) nationwide distributed rainfall-runoff model forced by ensemble precipitation forecasts with 39-h lead time. Results of the deterministic simulation at nowcasting mode with radar and gauge composite rainfall could reasonably simulate the storm runoff hydrographs at many dam reservoirs over western Japan for the case of heavy rainfall in 2018 (F18) with the default parameter setting. For the case of Typhoon Hagibis in 2019 (T19), a similar performance was obtained by incorporating unsaturated flow effect in the model applied to Kanto region. The performance of the ensemble forecast was evaluated based on the bias ratios and the relative operating characteristic curves, which suggested the higher predictability in peak runoff for T19. For the F18, the uncertainty arises due to the difficulty in accurately forecasting the storm positions by the frontal zone; as a result, the actual distribution of the peak runoff could not be well forecasted. Overall, this study showed that the predictability of flash floods was different between the two extreme events. The ensemble spreads contain quantitative information of predictive uncertainty, which can be utilized for the decision making of emergency responses against flash floods.


2018 ◽  
Vol 2 (2) ◽  
pp. 73
Author(s):  
Fara Diva Claudia ◽  
Cecylia Putri Mawarni ◽  
Kadek Krisna Yulianti ◽  
Paulus Agus Winarso

<p class="Abstract">On October 10, 2018 there has been extreme weather in the form of heavy rain accompanied by lightning in Tanah Datar District, West Sumatra. This extreme weather caused flash floods and landslides that killed many people. Therefore, by using remote sensing data in the form of radar and satellite as well as WRF modeling (Weather Research and Forecasting) the authors conducted analysis of heavy rainfall events to determine the estimated rainfall and atmospheric dynamics during the occurrence of flash floods and landslides. WRF modeling is used to determine the condition of atmospheric lability. For the calculation of rainfall estimation, the method used is the Convective Stratiform Technique (CST) method that utilizes satellite data and the Z-R relation selection method that utilizes radar data. Then the calculation results from each method are verified using observation data. Relative bias shows the CST method and the selection of Z-R relations tend to be overestimate, but has a very high correlation value with observation data. Information on rainfall estimation and atmospheric dynamics is expected to be used to provide early warnings aimed at minimizing losses from the impact of disasters.</p>


2018 ◽  
Vol 229 ◽  
pp. 03002 ◽  
Author(s):  
Irfan Pramono ◽  
Endang Savitri

Flash flood often occurs in West Sumatera. In spite of heavy rain, flash floods are also caused by the landslide in the riverside that blocks the river as a natural dam. The natural dam can be broken at any time, depending on storage capacity. Flash flood occurs when the dam is broken. The aim of the research is to mitigate flash floods based on parameters influencing flood and landslide. The research was conducted in Arau watershed, West Sumatera. Parameters that have a direct proportion of floods are maximum daily rainfall, watershed shape, river gradient, drainage density, slope, and land cover. Parameters influencing landslides are antecedent soil moisture, slope, geologic type especially fault line, soil depth, and land cover. GIS is used to analyze the factors influencing flood and landslide spatially. The results show that more than 50% of the Arau watershed are slightly high and high vulnerability due to its natural condition. Furthermore, the locations of fault, especially in the riverside, should be noticed because this location could become a natural dam causing flash flood. In order to reduce flash flood impact, the natural dam should be opened as soon as possible.


2020 ◽  
Author(s):  
Takahiro Sayama ◽  
Masafumi Yamada ◽  
Yoshito Sugawara ◽  
Dai Yamazaki

Abstract The heavy rain event of July 2018 and Typhoon Hagibis in October 2019 caused severe flash flood disasters in numerous parts of western and eastern Japan. Flash floods need to be predicted over a wide range with long forecasting lead time for effective evacuation. The predictability of flash floods caused by the two extreme events are investigated by using a high-resolution (~ 150 m) nationwide distributed rainfall-runoff model forced by ensemble precipitation forecasts with 39-h lead time. Results of the deterministic simulation at nowcasting mode with radar and gauge composite rainfall could reasonably simulate the storm runoff hydrographs at many dam reservoirs over western Japan for the case of heavy rainfall in 2018 (F18) with the default parameter setting. For the case of Typhoon Hagibis in 2019 (T19), a similar performance was obtained by incorporating unsaturated flow effect in the model applied to Kanto region. The performance of the ensemble forecast was evaluated based on the bias scores and the relative operating characteristic curves, which suggested the higher predictability in peak runoff for T19. For the F18, the uncertainty arises due to the difficulty in accurately forecasting the storm positions by the frontal zone; as a result, the actual distribution of the peak runoff could not be well forecasted. Overall, this study showed that the predictability of flash floods was different between the two extreme events. The ensemble spreads contain quantitative information of predictive uncertainty, which can be utilized for the decision making of emergency responses against flash floods.


2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Takahiro Sayama ◽  
Masafumi Yamada ◽  
Yoshito Sugawara ◽  
Dai Yamazaki

AbstractThe heavy rain event of July 2018 and Typhoon Hagibis in October 2019 caused severe flash flood disasters in numerous parts of western and eastern Japan. Flash floods need to be predicted over a wide range with long forecasting lead time for effective evacuation. The predictability of flash floods caused by the two extreme events is investigated by using a high-resolution (~ 150 m) nationwide distributed rainfall-runoff model forced by ensemble precipitation forecasts with 39 h lead time. Results of the deterministic simulation at nowcasting mode with radar and gauge composite rainfall could reasonably simulate the storm runoff hydrographs at many dam reservoirs over western Japan for the case of heavy rainfall in 2018 (F18) with the default parameter setting. For the case of Typhoon Hagibis in 2019 (T19), a similar performance was obtained by incorporating unsaturated flow effect in the model applied to Kanto Region. The performance of the ensemble forecast was evaluated based on the bias ratios and the relative operating characteristic curves, which suggested the higher predictability in peak runoff for T19. For the F18, the uncertainty arises due to the difficulty in accurately forecasting the storm positions by the frontal zone; as a result, the actual distribution of the peak runoff could not be well forecasted. Overall, this study showed that the predictability of flash floods was different between the two extreme events. The ensemble spreads contain quantitative information of predictive uncertainty, which can be utilized for the decision making of emergency responses against flash floods.


2019 ◽  
Vol 21 (2) ◽  
pp. 467-476
Author(s):  
Wanessa Janinne Eloy Da Silva ◽  
Maressa Oliveira Lopes Araújo ◽  
Marcelo De Oliveira Moura

O presente trabalho tem por objetivo analisar a distribuição espaço-temporal dos reconhecimentos de Situação de Emergência associados à dinâmica hidrometeorológica na microrregião pluviometricamente homogênea do Litoral paraibano, durante o período de 2003 a 2016. Para isso, foram utilizados dados adquiridos no site do Ministério da Integração Nacional, encontrados na página da Secretaria Nacional de Proteção e Defesa Civil, conforme reconhecimentos disponibilizados através de portarias. Como resultados principais, constatou-se um total de 29 reconhecimentos, em que 51,7% corresponde a enchentes; 20,7% a chuvas intensas; 24,2% correspondente a enxurradas e 3,4% a inundações. Considera-se que os resultados obtidos tiveram um cunho mais descritivo, necessitando assim de estudos mais avançados sobre a temática.Palavras chave: Litoral Paraibano, desastres hidrometeorológicos, situação de emergência. ABSTRACTThe present work has for objective analyze the space-temporal distribution of the emergency situations recognizements associated to the hydrometeorological dynamic on the pluviometrically homogenius microregion of the coast of Paraíba, during the period of 2003 to 2016. For that, data were used acquired from the Ministério da Integração Nacional’s site, found on the Secretaria Nacional de Proteção e Defesa Civil’s page, conform available recognizements through ordinances. As main results, a total of 29 recognizements were found, in which 51,7% corresponds to floods; 20,7% to heavy rain; 24,2% corresponding to flash flood and 3,4% to inundations. It’s considered that the obtained results have a descriptive label, needing then advanced studies about the theme.Keywords: Coast of Paraiba, hydrometeorlogical disasters, emergency situations. RESUMENEste documento tiene como objetivo analizar la distribución espacio-temporal de los reconocimientos de situaciones de emergencia com la dinâmica hidrometeorológica em la microrregión de lluvia homogénea de la costa paraibana, de 2003 a 2016. Para este propósito, se utilizaron los datos adquiridos del sitio web del Ministerio de Salud. Integración nacional, que se encuentra en la página de la Secretaría Nacional de Protección y Defensa Civil, como agradecimientos disponibles a través de ordenanzas. Como resultados principales, hubo un total de 29 reconocimientos, de los cuales el 51.7% correspondió a inundaciones; 20.7% a fuertes lluvias; 24.2% correspondientes a enxurradas y 3.4% a inundaciones. Se considera que los resultados obtenidos tuvieron una naturaleza más descriptiva, por lo que requirieron estúdios más avanzados sobre el tema.Palabras clave: Costa de Paraiba, desastres hidrometeorológicos, situación de emergencia.


2021 ◽  
Vol 13 (9) ◽  
pp. 1818
Author(s):  
Lisha Ding ◽  
Lei Ma ◽  
Longguo Li ◽  
Chao Liu ◽  
Naiwen Li ◽  
...  

Flash floods are among the most dangerous natural disasters. As climate change and urbanization advance, an increasing number of people are at risk of flash floods. The application of remote sensing and geographic information system (GIS) technologies in the study of flash floods has increased significantly over the last 20 years. In this paper, more than 200 articles published in the last 20 years are summarized and analyzed. First, a visualization analysis of the literature is performed, including a keyword co-occurrence analysis, time zone chart analysis, keyword burst analysis, and literature co-citation analysis. Then, the application of remote sensing and GIS technologies to flash flood disasters is analyzed in terms of aspects such as flash flood forecasting, flash flood disaster impact assessments, flash flood susceptibility analyses, flash flood risk assessments, and the identification of flash flood disaster risk areas. Finally, the current research status is summarized, and the orientation of future research is also discussed.


2020 ◽  
Vol 24 (4) ◽  
pp. 639-643
Author(s):  
M.M. Ogunbambo

Smoke-drying Clarias gariepinus (catfish) provides animal protein and a source of livelihood in Lagos, Nigeria. Changes occurring to seasonal and mineral compositions of smoke-dried catfish using local Traditional Drum Kiln (TDK) and a newly constructed Eco-Friendly Kiln (EFK) fitted with a flame, drying and electronic components was carried out in this study. The smoke-drying process was carried out in both wet and dry seasons and smoke-dried catfish samples stored at ambient and adjusted refrigerated temperatures of 28 and 4 0C. The smoke-drying procedure was  standardized at 60 - 80 0C and kiln lasted 24 ± 3 hours. Moisture content results showed a significant difference when the catfish samples were smoke-dried using TDK and EFK and stored in ambient and controlled temperatures in both wet and dry seasons while crude protein, lipid, ash and crude fibre values were significantly different when stored only in dry season. Mineral elements phosphorus, sodium, copper, magnesium and iron showed a significant difference when stored at both temperatures and seasons using both kilns. Mineral elements were found to be most stable in smoke-dried catfish samples when stored at controlled temperatures. This work proved that standardizing smoke-drying process using both kilns resulted in good quality smoke-dried catfish but showed that higher biochemical values were obtained when EFK is used. Key words: Nigeria, Smoke-drying Kilns, Seasons, Ambient, Controlled Temperatures


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