scholarly journals A Flash Flood Early Warning System for Rural Kenya: A Pilot Study

2018 ◽  
Vol 7 (4.38) ◽  
pp. 810
Author(s):  
Prof. Dr. Ir Vinesh Thiruchelvam ◽  
Mbau Stella Nyambura

The cost of climate change has increased phenomenally in recent years. Therefore, understanding climate change and its impacts, that are likely to get worse and worse into the future, gives us the ability to predict scenarios and plan for them. Flash floods, which are a common result of climate change, follow increased precipitation which then increases risk and associated vulnerability due to the unpredictable rainfall patterns. Developing countries suffer grave consequences in the event that weather disasters strike because they have the least adaptive capacity. At the equator where the hot days are hotter and winds carrying rainfall move faster, Kenya’s Tana River County is noted for its vulnerability towards flash floods. Additionally, this county and others that are classified as rural areas in Kenya do not receive short term early warnings for floods. This county was therefore selected as the study area for its vulnerability. The aim of the study is therefore to propose a flash flood early warning system framework that delivers short term early warnings. Using questionnaires, information about the existing warning system will be collected and analyzed using SPSS. The results will be used to interpret the relationships between variables of the study, with a particular interest in the moderation effect in order to confirm that the existing system can be modified; that is, if the moderation effect is confirmed.   

2018 ◽  
Vol 7 (4.38) ◽  
pp. 1310
Author(s):  
Prof. Dr. Ir Vinesh Thiruchelvam ◽  
Mbau Stella Nyambura

The cost of climate change has increased phenomenally in recent years. Therefore, understanding climate change and its impacts, that are likely to get worse and worse into the future, gives us the ability to predict scenarios and plan for them. Flash floods, which are a common result of climate change, follow increased precipitation which then increases risk and associated vulnerability due to the unpredictable rainfall patterns. Developing countries suffer grave consequences in the event that weather disasters strike because they have the least adaptive capacity. At the equator where the hot days are hotter and winds carrying rainfall move faster, Kenya’s Tana River County is noted for its vulnerability towards flash floods. Additionally, this county and others that are classified as rural areas in Kenya do not receive short term early warnings for floods. This county was therefore selected as the study area for its vulnerability. The aim of the study is therefore to propose a flash flood early warning system framework that delivers short term early warnings. Using questionnaires, information about the existing warning system will be collected and analyzed using SPSS. The results will be used to interpret the relationships between variables of the study, with a particular interest in the moderation effect in order to confirm that the existing system can be modified; that is, if the moderation effect is confirmed.       


Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 426 ◽  
Author(s):  
Zhehao Li ◽  
Hongbo Zhang ◽  
Vijay Singh ◽  
Ruihong Yu ◽  
Shuqi Zhang

Under climate change, flash floods have become more frequent and severe, and are posing a danger to society, especially in the ungauged catchments. The objective of this paper, is to construct a simple and early warning system, serving for flash floods risk management in the ungauged catchments of the Loess Plateau in China, and offer a reference for flash flood warning in other areas in the world. Considering the absence of hydrological data in the ungauged catchments, the early warning system for flash floods is established by combining the regional or watershed isograms of hydrological parameters and local empirical formulas. Therein, rainfall and water stage/flow are used as warning indices for real-time risk estimation of flash flood. For early warning, the disaster water stage was first determined according to the protected objects (e.g., residents and buildings), namely the critical water stage. The critical flow (flow threshold), was calculated based on the water stage, and the established relationship between water stage and flow using the cross-sectional measured data. Then, according to the flow frequency curve of the design flood, the frequency of critical flow was ascertained. Assuming that the rainfall and the flood have the same frequency, the critical rainfall threshold was calculated through the design rainstorm with the same frequency of the design flood. Due to the critical rainfall threshold being sensitive with different soil conditions, the design flood and frequency curve of flood flow were calculated under different soil conditions, and thus the rainfall threshold was given under different soil condition for early warning of the flash flood disaster. Taking two sections in Zichang County (within the Loess Plateau) as an example, we set the rainfall and water stage/flow thresholds to trigger immediate or preparation signals for the migration of the population along the river. The application of this method to the 7.26 flood events in 2017 in China, shows that the early warning system is feasible. It is expected that this simple early warning system can provide early warnings of flash floods in ungauged catchments in the Loess Plateau and other similar areas.


2012 ◽  
Vol 12 (2) ◽  
pp. 443-457 ◽  
Author(s):  
J. Cools ◽  
P. Vanderkimpen ◽  
G. El Afandi ◽  
A. Abdelkhalek ◽  
S. Fockedey ◽  
...  

Abstract. An early warning system (EWS) for flash floods has been developed for part of the Sinai peninsula of Egypt, an hyper-arid area confronted with limited availability of field data, limited understanding of the response of the wadi to rainfall, and a lack of correspondence between rainfall data and observed flash flood events. This paper shows that an EWS is not a "mission impossible" when confronted with large technical and scientific uncertainties and limited data availability. Firstly, the EWS has been developed and tested based on the best available information, this being quantitative data (field measurements, simulations and remote sensing images) complemented with qualitative "expert opinion" and local stakeholders' knowledge. Secondly, a set of essential parameters has been identified to be estimated or measured under data-poor conditions. These are: (1) an inventory of past significant rainfall and flash flood events, (2) the spatial and temporal distribution of the rainfall events and (3) transmission and infiltration losses and (4) thresholds for issuing warnings. Over a period of 30 yr (1979–2010), only 20 significant rain events have been measured. Nine of these resulted in a flash flood. Five flash floods were caused by regional storms and four by local convective storms. The results for the 2010 flash flood show that 90% of the total rainfall volume was lost to infiltration and transmission losses. Finally, it is discussed that the effectiveness of an EWS is only partially determined by technological performance. A strong institutional capacity is equally important, especially skilled staff to operate and maintain the system and clear communication pathways and emergency procedures in case of an upcoming disaster.


2018 ◽  
Vol 92 (2) ◽  
pp. 619-634 ◽  
Author(s):  
Changjun Liu ◽  
Liang Guo ◽  
Lei Ye ◽  
Shunfu Zhang ◽  
Yanzeng Zhao ◽  
...  

2015 ◽  
Vol 62 (4) ◽  
pp. 493-510 ◽  
Author(s):  
Vesna Bucevska

The purpose of this paper is to develop an econometric model of early warning system (EWS) for predicting currency crises in EU candidate countries. Using actual quarterly panel data for three EU candidate countries (Croatia, Macedonia and Turkey) in the period January 2005 - June 2010, we estimate a binomial logit model, which accurately predicts potential episodes of outbreak of currency crisis. In addition, we find that real GDP growth rate, participation in an IMF loan program, current account and fiscal balance and short-term external indebtedness are the most significant common predictors of currency crises across EU candidate countries. These results imply implementing policy measures aimed at raising the growth potential of the domestic economies of EU candidate countries, monitoring their short-term external indebtedness, improving their external competitiveness, cutting public spending and increasing the confidence of residents and non-residents in their domestic banking sectors.


Author(s):  
P. Vanderkimpen ◽  
I. Rocabado ◽  
J. Cools ◽  
M. El-Sammany ◽  
A. Abdelkhalek

2018 ◽  
Vol 40 (2) ◽  
pp. 312-333
Author(s):  
Thach Ngoc Nguyen ◽  
Canh Xuan Pham ◽  
Huy Quoc Nguyen ◽  
Toan Ngo Bao Dang

2021 ◽  
pp. 209-223
Author(s):  
Ekkehard Holzbecher ◽  
Ahmed Hadidi ◽  
Nicolette Volp ◽  
Jeroen de Koning ◽  
Humaid Al Badi ◽  
...  

AbstractTechnologies concerning integrated water resources management, in general, and flood management, in particular, have recently undergone rapid developments. New smart technologies have been implemented in every relevant sector and include hydrological sensors, remote sensing, sensor networks, data integration, hydrodynamic simulation and visualization, decision support and early warning systems as well as the dissemination of information to decision-makers and the public. After providing a rough review of current developments, we demonstrate the operation of an advanced system with a special focus on an early warning system. Two case studies are covered in this chapter: one specific urban case located in the city of Parrametta in Australia in an area that shows similar flood characteristics to those found in arid or semiarid regions and one case regarding the countrywide Flash Flood Guidance System in Oman (OmanFFGS).


2016 ◽  
Author(s):  
Ke Zhang ◽  
Xianwu Xue ◽  
Yang Hong ◽  
Jonathan J. Gourley ◽  
Ning Lu ◽  
...  

Abstract. Severe storm-triggered floods and landslides are two major natural hazards in the U.S., causing property losses of $6 billion and approximately 110–160 fatalities per year nationwide. Moreover, floods and landslides often occur in a cascading manner, posing significant risk and leading to losses that are significantly greater than the sum of the losses from the individual hazards. It is pertinent to couple hydrological and geotechnical modelling processes toward an integrated flood-landslide cascading disaster early warning system for improved disaster preparedness and hazard management. In this study, we developed the iCRESTRIGRS model, a coupled flash flood and landslide disaster early warning system, by integrating the Coupled Routing and Excess STorage (CREST) model with the physically based Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability (TRIGRS) landslide model. The iCRESTRIGRS system is evaluated in four river basins in western North Carolina that experienced a large number of floods, landslides and debris flows, triggered by heavy rainfall from Hurricane Ivan during September 16–18, 2004. The modelled hourly hydrographs at four USGS gauge stations show generally good agreement with the observations during the entire storm period. In terms of landslide prediction in this case study, the coupled model has a global accuracy of 89.5 % and a true positive rate of 50.6 %. More importantly, it shows an improved predictive capability for landslides relative to the stand-alone TRIGRS model. This study highlights the important physical connection between rainfall, hydrological processes and slope stability, and provides a useful prototype system for operational forecasting of flood and landslide.


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