scholarly journals Improving Flood Maps in Ungauged Fluvial Basins with Dendrogeomorphological Data. An Example from the Caldera de Taburiente National Park (Canary Islands, Spain)

Geosciences ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 300 ◽  
Author(s):  
Julio Garrote ◽  
Andrés Díez-Herrero ◽  
Mar Génova ◽  
José Bodoque ◽  
María Perucha ◽  
...  
Keyword(s):  
Canary Islands ◽  
National Park ◽  
Drainage Basin ◽  
Flash Flood ◽  
Flood Hazard ◽  
Significant Risk ◽  
Flood Hazards ◽  
Flow Data ◽  
Data Set ◽  
La Palma

Flash floods represent one of the more usual natural hazards in mountain basins, and, combined with the lack of reliable flow data and the recreational use of the drainage basin by tourists and hikers, there is a significant risk of catastrophe. Here, we present a dendro-geomorphological reconstruction of a past flash flood event in the Caldera de Taburiente N.P. (Canary Islands, Spain), an ungauged drainage basin in the SW side of the volcanic island of La Palma. We couple two-dimensional hydraulic modelling in a highly-resolved topographic environment (LiDAR data) with (1) peak flow data for various Tyear return periods from an uncalibrated hydrological model and (2) a data set of scars on trees, to investigate the magnitude of a 1997 dated flash-flood. From the results, flood hazards and associated risks would be clearly underestimated by using only the unique available hydrological data (a rainfall gauge station downstream of the study area). Hydraulic models using scars data show a higher flood hazard scenario, improving the flood hazard map by using all available flood evidence. Moreover, all this will allow for better implementation of appropriate adaptation policies by National Park managers, and therefore the mitigation of future disasters.

Geomorphic Modelling Application for Geospatial Flood Hazards and Flash Flood Thresholds Forecasting

2018 ◽  
pp. 285-303
Author(s):  
Berhanu F. Alemaw
Keyword(s):  
Drainage Basin ◽  
Flash Flood ◽  
Flood Hazard ◽  
Early Warning Systems ◽  
Flood Forecasting ◽  
Flood Frequency ◽  
Flood Hazards ◽  
Water Demands ◽  
Flooding Hazards ◽  
Flash Flood Guidance

In this chapter, a geomorphic modelling is presented and as a tool for geospatial flood hazard and flash flood thresholds forecasting in drainage basins. The flash flood thresholds have been estimated in terms of flash flood guidance values for the various tributary watersheds of a drainage basin considered. It has been demonstrated using the Limpopo drainage basin in southern Africa. This transboundary basin was chosen because of its importance to water supply for the growing population and water demands in its four riparian states. The basin is also subject to frequent flood and drought hazards. Even though, well established hydrological and flood frequency models do exist for flood forecasting, the purpose of this manuscript is to produce indicative flash flood guidance from a drainage basin of diverse regional development and intensive catchment land-use land cover dynamics by shading light on the geospatial portrayal of flood producing determinants. This will be important in lieu of the need for designing flood forecasting and flood early warning systems for this basin which is subject to frequent flooding hazards. Recommendations on flood forecasting and mitigation of flood hazards is provided considering the technical, human capital and institutional challenges that exist in this part of Africa.

scholarly journals Hydrodynamic characterization of past flash-flood events and their associated hazards from dendrogeomorphological evidence in Caldera de Taburiente National Park (Canary Islands, Spain)

2016 ◽  
Author(s):  
Julio Garrote ◽  
Andrés Diez-Herrero ◽  
José M. Bodoque ◽  
María A. Perucha ◽  
Pablo Mayer ◽  
...  
Keyword(s):  
Canary Islands ◽  
National Park ◽  
Single Channel ◽  
Flash Flood ◽  
Flood Hazard ◽  
Hazard Analysis ◽  
Flood Damage ◽  
Data Sources ◽  
Flood Events ◽  
River Bank

Abstract. Las Angustias river is an ungauged stream located in the Caldera de Taburiente National Park (La Palma, Canary Islands, Spain), where frequent intense flash-flood events occur, sometimes with fatal consequences (4 deaths, November 2001) and considerable financial implications (over 700 000 euros in recent years). The aim of this research is to analyse the flood hazard at the Playa de Taburiente, one of the most popular sites in this protected area, with more than 60 000 visitors per year. The use of classic data sources and hydrological or hydraulic modelling methods for flood hazard analysis has important limitations in this area because of incomplete precipitation and flow data information and low representative values of the statistical time series, which may lead to under- or over-estimated results. Alternative or complementary data sources and methods including palaeohydrological techniques can therefore be used here for flood hazard analysis. A detailed dendrogeomorphological study of the river system was carried out using Canarian pine trees located on the stream bed and river bank with external evidence of flash-flood damage, including scars and exposed roots. The preliminary results identify and date at least eight winter flood events between 1962–1963 and 2011–12. In spite of the uncertainties deriving from the incomplete precipitation data and the mobile alluvial riverbed, the models provide an estimate of past flood discharge magnitudes. E.g. for the 1997 flood event a 1235 m3 s-1 flood minimizes the RMSE over the disturbed tree sample; furthermore, this flow value clearly exceeds the return period considered and means a distinct behavioral change in this gorge, from a braided channel with emerged bars to a single channel occupying the whole river bed. These numerical results and maps could improve flood hazard and risk analysis and should be useful for the national park land use management and visitors planning.

scholarly journals Flood Hazard Management in Public Mountain Recreation Areas vs. Ungauged Fluvial Basins. Case Study of the Caldera de Taburiente National Park, Canary Islands (Spain)

Geosciences ◽  
2017 ◽  
Vol 8 (1) ◽  
pp. 6 ◽  
Author(s):  
Julio Garrote ◽  
Andrés Díez-Herrero ◽  
José Bodoque ◽  
María Perucha ◽  
Pablo Mayer ◽  
...  
Keyword(s):  
Canary Islands ◽  
National Park ◽  
Flood Hazard ◽  
Hazard Management ◽  
Recreation Areas ◽  
Flood Hazard Management

scholarly journals Mapping of GIS-Flood Hazard Using the Geomorphometric-Hazard Model: Case Study of the Al-Shamal Train Pathway in the City of Qurayyat, Kingdom of Saudi Arabia

Geosciences ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 333
Author(s):  
Ashraf Abdelkarim ◽  
Seham S. Al-Alola ◽  
Haya M. Alogayell ◽  
Soha A. Mohamed ◽  
Ibtesam I. Alkadi ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Drainage Basin ◽  
Flood Hazard ◽  
Hazard Model ◽  
Hazard Mapping ◽  
Flood Hazards ◽  
Drainage Basins ◽  
Kingdom Of Saudi Arabia ◽  
High Flood ◽  
The City

Drainage basins in dry and semiarid environments are exposed to sudden, irregular flooding that poses a threat to urban areas and infrastructure. The associated risk is exacerbated by land use changes. Geomorphometric analyses of drainage basins based on geographic information systems (GIS) are essential tools for assessing conceptual flood hazards. Geomorphological data extracted from high-precision digital elevation models (DEMs) provide valuable information for modeling the geomorphic, surface classifications of the earth, and for flood hazard mapping. This study aimed to develop an integrative approach to the mapping of flood hazards along the Al-Shamal train pathway in the city of Qurayyat in the Kingdom of Saudi Arabia (KSA) using GIS and hazard modeling for geomorphological ranking. Furthermore, we propose strategic solutions to provide mitigation and protection from negative impacts with the aim of improving the level of awareness of flood geomorphology. The hazard model of geomorphological ranking was used in mapping and calculating the degree of hazards using 24 geomorphometric criteria. These criteria were divided into formal criteria, terrain criteria, and criteria related to the drainage network. The results of the study revealed that the drainage sub-basins are exposed to flood hazards along the Al-Shamal train pathway in the city of Qurayyat. The very high flood hazard constituted 4228.3 km2, accounting for 70.3% and 65.7%, respectively, of the drainage basins of the wadis of Makhrouq and Bayer. The high flood hazard represented 61% (4712.4 km2) of the basin of the wadis of Sarmadaa. The medium flood hazard was concentrated in the drainage basin of the wadi of Hasidah, accounting for nearly 57.7% (1271.3 km2). The very low flood hazard was present in 46.5% of the drainage basin of the wadis of Hasidah Umm Nakhla, accounting for an area of 799.4 km2. The methodology applied in this study can be used in the estimation of flood hazards in different drainage basins throughout Saudi Arabia and in similar arid regions.

scholarly journals Flash Flood Hazard Using Optical, Radar, and Stereo-Pair Derived DEM: Eastern Desert, Egypt

2018 ◽  
Vol 10 (8) ◽  
pp. 1204 ◽  
Author(s):  
Jehan Mashaly ◽  
Eman Ghoneim
Keyword(s):  
Arid Regions ◽  
Hydrological Modeling ◽  
Flash Flood ◽  
Flood Hazard ◽  
Meteorological Data ◽  
Eastern Desert ◽  
Stereo Pair ◽  
Flood Hazards ◽  
Storm Events ◽  
Alos Palsar

Flash floods are classified among the Earth’s most deadly and destructive natural hazards, particularly in arid regions. Wadi El-Ambagi, one of the largest drainage basins in the Eastern Desert of Egypt, is frequently subjected to severe flash flood damage following intense, short-lived rainstorms. This wadi is home to one of the few road networks which connects the Nile River Valley to the Red Sea Coast. At its outlet lies Quseir, one of the major coastal towns in the area. Quseir is a developing tourism and scuba diving town, and is known for its historical importance as an ancient port; thus, efforts are in place to preserve the town’s heritage. The lack of hydrological and meteorological data in this region necessitates the use of a hydrological modeling approach to predict the spatial extent, depth, and velocity of the flood waters, and hence locate sites at risk of flood inundation. This was accomplished by understanding the characteristics of surface runoff through modeled hydrographs. Here, elevation data were extracted from Shuttle Radar Topography Mission (SRTM) and a two-meter digital elevation model (DEM) derived from WorldView-2 stereo pair imagery. The land use/land cover and soil properties were mapped from fused ASTER multispectral and ALOS-PALSAR Synthetic Aperture Radar (SAR) data to produce a hybrid image that combines spectral properties and surface roughness, respectively. The results showed that storm events with rainfall intensities of 30 mm and ~60 mm over a two-hour period would generate maximum peak flows of 165 m3 s−1 and 875 m3 s−1 , respectively. The latter peak flow would generate floods with depths of up to 2 m within the town of Quseir. A flood of this magnitude would inundate 217 buildings, 7 km of the highway, and 1.43 km of the railroad in the downstream area of Wadi El-Ambagi. Findings from this work indicate that the integration of remote sensing and hydrological modeling can be a practical and quick approach to predict flash flood hazards in arid regions where data are scarce.

Flood hazard in Hungary: a re-assessment

2010 ◽  
Vol 2 (4) ◽  
Author(s):  
Dénes Lóczy
Keyword(s):  
River Flow ◽  
Flash Flood ◽  
Flood Hazard ◽  
Flood Hazards ◽  
Rainfall Events ◽  
Groundwater Levels ◽  
Excess Water ◽  
Water Hazard ◽  
Map Series ◽  
The 19Th Century

AbstractSome decades ago the concept of flood hazard in the Carpathian Basin was interpreted solely as riverine flood hazard, mostly restricted to the Tisza and Danube Rivers, and was closely associated with the impacts of river flow regulation in the second half of the 19th century. Recent assessments, however, allow us to outline a more diverse picture. Climate change is predicted to bring about both an increase in the frequency of droughts and excessive rainfall events, resulting in irregulaties in the water regimes of rivers in Hungary. Excess water hazard from raised groundwater levels is found to affect much larger areas than previously thought. Recent strongly localized cloudbursts, point to the increasing significance of flash floods.Riverine flooding and excess water hazard are more common in lowlands, whereas flash flood hazards are primarily, but not exclusively, affect the mountainous and hilly regions of the country. This paper intends to assess the relative importance of the three types of inundation hazard analyzed and to illustrate their overall spatial occurrences by microregions on a map series.

scholarly journals Surface water floods in Switzerland: what insurance claim records tell us about the damage in space and time

2017 ◽  
Vol 17 (9) ◽  
pp. 1659-1682 ◽  
Author(s):  
Daniel B. Bernet ◽  
Volker Prasuhn ◽  
Rolf Weingartner
Keyword(s):  
Surface Water ◽  
Flood Hazard ◽  
Geographical Location ◽  
Flood Damage ◽  
Flood Hazards ◽  
Data Set ◽  
Space And Time ◽  
Alpine Regions ◽  
Spatial And Temporal Distributions ◽  
Almost All

Abstract. Surface water floods (SWFs) have received increasing attention in the recent years. Nevertheless, we still know relatively little about where, when and why such floods occur and cause damage, largely due to a lack of data but to some degree also because of terminological ambiguities. Therefore, in a preparatory step, we summarize related terms and identify the need for unequivocal terminology across disciplines and international boundaries in order to bring the science together. Thereafter, we introduce a large (n = 63 117), long (10–33 years) and representative (48 % of all Swiss buildings covered) data set of spatially explicit Swiss insurance flood claims. Based on registered flood damage to buildings, the main aims of this study are twofold: First, we introduce a method to differentiate damage caused by SWFs and fluvial floods based on the geographical location of each damaged object in relation to flood hazard maps and the hydrological network. Second, we analyze the data with respect to their spatial and temporal distributions aimed at quantitatively answering the fundamental questions of how relevant SWF damage really is, as well as where and when it occurs in space and time. This study reveals that SWFs are responsible for at least 45 % of the flood damage to buildings and 23 % of the associated direct tangible losses, whereas lower losses per claim are responsible for the lower loss share. The Swiss lowlands are affected more heavily by SWFs than the alpine regions. At the same time, the results show that the damage claims and associated losses are not evenly distributed within each region either. Damage caused by SWFs occurs by far most frequently in summer in almost all regions. The normalized SWF damage of all regions shows no significant upward trend between 1993 and 2013. We conclude that SWFs are in fact a highly relevant process in Switzerland that should receive similar attention like fluvial flood hazards. Moreover, as SWF damage almost always coincides with fluvial flood damage, we suggest considering SWFs, like fluvial floods, as integrated processes of our catchments.

scholarly journals Geomorphology-based index for detecting minimal flood stages in arid alluvial streams

2013 ◽  
Vol 17 (3) ◽  
pp. 1021-1034 ◽  
Author(s):  
E. Shamir ◽  
L. Ben-Moshe ◽  
A. Ronen ◽  
T. Grodek ◽  
Y. Enzel ◽  
...  
Keyword(s):  
Drainage Basin ◽  
Flash Flood ◽  
Flood Hazard ◽  
Ephemeral Streams ◽  
Arid Environments ◽  
Cross Sectional ◽  
Flood Warning ◽  
Extensive Field ◽  
Alluvial Streams ◽  
Flood Warning Systems

Abstract. Identification of a geomorphic index to represent lower thresholds for minor flows in ephemeral, alluvial streams in arid environments is an essential step as a precursor for reliable flash flood hazard estimations and establishing flood warning systems. An index, termed Alluvial wadi Flood Incipient Geomorphologic Index (AFIG), is presented. Analysis of data from an extensive field survey in the arid ephemeral streams in southern and eastern Israel was conducted to investigate the AFIG and the control over its value across the region. During the survey we identified distinguishable flow marks in the lower parts of streams' banks, such as niches, vegetation line, and change in bank material, which are indicative of low flows. The cross-sectional characteristics of the AFIG were studied in relationship with contributing drainage basin characteristics such as lithology, topography, and precipitation. Drainage area and hardness of the exposed lithology (presented as a basin-wide index) are the preferred descriptors to be used in estimating a specific AFIG in unsurveyed sites. Analyses of discharge records from seven hydrometric stations indicate that the recurrence interval of the determined AFIG is equal to or more frequent than 0.5 yr.

scholarly journals Geomorphology-based index for detecting minimal flood stages in arid alluvial streams

2012 ◽  
Vol 9 (11) ◽  
pp. 12357-12394 ◽  
Author(s):  
E. Shamir ◽  
L. Ben-Moshe ◽  
A. Ronen ◽  
T. Grodek ◽  
Y. Enzel ◽  
...  
Keyword(s):  
Drainage Basin ◽  
Flash Flood ◽  
Flood Hazard ◽  
Ephemeral Streams ◽  
Arid Environments ◽  
Cross Sectional ◽  
Flood Warning ◽  
Extensive Field ◽  
Alluvial Streams ◽  
Flood Warning Systems

Abstract. Identification of a geomorphic index to represent lower thresholds for minor flows in ephemeral, alluvial streams in arid environments is an essential step in reliable flash flood hazard estimations and establishing flood warning systems. An index, termed Alluvial wadi Flood Incipient Geomorphologic Index (AFIG), is presented. Analysis of data from an extensive field survey in the arid ephemeral streams in Southern and Eastern Israel was conducted to investigate the AFIG and the control over its value across the region. During the survey we identified distinguishable flow marks in the lower parts of streams' banks, such as niches, vegetation line, and change in bank material, which are indicative of low flows. The cross-sectional characteristics of the AFIG were studied in relationship with contributing drainage basin characteristics such as lithology, topography, and precipitation. Drainage area and hardness of the exposed lithology (presented as a basin-wide index) are the preferred descriptors to be used in estimating a specific AFIG in un-surveyed sites. Analyses of discharge records from seven hydrometric stations indicate that the recurrence interval of the determined AFIG is equal to or more frequent than 0.5 yr.

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