Dépouillements

Sungai Pahang digital flood mapping / Aminuddin Ab. Ghani in JRBM : International journal of river basin management, Vol. 10 N° 2 (Avril 2012) 

Public ISBD [article]  in JRBM : International journal of river basin management > Vol. 10 N° 2 (Avril 2012) . - pp. 139-148 Titre : Sungai Pahang digital flood mapping : 2007 flood Type de document : texte imprimé Auteurs : Aminuddin Ab. Ghani, Auteur ; Chun Kiat Chang, Auteur ; Cheng Siang Leow, Auteur Année de publication : 2012 Article en page(s) : pp. 139-148 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Flooding  Alluvial  river  Flood  mitigation  GIS  Sungai  pahang Résumé : In this study, visits to areas in the subcatchments of Sungai Pahang, including Mentakab, Temerloh, Maran and Pekan, were made throughout the year 2009 to obtain information regarding inundation areas, flood depth, flow discharge and water levels relevant to the 2007 flood. Interviews with local people were also made to ascertain the true picture of the 2007 flood. Analyses of rainfall data, water level, flow discharge and river cross-sectional changes were carried out from data gathering. The development of a digital elevation model (DEM) was made from a combination of digital topographical maps and satellite images which were purchased from Jabatan Ukur dan Pemetaan Malaysia. This visually enhanced DEM was then used for the development of the actual extent of the 2007 flood in the study area. Several options of flood mitigation works are proposed to reduce the impact of a similar flood in the future based on the developed DEM. ISSN : 1571-5124 En ligne : http://www.tandfonline.com/doi/full/10.1080/15715124.2012.680022 [article] Sungai Pahang digital flood mapping : 2007 flood [texte imprimé] / Aminuddin Ab. Ghani, Auteur ; Chun Kiat Chang, Auteur ; Cheng Siang Leow, Auteur . - 2012 . - pp. 139-148. Hydraulique Langues : Anglais (eng) in JRBM : International journal of river basin management > Vol. 10 N° 2 (Avril 2012) . - pp. 139-148 Mots-clés : Flooding  Alluvial  river  Flood  mitigation  GIS  Sungai  pahang Résumé : In this study, visits to areas in the subcatchments of Sungai Pahang, including Mentakab, Temerloh, Maran and Pekan, were made throughout the year 2009 to obtain information regarding inundation areas, flood depth, flow discharge and water levels relevant to the 2007 flood. Interviews with local people were also made to ascertain the true picture of the 2007 flood. Analyses of rainfall data, water level, flow discharge and river cross-sectional changes were carried out from data gathering. The development of a digital elevation model (DEM) was made from a combination of digital topographical maps and satellite images which were purchased from Jabatan Ukur dan Pemetaan Malaysia. This visually enhanced DEM was then used for the development of the actual extent of the 2007 flood in the study area. Several options of flood mitigation works are proposed to reduce the impact of a similar flood in the future based on the developed DEM. ISSN : 1571-5124 En ligne : http://www.tandfonline.com/doi/full/10.1080/15715124.2012.680022

Experimental studies on the interaction between vehicles and floodplain flows / Fang Yenn Teo in JRBM : International journal of river basin management, Vol. 10 N° 2 (Avril 2012) 

Public ISBD [article]  in JRBM : International journal of river basin management > Vol. 10 N° 2 (Avril 2012) . - pp. 149-160 Titre : Experimental studies on the interaction between vehicles and floodplain flows Type de document : texte imprimé Auteurs : Fang Yenn Teo, Auteur ; Junqiang Xia, Auteur ; Roger A. Falconer, Auteur Année de publication : 2012 Article en page(s) : pp. 149-160 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : River  and  floodplain  hydrodynamics  Urban  flooding  Urban  floodplain  with  vehicle Résumé : Floodwater flows through urban floodplains with storm water systems are often inadequate during extreme storm events and/ or when the river flood inundation extent becomes extreme. Such flows may cause potential hazard risks to humans and their properties along the floodplains. Recently, flood hazards relating to vehicles have become more noticeable and it is vital to investigate the hydraulic behaviour of vehicles on urban floodplains. Therefore, this paper outlines a study of the theoretical and experimental aspects of the hydrodynamics of floodwater flows over urban floodplains with vehicles. A theoretical background study is discussed to establish an understanding of the hydrodynamics of floodwater flows over urban floodplains with vehicles; a condition which can be very important for extreme storm events, or even moderate storm events, when the storm water system is insufficient to drain away the surface runoff. Extensive investigations have been undertaken on stationary scaled die cast model vehicles in laboratory hydraulics flumes by conducting a series of physical experimental studies on: (i) the threshold of vehicle instability, (ii) the effects of vehicle orientation, (iii) the effects of ground surface gradient, (iv) the vehicle stability on urban floodplains, and (v) the influence of vehicles on floodwater flows. The results for all the test cases have been analysed to investigate the effects of vehicles on floodwater flow propagation over urban floodplains and, on the other hand, the influence of the floodwater flows on the stability of model vehicles. The two principal factors of hazards (i.e. the floodwater depth and flow velocity) that affect the stability of model vehicles in urban floodplains have been identified to confirm the significant impact of hydrodynamic processes in urban floodplains with vehicles. All experiments undertaken so far have only looked into the conditions under which the model vehicles begin to be moved. Observations have been made from the theory studied and experiments conducted to systematically look into the hydraulic behaviour of vehicles in urban floodplains. The main findings have highlighted that: (i) the model vehicles had a significant impact on the floodwater flow propagation and the hydrodynamic processes in the flooded area, (ii) if the incoming flow depth was less than the vehicle height, then the threshold velocity increased for a decease in the depth of flow; (iii) if the incoming flow depth was greater than the vehicle height, then the threshold velocity would rise with an increase in the depth of flow, and (iv) a flooded vehicle was more likely to move if the incoming depth just approached the vehicle chassis height due to the buoyancy effects. Based on these findings, an innovative approach of a straightforward three colour zone envelope curve has been developed, and first introduced herein, which has been defined as the Traffic Light of Hydraulic Stability (TLHS) system. This novel approach can be readily used to evaluate the degree of hydraulic stability for model vehicles, and it is also invaluable for assessing the vehicle hazard conditions in urban floodplains. ISSN : 1571-5124 En ligne : http://www.tandfonline.com/doi/full/10.1080/15715124.2012.674040 [article] Experimental studies on the interaction between vehicles and floodplain flows [texte imprimé] / Fang Yenn Teo, Auteur ; Junqiang Xia, Auteur ; Roger A. Falconer, Auteur . - 2012 . - pp. 149-160. Hydraulique Langues : Anglais (eng) in JRBM : International journal of river basin management > Vol. 10 N° 2 (Avril 2012) . - pp. 149-160 Mots-clés : River  and  floodplain  hydrodynamics  Urban  flooding  Urban  floodplain  with  vehicle Résumé : Floodwater flows through urban floodplains with storm water systems are often inadequate during extreme storm events and/ or when the river flood inundation extent becomes extreme. Such flows may cause potential hazard risks to humans and their properties along the floodplains. Recently, flood hazards relating to vehicles have become more noticeable and it is vital to investigate the hydraulic behaviour of vehicles on urban floodplains. Therefore, this paper outlines a study of the theoretical and experimental aspects of the hydrodynamics of floodwater flows over urban floodplains with vehicles. A theoretical background study is discussed to establish an understanding of the hydrodynamics of floodwater flows over urban floodplains with vehicles; a condition which can be very important for extreme storm events, or even moderate storm events, when the storm water system is insufficient to drain away the surface runoff. Extensive investigations have been undertaken on stationary scaled die cast model vehicles in laboratory hydraulics flumes by conducting a series of physical experimental studies on: (i) the threshold of vehicle instability, (ii) the effects of vehicle orientation, (iii) the effects of ground surface gradient, (iv) the vehicle stability on urban floodplains, and (v) the influence of vehicles on floodwater flows. The results for all the test cases have been analysed to investigate the effects of vehicles on floodwater flow propagation over urban floodplains and, on the other hand, the influence of the floodwater flows on the stability of model vehicles. The two principal factors of hazards (i.e. the floodwater depth and flow velocity) that affect the stability of model vehicles in urban floodplains have been identified to confirm the significant impact of hydrodynamic processes in urban floodplains with vehicles. All experiments undertaken so far have only looked into the conditions under which the model vehicles begin to be moved. Observations have been made from the theory studied and experiments conducted to systematically look into the hydraulic behaviour of vehicles in urban floodplains. The main findings have highlighted that: (i) the model vehicles had a significant impact on the floodwater flow propagation and the hydrodynamic processes in the flooded area, (ii) if the incoming flow depth was less than the vehicle height, then the threshold velocity increased for a decease in the depth of flow; (iii) if the incoming flow depth was greater than the vehicle height, then the threshold velocity would rise with an increase in the depth of flow, and (iv) a flooded vehicle was more likely to move if the incoming depth just approached the vehicle chassis height due to the buoyancy effects. Based on these findings, an innovative approach of a straightforward three colour zone envelope curve has been developed, and first introduced herein, which has been defined as the Traffic Light of Hydraulic Stability (TLHS) system. This novel approach can be readily used to evaluate the degree of hydraulic stability for model vehicles, and it is also invaluable for assessing the vehicle hazard conditions in urban floodplains. ISSN : 1571-5124 En ligne : http://www.tandfonline.com/doi/full/10.1080/15715124.2012.674040

Guidelines for floodplain development / Ben Caddis in JRBM : International journal of river basin management, Vol. 10 N° 2 (Avril 2012) 

Public ISBD [article]  in JRBM : International journal of river basin management > Vol. 10 N° 2 (Avril 2012) . - pp. 161-170 Titre : Guidelines for floodplain development : A Malaysian case study Type de document : texte imprimé Auteurs : Ben Caddis, Auteur ; Chris Nielsen, Auteur ; Wedge Hong, Auteur Année de publication : 2012 Article en page(s) : pp. 161-170 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Flood  hazard  Floodplain  development  Flood  planning  level Résumé : Recognition that unplanned and uncontrolled development can increase the risk to life and damage to property is fundamental to successful floodplain management. Awareness of this issue is not just the responsibility of local authorities but all stakeholders, covering both public and private sectors. Whilst the land developer has the leading social responsibility for flood compatible development, the approving agencies share that responsibility through provision of relevant guidelines and information on floods, and adequate assessment of each development application in a transparent, impartial manner. In rural areas where informal approval processes are common, it is the combined responsibility of the community, respective community leaders and the local council to ensure that dwellings are not constructed on unsuitable land or in an unsuitable manner. The traditional approach to flood mitigation has primarily involved a structural approach to modify flood characteristics. Contingency measures, such as flood sirens, are also used to alert communities of impending floods. Whilst structural mitigation measures can reduce flood levels and extents, without adequate floodplain planning, the benefit from the structural works is lost due to increased flooding from unplanned development. The result is no net benefit, at a substantial financial cost to the community. The monetary benefit of improved planning through reduction of flood damages offers far greater cost-benefit measure than most structural approaches. This paper describes the principles used and development of a simple set of guidelines for controlling floodplain development in Malaysia. The guidelines have been prepared and recommended for implementation across three districts in Sabah. In time, it is expected that the principles used in the guidelines are incorporated into a national policy for floodplain development. ISSN : 1571-5124 En ligne : http://www.tandfonline.com/doi/full/10.1080/15715124.2012.688750 [article] Guidelines for floodplain development : A Malaysian case study [texte imprimé] / Ben Caddis, Auteur ; Chris Nielsen, Auteur ; Wedge Hong, Auteur . - 2012 . - pp. 161-170. Hydraulique Langues : Anglais (eng) in JRBM : International journal of river basin management > Vol. 10 N° 2 (Avril 2012) . - pp. 161-170 Mots-clés : Flood  hazard  Floodplain  development  Flood  planning  level Résumé : Recognition that unplanned and uncontrolled development can increase the risk to life and damage to property is fundamental to successful floodplain management. Awareness of this issue is not just the responsibility of local authorities but all stakeholders, covering both public and private sectors. Whilst the land developer has the leading social responsibility for flood compatible development, the approving agencies share that responsibility through provision of relevant guidelines and information on floods, and adequate assessment of each development application in a transparent, impartial manner. In rural areas where informal approval processes are common, it is the combined responsibility of the community, respective community leaders and the local council to ensure that dwellings are not constructed on unsuitable land or in an unsuitable manner. The traditional approach to flood mitigation has primarily involved a structural approach to modify flood characteristics. Contingency measures, such as flood sirens, are also used to alert communities of impending floods. Whilst structural mitigation measures can reduce flood levels and extents, without adequate floodplain planning, the benefit from the structural works is lost due to increased flooding from unplanned development. The result is no net benefit, at a substantial financial cost to the community. The monetary benefit of improved planning through reduction of flood damages offers far greater cost-benefit measure than most structural approaches. This paper describes the principles used and development of a simple set of guidelines for controlling floodplain development in Malaysia. The guidelines have been prepared and recommended for implementation across three districts in Sabah. In time, it is expected that the principles used in the guidelines are incorporated into a national policy for floodplain development. ISSN : 1571-5124 En ligne : http://www.tandfonline.com/doi/full/10.1080/15715124.2012.688750

Evaluation of bendway weir bank stabilization techniques for stream restoration / Kumud Acharya in JRBM : International journal of river basin management, Vol. 10 N° 2 (Avril 2012) 

Public ISBD [article]  in JRBM : International journal of river basin management > Vol. 10 N° 2 (Avril 2012) . - pp. 171-176 Titre : Evaluation of bendway weir bank stabilization techniques for stream restoration Type de document : texte imprimé Auteurs : Kumud Acharya, Auteur ; Mahesh Gautam, Auteur Année de publication : 2012 Article en page(s) : pp. 171-176 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Streambank  stabilization  Restoration  Spur  dikes  Las  Vegas  wash Résumé : In this study, velocity distribution patterns in a stream in the presence of bendway weirs were assessed for their effectiveness in bank stabilization in a demonstration site in the Las Vegas Wash, Nevada, USA. Streambanks of the target stream had been stabilized previously by longitudinal stone toe protection (LSTP) and stone spur dikes. Stone toes are meant to protect the toe of streambanks. Similarly, stone spur dikes consist of a series of dikes (of a crest relatively higher than that of the bendway weirs) protruding at right angles from the convex side of the streambanks. Velocity measurements were taken to evaluate the velocity field in the channel in the following three different cases: Case 1, channel with LSTP and the pre-existing spur dikes; Case 2, channel with LSTP with no deflecting structures (spur dikes removed); and Case 3, channel with LSTP and bendway weirs. The results suggested that bendway weirs caused a reduction in the uncontrolled high-velocity flow near the outer bank (right bank), allowing only controlled flow. Thus, bendway weirs were found to be more effective than spur dikes in reducing the velocity of flow at the vulnerable weir zones near the outer banks, thus providing a means to stabilize the streambanks. ISSN : 1571-5124 En ligne : http://www.tandfonline.com/doi/full/10.1080/15715124.2012.679737 [article] Evaluation of bendway weir bank stabilization techniques for stream restoration [texte imprimé] / Kumud Acharya, Auteur ; Mahesh Gautam, Auteur . - 2012 . - pp. 171-176. Hydraulique Langues : Anglais (eng) in JRBM : International journal of river basin management > Vol. 10 N° 2 (Avril 2012) . - pp. 171-176 Mots-clés : Streambank  stabilization  Restoration  Spur  dikes  Las  Vegas  wash Résumé : In this study, velocity distribution patterns in a stream in the presence of bendway weirs were assessed for their effectiveness in bank stabilization in a demonstration site in the Las Vegas Wash, Nevada, USA. Streambanks of the target stream had been stabilized previously by longitudinal stone toe protection (LSTP) and stone spur dikes. Stone toes are meant to protect the toe of streambanks. Similarly, stone spur dikes consist of a series of dikes (of a crest relatively higher than that of the bendway weirs) protruding at right angles from the convex side of the streambanks. Velocity measurements were taken to evaluate the velocity field in the channel in the following three different cases: Case 1, channel with LSTP and the pre-existing spur dikes; Case 2, channel with LSTP with no deflecting structures (spur dikes removed); and Case 3, channel with LSTP and bendway weirs. The results suggested that bendway weirs caused a reduction in the uncontrolled high-velocity flow near the outer bank (right bank), allowing only controlled flow. Thus, bendway weirs were found to be more effective than spur dikes in reducing the velocity of flow at the vulnerable weir zones near the outer banks, thus providing a means to stabilize the streambanks. ISSN : 1571-5124 En ligne : http://www.tandfonline.com/doi/full/10.1080/15715124.2012.679737

Numerical solution of the advection-diffusion equation using Laplace transform finite analytical method / Mahmud Ahsan in JRBM : International journal of river basin management, Vol. 10 N° 2 (Avril 2012) 

Public ISBD [article]  in JRBM : International journal of river basin management > Vol. 10 N° 2 (Avril 2012) . - pp. 177-188 Titre : Numerical solution of the advection-diffusion equation using Laplace transform finite analytical method Type de document : texte imprimé Auteurs : Mahmud Ahsan, Auteur Année de publication : 2012 Article en page(s) : pp. 177-188 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Advection-diffusion  Laplace  transform  Finite-difference  method  Finite  analytical  method  Water  quality Résumé : In this study, a numerical method has been investigated and developed to solve the one-dimensional advection-diffusion equation to predict the quality of water in rivers. In this method, time variable is eliminated first by the Laplace transformation, and then a finite analytical method is applied in space. Both are based on a local element of the discretized domain in a finite-volume method. Since the Laplace transformation has been used for temporal approximation, an efficient and accurate inverse Laplace transform method of De Hoog 1982 [An improved method for numerical inversion of Laplace transform. SIAM, Journal of Scientific and Statistical Computing, 3 (3), 357–366] is employed to obtain the solution in real time. The proposed method is compared against analytical solutions and two finite-difference methods. The present computations and comparisons show that the proposed method is superior to the finite-difference methods. The results of the proposed method also agree with analytical solutions without numerical oscillation or diffusion. The present method is applied to steady and unsteady flows and it also provides flexibility for uniform and non-uniform grid spacing and for a wide range of Péclet numbers. It takes less computational effort than finite-difference methods. ISSN : 1571-5124 En ligne : http://www.tandfonline.com/doi/full/10.1080/15715124.2012.679736 [article] Numerical solution of the advection-diffusion equation using Laplace transform finite analytical method [texte imprimé] / Mahmud Ahsan, Auteur . - 2012 . - pp. 177-188. Hydraulique Langues : Anglais (eng) in JRBM : International journal of river basin management > Vol. 10 N° 2 (Avril 2012) . - pp. 177-188 Mots-clés : Advection-diffusion  Laplace  transform  Finite-difference  method  Finite  analytical  method  Water  quality Résumé : In this study, a numerical method has been investigated and developed to solve the one-dimensional advection-diffusion equation to predict the quality of water in rivers. In this method, time variable is eliminated first by the Laplace transformation, and then a finite analytical method is applied in space. Both are based on a local element of the discretized domain in a finite-volume method. Since the Laplace transformation has been used for temporal approximation, an efficient and accurate inverse Laplace transform method of De Hoog 1982 [An improved method for numerical inversion of Laplace transform. SIAM, Journal of Scientific and Statistical Computing, 3 (3), 357–366] is employed to obtain the solution in real time. The proposed method is compared against analytical solutions and two finite-difference methods. The present computations and comparisons show that the proposed method is superior to the finite-difference methods. The results of the proposed method also agree with analytical solutions without numerical oscillation or diffusion. The present method is applied to steady and unsteady flows and it also provides flexibility for uniform and non-uniform grid spacing and for a wide range of Péclet numbers. It takes less computational effort than finite-difference methods. ISSN : 1571-5124 En ligne : http://www.tandfonline.com/doi/full/10.1080/15715124.2012.679736

Urban runoff impacts on receiving aquatic ecosystems assessed using periphyton community / Tan Chew Khun in JRBM : International journal of river basin management, Vol. 10 N° 2 (Avril 2012) 

Public ISBD [article]  in JRBM : International journal of river basin management > Vol. 10 N° 2 (Avril 2012) . - pp. 189-196 Titre : Urban runoff impacts on receiving aquatic ecosystems assessed using periphyton community Type de document : texte imprimé Auteurs : Tan Chew Khun, Auteur ; Carolyn Oldham, Auteur ; Louis Evans, Auteur Année de publication : 2012 Article en page(s) : pp. 189-196 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Community  tolerance  Runoff  Ecological  risk  Periphyton  Photosynthesis  Efficiency Résumé : Urban runoff is a major cause of stream degradation. For appropriate management action, there is a need to establish whether or not the runoff is degrading or potentially will degrade the receiving water. This work explored the use of local periphyton communities for assessing the ecological impacts of runoff of two urban catchments. Periphyton communities were colonized on glass substrate for 2 weeks in riverine waters receiving the urban runoff and in non-receiving waters at an upstream reference site. The receiving communities were evaluated against the reference community for photosynthetic efficiency and tolerance to copper, identified to be a significant runoff stressor. Photosynthesis efficiency was measured as a PSII quantum yield, and community tolerance was assessed using a laboratory ecotoxicological test. The hypothesis tested is that the runoff degrades by causing communities in receiving waters to become more sensitive to runoff stressors. The bioassessment indicated a much higher copper threshold than provided for in the generic water quality guidelines. The significance in the use of local community is that it allows for ecological risk analysis of exposure to runoff stressors, providing site-specific information relevant to management. ISSN : 1571-5124 En ligne : http://www.tandfonline.com/doi/full/10.1080/15715124.2012.683007 [article] Urban runoff impacts on receiving aquatic ecosystems assessed using periphyton community [texte imprimé] / Tan Chew Khun, Auteur ; Carolyn Oldham, Auteur ; Louis Evans, Auteur . - 2012 . - pp. 189-196. Hydraulique Langues : Anglais (eng) in JRBM : International journal of river basin management > Vol. 10 N° 2 (Avril 2012) . - pp. 189-196 Mots-clés : Community  tolerance  Runoff  Ecological  risk  Periphyton  Photosynthesis  Efficiency Résumé : Urban runoff is a major cause of stream degradation. For appropriate management action, there is a need to establish whether or not the runoff is degrading or potentially will degrade the receiving water. This work explored the use of local periphyton communities for assessing the ecological impacts of runoff of two urban catchments. Periphyton communities were colonized on glass substrate for 2 weeks in riverine waters receiving the urban runoff and in non-receiving waters at an upstream reference site. The receiving communities were evaluated against the reference community for photosynthetic efficiency and tolerance to copper, identified to be a significant runoff stressor. Photosynthesis efficiency was measured as a PSII quantum yield, and community tolerance was assessed using a laboratory ecotoxicological test. The hypothesis tested is that the runoff degrades by causing communities in receiving waters to become more sensitive to runoff stressors. The bioassessment indicated a much higher copper threshold than provided for in the generic water quality guidelines. The significance in the use of local community is that it allows for ecological risk analysis of exposure to runoff stressors, providing site-specific information relevant to management. ISSN : 1571-5124 En ligne : http://www.tandfonline.com/doi/full/10.1080/15715124.2012.683007

Flood vulnerability assessment in arid areas, western Saudi Arabia / Ali M. Subyani in JRBM : International journal of river basin management, Vol. 10 N° 2 (Avril 2012) 

Public ISBD [article]  in JRBM : International journal of river basin management > Vol. 10 N° 2 (Avril 2012) . - pp. 197-203 Titre : Flood vulnerability assessment in arid areas, western Saudi Arabia Type de document : texte imprimé Auteurs : Ali M. Subyani, Auteur Année de publication : 2012 Article en page(s) : pp. 197-203 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Flood  vulnerability  Arid  areas  Maximum  24-h  rainfall  Western  Saudi  Arabia Résumé : In arid regions, flash floods often occur as a consequence of excessive rainfall. Occasionally causing major loss of property and life, floods are large events of relatively short duration. Western Saudi Arabia is an extremely arid region where rainfall is characterized by extremely high spatial and temporal variability. This area is subject to environmental hazards such as flood risks because most of the infrastructure is located on wadis and flood plains. In this paper, an integrated approach was adopted in which geographic information system and rainfall–frequency analysis using annual maximum 24-h rainfall were utilized to identify, assess and mitigate hydrological and environmental flood hazards in the study area. The study shows that the prediction of annual maximum 24-h duration rainfall along with prediction of 25-, 50-, 100- and 200-year return periods for the best fit of Gumbel pdfs. In addition, probable maximum precipitation was also estimated for 50- and 100-year return periods, which will aid decision-making for future project designs and flood protection studies. ISSN : 1571-5124 En ligne : http://www.tandfonline.com/doi/full/10.1080/15715124.2012.688749 [article] Flood vulnerability assessment in arid areas, western Saudi Arabia [texte imprimé] / Ali M. Subyani, Auteur . - 2012 . - pp. 197-203. Hydraulique Langues : Anglais (eng) in JRBM : International journal of river basin management > Vol. 10 N° 2 (Avril 2012) . - pp. 197-203 Mots-clés : Flood  vulnerability  Arid  areas  Maximum  24-h  rainfall  Western  Saudi  Arabia Résumé : In arid regions, flash floods often occur as a consequence of excessive rainfall. Occasionally causing major loss of property and life, floods are large events of relatively short duration. Western Saudi Arabia is an extremely arid region where rainfall is characterized by extremely high spatial and temporal variability. This area is subject to environmental hazards such as flood risks because most of the infrastructure is located on wadis and flood plains. In this paper, an integrated approach was adopted in which geographic information system and rainfall–frequency analysis using annual maximum 24-h rainfall were utilized to identify, assess and mitigate hydrological and environmental flood hazards in the study area. The study shows that the prediction of annual maximum 24-h duration rainfall along with prediction of 25-, 50-, 100- and 200-year return periods for the best fit of Gumbel pdfs. In addition, probable maximum precipitation was also estimated for 50- and 100-year return periods, which will aid decision-making for future project designs and flood protection studies. ISSN : 1571-5124 En ligne : http://www.tandfonline.com/doi/full/10.1080/15715124.2012.688749

Two-dimensional analysis of flow patterns around a single backward-facing step / Alhinai Saif in JRBM : International journal of river basin management, Vol. 10 N° 2 (Avril 2012) 

Public ISBD [article]  in JRBM : International journal of river basin management > Vol. 10 N° 2 (Avril 2012) . - pp. 205-211 Titre : Two-dimensional analysis of flow patterns around a single backward-facing step Type de document : texte imprimé Auteurs : Alhinai Saif, Auteur ; Takashi Hosoda, Auteur Année de publication : 2012 Article en page(s) : pp. 205-211 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Two-dimensional  numerical  model  Backward-facing  step  Shockwaves  Hydraulic  jumps Résumé : A depth-averaged two-dimensional (2D) numerical model is applied to predict the flow over a single backward-facing step. The model is established using the finite-volume method on a curvilinear grid. The 2D basic governing shallow water equations used in the generalized curvilinear coordinate system are solved. This paper focuses on the generation of shockwaves and hydraulic jumps downstream of the step, in addition to the depth of the supercritical stream immediately downstream of the step. Such flow features occur because of the sudden change in the geometry of the channel, such as the abrupt expansion in the flow cross-section. The backwater effect due to in the water depth downstream the step is also considered. Six experimental cases are carried out with a water-free-fall step, a partially submerged step and fully submerged step. By comparing the numerical results with observed laboratory experimental results, the model is capable of reproducing the above-mentioned flow features, and shows a good agreement with the measured data. This study analyses the flow over a backward-facing step, better knowledge of which can reduce flood risk problems in urban rivers. ISSN : 1571-5124 En ligne : http://www.tandfonline.com/doi/full/10.1080/15715124.2012.692687 [article] Two-dimensional analysis of flow patterns around a single backward-facing step [texte imprimé] / Alhinai Saif, Auteur ; Takashi Hosoda, Auteur . - 2012 . - pp. 205-211. Hydraulique Langues : Anglais (eng) in JRBM : International journal of river basin management > Vol. 10 N° 2 (Avril 2012) . - pp. 205-211 Mots-clés : Two-dimensional  numerical  model  Backward-facing  step  Shockwaves  Hydraulic  jumps Résumé : A depth-averaged two-dimensional (2D) numerical model is applied to predict the flow over a single backward-facing step. The model is established using the finite-volume method on a curvilinear grid. The 2D basic governing shallow water equations used in the generalized curvilinear coordinate system are solved. This paper focuses on the generation of shockwaves and hydraulic jumps downstream of the step, in addition to the depth of the supercritical stream immediately downstream of the step. Such flow features occur because of the sudden change in the geometry of the channel, such as the abrupt expansion in the flow cross-section. The backwater effect due to in the water depth downstream the step is also considered. Six experimental cases are carried out with a water-free-fall step, a partially submerged step and fully submerged step. By comparing the numerical results with observed laboratory experimental results, the model is capable of reproducing the above-mentioned flow features, and shows a good agreement with the measured data. This study analyses the flow over a backward-facing step, better knowledge of which can reduce flood risk problems in urban rivers. ISSN : 1571-5124 En ligne : http://www.tandfonline.com/doi/full/10.1080/15715124.2012.692687

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