Your search found 14 records
1 McAleer, M.; Jakeman, A. (Eds.) 1993. International Congress on Modelling and Simulation: Proceedings, Volume 3, The University of Western Australia, 6-10 December 1993. Perth, Australia: University of Western Australia. pp.917-1352.
Simulation models ; Econometric models ; Mathematical models ; GIS ; Decision support tools ; Ecosystems ; Environmental effects ; Evapotranspiration ; Soil-water-plant relationships ; Health hazards ; Risks ; Water quality ; Pest insects ; Pollution control ; Lakes ; Hydrodynamics ; Rivers ; Estuaries ; Pastoralism
(Location: IWMI HQ Call no: 003.3 G000 MCA Record No: H040380)
International Congress organised by Modelling and Simulation Society of Australia (MSSA), Inc., International Association for Mathematics and Computers in Simulation (IMACS), International Society for Ecological Modelling, and The International Environmetrics Society.
2 Hoanh, Chu Thai; Phong, N. D.; Trung, N. H.; Dung, L. C.; Hien, N. X.; Ngoc, N. V.; Tuong, T. P. 2012. Modelling to support land and water management: experiences from the Mekong River Delta, Vietnam. Water International, 37(4):408-426. (Special issue on "How hydrological models support informed decision making in developing countries" with contributions by IWMI authors). [doi: https://doi.org/10.1080/02508060.2012.706797]
Water management ; Water use ; Land management ; Land use ; Rivers ; Deltas ; Simulation models ; Optimization ; Policy making ; Hydrodynamics ; Water quality ; Canals ; Flood control ; Salinity control ; Aquaculture / Vietnam / Mekong River Delta
(Location: IWMI HQ Call no: PER Record No: H045027)
(3.15 MB)
By comparing the successful story of a hydrodynamic model (based on its contribution to policy changes, management options and livelihood improvement) with other modelling cases in the Mekong River Delta, five success factors are identified. These are (1) simulated phenomena relevant to and understandable by policy makers; (2) response to the needs of policy setting; (3) developed and handled by national modellers with direct links to the policy process; (4) availability of input data; and (5) long application history. These success factors provide higher opportunities for engaging modelling activities with policy setting.
3 Podwojewski, Pascal; Janeau, Jean L. 2005. Short-term effects of agricultural practices on the soil structure and hydrodynamic in a deep tilled hardened sandy-silty volcanic–ash soil (cangahua) in Ecuador. In International Union of Soil Sciences (IUSS); Institut de Recherche pour le Developpement (IRD); Thailand. Land Development Department (LDD); International Water Management Institute (IWMI); FAO. Regional Office for Asia and the Pacific (FAO RAP); Khon Kaen University. Faculty of Agriculture. Management of tropical sandy soils for sustainable agriculture: a holistic approach for sustainable development of problem soils in the tropics. Proceedings of the First Symposium on Management of Tropical Sandy Soils for Sustainable Ariculture, Khon Kaen, Thailand, 27 November – 2 December 2005. Bangkok, Thailand: FAO Regional Office for Asia and the Pacific (FAO RAP). pp.215-222.
Agricultural practices ; Volcanic soils ; Soil structure ; Sandy soils ; Silty soils ; Clay soils ; Soil organic matter ; Carbon ; Hydrodynamics ; Simulated rainfall ; Erosion / Ecuador
(Location: IWMI HQ Call no: 630 G000 INT Record No: H047328)
(0.39 MB) (16.9 MB)
In the Ecuadorian Cordillera, the hardened volcanic ashes (cangahuas) account for 15% of the cultivated area. The soil resulting from the fragmentation of these materials, generally by heavy machinery, shows an apparent stable millimetric structure. However, this new structure is highly susceptible to disintegration under rain, because it contains no organic matter and has a sandy-silt composition with very little mineralogical clay, and the material itself is readily eroded. In consequence we studied the evolution of soil aggregate stability in two factorial experiments during five cultivation cycles with two kinds of soil preparation and five fertilization treatments. Rainfall simulation was implemented before and after three cycles of cultivation to asses the soils structure evolution and its erodibility. The cultivated plots had flat surfaces and the rainfall simulation tests were conducted after the harvest on bare surfaces. Surface soil crusting occurred rapidly within the cultivated plots when compared to the recent tilled cangahua. Runoff and soil loss were generally higher on plots with lower structural stability, generally with higher clay content. The aggregate stability was not influenced by either kind of soil preparation, nor by large additions of manure (80 t ha-1) or green fertilizers (10 t ha-1), nor by growing a perennial grass. The variation in the aggregate stability seemed to depend on the components inherited from the original volcanic material: in the plots with larger clay content, and with swelling clay minerals, the aggregates were less stable than those composed of isometric fine silt particles. In agreement with the structural stability measured in a laboratory, organic matter inputs increase the soil porosity but had no effect on the structural stability and resistance to crusting, and thus to runoff and to erosion. For these soils, no tillage and a permanent soil cover (pasture) would be the best agricultural option.
4 Galelli, S.; Castelletti, A.; Goedbloed, A. 2015. High-performance integrated control of water quality and quantity in urban water reservoirs. Water Resources Research, 51(11):9053-9072. [doi: https://doi.org/10.1002/2015WR017595]
Water quality control ; Reservoir operation ; Water management ; Simulation models ; Techniques ; Hydrodynamics ; Urban areas ; Water supply ; Drinking water ; Salinity control ; Hydrometeorology / Singapore / Marina Reservoir
(Location: IWMI HQ Call no: e-copy only Record No: H047443)
(3.82 MB)
This paper contributes a novel High-Performance Integrated Control framework to support the real-time operation of urban water supply storages affected by water quality problems. We use a 3-D, high- fidelity simulation model to predict the main water quality dynamics and inform a real-time controller based on Model Predictive Control. The integration of the simulation model into the control scheme is performed by a model reduction process that identifies a low-order, dynamic emulator running 4 orders of magnitude faster. The model reduction, which relies on a semiautomatic procedural approach integrating time series clustering and variable selection algorithms, generates a compact and physically meaningful emulator that can be coupled with the controller. The framework is used to design the hourly operation of Marina Reservoir, a 3.2 Mm3 storm-water-fed reservoir located in the center of Singapore, operated for drinking water supply and flood control. Because of its recent formation from a former estuary, the reservoir suffers from high salinity levels, whose behavior is modeled with Delft3D-FLOW. Results show that our control framework reduces the minimum salinity levels by nearly 40% and cuts the average annual deficit of drinking water supply by about 2 times the active storage of the reservoir (about 4% of the total annual demand).
5 Gning, A. A.; Orban, P.; Gesels, J.; Ngom, F. D.; Dassargues, A.; Malou, R.; Brouyere, S. 2017. Factors controlling the evolution of groundwater dynamics and chemistry in the Senegal River Delta. Journal of Hydrology: Regional Studies, 10:133-144. [doi: https://doi.org/10.1016/j.ejrh.2017.01.005]
Groundwater table ; Surface water ; Water levels ; Monitoring ; Saline water ; Soil salinization ; Irrigation water ; Rain ; Hydrogeology ; Geochemistry ; Chemical composition ; Hydrodynamics ; Models ; Multivariate analysis ; Rivers ; Deltas / Senegal / Senegal River Delta
(Location: IWMI HQ Call no: e-copy only Record No: H048129)
http://www.sciencedirect.com/science/article/pii/S221458181730037X/pdfft?md5=fba6295f07cffdb349955306459bdffd&pid=1-s2.0-S221458181730037X-main.pdf
https://vlibrary.iwmi.org/pdf/H048129.pdf
https://vlibrary.iwmi.org/pdf/H048129.pdf
(3.14 MB) (3.13 MB)
Study region: Senegal River Delta.
Study focus: The Senegal River Delta is a strategic region for the development of irrigated agriculture. Despite a Sahelian climatic context, the management of the river with dams ensures water availability throughout the year. With the intensification of agriculture, degradation of cultivated soils is observed, mostly linked to the existence of a shallow salty aquifer. In this context, regional surveys were performed to characterize groundwater–surface water interactions and to identify the impact of artificial river management and agricultural intensification on the evolution of groundwater dynamics and chemistry.
New hydrological insights for the region: Results show that groundwater far away from rivers and outside irrigated plots has evolved from marine water to brines under the influence of evapotranspiration. Near rivers, salinity of groundwater is lower than seawater and groundwater mineralization seems to evolve in the direction of softening through cationic exchanges related to permanent contact with fresh water. Despite large volumes of water used for rice cultivation, groundwater does not show any real softening trend in the cultivated parcels. Results show that the mechanisms that contribute to repel salt water from the sediments correspond to a lateral flush near permanent surface water streams and not to vertical drainage and dilution with rainfall or irrigation water. It is however difficult to estimate the time required to come back to more favorable conditions of groundwater salinity.
Study focus: The Senegal River Delta is a strategic region for the development of irrigated agriculture. Despite a Sahelian climatic context, the management of the river with dams ensures water availability throughout the year. With the intensification of agriculture, degradation of cultivated soils is observed, mostly linked to the existence of a shallow salty aquifer. In this context, regional surveys were performed to characterize groundwater–surface water interactions and to identify the impact of artificial river management and agricultural intensification on the evolution of groundwater dynamics and chemistry.
New hydrological insights for the region: Results show that groundwater far away from rivers and outside irrigated plots has evolved from marine water to brines under the influence of evapotranspiration. Near rivers, salinity of groundwater is lower than seawater and groundwater mineralization seems to evolve in the direction of softening through cationic exchanges related to permanent contact with fresh water. Despite large volumes of water used for rice cultivation, groundwater does not show any real softening trend in the cultivated parcels. Results show that the mechanisms that contribute to repel salt water from the sediments correspond to a lateral flush near permanent surface water streams and not to vertical drainage and dilution with rainfall or irrigation water. It is however difficult to estimate the time required to come back to more favorable conditions of groundwater salinity.
6 Amarnath, Giriraj; Matheswaran, Karthikeyan; Pandey, Pooja; Alahacoon, Niranga; Yoshimoto, Shuhei. 2017. Flood mapping tools for disaster preparedness and emergency response using satellite data and hydrodynamic models: a case study of Bagmathi Basin, India. Proceedings of the National Academy of Sciences India Section A-Physical Sciences, 87(4):941-950. [doi: https://doi.org/10.1007/s40010-017-0461-7]
Floodplains ; Flooding ; Disaster preparedness ; Satellite observation ; Satellite imagery ; Hydrodynamics ; Models ; Mapping ; Emergencies ; Rainfall-runoff relationships ; River basins ; Case studies / India / Bagmathi Basin
(Location: IWMI HQ Call no: e-copy only Record No: H048410)
Northern Bihar is one of the major flood prone region in India affecting thousands of human lives and livelihoods during the recurrent floods occurring due to the monsoonal rains. While it is impossible to prevent the occurrence of extreme flood events, disaster planning can help in mitigating its detrimental effects. Monitoring flood extent using satellite observations just after the flood disasters is a core component of rapid emergency response process, which enables the emergency rescue teams to prioritize their efforts in critical areas to save lives and protect health, in addition to providing near real-time flooding information to the decision makers and planners. The main objective of this study is to demonstrate the utility of less data intensive, but equally robust hydrodynamic models to develop flood extent maps in conjunction with freely available remote sensing imageries at different scales. MODIS TERRA satellite data was used to map flood extent from 2001 to 2016 for entire Bihar. Two hydraulic models namely FLDPLN and RRI applied for the Bagmathi basin to evaluate our objectives. Both these models are of varying complexity but generate flood extent patterns with minimum amount of input data. The proposed approach is suited for mapping flood extents to provide an input information in near real time (h) when there is no availability to detailed hydraulic models and satellite datasets. Flood inundation extents from FLDPLN and RRI models were validated with Landsat-7 and MODIS TERRA derived flood extents for model performance. The results show acceptable spatial agreement between model predicted and Landsat-7 observed flood extents, denoting the utility of these tools for flood mapping application in data scarce environments.
7 Logah, F. Y.; Amisigo, A. B.; Obuobie, E.; Kankam-Yeboah, K. 2017. Floodplain hydrodynamic modelling of the lower Volta River in Ghana. Journal of Hydrology: Regional Studies, 14:1-9. [doi: https://doi.org/10.1016/j.ejrh.2017.09.002]
Floodplains ; Hydrodynamics ; Models ; Rivers ; Stream flow ; Sediment ; Geomorphology ; Dams ; Downstream ; Communities ; Living standards / Ghana / Lower Volta River / Akosombo Dam / Kpong Dam
(Location: IWMI HQ Call no: e-copy only Record No: H048495)
https://www.sciencedirect.com/science/article/pii/S2214581817301635/pdfft?md5=8175e1742b62ee768daad95eae85209a&pid=1-s2.0-S2214581817301635-main.pdf
https://vlibrary.iwmi.org/pdf/H048495.pdf
https://vlibrary.iwmi.org/pdf/H048495.pdf
(1.16 MB) (1.16 MB)
The impacts of dam releases from re-operation scenarios of the Akosombo and Kpong hydropower facilities on downstream communities along the Lower Volta River were examined through hydrodynamic modelling using the HEC-RAS hydraulic model. The model was used to simulate surface water elevation along the river reach for specified discharge hydrographs from proposed re-operation dam release scenarios. The morphology of the river and its flood plains together with cross-sectional profiles at selected river sections were mapped and used in the hydrodynamic modelling. In addition, both suspended and bed-load sediment were sampled and analysed to determine the current sediment load of the river and its potential to carry more sediment. The modelling results indicate that large areas downstream of the dam including its flood plains would be inundated if dam releases came close to or exceeded 2300 m3 /s. It is therefore recommended to relocate communities along the banks and in the flood plains of the Lower Volta River when dam releases are to exceed 2300 m3 /s. Suspended sediment transport was found to be very low in the Lower Volta River and the predominant soil type in the river banks and bed is sandy soil. Thus, the geomorphology of the river can be expected to change considerably with time, particularly for sustained high releases from the Akosombo and Kpong dams. The results obtained from this study form a basis for assessing future sedimentation problems in the Lower Volta River and for underpinning the development of sediment control and management strategies for river basins in Ghana.
8 Islam, M. M. M.; Sokolova, E.; Hofstra, N. 2018. Modelling of river faecal indicator bacteria dynamics as a basis for faecal contamination reduction. Journal of Hydrology, 563:1000-1008. [doi: https://doi.org/10.1016/j.jhydrol.2018.06.077]
Water quality ; Rivers ; Biological contamination ; Faecal coliforms ; Escherichia coli ; Enterococcus ; Wastewater ; Hydrodynamics ; Models ; Performance testing ; Sensitivity analysis / Bangladesh / Betna River
(Location: IWMI HQ Call no: e-copy only Record No: H048842)
https://www.sciencedirect.com/science/article/pii/S0022169418304992/pdfft?md5=0e46b4fbb1e8dfbccf7385817bd66e44&pid=1-s2.0-S0022169418304992-main.pdf
https://vlibrary.iwmi.org/pdf/H048842.pdf
https://vlibrary.iwmi.org/pdf/H048842.pdf
(1.32 MB) (1.32 MB)
To improve microbial water quality and to prevent waterborne disease outbreaks, knowledge on the fate and transport of contaminants and on the contributions from different faecal sources to the total contamination is essential. The fate and transport of faecal indicators E. coli and enterococci within the Betna River in Bangladesh were simulated using a coupled hydrodynamic and water quality model. The hydrodynamic model for the river was set up, calibrated and validated with water level and discharge in our earlier study. In this study, the hydrodynamic model was further validated using measured water temperature and salinity and coupled with the water quality module. Bacterial load data from various faecal sources were collected and used as input in the water quality model. The model output corresponded very well with the measured E. coli and enterococci concentrations in the river; the Root Mean Square Error and the Nash-Sutcliffe efficiency for Log10-transformed concentrations were found to be 0.23 (Log10 CFU/100 ml) and 0.84 for E. coli, and 0.19 (Log10 CFU/100 ml) and 0.86 for enterococci, respectively. Then, the sensitivity of the model was tested by removing one process or forcing at a time. These simulations revealed that the microbial decay, the upstream concentrations and the discharge of untreated wastewater were the primary factors controlling the concentrations in the river, while wind and the contribution from the diffuse sources (i.e. urban and agricultural runoff) were unlikely to have a major influence. Finally, the model was applied to investigate the influence of wastewater treatment on the bacteria concentrations. This revealed that wastewater treatment would result in a considerable improvement of the microbial water quality of the Betna River. This paper demonstrates the application of a comprehensive state-of-art model in a river in a data-poor tropical area. The model can potentially be applied to other watersheds and can help in formulating solutions to improve the microbial water quality.
9 Dickens, Chris; O’Brien, G.; Stassen, R.; Eriyagama, Nishadi; Kleynhans, M.; Rowntree, K.; Graham, M.; Ross-Gillespie, V.; MacKenzie, J.; Wymenga, E.; Mapedza, Everisto; Burnet, M.; Desai, M.; Hean, J. 2018. E-flows for the Upper Niger River and Inner Niger Delta: synthesis report. [Project report prepared by the International Water Management Institute for Wetlands International]. Colombo, Sri Lanka: International Water Management Institute (IWMI). CGIAR Research Program on Water, Land and Ecosystems (WLE). 201p.
Environmental flows ; Rivers ; Deltas ; Water resources ; Aquatic ecosystems ; Monitoring ; Risk assessment ; Ecosystem services ; Habitats ; Invertebrates ; Birds ; Manatees ; Fisheries ; Floodplains ; Dams ; Sediment ; Water quality ; Flow discharge ; Vegetation ; Indicators ; Geomorphology ; Living standards ; Social aspects ; Ecological factors ; Hydrodynamics ; Modelling ; Case studies / West Africa / Mali / Niger / Upper Niger River / Inner Niger Delta / Bani River
(Location: IWMI HQ Call no: e-copy only Record No: H049434)
(13.80 MB)
10 Dickens, Chris; O’Brien, G.; Stassen, R.; Eriyagama, Nishadi; Kleynhans, M.; Rowntree, K.; Graham, M.; Ross-Gillespie, V. 2018. E-flows for the Upper Niger and Inner Niger Delta: specialist reports - hydrology, hydraulics, geomorphology and water quality. [Project report prepared by the International Water Management Institute for Wetlands International]. Colombo, Sri Lanka: International Water Management Institute (IWMI). CGIAR Research Program on Water, Land and Ecosystems (WLE). 210p.
Environmental flows ; Hydrology ; Hydraulics ; Geomorphology ; Water quality ; River basins ; Deltas ; Water resources ; Freshwater ; Surface water ; Groundwater ; Flow discharge ; Flooding ; Catchment areas ; Dams ; Sediment ; Habitats ; Risk assessment ; Climate change ; Hydrodynamics ; Land use ; Mining ; Population density ; Models / West Africa / Mali / Upper Niger River / Inner Niger Delta / Bani River / Sankarani River / Dialakoro / Gouala / Koulikoro / Ke Macina / Djenne / Koryoume
(Location: IWMI HQ Call no: e-copy only Record No: H049435)
(16.40 MB)
11 Hassaballah, K.; Mohamed, Y.; Omer, A.; Uhlenbrook, Stefan. 2020. Modelling the inundation and morphology of the seasonally flooded Mayas Wetlands in the Dinder National Park-Sudan. Environmental Processes, 7(3):723-747. [doi: https://doi.org/10.1007/s40710-020-00444-5]
Wetlands ; Floodplains ; Flooding ; Hydrodynamics ; Modelling ; Hydrological factors ; Morphology ; Water levels ; Sediment ; Erosion ; Canals ; Rivers ; National parks ; Ecosystems / Sudan / Dinder River / Dinder National Park / Mayas Wetlands
(Location: IWMI HQ Call no: e-copy only Record No: H049807)
https://link.springer.com/content/pdf/10.1007/s40710-020-00444-5.pdf
https://vlibrary.iwmi.org/pdf/H049807.pdf
https://vlibrary.iwmi.org/pdf/H049807.pdf
(2.83 MB) (2.83 MB)
Understanding the spatiotemporal dynamics of surface water in varied, remote and inaccessible isolated floodplain lakes is difficult. Seasonal inundation patterns of these isolated lakes can be misestimated in a hydrodynamic model due to the short time of connectivity. The seasonal and annual variability of the Dinder River flow has great impact on what is so called Mayas wetlands, and hence, on the habitats and the ecological status of the Dinder National Park. This variability produces large morphological changes due to sediment transported within the river or from the upper catchment, which affects inflows to Mayas wetlands and floodplain inundation in general. In this paper, we investigated the morphological dimension using a quasi-3D modelling approach to support the management of the valuable Mayas wetlands ecosystems, and in particular, assessment of hydrological and morphological regime of the Dinder River as well as the Musa Maya. Six scenarios were developed and tested. The first three scenarios consider three different hydrologic conditions of average, wet and dry years under the existing system with the constructed connection canal. While the other three scenarios consider the same hydrologic conditions but under the natural system without an artificial connection canal. The modelling helps to understand the effect of human intervention (connection canal) on the Musa Maya. The comparison between the simulated scenarios concludes that the hydrodynamics and sedimentology of the Maya are driven by the two main factors: a) the hydrological variability of Dinder River; and b) deposited sediment plugs in the connection canal.
12 Tom, R. O.; George, K. O.; Joanes, A. O.; Haron, A. 2022. Review of flood modelling and models in developing cities and informal settlements: a case of Nairobi City. Journal of Hydrology: Regional Studies, 43:101188. [doi: https://doi.org/10.1016/j.ejrh.2022.101188]
Flooding ; Models ; Towns ; Informal settlements ; Urban areas ; Hydrological modelling ; Hydrodynamics ; Calibration ; Risk management ; Land use ; Land cover ; Rain / Kenya / Nairobi / Mukuru
(Location: IWMI HQ Call no: e-copy only Record No: H051366)
https://www.sciencedirect.com/science/article/pii/S2214581822002014/pdfft?md5=dc97ed13fe781be9589ed989f335823f&pid=1-s2.0-S2214581822002014-main.pdf
https://vlibrary.iwmi.org/pdf/H051366.pdf
https://vlibrary.iwmi.org/pdf/H051366.pdf
(1.19 MB) (1.19 MB)
Study region: This study focuses on urban flood modeling in developing cities with a special focus on informal settlements giving a specific case study of Mukuru slums in Nairobi city of Kenya. Informal settlements refer to unplanned settlements and areas where the housing doesn’t comply with the current housing codes and regulations and is thus characterized by a lack of legal settlement and housing plan approvals resulting in poor physical infrastructures and social services. Urban flood risks have been given less attention compared to rural riverine flooding in developing cities yet they cause more havoc. Using the appropriate set of models, flood modeling in urban settings is critical in integrated flood risk management.
Study focus: This study uses a desk review format to promote urban flood modeling knowledge and practice in integrated flood risk management in developing cities. In this regard, the study presents the review of various flood models highlighting their strengths and weaknesses and the significant role of model calibrations in addressing uncertainties while capturing the local scenarios. The paper further presents the role of model stacking where different models are used to understand the same hazard evolution at various scales.
New hydrological insights for the region: As developing cities grow, so do the flood risks, especially in the informal settlement. This study reveals the importance of comprehensively understanding the flood dynamics at various scales. The study points out the important role of model stacking and calibrations which allows the understanding of flood risks at various city scales for an integrated city flood risk management.
Study focus: This study uses a desk review format to promote urban flood modeling knowledge and practice in integrated flood risk management in developing cities. In this regard, the study presents the review of various flood models highlighting their strengths and weaknesses and the significant role of model calibrations in addressing uncertainties while capturing the local scenarios. The paper further presents the role of model stacking where different models are used to understand the same hazard evolution at various scales.
New hydrological insights for the region: As developing cities grow, so do the flood risks, especially in the informal settlement. This study reveals the importance of comprehensively understanding the flood dynamics at various scales. The study points out the important role of model stacking and calibrations which allows the understanding of flood risks at various city scales for an integrated city flood risk management.
13 Loli, M.; Kefalas, G.; Dafis, S.; Mitoulis, S. A.; Schmidt, F. 2022. Bridge-specific flood risk assessment of transport networks using GIS and remotely sensed data. Science of the Total Environment, 850:157976. (Online first) [doi: https://doi.org/10.1016/j.scitotenv.2022.157976]
Flooding ; Risk assessment ; Bridges ; Transportation ; Geographical information systems ; Remote sensing ; Infrastructure ; Vulnerability ; Resilience ; Extreme weather events ; Hydrodynamics ; Precipitation ; Decision making ; Indicators ; Case studies / Greece / Thessaly / Karditsa
(Location: IWMI HQ Call no: e-copy only Record No: H051415)
https://www.sciencedirect.com/science/article/pii/S0048969722050756/pdfft?md5=fa5488c9b9f6389fa0e84729c56a18b7&pid=1-s2.0-S0048969722050756-main.pdf
https://vlibrary.iwmi.org/pdf/H051415.pdf
https://vlibrary.iwmi.org/pdf/H051415.pdf
(6.33 MB) (6.33 MB)
A novel framework for the expedient assessment of flood risk to transportation networks focused on the response of the most critical and vulnerable infrastructure assets, the bridges, is developed, validated and applied. Building upon the recent French guidelines on scour risk (CEREMA, 2019), this paper delivers a thorough methodology, that incorporates three key, risk parameters: (i) the hydrodynamic loading, a hazard component of equal significance to scour, for the assessment of hazard; (ii) the correlation of select scour indicators with a new index relating to flow velocity, a primary measure of the adverse impacts of flow–structure interaction, enabling a more accurate and automated, assessment of bridge susceptibility to scour; (iii) the use of a new, comprehensive indicator, namely the Indicator of Flood Hazard Intensity (IFHI) which incorporates, in a simple yet efficient way, the key parameters controlling the severity of flood impact on bridges, namely flow velocity, floodwater height, flow obstruction, and sediment type. The framework is implemented for the analysis of flood risk in a case study area, considering an inventory of 117 bridges of diverse construction characteristics, which were affected by a major flood that impacted Greece in September 2020. The reliability of the method is validated against an extensive record of inspected and documented bridge damages. Regional scale analysis is facilitated by the adoption of the Multi-Criteria Decision-Making method for flood hazard indexing, considering geomorphological, meteorological, hydrological, and land use/cover data, based on the processing of remotely sensed imagery and openly available geospatial datasets in GIS.
14 Wade, M.; Kaizer, A.; McNeil, T.; O’Brien, G. 2022. Digital technology to construct 3D hydrodynamic models for monitoring environmental flows. Colombo, Sri Lanka: International Water Management Institute (IWMI). CGIAR Initiative on Digital Innovation. 15p.
Environmental flows ; Monitoring ; Digital technology ; Hydrodynamics ; Models ; Rivers ; Ecosystems ; Habitats ; Discharges / South Africa / Crocodile River
(Location: IWMI HQ Call no: e-copy only Record No: H051645)
(1.18 MB)
To support the implementation of environmental flows (e-flows), we piloted a three-dimensional digital modeling approach to monitor the changes in river ecosystems. A high-resolution 3D model of study sites in the Crocodile River, South Africa, was constructed and used to test its utility and value to monitor changes in river ecosystem structure over time. The initial demonstration of the approach shows highly detailed 3D models of nine tracks across the study sites. The output represents the velocity-depth and bathymetry variability of each site in 3D. The dataset successfully demonstrated the potential value of adopting the approach for e-flow implementation to monitor the habitat dynamism to support the timely management of river health. In the next phase, this assessment will integrate the 3D modeling approach into a hydrodynamic modeling framework to investigate dynamic relationships between flow-ecosystem and ecosystem services.
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