Postgraduate researcher(PhD), University of Bristol
Flood forecasting in an Indian river river basin using WRF-Hydro
Floods have been recurrent phenomenon in many parts of India. Therefore Flood forecasting and mitigation is quite essential to help the decision makers to make adaptive measures.
Abstract: In the past decades, the influence of climate change has caused changes in the amount of rainfall in many areas which may affect the flood assessment and mitigation. This research aims to determine amount of rainfall which impacts on changes of the water levels in canals and evaluate the appropriate mitigation measures for floods in the inner Bangkok area, Bangkok Noi and Bangkok Yai districts of Bangkok. The maximum 1-day rainfall during 1997–2010 was determined under different return periods of 2, 5, 10, 25, 50 and 100 year. The MIKE 11 model was then applied to assess changes of the water levels in canals caused by design rainfall events for those return periods. The flood mitigation was also proposed by applying various pumping capacities and initial water levels, incorporating with building dykes and a floodgate. This study has found that the highest flood-risk areas are along Chak Phra and Bangkhunnon canals and the eastern part of Jakthong Canal while the lowest flood-risk area is Bangkok Yai district. Flood caused from the 10-year rainfall can be mitigated by building dykes with the height of 0.75 m [mean sea level (MSL)] and maintaining the initial water level of 0.70 m (MSL). Furthermore, it has also been found that flood caused from the 25-year rainfall can be mitigated by building the floodgate to prevent the flowing back water at Wat Yangsuttharam Canal. However, 50- and 100-year rainfalls seem to cause floods which are too large to mitigate.
Pub.: 04 May '14, Pinned: 12 Oct '17
Abstract: Flood risk assessments are an objective and quantitative basis for implementing harmonized flood mitigation policies at the basin scale. However, the generated results are subject to different sources of uncertainty arising from underlying assumptions, data availability and the random nature of the phenomenon. These sources of uncertainty are likely to bias conclusions because they are irregularly distributed in space. Therefore, this paper addresses the question of the influence of local features on the expected annual damage in different municipalities. Based on results generated in the frame of a transnational flood risk assessment project for the river Meuse (Western Europe) taking climate change into account, the paper presents an analysis of the relative contributions of different sources of uncertainty within one single administrative region (the Walloon region in Belgium, i.e., a river reach of approximately 150 km). The main sources of uncertainty are not only found to vary both from one municipality to the other and in time, but also to induce opposite effects on the computed damage. Nevertheless, practical conclusions for policy makers can still be drawn.
Pub.: 04 Mar '15, Pinned: 12 Oct '17
Abstract: The water content of wetlands represents a key driver of their hydrological services and it is highly dependent on short- and long-term weather conditions, which will change, to some extent, under evolving climate conditions. The impact on stream flows of this critical dynamic component of wetlands remains poorly studied. While hydrodynamic modelling provide a framework to describe the functioning of individual wetland, hydrological modelling offers the opportunity to assess their services at the watershed scale with respect to their type (i.e., isolated or riparian). This study uses a novel approach combining hydrological modelling and limited field monitoring, to explore the effectiveness of wetlands under changing climate conditions. To achieve this, two isolated wetlands and two riparian wetlands, located in the Becancour River watershed within the St Lawrence Lowlands (Quebec, Canada), were monitored using piezometers and stable water isotopes (δD – δ18O) between October 2013 and October 2014. For the watershed hydrology component of this study, reference (1986–2015) and future meteorological data (2041–2070) were used as inputs to the PHYSITEL/HYDROTEL modelling platform. Results obtained from in-situ data illustrate singular hydrological dynamics for each typology of wetlands (i.e., isolated and riparian) and support the hydrological modelling approach used in this study. Meanwhile, simulation results indicate that climate change could affect differently the hydrological dynamics of wetlands and associated services (e.g., storage and slow release of water), including their seasonal contribution (i.e., flood mitigation and low flow support) according to each wetland typology. The methodological framework proposed in this paper meets the requirements of a functional tool capable of anticipating hydrological changes in wetlands at both the land management scale and the watershed management scale. Accordingly, this framework represents a starting point towards the design of effective wetland conservation and/or restoration programs.
Pub.: 18 Aug '16, Pinned: 12 Oct '17
Abstract: This paper evaluates the combined impacts of climatic and demographic changes on a multipurpose reservoir system in the Harz mountains in northern Germany. For this purpose, the spatially distributed hydrological model PANTA RHEI was firstly calibrated and validated with gridded observational data. Secondly, the hydrological model was forced with data from two regional climate models. The possibilities and limitations of using current regional climate models as an input for hydrological modelling in very high resolution in space and time were evaluated. Their applicability in reservoir operation optimization on an hourly time step was demonstrated. For an increase in extreme events, indicated by one regional climate model, the impact of an adaptation of operation rules with respect to flood protection on the other uses of the system was assessed. Furthermore, a new method was presented, how economic information from national accounting in combination with demographic scenarios can be used in exposure analysis. The paper ends with a demonstration of the importance of combining the impacts of climatic and demographic change, while developing sound and cost-efficient water resources management strategies for the near and distant future.
Pub.: 25 Oct '16, Pinned: 12 Oct '17
Abstract: Authors: David Dorchies, Guillaume Thirel, Charles Perrin, Jean-Claude Bader, Régis Thepot, Jean-Louis Rizzoli, Claudine Jost and Stéphane Demerliac.La Houille Blanche , page 32Published online: 10/11/2016 Keywords: Flood ; Low flows ; Reservoir management adaptation ; Climate change impacts ; Hydrological modelling ; Seine Basin ; Crue ; Etiage ; Adaptation de la gestion de réservoirs ; Impacts des changements climatiques ; Modélisation hydrologique ; Bassin de la Seine.
Pub.: 10 Nov '16, Pinned: 12 Oct '17
Abstract: Climate change has serious impacts on forest services with regard to the spatial and temporal distribution of water within catchments. Hence, combined forest and catchment management in a changing climate is a crucial concern for people and society. To assess hydrological processes and water resources in two forested headwater catchments in south-west Germany the physical based hydrological model ArcAPEX was calibrated to investigate climate change scenarios for the near (2021–2050) and far (2071–2100) future. Even though the trend in temperature is positive in most regional climate change scenarios for south-west Germany, the precipitation trend is quite ambiguous. Different precipitation scenarios give access to the possible bandwidth between water stress and flood generation. Our results can be used to describe water resources and discharge characteristics under conditions of different land use change scenarios.Management option for a sustainable forestry and flood mitigation will be to “spread the risk” by creating forests with a high biodiversity and a prioritization of forest services and functions. The principle is to find “no-regret” decisions. In this sense, final decisions should not be taken too early, and several options should be kept open, such as dealing with increasingly frequent droughts on one hand and increased runoff generation on the other hand. Thus, it should remain possible for forest and catchment management authorities to react to possible developments in an uncertain future.
Pub.: 19 Dec '16, Pinned: 12 Oct '17