Strategies to harmonize urbanization and flood risk management in deltas

In many countries, important economic centres and major cities are located in a flood-prone area at the confluence of a large river and the sea. The expansion of these cities increases the risk of major flood disasters, a risk that is further increased if the predicted effects of climate change come true. Recent thinking about flood prevention stresses the importance of restricting city expansions into flood-prone areas, flood-proofing cities and accomodating floods by reserving space for water. These ideas require innovative city design, cooperation between city planners and water managers, and a policy that connects various levels of government with business and the public. The choice of strategy may be culture-specific, but will in any case involve large investments, and have long-term and large-scale consequences. Thus, it is worthwhile to exchange experiences between delta's that are tackling this problem. In the paper we will compare the approaches in a number of "typical" urbanized flood-prone delta's: New Orleans in the Mississippi delta, the Randstad in the Rhine delta, Venice in the Po delta, Wuhan along the Yangtze, Yokohama along the Tsurumi, Dhaka in the Ganges-Brahmaputra delta and London along the Thames.

Participatory action research on climate risk management, Bangladesh

The rural populations of southern Bangladesh are some of the most vulnerable communities in the world to the future impacts of climate change. They are particularly at risk from floods, waterlogged soils, and increasing salinity of both land and water. The objective of this project was to analyze the vulnerability of people in four villages that are experiencing different levels of soil salinity. The study evaluated the strengths and weaknesses of current coping strategies and assessed the potential of an index-based insurance scheme, designed diversification and better information products to improve adaptive capacity

Urban flood simulation and integrated flood risk management

Climate change induces the probability of occurring natural disasters; e.g. floods, Sea Level Rise, Green House Gases. Flood is considered one of the most dangerous phenomena that tremendously and dramatically threatening the human being and environment worldwide. Rapid urban growth, demographic explosion, and unplanned land uses have exacerbated the problem of urban flooding, particularly in the cities of China. In addition to that, the concept of flood risk management and adaptation measures and strategies are still missed in the cities’ development future plans. The main objective of this Ph.D. dissertation is to investigate the flood risk analysis and assessment based on flood simulation and adaptive strategies for flood event through two case studies of Changsha city in south-central China. In case study I, fluvial flooding was considered on mesoscale and an MCA-based approach was proposed to assess the integrated flood risk of Changsha central city. HEC-RAS 1-D model was used to simulation the inundation characteristics for hazard analysis based on four risk dimensions: economic, social, environmental, and infrastructural risk. For infrastructural dimension, apart for direct damage on road segments, network analysis method was combined with inundation information and macroscopic traffic simulation to evaluate the impact on traffic volume as well as a decrease of road service level. Closeness centrality weighted with a travel time of pre- and after- flood was compared in order to measure the impact on urban accessibility. Integrated risk values were calculated using various weighting criteria sets. Sobol' indices were used as a tool of spatially-explicit global Uncertainty Analysis and Sensitivity Analysis (UA/SA) for damage models. In case study II, an agent-based modeling approach was proposed to simulate the emergency pluvial flood event caused by a short-time rainstorm in local areas of cities aiming at developing an interactive flood emergency management system capable of interpreting the risk and reduction strategy of the pluvial flood. The simulation integrated an inundation model with microscopic traffic simulation. It also reveals that all agents can benefit significantly from both engineering measures and the only pedestrian obtain relatively more benefits from risk warning with high awareness. The method provided potentials in studies on the adaptive emergency management and risk reduction, help both decision-makers and stakeholders to acquire deeper and comprehensive understanding of the flood risk. This Ph.D. study has investigated holistic methods and models’ selection in flood risk assessment and management to overcome data deficiency and to achieve the integration of different data. The results of the first case study reveal that the integrated methods have proved to be able to improved flood risk analysis and assessment especially for indirect damage of infrastructural system with network features. The global UA/SA based on Sobol' method and visualization with maps enable to gain the spatial distribution of uncertainty for various factors, the validation of damage models, and deeper and more comprehensive understanding of flood risk. Then based on the integrated risk assessment, functions of spatial planning in flood risk management were discussed, potentially providing guidance and support for decision-making. The results of the second case study denote that agent-based modeling and simulation can be effectively utilized for flood emergency management. Two scenarios focusing on specific risk reduction interventions were designed and compared. Engineering measures by improving capability of the drainage system and the surface permeability of waterlogging areas are the most effective means for damage mitigation. High public risk awareness still has great potential benefits of the in the event of emergencies, which can greatly enhance the effectiveness of the official warning. The agent-based modeling and simulation provided an effective method for analyzing the effectiveness of different strategies for reducing flood risk at the local scale and for supporting urban flood emergency management. The case studies also indicate the significance and necessity of establishing a platform and database to realize full sharing and synergies of spatial information resources for flood risk management, which is a vital issue to manage the urban flood risk and take effective measures correspondingly with responding to emergency extreme flood event. Keywords: urban flood; flood risk assessment; network analysis; flood simulation; flood risk managemen

The adaptation continuum: groundwork for the future

The focus of the program was to understand the challenges posed by climate change and climate variability on vulnerable groups and the policies needed to support climate adaptation in developing countries. The aim of the book is to share this experience in the hope that it will be helpful to those involved in shaping and implementing climate change policy

Flood risk management in sponge cities:The role of integrated simulation and 3D visualization

The Sponge City concept has been promoted as a major programme of work to address increasing flood risk in urban areas, in combination with wider benefits for water resources and urban renewal. However, realization of the concept requires collaborative engagement with a wide range of professionals and with affected communities. Visualization can play an important role in this process. In this research, a sponge city flood simulation and forecasting system has been built which combines hydrological data, topographic data, GIS data and hydrodynamic models in real-time and interactive display in a three-dimensional environment. Actual and design flood events in a pilot sponge city have been simulated. The validation results show that the simulated urban water accumulation process is consistent with the actual monitoring data. Use of advanced virtual reality technology can enable simulations to be placed in the wider design context including enhanced awareness of multiple functions of urban ecosystems. This procedure can therefore reduce the information communication gap and encourage innovation regarding low impact development required for sponge city construction

Strategies to harmonize urbanization and flood risk management in delta's 1

Abstract In many countries, major cities are located in flood-prone areas at the confluence of rivers and sea. The expansion of these cities and the expected effects of climate change are increasing the risk of floods. Recent thinking about flood risk management stresses the importance of reserving space for water, restricting city expansions into flood-prone areas and flood-proofing cities. The Dutch flood risk policy is paying more attention to these approaches, but the consequences for the urbanization in the Netherlands have not yet been well explored. Thus it is worthwhile to learn from the experience in other areas that are tackling this problem. In the paper we describe the approaches in a number of "typical" urbanized deltas: Yokohama along the Tsurumi river, New Orleans in the Mississippi delta, the Randstad in the Rhine-Meuse delta, Wuhan along the Yangtze, and Dhaka in the Ganges-Brahmaputra delta. From these cases we identify 3 main strategies to harmonize urbanization and flood risk management: keep floods away from urban areas; prepare urban areas for floods; keep urban areas away from floods. We give examples, requirements and constraints of these strategies and draw some lessons for the Randstad

Socially-integrated resilience in building-level water networks using smart microgrid+net

Environmental change and natural events can impact on multiple dimensions of human life; economic, social, political, physical (built) and natural (ecosystems) environments. Water distribution networks cover both the built and natural realms and are as such inherently vulnerable to accidental or deliberate physical, natural, chemical, or biological threats. An example of such threats include flooding. The damage to water networks from flooding at the building level can include disrupted supply, pipe damage, sink and sewer overflows, fittings and appliance malfunctions etc. as well as the consequential socio-economic loss and distress. It has also been highlighted that the cost of damage caused by disasters including flooding can be correlated to the warning-time given before it occurs. Therefore, contiguous and continuous preparedness is essential to sustain disaster resilience. This paper presents an early stage review to: 1. Understand the challenges and opportunities posed by disaster risks to critical infrastructure at the building level. 2. Examine the role and importance of early warnings within the smart systems context to promote anticipatory preparedness and reduce physical, economic, environmental and social vulnerability 3. Review the opportunities provided by smart water microgrid/net to deliver such an early warning system and 4. Define the basis for a socially-integrated framework for resilience in building water networks based on smart water micro grids and micronets. The objective is to establish the theoretical approach for smart system integration for risk mitigation in water networks at the building level. Also, to explore the importance and scope integration of other social-political dimensions within such framework and associated solutions. The findings will inform further studies to address the gaps in understanding the disaster risks in micro water infrastructure e.g. flooding, and; to develop strategies and systems to strengthen disaster preparedness for effective response and anticipatory action for such risks

Impact of flood on rural population and strategies for mitigation: A case study of Darbhanga district, Bihar state, India

Floods are one of the most disastrous acts of nature and impact human life in multiple ways. Damages by floods in rural areas are more severe compared to urban counterparts due to poverty, limited infrastructures and access to resources and health care services. The Province of Bihar in India, with a population of 104.1 million, has 76 per cent of the population living under recurring threat of floods. In 2008, Bihar experienced severe floods in the northern region that affected more than 2.3 million people; and in 2013, they affected more than 5.9 million in 3768 villages across 20 rural districts. Floods damage property, infrastructure and further decreases access to health care and social services. This paper draws from the data collected for the primary author’s master’s thesis, along with his personal experience on floods as an inhabitant of a flooded community. It outlines the impact of floods in the rural areas of Bihar and highlights the continuous marginalization and exclusion of flood-affected communities. This paper will raise awareness of the issue and call for global support to advocate for more effective flood mitigation strategies

Water Management Plan for the Town of Perenjori

The Rural Towns – Liquid Assets (RT–LA) project was established with the aim of integrating salinity, waterlogging and flooding control with development of new water supplies in wheatbelt towns, and where possible, finding ways of putting the excess water to commercial use. Following the identification of effective integrated water management strategies, these have been applied to the 15 Shires participating in the DAFWA led RT–LA project. This report summarises the outcomes from all scientific investigations undertaken for Perenjori. In addition it presents the water management options, a preliminary analysis of those options and the priority recommended ones. Due to the decline in rainfall over the past 10 years, Perenjori groundwater levels have shown a declining trend below the townsite since 2000, when groundwater monitoring by DAFWA in the townsite commenced. Hydrogeological studies identified groundwater pumping was not an effective solution for Perenjori to control watertable levels in the high salinity risk areas of the townsite. The studies demonstrated that only limited volumes of groundwater could be abstracted by pumping because the drawdown affects would be constrained by the geological properties. It is concluded that salinity control or water production from under the townsite via groundwater pumping is not a technically viable option. Instead, the RT–LA project has focused on surface water management options that will enable new water supplies to be developed which will also alleviate salinity, watertable, waterlogging and flooding problems. An integrated scheme such as this will provide cost effective solutions to the annual problem of irrigation water shortages. Over time, the proposed surface water diversion and harvesting schemes will reduce salinity risk by diverting and utilising runoff water which would otherwise have contributed to local recharge. Option 1, construction of a new 30ML dam in the paddock east of town belonging to Mr Jim Gilmour, is recommended as the first priority action. Along with the other options outlined in this Water Management Plan, Option 1 offers a combination of surface water engineering solutions to capture the town’s runoff and provide up to an additional 31 ML/yr, or 155 per cent of the total existing demand