Effective Flood Risk Research Articles

A critical analysis of 2010 floods in Pakistan

Pakistan has diverse geography with Northern alpines covered with glaciers and Southern Plains bordering the Arabian Sea. There are five big rivers flowing through the country from north to south namely the mighty Indus and its tributaries, that is, Jhelum, Chenab, Ravi and Sutlej. There is a well marked monsoon season from July to mid September in which most of the country receives rainfall. Riverine flooding is common in the low lying areas along the rivers during monsoon season while flash flooding is also experienced in hilly and semi hilly areas. Since its creation, Pakistan has faced severe floods in 1950, 1956, 1957, 1973, 1976, 1978, 1988, 1992 and now in 2010. These floods affected the basins of the rivers in Punjab and Sindh. In Khyber Pakhtunkhwa (KPK), Balochistan, Federally Administrated Tribal Areas (FATA), Gilgit Baltistan(G-B), Azad Jammu and Kashmir(AJK) and in some areas of Punjab, damages are caused mainly due to flash floods in secondary and tertiary rivers including hill torrents. Pakistan has suffered from the worst flood of its history in monsoon season of 2010. As per Damage Need Assessment (DNA) report of ADB /World Bank, the floods affected an area of about 160,000 km2 (one fifth of the country), claiming about 1,985 lives, damaging around 1.5 million houses, wiping out cropped area of more than 17 million acres, displacing a population of about 20 million and resulting in economic loss of PKR 10 Billion. Pakistan needs to do all it can to stop weather disasters becoming catastrophes and to protect people from future catastrophic flood disasters and increase the resilience of infrastructure, economies and communities including better emergency warning and evacuation systems, better flood protection for key infrastructure and plans to help communities recover once the waters recede. There is immense need for effective technical planning for flood damage mitigation in the country. This paper critically discusses in detail the causes and mechanism of 2010 flood on country wide basis. To prevent future catastrophic flood disasters, the priority improvements have been identified and recommendations have been made for effective flood risk management in the country. Key words: Flood management, flood damage mitigation, 2010 Pakistan flood.

Flood hydraulics due to cascade landslide dam failure

AbstractLandslide dams are usually unconsolidated and when they act to impound water, they are subjected to failure that triggers catastrophic flooding downstream. However, the flood hydraulics due to landslide dam failure has remained poorly understood and cannot be reliably predicted at present. Inevitably, this militates against effective flood risk management in areas prone to landslides. Extending the recent investigation of a single landslide dam failure and the resulting flood, here, we present an experimental and computational study on the flood flow induced by cascade landslide dam failure. A total of 12 runs of experiments are conducted in a flume of 80 m × 1.2 m × 0.8 m, with differing inflow discharge and dam composition. An array of 12 automatic water‐level probes is deployed to measure the stage hydrographs along the flume. The coupled shallow water hydrodynamic model calibrated for cases of a single landslide dam failure is demonstrated to perform reasonably well for cascade landslide dam failure. Most notably, under appropriate conditions, the occurrence of streamwise progressive enhancement of the flood induced by cascade landslide dam failure is demonstrated. This features a higher risk of flooding downstream and therefore warrants careful consideration in flood risk management.

Managing water as a socio-technical system: the shift from ‘experts’ to ‘alliances’

This paper argues that the management of flooding in England has shifted from a technocratic focus, in which engineering expertise was reified, to a more socially diffuse set of approaches seeking to disassemble the predominant institutional hegemony. Some explanation for this shift, commonly referred to as the transition from flood defence to flood risk management, can be found by situating changes historically: Food shortages after World War I prompted the Land Drainage Act (1930), generating a new financial structure linked to increased food productivity. The Act created a centralised funding mechanism for flood defences, enabling large-scale re-engineering of the countryside, but removed the guarantee of an individual's protection from flooding that had existed since the Sewers Act of 1532. Climate change and ongoing development of urban areas on flood plains present new challenges to flood risk management. Looking forward, this paper illustrates that the concept of learning alliances, which draw on Habermassian ideas of communicative action, provide an appropriate platform to facilitate the transition to effective flood risk management. Through reference to a current English case study, the Don Catchment learning alliance (situated within the wider Yorkshire and Humber learning alliance), this paper maps ongoing transitions.

An integrated flood risk assessment model for property insurance industry in Taiwan

Taiwan is located in an area affected by Northwest Pacific typhoons, which are also one of the most important sources of rainfall to the island. Unfortunately, the abundant rainfall brought by typhoons frequently produces hazards. In recent years, typhoons and floods have caused serious damage, especially Typhoon Morakot in 2009. In this study, a probabilistic model is developed based on historical events which can be used to assess flood risk in Taiwan. There are 4 separate modules in this model, including a rainfall event module, a hydraulic module, a vulnerability module, and a financial loss module. Local data obtained from the Taiwan government are used to construct this model. Historical rainfall data for typhoon and flood events that have occurred since 1960, obtained from the Central Weather Bureau, are used for computing the maximum daily rainfall for each basin. In addition, the latest flood maps from the Water Resources Agency are collected to assess the probable inundation depth. A case study using the local data is carried out. Assessment is made to predict possible economic loss from different financial perspectives such as the total loss, insured loss, and loss exceeding probabilities. The assessment results can be used as a reference for making effective flood risk management strategies in Taiwan.

Optimal management of wetlands: Quantifying trade‐offs between flood risks, recreation, and biodiversity conservation

This paper employs a simple choice experiment to estimate the value of management options for the Bobrek wetland in Poland. The local public's valuation of several wetland management attributes, including flood risk reduction, biodiversity conservation and improvement of recreational access, are investigated. A latent class model is estimated to account for heterogeneity in the wetland management choices of the local public. The results reveal that there is considerable heterogeneity among the local public as two distinct segments are identified. For both of the segments, flood risk reduction, in the ranges considered, is more important than the other two attributes. The results of this study are expected to assist policy makers in undertaking effective flood risk reduction measures and formulating efficient, equitable and sustainable wetland management policies in accordance with the European Union's Water Framework Directive (2000/60/EC).

Do social housing providers across Yorkshire and the East Midlands have effective flood risk management in place when maintaining and repairing their housing stock?

This paper investigates whether social housing providers across Yorkshire and the East Midlands have effective flood risk management in place to mitigate the impacts of inevitable future flooding. A comprehensive review of current literature highlights a plethora of variables magnifying the risk of future flooding in the UK and a number of measures available to reduce the impacts of future flooding on both property and occupiers. Further research has suggested a lack of preparedness on behalf of the social housing providers in respect of managing the risk of future flooding. In addition, there is limited awareness of flood-resilient repair and a lack of both technical skills and experience available to manage what is a specialist process in a very immature market — flood damage remediation.

Book Reviews

Book Reviews

Use of computer models of flood inundation to facilitate communication in flood risk management

It is now widely recognised that good communication between multi-disciplinary stakeholders is central to effective flood risk management. Recent developments in Geographical Information Systems, increased availability of accurate digital terrain models from remotely sensed data sources and improved graphical computer interfaces have made the outputs from computer models of flood inundation easily accessible to the stakeholder community. As a consequence, predictions from such models are now being used routinely as a means of communication between engineers and other stakeholders in flood risk management. This paper provides a review of the modelling methods most appropriate for flood risk communication. These are one-dimensional models which are suitable for simulating flood risk at a catchment or sub-catchment scale and appropriate for communicating the impact of strategic flood management decisions and two-dimensional models which can be applied across a range of scales but, are now being regularly applied at the relatively small scale, less than 10 km 2, where they have the potential to inform and communicate disaster management decisions. The role of such models in communicating between modellers and non-modellers by providing a means for immediate visualisation of “the future” is discussed and illustrated by application to two case studies.