Flood is one of the major natural disasters in Australia. It breaks down transportation and communication systems, disrupts businesses and causes damage to properties, loss of stock, crops and also loss of human lives. Better understanding of the impacts resulting from floods and other natural hazards can help to reduce the damages or losses. Flood damage assessment procedures estimate the impact of flood in monetary terms to help decision makers develop new policies, programs and development plans. This study examines different techniques, procedures and underpinning philosophies that have been used in some major emergency management and insurance organizations in the world such as RAM, ANUFLOOD, and HAZUS and NHRC. From this examination the study finds that none of them are suitable for mitigation and emergency purposes in producing economic flood damage estimation at fine resolution with high accuracy. From this perspective the study develops a rigorous procedure for property level economic flood damage assessment. The assessment procedures are embedded within GIS (Geographic Information System) technology which can model and analyse the multidimensional phenomenon of flood and damage characteristics of residential buildings. The damage estimation procedures developed in this study include flood modelling, collection and organisation of building inventory data; adopting a set of stage-damage curves; and measuring damage at property level. The quality of damage estimates derived from the procedures is highly influenced by quality of input data. The study also includes the implementation of the damage assessment procedure on the study area (a segment of Kororoit Creek and its adjacent area). The study uses data from a number of sources including Melbourne Water, NEXIS, VICMAP, a quick survey and literature. The developed procedure will help many practitioners in flood loss assessment and natural hazard risk management to face the challenges they have in establishing damage estimates with high accuracy.

Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

No description available.

Thesis (M.S. - Hydrology and Water Resources)--University of Arizona. / Includes bibliographical references (leaves 168-171).

Thesis (M.P.A.)--University of Hong Kong, 1999. / Includes bibliographical references.

Thesis (M.P.A.)--University of Hong Kong, 1999. / Includes bibliographical references. Also available in print.

system model and computational methodology have been developed which evaluate the worth of flood forecast - response systems in reducing the economic damage caused by floods. The efficiencies of the forecast system, the response system, and the overall system may be individually obtained and compared. In this report the case study of Milton, Pennsylvania, was extended and further case studies were performed including a large residential section of Victoria, Texas, and all the residences in Columbus, Mississippi. These locations show better forecast and response efficiencies than obtained for Milton, Pennsylvania. The difference is attributed to longer forecast lead times at Columbus and Victoria. Sensitivity analyses were run at all three locations. These show the effects of many system factors, such as the time required to produce, disseminate and respond to a forecast, on the efficiency of the system. The forecast efficiency improves significantly as these times are reduced. Further analysis of the response system based on human factors involved has led to the development of a simulation model of the process by which the floodplain dweller determines the appropriate response to a flood warning. Investigation of ways to extend the methodology to evaluate regions lacking the detailed data used for the case studies has indicated more problems than answers. Extrapolation based on overall system efficiency related to published regional and national flood damage estimates was used to provide an approximate value of the flood forecast - response system for two regions and for the nation.A listing of simplicities and approximations which make computations tractable but which may affect accuracy is given. Finally, an evaluation of the work accomplished for this project and suggestions for the constructive use of the flood forecast -response system model and computational procedures is given.

No description available.

This study deals with the fundamental problems of hydrological design. Specifically, it explores the boundary conditions for design flood analysis. The problem of extrapolation of design relationships has been investigated by the systematic analysis of important design parameters namely unit hydrograph time to peak (tp), catchment antecedent conditions (CWI), runoff losses (PR) and the relationship between rainfall and flood return periods. In particular, this thesis investigates the combination of these variables representative of design analysis. A review of the hydrological design tools of response identification along with the physical evidence of catchment response is presented. The results of the investigation regarding time to peak (tp) show that it varies significantly between events, and the relationships developed between tp and flood magnitude (Qp) show the non-linear catchment behaviour which conform with most of the physical and field investigations. The relationships suggest that the unit hydrograph (UH) parameters derived from moderate events should be adjusted for extreme events and therefore a correction in UH tp has been developed which depends on the flood return period (Ashfaq and Webster, 2000a). The analysis of catchment wetness index (CWI) from a large number of observed events showed that antecedent conditions observed in the flood season are reasonably representative of the major events. This contrasts with the existing design recommendations which suggest consistently lower values. An alternative relationship of CWI therefore has been developed for design purposes (Webster and Ashfaq, submitted manuscript). The investigation showed that the percentage runoff (PR) characteristics of large events are consistently different than available from the existing design PR-method. The design method underestimates for the standardised conditions especially for large events because of its limited range of estimates for a wide range of return periods (e.g. 11% range in PR for 2 to 1000 year return periods). This problem is related with the PR-method itself for catchments having higher mean annual rainfall (SAAR> 800 mm) whereas for lower SAAR areas « 800 mm), it is related to the selection of design CWI values. The analysis of observed large events also revealed that a flood is generally associated with the storm of less return period than that of the flood. This contrasts with the suggested design rainfall-flood return periods relationship in the FSR (NERC, 1975; [H, 1999), but conforms with the curves presented by Webster (1998, 1999). This observation is further established by a detailed investigation of the characteristics of extreme events through a continuous model as well as the hydrological analysis of observed extreme floods of Easter-1998 (Ashfaq and Webster,2000b). The study demonstrates that the characteristics of extreme floods are different from those of small and moderate events. Relationships based on moderate events should be adjusted for the design of major events. The aggregated and integrated findings based on a comprehensive series of analysis led to the proposal of an alternative combination of design parameters. The performance of this combination showed improved flood estimates without any prior calibration in comparison to the FSR as well as FEH. A revised design methodology has therefore been proposed on the philosophy of 'independent treatment of input variables'. The application of this methodology on new catchments also provides encouraging estimates of flood quantiles. It is suggested that the methodology is equally applicable for both gauged and ungauged catchments especially where the observed data are limited or no data are available.

No description available.