Assessment of the Impact of Climate Variability and Change on the Reliability, Resiliency and Vulnerability of Complex Flood Protection Systems

An original modeling framework (DYHAM) for assessment of climate variation and change impacts on the performance of complex flood protection system has been developed and tested using the Red River basin (Manitoba) as a case study. Modeling framework allows for evaluation of different climate change scenarios generated by the global climate models. Temperature and precipitation are used as the main factors affecting flood flow generation. System dynamics modeling approach proved to be of great value in the development of system performance assessment model.The most important impact of climate variability and change on hydrologic processes is reflected in the change of flood patterns: flood starting time, peak value and timing. Floods in the Red River basin generally occur in spring when the increase in temperature initiates snowmelt that usually coincides with heavy rain. In this study more than 90% of floods (at Shellmouth reservoir on the Assiniboine River and at Ste. Agathe on the Red River) generated using three different climate models started earlier in March and April. We conclude that the increase in temperature from climate variation and change results in an earlier flood starting time in the Red River basin. The DYHAM assessment of the performance of Red River flood protection system is based on the flood flows, the capacity of flood control structures and failure flow levels at different locations in the basin. In the Assiniboine River basin, higher reliabilities at downstream locations are obtained indicating that Shellmouth reservoir plays an important role in reducing downstream flooding. However, a different trend was identified in the Red River basin. The study results show that flood protection capacity of the Red River infrastructure is sufficient under low reliability criteria but may not be sufficient under high reliability criteria.https://ir.lib.uwo.ca/wrrr/1000/thumbnail.jp

Role of Remote Sensing in Disaster Management

The objective of this report is to review the existing satellites monitoring Earth’s resources and natural disasters. Each satellite has different repeat pass frequency and spatial resolution (unless it belongs to the same series of satellites for the purpose of continuation of data flow with same specifications). Similarly, different satellites have different types of sensors on-board, such as, panchromatic, multispectral, infrared and thermal. All these sensors have applications in disaster mitigation, though depending on the electromagnetic characteristics of the objects on Earth and the nature of disaster itself. With a review of the satellites in orbit and their sensors the present work provides an insight to suitability of satellites and sensors to different natural disasters. For example, thermal sensors capture fire hazards, infrared sensors are more suitable for floods and microwave sensors can record soil moisture. Several kinds of disasters, such as, earthquake, volcano, tsunami, forest fire, hurricane and floods are considered for the purpose of disaster mitigation studies in this report. However, flood phenomenon has been emphasized upon in this study with more detailed account of remote sensing and GIS (Geographic Information Systems) applicability. Examples of flood forecasting and flood mapping presented in this report illustrate the capability of remote sensing and GIS technology in delineating flood risk areas and assessing the damages after the flood recedes. With the help of a case study of the Upper Thames River watershed the use of remote sensing and GIS has been illustrated for better understanding. The case study enables the professionals and planning authorities to realize the impact of urbanization on river flows. As the urban sprawl increases with the increase of population, the rainfall and snow melt reaches the river channels at a faster rate with higher intensity. In other words it can be inferred that through careful land use planning flood disasters can be mitigated.https://ir.lib.uwo.ca/wrrr/1002/thumbnail.jp

A Spatial Fuzzy Compromise Approach for Flood Disaster Management

Natural disasters affect regions with different intensity and produce damages that vary in space. Topographical features of the region; location of properties that may be exposed to the peril; level of exposure; impact of different mitigation measures; are all variables with considerable spatial variability. A new method for evaluation of disaster impacts has been presented in this report that takes into consideration spatial variability of variables involved and associated uncertainty. Flood management has been used to illustrate the utility of proposed approach. Floodplain management is a spatial problem. Representation of flood damage mitigation alternatives and objectives in space provides a better insight into the management problem and its characteristics. Protection of a region from floods can be achieved through various structural and non-structural measures. Comparison of different measures and evaluation of their impacts is based on the multiple criteria. If they are described spatially, decision-making problem can be conceptualized as spatial multi criteria decision-making (MCDM). Tkach and Simonovic (1997) introduced spatial Compromise Programming (SPC) technique to account for spatial variability in flood management. Some of the criteria and preferences of the stakeholders involved with flood management are subject to uncertainty that may originate in the data, knowledge of the domain or our ability to adequately describe the decision problem. The main characteristic of flood management is the existence of objective and subjective uncertainty. Fuzzy set theory has been successfully used to address both, objective and subjective uncertainty. Bender and Simonovic (2000) incorporated vagueness and imprecision as sources of uncertainty into multi criteria decision-making in water resources. In this report a new technique named Spatial Fuzzy Compromise Programming (SFCP) has been developed to enhance our ability to address the issues related to uncertainties in spatial environment. A general fuzzy compromise programming technique, when made 2 spatially distributed, proved to be a powerful and flexible addition to the list of techniques available for decision making where multiple criteria are used to judge multiple alternatives. All uncertain variables (subjective and objective) are modeled by way of fuzzy sets. In the present study, fuzzy measures have been introduced to spatial multi criteria decision-making in the GIS environment in order to account for uncertainties. Through a case study of the Red River floodplain near the City of St. Adolphe in Manitoba, Canada, it has been illustrated that the new technique provides measurable improvement in flood management. Final results in the form of maps that shown spatial distribution of the impacts of mitigation measures on the region can be of great value to insurance industry.https://ir.lib.uwo.ca/wrrr/1004/thumbnail.jp

Inverse Drought Risk Modelling of the Upper Thames River Basin

This report aims to present an alternate approach to climate change impact mod- elling of water resources. The focus of the project is on the analysis of existing water resources management guidelines specifically targeting critical hydrologic events (ex- treme droughts in this case). The critical hydrologic events are converted to their corresponding meteorologic conditions via use of an appropriate hydrologic model (continuous based hydrologic model for drought analysis). The local climatic signal is generated by use of a non-parametric weather generator linked to outputs from a global circulation model for three climate scenarios, and their corresponding fre- quency curves generated. Then, a critical hydrologic event of interest is selected, its corresponding meteorological condition obtained, and its frequency of occurrence for each climate scenario determined. It is noted that all climate change scenarios showed less frequent occurrence of extreme droughts. However, potentially severe droughts are still possible (with a chance of 1 in 10 any given year, sometime less) in the basin; this coupled with the fact that drought damage assessments are non existent in the basin suggests that new or improved drought management guidelines should be investigated. Based on the analysis presented, recommendations are made for future work to in- clude: (i) drought impact studies (where impacts to agriculture, recreation, wetlands, reservoir operation, ground water withdrawal and streamflow quality are assessed); (ii) definition of local drought triggers (including guidelines on subwatershed scale, as well as monitoring how drought triggers change over time); (iii) water quality man- agement (setting in place practises that enhance water quality over short and long term); (iv) education programs (to bring up to date knowledge in science to all who stand to be adversely impacted by drought).https://ir.lib.uwo.ca/wrrr/1015/thumbnail.jp

NDM-515: AN ORIGINAL MODEL OF INFRASTRUCTURE SYSTEM RESILIENCE

Infrastructure systems of transportation, water supply, telecommunications, power supply, etc. are not isolated but highly interconnected and mutually coupled. Infrastructure interdependences can increase system vulnerability and produce cascading failures at the regional or national scales. Taking the advantage of network theory structure analysis, this paper models street, water supply network, power grid and information infrastructure as network layers that are integrated into a multilayer network. The infrastructure interdependences are detailed using five basic dependence patterns of network fundamental elements. Definitions of dynamic cascading failures and recovery mechanisms of infrastructure systems are also established. The main focus of the paper is introduction of a new infrastructure network resilience measure capable of addressing infrastructure system as well as network component (layer) interdependences. The new measure is based on infrastructure network performance, proactive infrastructure network resistance capacity and reactive infrastructure network recovery capacity. With three resilience features and corresponding network properties develops paper, this the of dynamic space new quantitative measure -time resilience and a resilience simulation model resilience and network properties three dimensions of use for infrastructure network assessments. The resilience model is applicable to any type of infrastructure and its application can improve the infrastructure planning, design and maintenance decision making

Inverse Flood Risk Modelling of The Upper Thames River Basin

This report aims to present an alternate approach to climate change impact mod- elling of water resources. The focus of the project is on the analysis of existing wa- ter resources management guidelines specifically targeting critical hydrologic events (extreme floods in this case). The critical hydrologic events are converted to their corresponding meteorologic conditions via use of an event based hydrologic model. The local climatic signal is generated by use of a non-parametric weather generator linked to outputs from a global climate model for three climate scenarios, and their corresponding frequency curves generated. Then, a critical hydrologic event of inter- est is selected, its corresponding meteorological condition obtained, and its frequency of occurrence (one for each climate scenario) determined. A scenario selected specifically to study the problem of flooding in the basin showed more frequent occurrence of flooding for nearly all magnitudes of floods. An- other scenario, selected for studying droughts depicts a lesser tendency of extreme flooding events. Therefore, ranges of estimates of changes of frequency of occurrence of critical hydrologic events are obtained in response to changing climatic conditions. Based on these estimates, recommendations for changing current basin management guidelines are provided. They are categorized into three distinct categories: (i) regula- tory (where a review of rules, regulations and operation of current flood management infrastructure are suggested); (ii) budgetary (where investment in new infrastructure, as well as increased maintenance costs of present and future infrastructure, can lead to a need of having higher operating budgets); and (iii) engineering (recommending a review of current design standards of critical infrastructure).https://ir.lib.uwo.ca/wrrr/1014/thumbnail.jp

Development of Rainfall Intensity duration Frequency Curves for the City of London under the Changing Climate

The main focus of this study is the analysis of short duration high intensity rainfall for London, Ontario under the conditions of the changed climate. Predicted future climate change impacts for Southwestern Ontario include higher temperatures and increases in precipitation, leading to an intensification of the hydrologic cycle. One of the expected consequences of change is an increase in the magnitude and frequency of extreme events (e.g. high intensity rainfall, flash flooding, severe droughts, etc.). Changes in extreme events are of particular importance to the design, operation and maintenance of municipal water management infrastructure. Municipal water management infrastructure (sewers, storm water management ponds or detention basins, street curbs and gutters, catchbasins, swales, etc) designs are typically based on the use of local rainfall Intensity Duration Frequency (IDF) curves. IDF curves are developed using historical rainfall time series data. Annual extreme rainfall is fitted to a theoretical probability distribution from which rainfall intensities, corresponding to particular durations, are obtained. In the use of this procedure an assumption is made that historic extremes can be used to characterize extremes of the future (i.e., the historic record is assumed to be stationary). This assumption is not valid under changing climatic conditions that may bring shifts in the magnitude and frequency of extreme rainfall. Such shifts in extreme rainfall at the local level demand new regulations for water infrastructure management as well as changes in design practices. The objective of this report is to assess the change in IDF curves for use by the City of London under changing climatic conditions. The methodology implemented to assess changes in rainfall magnitude resulting from climate change includes the following components: (a) Development and use of a daily weather generator model for synthetic generation of rainfall under current and future climates; (b) Disaggregation of daily rainfall into hourly; (c) Statistical analysis of rainfall of various durations, and development of IDF curves under changed climatic conditions; (d) Comparative analysis of IDF curves; and (e) Recommendation for possible modification of municipal infrastructure design standards. The two IDF curves currently used by the City of London (i.e., MacLauren IDF curve for design of conveyance systems, and Atmospheric Environment Service IDF curve for storm water management facilities) could have not be reproduced in this research using the data currently available from Meteorological Service of Canada. The IDF curves in use by the City are based on data sets that are no longer available. In addition, methods used by either MacLauren or Meteorological Service of Canada to estimate rainfall quantiles for durations shorter than one hour are not available. Therefore, comparing the IDF curves generated in this research to those currently used by the City of London is not appropriate. More confidence is placed in the relative difference between the three scenarios generated in this research: simulated historic climate (no change), and wet and dry climates (change guided by outputs of global circulation model outputs). The results of simulations in this research indicate that rainfall magnitude (as well as intensity) will be different than historically observed. The climate change scenario recommended for use in the evaluation of storm water management design standards (i.e., the wet scenario) reveals a significant increase in rainfall magnitude (and intensity) for a range of durations and return periods. This increase has major implications on the ways in which current (and future) municipal water management infrastructure is designed, operated, and maintained. The main recommendation from this work is that the design standards and guidelines currently employed by the City of London be reviewed and/or revised in light of the information presented in this report.https://ir.lib.uwo.ca/wrrr/1020/thumbnail.jp

Calibration, Verification and Sensitivity Analysis of the HEC-HMS Hydrologic Model

The main objective of this report is to describe the calibration, verification, and sensitivity analysis of the United States Army Corps of Engineers (USACE) Hydrologic Engineering Center’s Hydrologic Modeling System (HEC-HMS) on the data from the Upper Thames River basin (UTRb) study area. The HEC-HMS model was chosen to be the most appropriate hydrologic modeling tool for achieving the goals set in the Canadian Foundation for Climatic and Atmospheric Sciences (CFCAS) funded project “Assessment of Water Resources Risk and Vulnerability to Changing Climatic Conditions” (“project” hereafter), (Cunderlik and Simonovic, 2003). The calibration, verification and sensitivity analysis of the HMS model are parts of the project Task 1: Development of a hydrologic model (ICLR, 2004).https://ir.lib.uwo.ca/wrrr/1010/thumbnail.jp