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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Modeling to support acceleration of restoration of a residential building system in southeastern B.C. due to riverine flooding

Ivy, Afia Siddika 30 January 2020 (has links)
Floods are among some of the most damaging natural disasters. They can cause major interruptions to buildings and infrastructure and can have lasting impacts. In the case of flood damage estimation to buildings, structural and non-structural damages are of interest to most flood risk research. Very few studies, conversely analyze the impact of the recovery timeline on losses. There is a challenge to clearly understand the cause of failures within an interconnected system such as a building, and the requirements for accelerating restoration to overcome the adverse results of flood in the most convenient way possible. This work seeks to map the various components involved in functional failures of flood damaged buildings to understand their recovery. A novel model of a residential building is constructed using the Graph Model for Operational Resilience (GMOR) to model the complex interaction among dependencies in building systems to understand the cascade of failure of restoration. A case study is performed to generate recovery model to simulate the restoration of a single residential building in a flood prone neighborhood of Surrey, BC, Canada. The depth-damage functions, along with construction and repair guides, are used to identify restoration dependencies and to formulate a unique sequence of flood recovery steps for several possible flood depths. This study demonstrates how restoration can be delayed and probable solutions to improve the resilience of the city through recovery planning of flooded buildings. The results provide insights that should be useful to help emergency managers and other decision makers to develop and implement resilience thinking while revealing the economic benefits associated with increased flood risk management. In future, the custom flood model can be adapted to other locations. / Graduate / 2020-12-04
2

Recovery From and Effects of a Catastrophic Flood and Debris Flow on the Brook Trout (<i>Salvelinus fontinalis</i>) Population and Instream Habitat of the Staunton River, Shenandoah National Park, VA

Roghair, Craig N. 03 August 2000 (has links)
The Staunton River is a high gradient, second order stream approximately 6 km in length located on the eastern slope of the Blue Ridge Mountains in Shenandoah National Park, VA. In June 1995, a catastrophic flood and debris flow altered the instream habitat and <i>Salvelinus fontinalis</i> population of the Staunton River. The debris flow scoured the streambed, deposited new substrate materials, removed trees from the riparian zone, and eliminated fish from a 1.9km section of the stream. By June 1998, both young-of-year (YOY) and age 1+ <i>S. fontinalis</i> had recolonized the debris flow affected area. The event provided a rare opportunity to examine recovery of the <i>S. fontinalis</i> population and instream habitat in addition to addressing potential effects of the debris flow on movement, activity, and growth of fish in the debris flow affected and unaffected areas of the stream. Post-recolonization movement and activity were monitored using two-way fish traps (weirs), mark-recapture techniques, and radio telemetry. The weirs failed to produce any movement data. Most fish (91%) in the mark-recapture study had range sizes less than 100m, however biases common to mark-recapture study designs (low recapture rate, flawed logic, etc.) hampered interpretation of results. For example, subsequent recapture of individually marked fish indicated that as many as 54% of marked fish confirmed to have been alive at the time of a recapture session were not recaptured. Radio telemetry provided information on <i>S. fontinalis</i> movement and activity at seasonal and diel scales during summer and fall. Differences in movement and activity between the debris flow affected and unaffected areas were minimal when compared to seasonal variations. During summer, range sizes were near 0m and crepuscular activity patterns were observed. During the fall range size increased and diel activity was concentrated in the mid-afternoon with a much higher peak than during summer. Basin-wide visual estimation technique (BVET) fish population surveys performed each spring and fall from 1993 = 1999 provided pre- and post-event fish population abundance and density estimates. Post-event fish growth in the debris flow affected and unaffected areas was monitored using mark-recapture techniques. Abundance and density of both YOY and age 1+ <i>S. fontinalis</i> exceeded pre-event levels within 2-3 years. Growth of YOY and age 1+ fish was significantly greater in the debris flow affected area until spring 1999. Population density appeared to have a strong negative influence on growth. The observed changes in fish growth and differences in fish size associated with population density would be of minimal importance to the typical angler but may suggest a mechanism by which <i>S. fontinalis</i> populations can quickly recover from catastrophic events. BVET habitat surveys provided information on total stream area, number of pools and riffles, pool and riffle surface area and depth, substrate composition, and large woody debris (LWD) before (1993), immediately following (1995), and four years post-event (1999). Immediately following the debris flow, the stream channel was highly disordered which resulted in an increase in the total number of habitat units and a decrease in average habitat unit surface area, total stream area, and average depth when compared with pre-event conditions. In addition, substrate composition had shifted from small to large diameter particles and LWD loading had increased in both debris flow affected and unaffected areas. Four years after the event, the total number of habitat units, average habitat unit surface area, total stream area, and average depth had all returned to near pre-debris flow levels and substrate composition had begun to shift towards smaller particle sizes. Changes in LWD loading from 1995-1999 reflected changes in the riparian zone following the debris flow. In the unaffected area, where riparian trees remained intact, LWD loading increased, whereas in the debris flow affected area, where riparian trees were eliminated, LWD loading decreased. For the most part the effects of the debris flow, although immediately dramatic, were in the long term minimal. The debris flow affected area was recolonized rapidly and abundance and density quickly rebounded past pre-event levels. Differences in fish growth between the affected and unaffected area were short lived. Any effect the debris flow affected area may have had on movement or activity was minimal when compared with seasonal variations. Most habitat characteristics reverted to near pre-event levels just four years after the flood and debris flow. Although a number of factors will influence recovery time from such events, these results indicate that immediate management action, such as stocking or habitat modifications, are not necessary in all cases. / Master of Science

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