Case-Based Reasoning of Man-Made Geohazards Induced by Rainfall on Transportation Systems

Due to global warming and environmental change, disastrous natural events have increased in scale and impact, e.g., Typhoon Morakot, in 2009 and 2011 Tōhoku earthquake and resulting tsunami in Japan. Hazard management is becoming increasingly important, making it a necessity to manage risk and fully understand critical scenarios. For example, the National Infrastructure Protection Plan of the United States emphasizes on lessons learned from past disasters. In this chapter, several selected cases of accidents caused by man-made geohazards in Taiwan are studied

Natural and Technological Hazards in Urban Areas

Natural hazard events and technological accidents are separate causes of environmental impacts. Natural hazards are physical phenomena active in geological times, whereas technological hazards result from actions or facilities created by humans. In our time, combined natural and man-made hazards have been induced. Overpopulation and urban development in areas prone to natural hazards increase the impact of natural disasters worldwide. Additionally, urban areas are frequently characterized by intense industrial activity and rapid, poorly planned growth that threatens the environment and degrades the quality of life. Therefore, proper urban planning is crucial to minimize fatalities and reduce the environmental and economic impacts that accompany both natural and technological hazardous events

ANALYZING THE LIFE-CYCLE OF UNSTABLE SLOPES USING APPLIED REMOTE SENSING WITHIN AN ASSET MANAGEMENT FRAMEWORK

An asset management framework provides a methodology for monitoring and maintaining assets, which include anthropogenic infrastructure (e.g., dams, embankments, and retaining structures) and natural geological features (e.g., soil and rock slopes). It is imperative that these assets operate efficiently, effectively, safely, and at a high standard since many assets are located along transportation corridors (highways, railways, and waterways) and can cause severe damage if compromised. Assets built on or around regions prone to natural hazards are at an increased risk of deterioration and failure. The objective of this study is to utilize remote sensing techniques such as InSAR, LiDAR, and optical photogrammetry to identify assets, assess past and current conditions, and perform long-term monitoring in transportation corridors and urbanized areas prone to natural hazards. Provided are examples of remote sensing techniques successfully applied to various asset management procedures: the characterization of rock slopes (Chapter 2), identification of potentially hazardous slopes along a railroad corridor (Chapter 3), monitoring subsidence rates of buildings in San Pedro, California (Chapter 4), and mapping displacement rates on dams in India (Chapter 5) and California (Chapter 6). A demonstration of how InSAR can be used to map slow landslides (those with a displacement rate \u3c 16 mm/year and may be undetectable without sensitive instrumentation) and update the California Landslide Inventory on the Palos Verdes Peninsula is provided in Chapter 7. Long-term landslide monitoring using optical photogrammetry, GPS, and InSAR measurements is also used to map landslide activity at three orders of magnitude (meter to millimeter scales) in Chapter 8. Remote sensing has proven to be an effective tool at measuring ground deformation, which is an implicit indicator of how geotechnical asset condition changes (e.g., deteriorates) over time. Incorporating these techniques into a geotechnical asset management framework will provide greater spatial and temporal data for preventative approaches towards natural hazards

Synthesis and Assessment Product

This document, part of the Synthesis and Assessment Products described in the U.S. Climate Change Science Program (CCSP) Strategic Plan. Climate affects the design, construction, safety, operations, and maintenance of transportation infrastructure and systems. The prospect of a changing climate raises critical questions regarding how alterations in temperature, precipitation, storm events, and other aspects of the climate could affect the nation's roads, airports, rail, transit systems, pipelines, ports, and waterways. Phase I of this regional assessment of climate change and its potential impacts on transportation systems addresses these questions for the region of the U.S. central Gulf Coast between Galveston, Texas and Mobile, Alabama. This region contains multimodal transportation infrastructure that is critical to regional and national transportation services. The significance of various climate factors for transportation systems was assessed

Investigation of the Performance of the New Orleans Flood Protection System in Hurricane Katrina on August 29, 2005: Volume 1

This report presents the results of an investigation of the performance of the New Orleans regional flood protection system during and after Hurricane Katrina, which struck the New Orleans region on August 29, 2005. This event resulted in the single most costly catastrophic failure of an engineered system in history. Current damage estimates at the time of this writing are on the order of $100 to$200 billion in the greater New Orleans area, and the official death count in New Orleans and southern Louisiana at the time of this writing stands at 1,293, with an additional 306 deaths in nearby southern Mississippi. An additional approximately 300 people are currently still listed as “missing”; it is expected that some of these missing were temporarily lost in the shuffle of the regional evacuation, but some of these are expected to have been carried out into the swamps and the Gulf of Mexico by the storm’s floodwaters, and some are expected to be recovered in the ongoing sifting through the debris of wrecked homes and businesses, so the current overall regional death count of 1,599 is expected to continue to rise a bit further. More than 450,000 people were initially displaced by this catastrophe, and at the time of this writing more than 200,000 residents of the greater New Orleans metropolitan area continue to be displaced from their homes by the floodwater damages from this storm event. This investigation has targeted three main questions as follow: (1) What happened?, (2) Why?, and (3) What types of changes are necessary to prevent recurrence of a disaster of this scale again in the future? To address these questions, this investigation has involved: (1) an initial field reconnaissance, forensic study and data gathering effort performed quickly after the arrival of Hurricanes Katrina (August 29, 2005) and Rita (September 24, 2005), (2) a review of the history of the regional flood protection system and its development, (3) a review of the challenging regional geology, (4) detailed studies of the events during Hurricanes Katrina and Rita, as well as the causes and mechanisms of the principal failures, (4) studies of the organizational and institutional issues affecting the performance of the flood protection system, (5) observations regarding the emergency repair and ongoing interim levee reconstruction efforts, and (6) development of findings and preliminary recommendations regarding changes that appear warranted in order to prevent recurrence of this type of catastrophe in the future. In the end, it is concluded that many things went wrong with the New Orleans flood protection system during Hurricane Katrina, and that the resulting catastrophe had it roots in three main causes: (1) a major natural disaster (the Hurricane itself), (2) the poor performance of the flood protection system, due to localized engineering failures, questionable judgments, errors, etc. involved in the detailed design, construction, operation and maintenance of the system, and (3) more global “organizational” and institutional problems associated with the governmental and local organizations responsible for the design, construction, operation, maintenance and funding of the overall flood protection system

Spatial variability of aircraft-measured surface energy fluxes in permafrost landscapes

Arctic ecosystems are undergoing a very rapid change due to global warming and their response to climate change has important implications for the global energy budget. Therefore, it is crucial to understand how energy fluxes in the Arctic will respond to any changes in climate related parameters. However, attribution of these responses is challenging because measured fluxes are the sum of multiple processes that respond differently to environmental factors. Here, we present the potential of environmental response functions for quantitatively linking energy flux observations over high latitude permafrost wetlands to environmental drivers in the flux footprints. We used the research aircraft POLAR 5 equipped with a turbulence probe and fast temperature and humidity sensors to measure turbulent energy fluxes along flight tracks across the Alaskan North Slope with the aim to extrapolate the airborne eddy covariance flux measurements from their specific footprint to the entire North Slope. After thorough data pre-processing, wavelet transforms are used to improve spatial discretization of flux observations in order to relate them to biophysically relevant surface properties in the flux footprint. Boosted regression trees are then employed to extract and quantify the functional relationships between the energy fluxes and environmental drivers. Finally, the resulting environmental response functions are used to extrapolate the sensible heat and water vapor exchange over spatio-temporally explicit grids of the Alaskan North Slope. Additionally, simulations from the Weather Research and Forecasting (WRF) model were used to explore the dynamics of the atmospheric boundary layer and to examine results of our extrapolation

Multiple simulation experimental studies of gas emission, distribution and migration rules in mine ventilation system and goaf area

Gas problems have created severe difficulties for the mining industry around the world, leading to high expenditures and intensity research efforts, and determined attempts to enhance the various ventilation optimization and gas drainage techniques. Meanwhile, gas research is thriving in recent years, and gas drainage technology will continue to be a growing industry over the coming decades in many mining countries. Safety mining technologies including field investigation, numerical simulation and laboratorial experiments have been improved to develop a better understanding of the causes of mine gas-related disasters over the last two decades. In addition, new and multiple gas control strategies and technologies have been developed, including optimizing the ventilation system constantly, preventing goaf spontaneous combustion timely, enhancing gas risk management effectively, determining the gas emission zone exactly, and implementing a reasonable gas drainage plan correctly. The first part of the dissertation introduces a multiple gas disaster prevention, control and reduction strategy. Firstly, the basic theories of gas emission, distribution and migration are discussed. Then a numerical prediction model based on a specific coal mine is established to predict its gas emission. The second part of the dissertation offers the establishment of the numerical simulation model (CFD) and laboratorial experimental model for the purpose of discussing the gas distribution and migration rule and determining the most effective gas drainage zones in the working face and goaf. Both of the numerical simulation results and the laboratorial experimental results also demonstrate that the most effective gas drainage spot constantly varies with the area where mining activities are performed. In the case of numerical simulation experimental results, it is mainly located in the area of 40m-250m (between working face and deep goaf), 30m-40m from the working face floor (between the working face floor to the roof), and approximately 60m-170m (between air inlet and air outlet). In the case of laboratorial simulation experimental results, it mainly locates in coal seam and rock stratum separation area of 27cm-243cm (between working face and deep goaf), 28cm-42cm (between the working face floor to the roof) and 78cm-182cm (between air inlet and air outlet). The last part of this dissertation provides a field study in order to obtain the gas distribution and migration rule in the working face and goaf. The field measured results show the average gas drainage rate increased from 39.6 m3·min-1 (U-type ventilation system) to approximately 48.9 m3·min-1 (U+L-type ventilation system) while the gas concentration of the special drainage tunnel, upper corner and air outlet decreased from 1.88%, 0.85% and 0.61% (U-type ventilation system) to 1.69%, 0.75% and 0.55% (U+L-type ventilation system), respectively. These results indicate the layout of the gas drainage boreholes is rational and effective; the gas drainage volume is reliable. Therefore, it is feasible and reliable to arrange the layout of gas drainage tunnels based on the experimental results of numerical simulation and laboratorial test.Los problemas ocasionados por gas han creado graves dificultades para la industria minera en todo el mundo, por lo que ha implicado altos gastos y esfuerzos de investigación y intentos de mejorar en diversas técnicas de optimización de la ventilación y drenaje de gas. Mientras tanto, la investigación sobre gas ha aumentado considerable en los últimos años y la tecnología de drenaje de gas seguirá siendo una industria en crecimiento en las próximas décadas en muchos países mineros. Las tecnologías mineras de seguridad, incluyendo la investigación de campo, la simulación numérica y experimentos en laboratorio han mejorado para una mejor comprensión de las causas de los desastres relacionados con el gas de las minas en las últimas dos décadas. Además, se han desarrollado nuevos y múltiples estrategias y tecnologías de control de gas, incluyendo la optimización del sistema de ventilación, impidiendo excavaciones de combustión espontánea oportuna, mejorando así la gestión eficaz de riesgos causados por gases, determinando la zona de emisión de gases con exactitud, y la implementación de un plan de drenaje de gas correctamente. La primera parte de la tesis se presenta una estrategia múltiple de la prevención de desastres de gas, control y reducción. En primer lugar, se analizarán las teorías básicas de la emisión de gases, la distribución y la migración. Luego se establecerá un modelo de predicción numérica basada en una mina de carbón específica para predecir su emisión de gases. La segunda parte de la tesis ofrece el establecimiento del modelo numérico de simulación (CFD) y el modelo experimental de laboratorio con el fin de discutir la distribución de gas y norma de migración y la determinación de las zonas de drenaje de gas más eficaces en el frente de trabajo y terraplén. Tanto los resultados del simulación numéricos como los resultados experimentales de laboratorio demuestran que el punto de drenaje más eficaz de gas varía constantemente según el área donde se realizan las actividades mineras. En el caso de los resultados experimentales de simulación numérica, que se encuentra principalmente en el área de 40m-250m (entre la superficie del tierra y el zona excavada), 30m-40m desde la superficie de trabajo (desde la superficie del trabajo hasta el techo), y aproximadamente 60m-170m (entre el entrada y salida de aire). En el caso de los resultados experimentales de simulación en el laboratorio, se localiza principalmente en la veta de carbón y la zona de separación del estrato rocoso de 27cm-243cm (entre la superficie de la tierra y la zona excavada), 28cm-42cm (desde la superficie del trabajo hasta el techo) y 78cm-182cm (entre la entrada y salida de aire). La última parte de esta tesis concluye un estudio de campo con el fin de obtener la distribución de gas y el estado migratorio entre la superficie y la zona escavada. Los resultados de campo medidos muestran que la tasa de drenaje de gas en promedio aumentó 39,6 m3·min-1 (sistema de ventilación de tipo T) a aproximadamente 48,9 m3 · min-1 (sistema de ventilación de T + L-tipo), mientras que la concentración de gas del drenaje especial en túnel, esquina superior y salida de aire se redujo de 1,88%, 0,85% y 0,61% (sistema de ventilación de tipo U) a 1,69%, 0,75% y 0,55% (U + de tipo L sistema de ventilación), respectivamente. Estos resultados indican que la disposición de las perforaciones de drenaje de gas es racional y eficaz; el volumen de drenaje de gas es fiable. Por lo tanto, es factible y fiable para organizar la disposición de túneles de drenaje de gas sobre la base de los resultados experimentales de simulación numérica y la prueba de laboratorio

Soil physical impacts and recovery rates following human-induced disturbances in the Ross Sea region of Antarctica

With increasing visitor numbers an understanding of the impacts of human activities on Antarctic soil environments has become an important issue. The overall objective of this thesis was to investigate soil physical impacts, and soil recovery rates, following human disturbance in the Ross Sea region of Antarctica. Visually disturbed and nearby control sites were assessed using a combination of techniques, including field-based visual site assessments, comparative photo-records, a desert pavement recovery assessment method, soil sampling, and soil dry bulk density measurements. An experimental soil disturbance trial was set up near Scott Base and bacterial DNA profiling was used to investigate the response of communities to removal of the top 2 cm of soil. Infra-red track counters were installed on Ross Island walking tracks to record visitor use over a two-year period. Five case studies, from former research stations to field campsites, were investigated to assess the accuracy of the impacts predicted in environmental impact assessments and the observed impacts. In all cases there was a high level of consistency between predicted and observed impacts. It was apparent that the environmental impact assessment process raised environmental awareness of visitors; motivating them to avoid, remedy, or mitigate, their environmental impacts. A field-based method was developed to assess desert pavement recovery and tested on 54 sites. Eleven criteria were used: embeddedness of surface clasts; impressions of removed clasts; degree of clast surface weathering; % overturned clasts; salt on underside of clasts; development of salt coatings; armouring per m2; colour contrast; evidence of subsidence/melt out; accumulation of salt on cut surfaces; and evidence of patterned ground development. Recovery criteria were assigned a severity rating on a scale from zero to four, and the Mean Recovery Index (MRI) of the site was calculated relative to an equivalent control. Five recovery stages were defined as recently or highly disturbed (MRI of 0-24%), through to indistinguishable from control site (MRI = 100%). Fifty of the 54 sites investigated were in an intermediate or higher stage of desert pavement recovery (MRI > 50%), 30 sites were in an advanced stage of recovery (MRI > 75%), and four sites were indistinguishable from adjacent control sites (MRI = 100%). Active surfaces, such as gravel beach deposits, aeolian sand, and alluvial fan deposits, recovered relatively quickly and had higher MRIs, whereas less active sites of higher intensity disturbances, such as bulldozed tracks at Marble Point, had lower MRIs, with only intermediate recovery up to 50 years after disturbance. Following physical impacts such as foot and vehicle traffic the surface recovery recorded here was often greater than that predicted by previous researchers. At one-off campsites, footprints from dispersed trampling were undetectable within five years. At some sites walking tracks remained visible in the landscape 17 years after they were formed (due to surface recontouring and larger clasts concentrating along track margins). For steep slopes and sites where repeated visits occur, use of a single track is recommended. At sites where visually obvious impacts were remediated by replacing larger stones back in their original positions, ensuring that surface stones are placed with the weathered side up, and raking of gravel sand-sized displaced materials, visible evidence of former occupation was almost undetectable. Concentrating activity on young, active, and readily recoverable surfaces, or resilient bedrock, is recommended. There were no significant changes in bacterial community structure in response to experimental removal of the top 2 cm of soil over a 35 day sampling period. Differences in bacterial community structure between samples correlated with differences in soil electricity conductivity (R2 = 0.55) and soil pH (R2 = 0.67), reflecting small scale (< 2 m) soil heterogeneity. Infrared track counters recorded: 5084 passes on the Scott Base to McMurdo Station walking track, 2842 on the Wind Vane Hill walking track, 3561 on the Round Observation Hill walking track, and 10936 on the Up Observation Hill track between January 2009 and January 2011. On the Crater Hill summit walking track there were 693 passes in 2009. Higher counts were recorded on all tracks in the 2010/2011 summer season, compared with the 2009/2010 summer, and the highest frequency of visitors occurred on Sundays in the summer months. Peak daily counts at the Wind Vane Hill track coincided with the arrival of tourist ships. There was no relationship between the number of passes on the track and the measured impacts, indicating that higher usage of a formed track had little cumulative impact. Track width and track incision were related to the slope of the terrain, with tracks traversing flatter areas generally wider (R² = 0.85) and less incised (R² = 0.96) than those traversing steeper hillsides. Soil dry bulk density was higher in the walking tracks compared with the adjacent control areas (p <0.05)