Geo-Extreme 2021: Case Histories and Best Practices

The surface temperature of two municipal solid waste (MSW) containment facilities that were experiencing combustion was measured in the early morning with a clear sky. The highest surface temperature measured is 665°C (1,225°F), which confirms that open flame combustion can occur in an MSW landfill (MSWL). Additional field temperatures over 150°C (302°F) along with field carbon monoxide (CO) detection and site observations confirmed the presence of smoldering combustion. Char, scorched earth, and smoking were visible along the landfill surface through cracks and vents, which facilitated air intrusion. Air intrusion was initially facilitated by use of a thin sand cover that is more permeable than a fine-grained soil cover. It is recommended that thicker fine-grained soil cover be applied to MSWLs before installation of the final cover system to reduce combustion potential.

Located near the western tip of Coney Island, 3514 Surf Avenue includes two 20- and 22-story towers, a three- to five-story podium, and an attached garage. This paper describes the numerous challenges that arose during design and construction, including complex soil conditions, strict settlement tolerances, aggressive design criteria, and flood concerns magnified by Hurricane Sandy. High-foundation loads under the towers, combined with a deep compressible clay layer [65–105 ft (20–32 m) below grade], would have resulted in unacceptable settlement of the towers if shallow foundations were used. However, the relatively light garage loads did not present settlement issues and therefore did not warrant expensive pile foundations. To address differential settlement between the towers and garage, the geotechnical and structural engineers proposed a hybrid foundation system of pile foundations under the towers and spread footings under the garage. The interaction and settlement at the interface of the two foundation types were considered while designing this cost-effective solution that satisfied serviceability requirements. Multiple rounds of subsurface explorations (16 test borings, 11 CPT probes, and 22 test pits), index-pile driving (20 piles), and pile load testing (40 PDAs, 22 CAPWAPs, five compression load tests, and three lateral load tests) were performed during the design phase to optimize the foundations. The project team considered different pile types and sizes during the index-pile program as recommended by the geotechnical engineer and foundation contractor.

Until recent Hurricanes Matthew and Irma struck northeast Florida, Hurricane Dora had been the first and only hurricane-strength storm in recorded history to strike the region. The area had gradually become regarded as a safe spot as storms at that latitude generally curved away from Jacksonville and northeast Florida, and turned north to make landfall in the Carolinas. Unknown to most, Vilano Beach had been experiencing steady yet chronic beach erosion and was already in a highly vulnerable state in many places when the recent storms struck. The cause of the ongoing background erosion continues to be a source of contention among residents and some experts. This paper presents prestorm historic beach conditions, the potential causes and progression of erosional events surrounding Hurricanes Matthew and Irma at three locations in northeast Florida, and an assessment of protection measures implemented by homeowners. Observations made during field investigations show that bulkheads constructed to protect single or multiple houses exacerbate erosion at the ends of the bulkheads. This results in both failure of the bulkheads as well as increased erosion for neighboring properties.

The water level of Lake Michigan has recently risen to record highs, rising over 6 ft compared to the water level only seven years ago. The rise in water level has resulted in significant marine erosion along the shoreline of Lake Michigan. As a result, many property owners along Lake Michigan have initiated the implementation of measures to protect their properties, including expensive homes situated on coastal bluffs overlooking the lake. This paper presents three case studies that demonstrate how dramatic beach erosion/retreat has resulted from the higher water levels, the variable technical nature of solutions to address erosion and bluff retreat, and the importance that owners of neighboring lakefront properties work together to implement protective measures.

Hurricanes and tropical storms represent short duration, high-magnitude events that can significantly deteriorate coastal wetlands. Aside from marsh-edge erosion, changes in marsh ecology, and geomorphology may occur that in turn affect geotechnical properties of the substrata. In June 2020, a multidisciplinary team rapidly assembled and deployed instrumentation to monitor a coastal wetland in southern Louisiana during Tropical Storm Cristobal. The instrumentation deployed to measure the storm effects includes wave gauges, piezometers, sediment traps, erosion pins, and time-lapse cameras. A thorough poststorm reconnaissance effort was conducted less than a week after storm impact. Slump failures across the marsh edge were observed, with the vegetated mat still intact on the now-submerged sections. Cross sections of the slumping failures were measured alongside marsh-edge erosion values. Erosion pin data show that erosion rates are highest in the center of the transect. A suite of RTK-GPS elevation measurements were taken to identify geomorphological changes. Water level measurements are compared to pore-pressure values along a transect from marsh-edge inland. The marsh becomes inundated rapidly except for a high-elevation strip along the marsh edge. A systematic review of lessons learned from deploying instrumentations and the mechanisms of failure imparted on the marsh by the storm are presented.

The aim of this paper is to present the performance of different types of geomembranes used for the rehabilitation of concrete and masonry dams in Europe, particularly in Italy and France. In all these applications, the geomembranes used were made by plasticized polyvinyl chloride (PVC-P) and have been left exposed on the upstream face, without external protection, to very extreme environmental factors and atmospheric agents, especially to Ultraviolet (UV) rays, at high elevations on the Alps. To verify the effective performance of the barrier system over time, several geomembrane samples—taken from a considerable number of dams—have been subjected to destructive chemical, physical, and mechanical tests. The results were interpreted with reference to the measure of some main properties, as plasticizer content, tensile characteristics, flexibility at low temperatures, volumic mass, and water vapor permeability. In particular, the plasticizer content plays a fundamental role in terms of variation of the intrinsic properties of the PVC-P geomembranes. In some cases, when the results of tests on virgin samples were available and several data points of plasticizer content versus time are available, the service life of the PVC-P geomembrane can be predicted. In fact, the prediction of the time in which it could be necessary to replace the geomembrane becomes of a crucial importance also for the owner of the dam.

This is a case history of the design, construction, and performance of a geogrid stabilized ringer crane platform used during construction of a petrochemical facility in southern Louisiana. Unbeknownst to designers and engineers would be the onslaught of Hurricane Harvey during operation of the ringer crane in summer 2017. The PTC-200 DS ringer crane was configured with a maximum bearing pressure of 192 kPa, a load spreader ring with outside and inside diameters of 56 and 33.2 m, respectively, and was rated the third largest crane in the world. Challenges included stringent differential settlement criteria, site conditions of predominantly moist expansive clays, providing sufficient drainage for the unique geometry of the crane, and preventing the sand bed leveling surface from displacing or eroding. The resiliency and performance of the geogrid stabilized platform was demonstrated when the working platform withstood the devastating tropical storm without damage and the crane resumed operation the day after the storm passed. Primary success of this project is attributed to timely involvement of the teams of engineers and consultants, the design of an aggressive drainage system and refinement of the sand pontoon surface, and the willingness of the owner and his engineers to consider an alternative design solution.

Within the State of California, an extensive infrastructure of storage facilities and transmission pipelines provides natural gas to residential and commercial customers. A project funded by the California Energy Commission is developing a tool to evaluate the risk of this infrastructure system to earthquake hazards. This tool will have modules that characterize various hazards, infrastructure component fragilities, and system level risk.

This paper will address the feasibility of using Permeable Low-Density Cellular Concrete (PLDCC) in soft soil remediation and roadway elevation applications. In this discussion, the paper will examine the case study of a project conducted at West Lake Eloise Drive in Winter Haven, Florida, and will also review and evaluate data from recent studies conducted at the University of Missouri–Kansas City related to the physical properties of PLDCC, including permeability, lightweight characteristics, compressive strength, and resistance to buoyancy. In its discussion of the West Lake Eloise Drive project, this paper will posit the effectiveness of 481 kg/m³ (30 lb/f³) PLDCC in the remediation of settlement caused by soft soils as well as the proposed increase in elevation of roadways in areas that experience high-water tables.

This paper presents a computer vision analysis to extract data from the footage of the Edenville Dam breach. The Edenville Dam breached on May 19, 2020, leading to extensive flooding in Central Michigan. Engineers have been eagerly seeking first-hand information to study this catastrophic event. Fortunately, the dam breach was captured by a local resident with a smartphone and was published online. Leveraging computer vision technology, we conducted an in-depth analysis of the video in the following steps: (1) geo-reference the 2D scene of the video with 3D real-world coordinate; (2) stabilize the camera movement and recover the dam motion; (3) track soil body motion via optical flow and interpret geotechnical failure mechanism; and (4) extract data for displacement and velocity and reconstruct 3D scene. The acquired data offer better visualization and insights of the dam failure mechanism. The proposed method has great potential in forensic analyses of geohazards’ events.

An irrigation project included a well-distributed network of canals. The trapezoidal section of the main canal made a deep cut through lateritic soil and faced several major and minor slope failures during its construction. The failures, in general, were of two types: (1) retaining wall failure, and (2) surficial slope failure. The laboratory and mineralogical studies identified the dispersive nature of the lateritic soil as the primary cause of the slope failures. The results of stability analysis performed in GEO5 showed that internal and surficial erosion occurring in dispersive lateritic soil aggravated the slope failures. The high-pore pressure development during heavy rainfalls and excessive erosion of the soil from the canal slope pushed the retaining wall into the canal, thereby hindering the irrigation project. The soft and nearly saturated clayey foundation soil at these locations contributed to this sliding failure due to the loss of friction between the soil beneath and the retaining wall.

This paper presents a forensic investigation of a large flood event and resulting damage during a substantial rain storm event in 2019 that was preceded by wildfires in the previous two years. Wildfires throughout California in 2017 and 2018 resulted in damages estimated over $20 billion. The Rose Fire of 2017 and Holy Fire of 2018 burned over 23,000 acres of the Santa Ana Mountains in Southern California. About 1,700 acres of the Leach and Dickey Canyon watersheds were burned, denuding the slopes, and leaving the soils vulnerable to erosion. Less than six months after the Holy Fire was extinguished, a 20-year storm occurred at the Leach and Dickey Canyon watersheds, generating large amounts of erosion. The rainfall runoff and the eroded soil/debris caused damage to a dam spillway and discharged uncontrolled debris and stormwater into a 200-ft-wide floodway easement sized to convey runoff from a 100-year storm event. Large amounts of soil erosion occurred at localized areas within the floodway easement, resulting in extensive damage to private properties. A comprehensive study was performed to determine the cause of uncontrolled channel erosion, resulting in damage to the properties along the floodway easement. The study included evaluation of the soil erosion, debris flow, rainfall data, and historical floodway documentation, as well as capturing detailed UAV imagery, and performing a topographic survey. The findings of the study identified unpermitted modifications made by the various property owners along the floodway, including the placement of fill that extended into the floodway easement and other obstructions that had reduced the effective width of the channel by as much as 75%. A detailed review of the investigation methodology, technology utilized, and analysis performed is provided.

Recently, India has witnessed several extreme rainfall events that caused moderate to severe landslides. However, extreme landslide events and their impacts can be mitigated by implementing effective preventive measures and policies derived from well-documented reports. Systematic and efficient postdisaster reconnaissance practices coupled with imagery-based technologies are essential for collecting perishable data and detailed geodisasters documentation. A review of the current practices that are being implemented globally for acquiring spatial–temporal information using advanced technologies is presented. To this end, research articles, reconnaissance, and social media reports of a few notable extreme landslide events, namely 2013 Uttarakhand India, 2015 Kfarnabrakh Lebanon, 2018 Hokkaido Japan Eastern, were summarized. The best practices for future landslide reconnaissance studies in India, including the benefits of methodically acquiring and archiving photographic imagery using mobile devices and cloud apps, are presented.

Work in this study utilizes coupled, partially coupled, and uncoupled transient seepage analysis approaches to investigate the Pilarcitos Dam failure due to the rapid drawdown (RDD) condition. The Pilarcitos Dam is modeled using the finite-element (FE) software PLAXIS utilizing nonlinear advanced elastic–plastic constitutive relation. The modeled embankment is subjected to rapid drawdown, and the stability factor of safety (FS) is determined using the strength reduction method (SRM). The uncoupled seepage/stability approach is also applied whereas the partially coupled seepage analysis and the subsequent stability analysis are performed using FE program SEEP/W and limit equilibrium (LEM) software SLOPE/W, respectively. Results indicated that the use of coupled analyses leads to more realistic estimation of pore water pressures after RDD, as compared to the partially coupled and uncoupled analysis approaches. In this case, only the coupled analysis approach yielded representative FS and maximum depth of potential slip surface that reflect conditions observed for Pilarcitos Dam failure. In addition, the results indicated that the estimated time for complete dissipation of pore pressure after drawdown is significantly higher for uncoupled and partially coupled analyses as compared to the coupled analysis approach.

The November 2016 M 7.8 Kaikoura earthquake caused thousands of landslides in the northeastern part of New Zealand’s South Island. More than 80 landslides directly impacted a coastal road and rail transportation corridor, resulting in closure of a critical national transportation corridor for 13 months. A key part of the work to restore the route involved mitigating the rockfall risk posed by unstable slopes. This included installing more than 80 rockfall protection structures along the base of the slopes. In a few areas, slope conditions and space constraints meant that existing rockfall protection solutions could not be readily utilized in the narrow space available. A new type of modular rockfall protection wall, comprised of interconnected concrete blocks and sand and rock-filled gabion baskets, was designed, tested, and approved for use on site. Two of these walls have been constructed to provide permanent rockfall protection to users of this important transportation link.

The 2005 El Niño weather phenomenon caused intense rainfall in Southern California that resulted in floods and numerous slope failures. In northern Los Angeles County, surficial failures originating in natural slopes resulted in debris flows that affected many residential properties in the town of Santa Clarita. Because surficial failures are shallow, that is, 2–4 ft (60–120 cm) deep, generally the debris they generate are individually small. However, when surficial failures are clustered and numerous, they tend to affect large surface areas and they generate considerable volumes of slide debris. This paper describes the characteristics of surficial failures that occurred on slopes in Santa Clarita, California, discusses methods of analyses, common testing practices by local consultants, and analysis requirements from controlling agencies.

The NHERI Natural Hazard Reconnaissance Facility (known as the “RAPID”), headquartered at the University of Washington (UW), is a collaboration between UW, Oregon State University, Virginia Tech, and the University of Florida. The RAPID facility enables geoextreme event researchers to conduct next-generation quick response research through reliable acquisition and community sharing of high-quality, postdisaster data sets that will allow characterization of civil infrastructure performance under natural hazard loads, evaluation of the effectiveness of current and previous design methodologies, understanding of socioeconomic dynamics, calibration of computational models used to predict civil infrastructure component and system response, and development of solutions for resilient communities. The facility provides investigators with the hardware, software, and support services needed to collect, process, and assess perishable interdisciplinary data following extreme natural hazard events. This paper describes the RAPID facility, the equipment portfolio, and the services provided by the RAPID. It concludes by highlighting the support of a Geotechnical Extreme Events Reconnaissance (GEER) Association mission following the 2018 Palu, Indonesia, earthquake.

The increase in the frequency of geohazards and extreme weather events in recent times is alarming. Most of these events such as hurricanes, wildfires, floods, avalanches, earthquakes, and other natural disasters are dependent on many factors that cannot be controlled by human beings; however, they can be well prepared for with proper planning. Landslides, washouts, and slope failures triggered by natural disasters cause tremendous damage to human lives as well as infrastructure assets. Many states across the United States have established emergency operations centers (EOCs) to coordinate the emergency response operations. These operations include various activities ranging from monitoring critical infrastructure areas to creating public awareness during and after natural disasters. Certain natural disasters can be overwhelming that these agencies become shorthanded, and hence they need to prioritize rescue and recovery operations over reconnaissance surveys of infrastructure conditions. The rise in the applications of unmanned aerial vehicles (UAVs) or drones for monitoring infrastructure and emergency responses has been propelled by recent advancements in aerial vehicle platforms and compact sensors. This study presents an efficient way to transform the aerial imagery data of infrastructure into knowledge for quick and efficient responses to these unexpected natural calamities. Aerial data collected at two case study locations affected by natural disasters were analyzed and transformed into useful knowledge about the existing pavement conditions. This can help the EOCs in efficiently managing and analyzing the pavement infrastructure conditions to assist in the decision-making process. These practices are expected to contribute toward planning response and recovery tasks to facilitate the process of bringing back normalcy to the communities.

The Geotechnical Extreme Events Reconnaissance Association (GEER) Florence team of engineers deployed to southeastern North Carolina and northeastern South Carolina following Hurricane Florence with the GEER mission to “collect perishable postdisaster data that can be useful in advancing our understanding of extreme events,” and specifically, the effects of the extreme events on the geotechnical features of infrastructure. Florence’s impacts were significant and widespread because of the storm’s slow progression (4 days) across and massive rainfall (up to 34 in) on the study area. The team visited 23 dams, one levee system, seven bridges, eight roadway sites, two railroad impact areas, coastal sites in four counties, and one cemetery slope. This paper summarizes observations made by the team that characterize the event and the geotechnical infrastructure impacts along with lessons learned, both old and new. Event characteristics of note included rainfall, resulting flood flows, and impact location clusters. Infrastructure impact observations generally relate to the capacity of various structures to survive the flood flows, which typically overtopped most of the damaged structures. Lessons learned ranged from the obvious need for suitably sized spillways and culverts, bridge scour protection, and levee closures to smaller scale erosion characteristics of various infrastructure soils on dams with vegetation.

According to the United States Army Corps of Engineering National Inventory of Dams (NID), there are over 91,000 dams in the United States, of which more than half are privately owned smaller dams. The average age of the dams is over 50 years, and therefore it is not surprising to find that the 2017 ASCE Infrastructure Report gave dams in America a grade of D. Many small dam owners do not fully understand the importance of periodic maintenance and inspections to extend their life and minimize risk to downstream areas. Furthermore, limited funds may burden the ability to properly maintain a small dam. This paper will identify maintenance issues for small dams that could lead to hazardous conditions in both steady state and extreme events. Recommendations will be provided for the development of guidance documents to assist small dam owners in determining how to make corrective actions on a limited budget.

Extreme events generally occur without much advance warning, and certainly without enough lead-time to schedule and budget for repair projects as part of typical long-term highway investment programs. In addition to roadway and structure damage, roadway detours and closures result in inconvenience to the traveling public. Decision makers look for quick answers and rapid solutions as there are frequently substantial pressures to reduce the design time. Project teams are tasked to let emergency repair contracts quickly, and the incentive to rely on historic information and observations from initial forensic site visits is strong. The merits of geotechnical investigation are often debated, under pressure for designers to make foundation selections and estimates of material quantities with immediately available information. Newer geotechnical tools and investigation capabilities need not delay a project. Depending on the site, a well-planned emergency-response investigation plan may result in faster overall project delivery by reducing project uncertainties, accelerating decisions on appropriate project means, methods, and scope. Several proven technologies provide rapid characterization of sites that have experienced failure due to geohazards. This paper explores the risk-reward relationship that effective site characterization provides when speed and timeliness are overriding goals. Examples illustrate today’s tools and techniques can enhance quality and minimize performance risks, even when time is critical, for risk reduction and significant project benefit.

The stability of earth slopes subjected to extreme hydrological events such as infiltration, flooding, and evapotranspiration was investigated using a coupled Geotechnical-Hydrological finite element software, PLAXIS 2D. The site-specific parameters were collected for a site in Levelland, Texas, and used as the study area. The effects of the individual and simultaneous occurrence of infiltration, flooding, and evapotranspiration were investigated. The results show that the FoS against slope failure reduced with the flooding and infiltration and increased with the evapotranspiration. The FoS reduced by 62% at the end of the simultaneous occurrence of infiltration and flooding, leading to the failure of a 2H:1V slope. In the case of a 3H:1V slope, the FoS reduced by 69.4% at the end of the simultaneous occurrence of infiltration and flooding and increased by 57.4% at the end of evapotranspiration. The study concluded that extreme infiltration, flooding, and evapotranspiration could provoke slope instability and massive mass movements of the slope.

The engineered turf cover is a relatively new landfill capping technology. It has been increasingly used in the last decade for closure of municipal and industrial solid waste landfills and other waste disposal facilities. Compared to traditional soil-geosynthetic covers, the engineered turf cover does not have protective and vegetative soil layers; therefore, there is no veneer slope failure that involves the soil mass and underlying geosynthetic components. The engineered turf cover consists of structured geomembrane and engineered turf, both of which are flexible geosynthetic materials and can tolerate tension and elongation due to differential settlement. Geotechnical performance of the engineered turf cover is discussed in the paper. Wind tunnel tests were conducted to investigate wind performance of the engineered turf cover. An example calculation is provided to illustrate the procedure of using the pressure coefficients obtained from the wind tunnel tests to estimate the factor of safety of the engineered turf cover against initiation of wind uplift.

Slope failures are one type of geohazard that affects state trunk highways. Previous research efforts that model slope failures are limited by failure type, limited in geographic coverage, and are often subjective. This paper presents a new approach for risk assessment of slopes that accounts for all failure types unique to varying geographic regions. The new slope vulnerability model was developed by WSB and Minnesota Department of Transportation (MnDOT). This paper outlines the methods and results of the new geographic information systems’ (GIS) model. The results of this study are intended to be the first step of proactive measures to minimize the effects of slope failure including costly repairs and potential threats to public safety. Expected benefits from the results of this study include (1) enhancing risk-based asset management, (2) guiding recommendations in MnDOT’s Asset Management Strategic Implementation Plan, and (3) integration into the federally required Transportation Asset Management Plan.

Yazoo clay is highly expansive in nature, which experiences shrink-swell behavior with seasonal moisture variations. Currently, concerning Yazoo clay characteristics, several natural and artificial slopes in Mississippi are vulnerable to failure due to a high volume of precipitation. Among available nondestructive methods to investigate the subsurface conditions, the Electrical Resistivity Imaging (ERI) method is becoming popular in recent years. Using the 2D ERI technique, the moisture variation at different soil layer depths can be easily detected. The current study investigates the failure of artificial highway slopes on Yazoo clay in Jackson, Mississippi. Qualitative evaluation of temporal moisture variation of the slope was conducted using ERI. The 2D ERI tests were conducted at the crest and toe of the 3H:1V slope. Based on the ERI test results, the overall degree of saturation was between 80% and 90%. The high-saturation condition indicated the formation of perched water zones.

On May 19, 2020, after several days of heavy precipitation, two earth dams failed (Edenville and Sanford) and two other dams were damaged (Secord and Smallwood), north of the town of Midland, MI. The failures resulted in about $100M in damages and the evacuation of about 11,000 people during the COVID-19 pandemic. In response to this destructive event, the Geo-Institute Embankment, Dams, and Slopes Technical Committee organized a team with the main objective of capturing perishable data. The Edenville Dam site was of interest because the slope failure was captured on video and occurred prior to the dam being overtopped. Based on our observations, investigation and analyses, two failure mechanisms were considered likely for Edenville Dam: (1) static liquefaction (similar to 2019 failure of Brumadinho Dam in Brazil); and (2) slope instability, where the slide debris which was contractive in nature, expelled pore water in the form of water jets and flowed as it became liquefied along the toe of the dam.

Ground subsidence is a major engineering problem in urban areas where population growth and rapid urban development are taking place. Central Florida is also known as the karst area with its unique hydrogeological setting, posing potential ground instability such as sinkhole-induced subsidence and ground settlement due to urban construction and development. Monitoring of ground subsidence can help not only mitigate its negative impacts in many engineering ways but also enhance the related risk management. With recent advances in remote sensing technology, Interferometric Synthetic Aperture Radar (InSAR) can be a promising tool to measure and monitor ground subsidence. The goal of this study is to explore the feasibility of InSAR for the ground subsidence assessment. Particularly, we investigated the spatial distribution of ground subsidence in the Orlando metropolitan area and its near vicinities over two different times. For this, the Differential Interferometric Synthetic Aperture Radar (DInSAR) method was applied to develop a ground subsidence map between May 8, 2018, and May 9, 2020, using the European Space Agency (ESA) Sentinel-1 SAR images. The results show that the study area is clearly showing a cumulative ground movement trend of varying degrees, with −22.9 cm (subsidence) and +2.0 cm (uplift), over the past two years. It also shows that the magnitude of ground subsidence in this area was largely related to land use and development activities. This study demonstrates that the multitemporal InSAR processing technique is capable of high-precision monitoring of ground subsidence in urban areas for engineering purposes.

Rainfall is one of the essential climatic elements that affects the instability of geostructures. In recent years, extreme events, such as rainstorms in semiarid to arid regions subjected to long drought periods, have exacerbated the failure of natural and artificial earth fill slopes. Such severe instabilities were reported in parts of a railway embankment in southeastern Iran during the 2020-spring rainstorm. Most hazards, such as landslides due to floods, are specific extreme events in the north of Iran. However, most of the analyses have been focused on the maximum rainfall amount obtained from the rainfall station output data as the worst-case scenario, which has been proved that may not always be the case. More importantly, the distribution of rain stations in remote areas is very sparse in the order of tens to hundreds of kilometers. In other words, the uncertainty of rainfall events becomes even more pronounced. Therefore, the primary purpose of this study is to explore the application of an alternative method based on evenly distributed satellite data. To achieve this goal, monthly precipitation from 2015 to 2020 is compared between Global Precipitation Measurement (GPM) data and rain gauge data recorded in the southern and northern regions. Afterward, rainfall data are examined based on the quantitative statistical criteria, and the most appropriate probability distributions are estimated and proposed accordingly. The Generalized Extreme Value (GEV) distribution is the most suitable one for low-to-intermediate rainfall. The Logistic and Frechet distributions are presented for heavy rain. The satellite precipitation distribution of the southern region is eventually modified based on the more reliable and robust correlations for the northern region. Results suggest that the underestimated rainfall amount obtained from traditional rain station records could be a potential reason for the unconventional design and consequential damage to some infrastructure in the southern region.

Tropical Storm Cristobal made landfall near New Orleans, LA, on June 7, 2020. The storm weakened into Tropical Depression Cristobal as it proceeded northward. The center of the storm passed 50 miles away from a fiber-optic array installed about 0.5 m (about 2 ft) deep in loess soil. The fiber optic array is connected to a distributed acoustic sensing (DAS) interrogator, which is sensitive to strains in the fiber-optic cable caused by seismic waves passing through the surrounding soil, including sound waves transmitted into the soil. The purpose of this research was to identify changes in the ambient noise amplitude collected via DAS during Tropical Depression Cristobal. The study area was an open field with a gravel access road to minimize potential impacts of tree cover. Data were collected via DAS continuously during the storm with a sampling rate of 2,500 Hz. A meteorological station is located onsite and recorded hourly average temperatures and hourly rainfall totals. Sustained winds of 37 kph (23 mph) and gusts of 60 kph (37 mph) were observed at a nearby weather station. Onsite 17.8 mm (0.70 in.) of rain fell from 2:00 a.m. to 3:00 a.m. Along three DAS channels, ambient noise levels at three time points—during the storm, at the same time of day once the storm had passed, and for typical activity noise levels along the study section—were compared. Results show a very significant increase in noise attributable to the storm.

The urban heat island (UHI) is among the major environmental issues encountered in urban regions. To better predict the dynamics of the UHI and its impact on extreme heat events, accurate characterization of the surface energy balance in urban regions is required. However, the ability to accurately understand the climate processes in urban areas due to heterogeneity of the surfaces is limited due to incomplete knowledge of the urban surface energy balance. This study aims to enhance the understanding of the urban surface energy budget and land surface temperature from satellite observations. Here, a multisensor LST data with 5-min temporal and 30 m spatial resolution is developed by downscaling the Geostationary Operational Environmental Satellites–R series (GOES-R) LST data over New York City. In situ LST data are used to evaluate the accuracy of the downscaled LST. Differences between the predicted and the observed LSTs ranged from −0.09 to 3.30 °C.

Monitoring dams is critical for identifying vulnerabilities affecting its performance and managing the risk of failure. Traditionally, dam monitoring is performed by a combination of visual surveillance and instrumentation. American Society of Civil Engineers (ASCE) has been giving a D grade for the nation’s 91,000-plus dams since the beginning of the grading system (1998) to date. The traditional approach can be subjective and laborious, considering the monitoring needs in the United States. This study presents the Interferometric Synthetic Aperture Radar (InSAR) application for monitoring deformations at dam sites to understand its vulnerability. The study evaluates the use of InSAR at three (two in India and one in the United States) dam sites to monitor its safety. The Sentinel-1 and ENVISAT Advanced Synthetic Aperture Radar (ASAR) images were processed using Persistent Scatterers Interferometry (PSI). Results indicate that, combined with traditional methods, remote sensing using radar offers an opportunity for long-term dam monitoring and the development of a deformation-based early warning system.

Current methods for flood risk assessment do not incorporate the concept of flood damage, structural resiliency, and community vulnerability into a single holistic framework. Within this study, a robust flood risk assessment framework has been developed which includes hydrodynamic characteristic of flooding coupled with the concept of flood damage, resiliency, and vulnerability through various modeling and geospatial analytics. First a state-of-the-art, high-resolution two-dimensional (2D) hydrodynamic model was developed to analyze the impact of storm surge into the coastal communities. Next, a new flood damage model was proposed which includes the dynamic characteristics of flooding as well as various relevant characteristics of a building including age, materials, height, and location. A resiliency model was also developed incorporating the flood induced damage level with the recovery factor of the structures at micro- and mesoscale. Finally, the vulnerability of a community due to extreme storm events was quantified by including damage and the resiliency of the community at mesoscale.

The northern sound-side shoreline of Pea Island, which is adjacent to Oregon Inlet on the Outer Banks, NC, is steadily eroding, increasing the proximity of the NC 12 highway to the Pamlico Sound. Field observations of bathymetry, sediment grain size, vegetation, and water levels, along with pre- and poststorm shoreline surveys were used to examine the spatial variability in hydrodynamics, morphodynamics, and vegetation in the region. Local hydrodynamics are driven by a complex interaction of ocean- and sound-side processes. Erosion is likely driven by inlet-driven processes and major storms causing overland flow. Spatial heterogeneity in erosion may be owing to differences in bathymetry, topography, sediment sizes, and vegetation. The field data are being used to calibrate a numerical model and develop planning level tools to improve the understanding of flooding and erosion and to enhance the sound-side resilience of a coastal transportation corridor.

The Squibnocket Causeway and Beach Restoration projects (the “Projects”) located in Martha’s Vineyard, Massachusetts, were two independent projects constructed as a public–private partnership. The projects focused on environmentally responsible managed retreat and were critical in addressing threats from sea level rise and increasing storm intensity. To protect the only access to their 16 private homes, located in the Town of Chilmark along the southwestern coastline of the island known as Martha’s Vineyard, the Squibnocket Farm Homeowner’s Association (“SFHA”) decided to proactively relocate a portion of their existing roadway and utilities, which were repeatedly being compromised by storms, further in-land and at a higher elevation. The solution was a privately funded 107 m (352 ft) long, single vehicle lane, pile-supported causeway designed to account for future sea level rise and coastal erosion. The Town of Chilmark (“Chilmark”), when presented with the SFHA’s plans for the causeway, recognized the opportunity to remove an existing beach parking lot, approximately 143 m (470 ft) of stone revetment adjacent to it and re-establish the coastal beach. The stone revetment was causing increased erosion of the beach especially at both ends of the revetment, as well as inhibiting the natural migration of sand and sediment along the beach. Following the removal of the revetment, the coastal beach was renourished to its natural state by placement of sand from an adjacent dredging project. A new parking lot was constructed further in-land at a higher elevation. This paper will mainly focus on permitting and design of the Squibnocket Causeway project but will also explain the interdependency of the two projects.

The sound-side shoreline of Pea Island located on the Outer Banks, NC, has been eroding over the last two decades. As part of the pilot During Nearshore Event Experiment (DUNEX) carried out in October 2019, sediment strength, grain size, and currents were measured in a tidal inlet flood channel in the back-barrier zone of Pea Island using a portable free fall penetrometer, grab samples, and an acoustic Doppler current profiler. Results indicate a general trend of a decrease in the surficial (upper 10 cm) sediment strength toward the shoreline (from 130 to 75 kPa) and from downstream to upstream (from 150 to 70 kPa). The cross-shore directed trend can be explained by sediment fining toward the shoreline with a lowest median grain size of 22 μm. Variations in sediment strength were related to current velocities and local sediment transport processes; thus, the results contribute to a better understanding of the erosional processes of the sediments.

Rising sea levels continue to gain the attention of engineers, planners, the insurance industry, and property owners. The East Coast of the United States is particularly vulnerable to impacts from sea level rise given its densely populated environment coupled with relatively higher rates of sea level rise compared to the global average. While historically the value of coastal real estate has been higher than inland property values, a recent study performed by First Street Foundation and Columbia University noted that coastal real estate appreciation values are lagging their inland counterparts due to the risk of coastal flooding connected to sea level rise. Geotechnical engineering has focused on allowable stress design and factors of safety; however, due to the uncertainty associated with sea level rise, the future of coastal geotechnical consulting will require a skillset founded in reliability-based design. This paper outlines an example approach for a site-specific risk assessment.

The City of Columbia, South Carolina’s Metro Wastewater Treatment Plant (WWTP) is located immediately at the land side toe of the Congaree River levee. Built in the 1960s and 1970s, the levee is classified as nonaccredited for the National Flood Insurance Program (NFIP). In October 2015, historic rainfall led to widespread flooding in the region and a section of the levee just downstream of the WWTP breached. Because the WWTP is higher in elevation than surrounding areas, it did not flood, but it was inaccessible to vehicular traffic for more than three days, employees had to be transported to and from the facility by boat, and the plant could not receive supplies. The City of Columbia was awarded a grant by the Federal Emergency Management Agency (FEMA), which they used to conduct a geotechnical, climate resiliency, and flood protection study to evaluate alternative methods to protect the plant, its planned expansion, and its supply route from future flood conditions. Our study involved existing levee inspection, regional hydraulic and hydrologic analyses, subsurface exploration, stability and seepage analyses for the existing levee in future flood conditions, recommendation for a new ring levee and location, recommendations for supply route improvements and locations, and recommendations for handling of local soil borrow for construction of the levees. At the completion of the study, the city was provided recommendations including improvements to the existing levee, construction of a new ring levee, two emergency ingress/egress access points, stormwater improvements for the interior of the ring levee, and alternatives. Our study also included proposed additional studies and projects, as well as the path to getting the existing levee section to be accredited by the NFIP. These recommendations are critical in building resiliency into the plant and levee to better withstand threats from flooding both during today’s storm events and future storm events that are predicted to be more frequent and severe due to climate change.

Geotechnical site characterization of energetic beach and nearshore environments is generally challenging due to harsh environmental conditions. In addition, few methods and sensors have been developed, tested, and/or validated for these conditions. Advances in remote sensing provide new pathways for data collection without physical presence of surveyors and with greater spatial coverage in a shorter period of time. This article presents initial lessons learned from testing satellite-sensed data, rapid physical testing tools, and buried pressure sensors for geotechnical characterization of intertidal environments pre-, during, and postextreme events for applications such as rapid assessment of erosion hotspots and emergency response.

One of the most critical climate change processes affecting coastal areas is sea level rise. In addition to inundating low-lying areas near the coast and increasing the frequency of flooding, sea level rise may raise the groundwater table, drive saltwater intrusion, and increase the risk for erosion and scour. These impacts represent key equilibrium shifts that will affect geotechnical site conditions and design parameters. Frequent inundation will likely increase the demand for floodable, elevated, and floating foundation systems; frequent flooding of roads may reduce the service life of pavements and erode unbound subgrade material. Groundwater rise will increase hydrostatic pressures on earth retaining structures and foundations and may complicate construction projects requiring excavation. The threat of saltwater intrusion will encourage innovative strategies for developing hydraulic barriers. Increased erosion may reduce the longevity of beach nourishment projects and increase the rate of scour around infrastructure. This paper expands on the implications of sea level rise listed above and provides an outlook on how sea level rise might impact future projects and drive trends in coastal geotechnical practice.

The purpose of this paper is to investigate the vulnerability of Leme Beach, in the city of Rio de Janeiro, Brazil, to the risk of sand erosion and high-tide effects in the urban infrastructure provoked by sea level rises as consequence of climate change. Several tests were carried out with small-scale models in a wave channel, considering different sea levels and significant wave heights generated by storms at recurrence periods of one, ten, and one hundred years. Considering the current profile of Leme Beach, the effects of sea level rise may cause beach erosion, with seawater surpassing the waterfront ridge, invading the residential buildings situated nearby and depositing large amounts of sand on the seaside avenue. To mitigate these effects, the efficiency of submerged concrete breakwaters was investigated through a series of tests in small-scale models. The results suggest that Leme Beach is quite vulnerable to a sea level rise, combined with the occurrence of storms that could generate waves greater than 3 m high.

A multiline ring anchor (MRA) system has been developed as a cost-effective alternative for securing arrays of floating offshore wind turbines (FOWTs) to the seabed. Multiline attachments can improve the economically competitiveness of FOWTs by reducing the capital cost of the support system for the floating structures. FOWTs can be subjected to severe wind and wave conditions resulting in extreme loads to the anchor system. Thus, the reliable design of the anchor system requires proper determination of the extreme mooring line loads acting on the anchor needed to secure FOWTs to the seabed. Previous studies showed the MRA in soft clay has clear advantages over existing anchors under the extreme horizontal loading conditions imposed by catenary moorings; however, its performance relative to conventional anchors under extreme vertical loading imposed by taut mooring systems requires further investigation. This study presents predictions of extreme loads on floating structures secured by taut mooring systems and evaluates the potential for developing an economical anchor for resisting these extreme loads.

A new reinforcement measure, double row steel sheet piles, is proposed to keep the safety of coastal levees under the action of the extreme storm surge. Large-scale flume experiments, considering variable wave height, were used to study the dynamic behavior of embankment-pile system, including erosion, stress, and deformation. When the wave height is relatively low, a stable eroded surface would incur on the upstream slope of the embankment. When the wave height is relatively high, it would overtop the embankment and erode the crest and downstream slope, leading to significant deformation and stress in both outer and inner row piles. Despite large deformations, the levee with the support of the double-row steel sheet piles system did not fail. While, the same levee without the protective was almost completely eroded, which indicated the significant protection effect of pile structure. Under overtop condition, the downstream slope was eroded soon after the start of overtopping. Under surge wave condition, erosion proceed at the upstream first. When the embankment is protected by double-row sheet piles, less erosion of the soil would occur, and the embankment could be more recoverable after overtopping or extreme storm surges.

Many project sites located near shorelines or waterways have been faced with accommodating significantly higher flood elevations to offer resilience against extreme weather events or because of rising sea levels. The project sites are also often faced with soft compressible soil ground conditions that will lead to settlement over time or require ground improvement to mitigate this settlement. In addition, many states and municipalities have regulations in place that prohibit the reduction of onsite flood storage due to construction activities. The engineering community has been confronted with these issues in recent years, and these issues are likely to remain on the forefront of design and construction challenges in the future. One ground improvement option that is available is to raise grades with ultralightweight foamed glass aggregate (UL-FGA). UL-FGA has an in-place unit weight between 240 and 375 kN/m³ (15–23.5 pcf), has a high angle of internal friction, and is very permeable. These properties make UL-FGA well-suited for use over soft soil layers and to provide stormwater storage. In addition, UL-FGA is a sustainable choice as it is manufactured from postconsumer recycled glass and has a lower carbon footprint than other lightweight fill options. This paper also briefly describes two projects, a roadway embankment and a new residential development, in New York State that utilized foamed glass aggregate to raise elevations due to resiliency concerns.

Levee failures can adversely affect the performance of electric power networks in levee-protected areas. Projections from climate models suggest likelihood of more severe flooding in some regions if our planet continues to warm. Such changes in statistics of floods can increase the probability of failure of levees, which in turn, may cause disruptions of an electric power network such as generation, transmission, and distribution in a cascading manner. The main objective of this study is to examine the resiliency of electric power networks to flooding in levee-protected areas under a changing climate. For this purpose, a resiliency index is proposed that quantifies the resiliency of electric power networks against flooding in levee-protected areas. Using different Representative Concentration Pathways (RCPs), changes in the hazard level and exposure of levee-protected electric power networks are determined for a study area in the Central Valley, California. The DC power flow method is employed to evaluate the affected electric network, to minimize the number of out-of-service customers, and to obtain a quantitative resiliency index. Modeling an electric power network using the proposed approach allows establishing a relationship between flood levels and the number of affected customers under different scenarios. For the study area, three-dimensional graphs show the percentage of power outage versus the number of nodes in the lower elevations under different levels of flooding. The model offers a valuable tool for assessing the risk imposed by flooding to electric infrastructures under a changing climate. The proposed resiliency index can be employed to assess the impacts of natural hazards and climate extremes on electric power networks in levee-protected areas.

This paper summarizes some of the preliminary findings by the Geotechnical Extreme Events Reconnaissance (GEER) team from the 2020 magnitude 6.5 Monte Cristo Range earthquake in Nevada. The team visited the Monte Cristo Range area three weeks after the main event mainly focusing on some interesting ground failure patterns reported by other advance teams. This paper first presents the geological and seismological aspects of the studied area, and then discusses the observed ground failure patterns which are mainly attributed to the widespread liquefaction-induced lateral spreads and associated settlements. This paper also presents the observed extensive surface manifestations of liquefaction. Additional discussions consist of recorded ground motions and a comprehensive series of field and laboratory tests. The in situ tests included Refraction Microtremor (ReMi) surveys, and several soil samples were taken in the observed ground failure area and tested in the laboratory for basic index properties and soil classifications. These test results were the basis for a preliminary assessment of liquefaction triggering, the details of which are presented and discussed in this paper.

A seismic sequence along the south coast of Puerto Rico (PR) initiated on December 28, 2019. The strongest event, an M_w 6.4 earthquake with epicenter just offshore (17.9578, −66.8113) near Guayanilla on January 7, 2020. The ongoing (as of January 2021) sequence has involved hundreds of additional felt seismic events, many of which registered above M_w 5.0. The earthquakes resulted in moderate to locally severe structural damage in several south coast municipalities. Several specialized teams (e.g., USGS, GEER, STEER) were deployed and worked synergistically to assess and document perishable structural and geotechnical damages after the M_w 6.4 event. This paper summarizes geotechnical failure documented by the GEER reconnaissance mission. The locations of common liquefaction, ground extension, settlement, and mass wasting features are concentrated in the immediate epicentral area in the municipalities of Guánica, Yauco, Guayanilla, Peñuelas, and Ponce. Abundant small to medium sized sand boils and longitudinal blows were documented mostly in low-lying areas very near the coastline in Guánica and Guayanilla. Ground extension was observed almost always parallel to a nearby coastline or river channel. Several of these sites were noted to have reactivated during the episodic seismicity. Along the coastline in Ponce, the widest spreading features at La Guancha were measured to have 20 cm separation. The dominant mass wasting mechanism was rock fall, which was common across the south coast limestone bedrock exposed in the epicentral area. Similar failures in limestone of northwestern Puerto Rico were reported after the 1918 M 7.0 Mona Passage event. Failures along roadways were almost exclusively small, but temporarily blocked some routes. Rock falls and slumps on unmodified hillslopes were generally larger and involved much longer run out distances, especially for boulders commonly larger than 2 m across.

Recorded data along with several studies suggest an ever-increasing trend of wildfires in several areas in the United States. For example, Southern California has been devastated by several wildfires during the 2020 fire season, which has set a new state wildfire record. Limited data indicate that wildfires may pose considerable changes in some geotechnical properties of near surface soil in the fire-affected areas. Valuable information can be obtained from comparison of physical soil samples collected from wildfire impacted and nonimpacted areas. The main objective of this study is to investigate the effects of the El Dorado Ranch Park Fire on select geotechnical soil properties. The El Dorado Ranch Fire started in September 2020 with burning areas distributed in several cities across Southern California. In this study, laboratory tests were performed on a total of forty (40) soil samples collected from the El Dorado Ranch Park Fire area. A set of grain size distribution, organic content, and pH tests were performed on soil samples collected from the impacted and nonimpacted areas. In addition, hydraulic conductivity tests were performed on the soil present in both the impacted and nonimpacted sample locations. Results indicate that each of the properties tested exhibited larger variability when comparing the wildfire impacted to nonimpacted soil. Findings of this study are believed to support further research and evaluation of the impact wildfires have on geotechnical outcomes and the cascading geohazards such as erosion, mudslides, and debris flow.

Over 25 years have passed since the 1994 Northridge earthquake required a major mobilization of practicing civil/geotechnical engineers for postearthquake damage assessments in the United States. Practitioners were inundated with requests to perform investigations and provide damage repair recommendations, with the resulting assessments often utilizing conflicting and disparate methodologies. In response, the Consortium of Universities for Research in Earthquake Engineering in 2005 developed the “Engineering Guidelines for the Assessment and Repair of Earthquake Damage in Residential Woodframe Buildings” to provide a consistent framework for conducting geotechnical postearthquake damage assessments in practice. In 2020, the California Earthquake Authority and Applied Technology Council updated these guidelines and issued the “Earthquake Damage Assessment and Repair Guidelines for Residential Wood-Frame Buildings.” This paper presents the framework for practice-focused geotechnical postearthquake damage assessments and demonstrates the implementation through a case history. The motivation, scope, and goals of these assessments are highlighted in the context of community rebuild needs.

Izu-Oshima, a 91-square-kilometer volcanic island located 120 km south–southwest of Tokyo, Japan, experienced disastrous debris flows (900 m wide and 1.2 km long) in October 2013 after heavy rainfall associated with a typhoon. Unfortunately, 39 persons were killed including 3 missing and 22 others were injured because the debris flows inundated a residential area before it reached the ocean. The agency in charge of the island’s infrastructure built a solid guide wall with steel sheet piles as an emergency measure for diverting future debris flow from cascading down to another residential area. The site was on the slope with an uneven surface covered with sandy gravel and hard lava. Sheet piles were installed into the underlying lava layer with press-in piling using an auger attachment to overcome these difficult site conditions.