Towards the Circular Soil Concept: Optimization of Engineered Soils for Green Infrastructure Application

At conventional construction sites, the removal of soil and other excavated materials causes enormous mass movement, with a significant climate impact and contribution to global CO2 release. This study aimed to generate a Circular Soil concept for reusing excavated materials by creating engineered soils for landscape construction at large building sites. Engineered soils act as a substitute for natural soils and fulfill vital technical and soil functions when installing an urban green infrastructure (GI). In a field study, the vegetation performance on engineered soils was evaluated to establish a methodological approach, to assess the applicability of the Circular Soil concept. First, the technical specifications (grain-size distribution) were modeled for intensive green roof and turfgrass applications. Then, the soil components were optimized, mixed, installed and tested for greenery purposes, focusing on plant growth performance indicators (vitality, projective cover ratio and grass-herb ratio) to assess the vegetation performance. The results showed that the engineered soils match the performance of the reference soil alternatives. In conclusion, the Circular Soil concept has a high potential to contribute considerably to sustainable on-site soil management and the circular economy. It can be applied on a larger scale for urban GI development and sustainable resources management in the landscaping and construction sector.

Could road constructions be more hazardous than an earthquake in terms of mass movement?

Roads can have a significant impact on the frequency of mass wasting events in mountainous areas. However, characterizing the extent and pervasiveness of mass movements over time has rarely been documented due to limitations in available data sources to consistently map such events. We monitored the evolution of a road network and assessed its effect on mass movements for a 11-year window in Arhavi, Turkey. The main road construction projects run in the area are associated with a hydroelectric power plant as well as other road extension works and are clearly associated with the vast majority (90.1%) of mass movements in the area. We also notice that the overall number and size of the mass movements are much larger than in the naturally occurring comparison area. This means that the sediment load originating from the anthropogenically induced mass movements is larger than its counterpart associated with naturally occurring landslides. Notably, this extra sediment load could cause river channel aggregation, reduce accommodation space and as a consequence, it could lead to an increase in the probability and severity of flooding along the river channel. This marks a strong and negative effect of human activities on the natural course of earth surface processes. We also compare frequency-area distributions of human-induced mass movements mapped in this study and co-seismic landslide inventories from the literature. By doing so, we aim to better understand the consequences of human effects on mass movements in a comparative manner. Our findings show that the damage generated by the road construction in terms of sediment loads to river channels is compatible with the possible effect of a theoretical earthquake with a magnitude greater than Mw = 6.0.

How Do Roots Interact with Layered Soils?

Vegetation alters soil fabric by providing biological reinforcement and enhancing the overall mechanical behaviour of slopes, thereby controlling shallow mass movement. To predict the behaviour of vegetated slopes, parameters representing the root system structure, such as root distribution, length, orientation and diameter, should be considered in slope stability models. This study quantifies the relationship between soil physical characteristics and root growth, giving special emphasis on (1) how roots influence the physical architecture of the surrounding soil structure and (2) how soil structure influences the root growth. A systematic experimental study is carried out using high-resolution X-ray micro-computed tomography (µCT) to observe the root behaviour in layered soil. In total, 2 samples are scanned over 15 days, enabling the acquisition of 10 sets of images. A machine learning algorithm for image segmentation is trained to act at 3 different training percentages, resulting in the processing of 30 sets of images, with the outcomes prompting a discussion on the size of the training data set. An automated in-house image processing algorithm is employed to quantify the void ratio and root volume ratio. This script enables post processing and image analysis of all 30 cases within few hours. This work investigates the effect of stratigraphy on root growth, along with the effect of image-segmentation parameters on soil constitutive properties.

Environmental Movements and Rise of Indigenous Communication Strategies during CHIPKO

Use and control over natural resources was the main agenda behind ecological movements in India. Environmental movements brought environmental sensitivity. Uttarakhand has had been a beautiful state but the region remained isolated and unsung for a longer period of time. However, the local organizations and protests linked the region with the rest of the country. The central motivation of the study is to trace out the tactics adopted when hardly any tech-based communication existed to set Chipko as the mass movement. The study is exploratory in nature and data has been gathered using Schedule which has been analyzed via percent analysis. Results of the study approves that Chipko validated nonviolent resistance and brought out unique strategies to sustain the Chipko as the movement. Chipko was a continuation of the old peasant struggle where the population mainly stressed on the group communication.

Aeolian transportation mechanics and mass movement of surficial beach sands – a case study on Bendi-BaruvaMineral Sand Deposit, Srikakulam District, Andhra Pradesh

Surficial sediment transportation studies carried out in the beach zone of Bendi-Baruva mineral sand deposit show that sand grains are transported by wind (saltation and suspension) beyond the high water line. The sand population of the study area contains heavy mineral sands (~20%) like ilmenite, garnet and sillimanite which covers 95% of the heavy mineral distribution with subordinate amounts of monazite, rutile, and zircon whereas light mineral sands (~80%) contain mostly quartz. Due to the sorted nature of these beach and dune sands the whole spectra falls within a specific range of grain size which shows a bi-modal distribution, primary mode at 0.025cm and secondary at 0.015cm. Due to this variation in density and grain size, mass of these sand particles vary resulting in differential transportation in any energy regime. In the study area, on the beach near the frontal dunes, surficial concentration of garnet grains are observed in patches having an average thickness 0.2cm i.e. around ten times of the dominant grain diameter. This surficial enrichment of garnet grains resting on a semi-uniform sand surface is the result of differential transportation of the dominant mineral grains. As more than 80% of the grain size population show a dominant grain size of 0.025cm, the wind flow parameters for the whole population is standardized with mean grain diameter (D) of 0.025cm. Mass of dominant individual minerals arrived from the grain counting technique was tallied with the theoretical mass considering spherical shape of the grains indicates a difference of mass to be within 5%. For ease of calculation and generalization the grains were considered to be spherical and their theoretical masses were taken into consideration in calculations. Considering the whole spectra of mineralogical distribution, a theoretical mass group distribution for dominant different minerals of different dominant grain sizes were formulated and total six mass groups were identified. Because quartz (~80%), ilmenite, sillimanite and garnet (together ~20%) are the most abundant, their positions were identified specifically in the theoretical mass groups and only these are considered for further discussion. To analyse wind velocity and pressure at different heights from the surface, a sediment trap was fabricated using piezo-electric sensors. A tail was attached to orient the device parallel to the wind flow so that the piezo surfaces always face the wind flow at 900 angle. The device records pressure data and converts those into voltage. Using the velocity data, macroscopic physical quantities of aeolian transportation were calculated for the study area, which empirically show the effect of mass in differential transportation of the dominant minerals that gives rise to these surficial garnet patches.

Influence of Aerosols on Atmospheric Gravity Waves at an Urban Tropical Location

The elevated layer of heat-absorbing pollutant aerosols causes temperature perturbations in the pre-monsoon period above the boundary layer height (1.6-4 km) as observed over a polluted tropical urban location Kolkata (22°34' N, 88°22' E) during 2007-2016. Satellite observations of different types of aerosols show an increase in aerosol extinction coefficient around 1.6-4 km altitude, enhancing the perturbations in both temperature and wind profiles at that height. The opposing air mass movement within and above the boundary layer, which is strengthened by elevated heat-absorbing aerosols, is illustrated by height profiles of atmospheric vorticity and divergence. This results in higher Brunt-Vaisala frequencies indicating increased atmospheric oscillations. Consequently, atmospheric gravity waves, which manifest the temperature and wind profile perturbations, have enhanced energy in the upper troposphere (6-10 km). Based on multi- technique observations consisting of radiosonde, space-borne lidar and model data, this study reveals the interactions between aerosol and other atmospheric processes such as temperature variations and wind perturbations, which affect the atmospheric instability and increase gravity wave activities during the pre-monsoon period over a tropical metropolis.

AIMED CONTROL OF THE FREQUENCY SPECTRUM OF EIGENVIBRATIONS OF ELASTIC PLATES WITH A FINITE NUMBER OF DEGREES OF MASS FREEDOM BY INTRODUCING ADDITIONAL GENERALIZED KINEMATIC DEVICES

As is known, targeted regulation of the frequency spectrum of natural vibrations of elastic systems with a finite number of degrees of mass freedom can be performed by introducing additional generalized constraints and generalized kinematic devices. Each targeted generalized constraint increases, and each generalized kinematic device reduces the value of only one selected natural frequency to a predetermined value, without changing the remaining natural frequencies and all forms of natural vibrations (natural modes). To date, for some elastic systems with a finite number of degrees of freedom of masses, in which the directions of mass movement are parallel and lie in the same plane, special methods have been already developed for creating additional constraints and generalized kinematic devices that change the frequency spectrum of natural vibrations in a targeted manner. In particular, a theory and an algorithm for the creation of targeted generalized constraints and generalized kinematic devices have been developed for rods. It was previously proved that the method of forming a matrix of additional stiffness coefficients, specifying targeted generalized constraint, in the problem of natural vibrations of rods can also be applied to solving a similar problem for elastic systems with a finite number of degrees of freedom, in which the directions of mass movement are parallel, but do not lie in the same plane. In particular, such systems include plates. The distinctive paper shows that the method of forming a matrix for taking into account the action of additional inertial forces, specifying targeted kinematic devices in the problem of natural vibrations of rods can also be applied to solving a similar problem for elastic systems with a finite number of degrees of freedom, in which the directions of mass movement are parallel, but do not lie in the same plane. However, the algorithms for the creation of targeted generalized kinematic devices developed for rods based on the properties of rope polygons cannot be used without significant changes in a similar problem for plates. The method of creation of computational schemes of kinematic devices that precisely change the frequency spectrum of natural vibrations of elastic plates with a finite number of degrees of mass freedom is a separate problem and will be considered in a subsequent paper.

Sequence Analysis of Several Ancient River Blocking Events in the Suwalong Reach of the Upper Jinsha River Based on Multidisciplinary Approaches, SE Tibetan Plateau

The temporary or permanent river blocking event caused by mass movement usually occurs on steep terrain. With the increase of mountain population and land use pressure and the construction of water conservancy and hydropower projects, river blocking event has gradually attracted people’s attention and understanding. The study area (Wangdalong-Gangda reach) is located in the upper reaches of the Jinsha River and the southeast edge of the Qinghai-Tibet Plateau. Affected by strong tectonic activity in the Jinsha River suture zone and the rapid uplift of the Tibetan Plateau, in the past 6000 years, there have been at least five obvious river blocking events in the reach of about 30 km in the study area. The number and density are very rare. Combined with the field investigation, indoor interpretation, laboratory tests, optically stimulated luminescence (OSL) dating, SBAS-InSAR and previous studies, multidisciplinary approaches are used to systematically summarize the analysis methods and further the understanding of one river blocking event and multiple river blocking events from difference perspectives. Especially in multiple river blocking events, we could get the wrong results, even the opposite conclusion if interaction is not considered. Through this study, the general method of analyzing the river blocking event and the problems that should be paid attention to in sampling are given, and relatively reliable historical results of river blocking events are obtained. This method has extensive applicability to the identification and analysis of river blocking events in other areas.

Hospital Effluents and Wastewater Treatment Plants: A Source of Oxytetracycline and Antimicrobial-Resistant Bacteria in Seafood

The present study employs a data review on the presence and aggregation of oxytetracycline (OTC) and resistance (AMR) bacteria in wastewater treatment plants (WWTPs), and the distribution of the contaminated effluent with the aid of shallow and deep ocean currents. The study aims to determine the fate of OTC and AMR bacteria in seafood, and demonstrate a relationship between AMR levels and human health. This review includes (1) OTC, (2) AMR bacteria, (3) heavy metals in aquatic environments, and their relationship. Few publications describe OCT in surface waters. Although OTC and other tetracyclines were found in 10 countries in relatively low concentrations, the continuous water mass movement poses a contamination risk for mariculture and aquaculture. There are 10 locations showing AMR bacteria in treated and untreated hospital effluent. Special effort was made to define the geography distribution of OTC, AMR bacteria, and heavy metals detected in WWTPs to show the likely dissemination in an aquatic environment. The presence of OTC in surface waters in Asia, USA, and Europe can potentially impact seafood globally with the aid of ocean currents. Moreover, low concentrations of heavy metals exert environmental pressure and contribute to AMR dissemination. Recommended solutions are (1) quantitative analysis of OTC, heavy metals, and AMR bacteria to define their main sources; (2) employing effective technologies in urban and industrial wastewater treatment; and (3) selecting appropriate modelling from Global Ocean Observing System to predict the OTC, heavy metals, and AMR bacteria distribution.

Long-Term Evolution and Monitoring at High Temporal Resolution of a Rapidly Retreating Cliff in a Cold Temperate Climate Affected by Cryogenic Processes, North Shore of the St. Lawrence Gulf, Quebec (Canada)

This article focuses on the quantification of retreat rates, geomorphological processes, and hydroclimatic and environmental drivers responsible for the erosion of an unconsolidated fine-sediment cliff along the north shore of the Gulf of St. Lawrence (Quebec, Canada). Annual monitoring using field markers over a period of twenty years, coupled with photo interpretation and historical archive analysis, indicates an average annual erosion rate of 2.2 m per year between 1948 and 2017. An acceleration in retreat occurred during the last 70 years, leading to a maximum between 1997 and 2017 (3.4 m per year) and 2000–2020 (3.3 m per year). Daily observations based on six monitoring cameras installed along the cliff between 2008 and 2012 allowed the identification of mechanisms and geomorphological processes responsible for cliff retreat. Data analysis reveals seasonal activity peaks during winter and spring, which account for 75% of total erosional events. On an annual basis, cryogenic processes represent 68% of the erosion events observed and subaerial and hydrogeological processes account for 73%. Small-scale processes, such as gelifraction, solifluction, suffosion, debris collapse, and thermoabrasion, as well as mass movement events, such as slides and mudflows, induced rapid cliff retreat. Lithostratigraphy and cliff height exert an important control on erosion rates and retreat modes, which are described by three main drivers (hydrogeologic, cryogenic, and hydrodynamic processes). Critical conditions promoting high erosion rates include the absence of an ice-foot in winter, the absence of snow cover on the cliff face allowing unrestricted solar radiation, the repetition of winter warm spells, snow melting and sediment thawing, and high rainfall conditions (>30 mm or SPI > 2). The relationships between hydroclimatic forcing and retreat rates are difficult to establish without taking into account the quantification of the geomorphological processes involved. The absence of quantitative data on the relative contribution of geomorphological processes can constitute a major obstacle in modeling the retreat of cliffs with regard to climate change.