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This document is a discussion of a research paper titled "Reusing Life-Expired Railway Ballast: Laboratory Testing, Shape Analysis, and Petrographic Evaluation." The paper explores the reuse of life-expired ballast aggregates from railway tracks as an environmentally responsible approach to reducing the use of nonrenewable resources and minimizing the carbon footprint. The authors' findings demonstrate the benefits of combining life-expired ballast with fresh ballast to create suitable track substructure support. The discussion also includes specific comments on permanent settlement and aggregate degradation in triaxial testing. Overall, the research provides valuable insights into the recycling of railway ballast and offers direction for future research and application. [Extracted from the article]

Adapting reservoir operation to a changing climate is important to improve water system performance toward benefits including water security, and energy production. However, managers still need to know if and how reoperation can also assist long-term mitigation of climate change impacts on aquatic ecosystems, creating, for example, opportunities to revert fish migration and recruitment losses. This paper investigates the operational adaptive capacity of water systems to mitigate climate change impacts on both hydropower and aquatic ecosystems, with a detailed representation of fish species recruitment response to flow regime changes. The methodology framework combines hydroclimatic modeling, explicit stochastic reservoir operation modeling, and predictive modeling of migratory fish recruitment abundance, illustrated using the large-scale hydropower system of the Paraná River Basin in Brazil. Results identified that operating policies can be adapted to improve hydropower production under a changing climate with drier conditions by 2% to 8% compared with current operating policies. Although insufficient to eliminate all energy losses that climate change may cause, the optimized operation provided flexibility to adjust flow releases and reduce the likelihood of future severe multiyear deficits, which are very harmful to fish populations. Adapting operation to climate change sacrificed fish recruitment performance over a few years of the time horizon to maintain an overall higher storage, but it also improved the chances of producing flow releases in magnitude, timing, and duration during long drier periods that prevented more severe impacts of climate change on fish recruitment and population. This indicates that it might be possible to have synergies in adapting reservoir operation to not only prevent energy losses, but also to improve fish recruitment under climate change. The ecosystem resiliency under adapted operation increased up to 2 times compared with the isolated climate change effect. [ABSTRACT FROM AUTHOR]

In the face of climate change and rising mean global temperature, urban planning is required to transform cities into resilient living areas for present and future generations. Within this task, microclimate simulation models are an important tool to assess the impact of nature-based solutions (NBSs), building morphology, design of urban quarters, and other measures on the local microclimate. As simulation tools are open to be applied by different user groups, the utilization of the software is often kept as easy as possible. This seeming simplicity bears the risk for users to fall into traps during the model configuration, interpretation of results, or not making use of the full potential of simulations. While scientific literature mainly describes successful application of case studies, it does not cover potential misapplication and related consequences. The present study contributes to closing this research gap and supports the urban planning community with a selection of pitfalls in the model setup and interpretation of results. Clear examples of wrong configuration of wind direction, inaccurate evaluation of mean radiant temperature (MRT), and improper selection of performance indicators are presented by the means of sensitivity experiments and case studies with the modeling software ENVI-Met. The prevailing study demonstrates why MRT values are not suitable to explain effects of NBS during nighttime and contrasts the effects of façade greening on air temperature (0.85°C) with building surface temperature (6.1°C or even 27.5°C with substrate layer). In addition, it highlights the potentials of the multitude of possible performance indicators of microclimate simulations. The selection of avoidable mistakes in the assessment of the local microclimate supports users of microclimate models to promote effective and impactful climate adaption and mitigation measures in urban planning. [ABSTRACT FROM AUTHOR]

Urban transportation is viewed as the second leading source of carbon dioxide emissions. The growing number of vehicles and road infrastructure-based supply in Indian cities is viewed as the essential driver of climate change and relevant consequences affecting the sustainability of cities. In this study, sustainable transport measures were analyzed to understand the emission mitigation potential of the Bengaluru Metropolitan Region's transport sector in Karnataka, India. Relevant policies were identified under the planning, regulatory, economic, and technological instruments and grouped under four policy bundles. The mitigation potential of the policy bundles was quantitatively evaluated in terms of vehicle kilometers traveled (VKT), exhaust emissions, and greenhouse gas emissions. The study also estimated the carbon emission intensity and consumer surplus for different mode users across all policy bundles. The findings from this showed that Policy bundle 4, a comprehensive mix of various policies, demonstrated a critical decrease in VKT and emissions compared with the other policy bundles and, thus, provided good scientific decision support for transport policymakers. The study helps Bengaluru's transport planning authorities in designing comprehensive mobility plans in a much more sophisticated way. The inclusion of public participation in the planning process helps improve sustainability. The consumer surplus provides a better understanding of social benefits derived from the policies, and emissions intensity estimates help understand whether the emissions have decoupled from the economic growth. The study also presents that public transportation plays a major role in solving congestion problems. Thus, it helps the planning authorities to prioritize their investments to make cities more liveable. [ABSTRACT FROM AUTHOR]

This study analyzes the news media coverage of floods in a major flood-prone state of India, Bihar. Although news media helps shape public perception and political actions, little analysis of this means of communication has been conducted in India. Major topics and issues discussed during the coverage of Bihar floods in years 2013, 2017, and 2019 were provision of food, shelter, and health facilities, failure of the transportation system, waterlogging in urban areas, and failure or management of embankments. There was no skepticism on whether climate change was real. Political parties took contradictory positions: the ruling party attributed floods to a changing climate but other parties, and news media, emphasized the lack of disaster mitigation actions and were uninterested in climate change. This study suggests that it is more important to prepare for disaster mitigation actions around the major issues discussed and communicate them to the public. Media should become a major stakeholder by questioning the authorities about disaster preparations prior to the monsoon season and communicating mitigation actions to the public once disaster has struck, and help both public and government to better manage and mitigate the disaster. [ABSTRACT FROM AUTHOR]

The greatest challenge that the human society is facing in the 21st century is climate change. Climate change debates advocate that although urban areas largely contribute to climate change they also play an important role in addressing it. This research puts forth an effort to identify whether statistically significant relationships exist between carbon dioxide (CO2) emissions and urban planning policies, as well as between CO2 emissions and gender. In this regard, this research investigates whether urban planning policies in master plans have an impact on local CO2 emission levels. As a first step, a qualitative content analysis of the policy framework of sampled master plans that were involved in the sample was undertaken and climate change mitigation indexes were developed by assessing the sampled master plan's urban policies against climate change mitigation evaluation protocols. Later, using climate change mitigation, the impact of urban planning policies on local CO2 emissions, while controlling for socioeconomic characteristics, was examined by undertaking regression analysis. This research develops empirical evidences that analyze the impact of urban planning policies on CO2 emission levels, thereby contributing significantly to the urban planning and public policy field. This research highlights that master plans are effective tools in promoting low-carbon regions through urban planning thereby mitigating climate change. This research emphasizes urban planning as a policy tool for mitigating climate change and has an implication for mainstreaming climate change mitigation in local urban planning. [ABSTRACT FROM AUTHOR]

Climate change and the ever-increasing water demands have led to the introduction of mitigation and adaptation interventions in water systems, which need to be understood. The effects of these countermeasures on the upgrade requirements and hydraulic performances of existing water distribution systems (WDSs) and sanitary sewers (SSs) are analyzed in this study. In addition to the common two-objective problems, a three-objective problem that provides cost-effective water-saving schemes (WSSs) that also reduce greenhouse gas (GHG) emissions have been proposed. In order to obtain and analyze solutions for all the aforementioned optimizations, the tasks of selecting WSSs considering different performances were formulated and solved as multiobjective optimization problems. The objectives considered are the minimization of the overall cost (i.e., less savings) versus minimization of water demand or maximization of network upgrade postponement introduced by WSS measures. Optimizing the GHG emissions and reductions to any of these two-objective problems completes a three-objective problem. The decision variables are the domestic water saving appliance and fitting capacities, and the tank sizes of the rainwater harvesting systems (RWHSs). The method provides Pareto fronts, which are the outputs from a nondominated sorting genetic algorithm. The proposed method was applied to the subsystems of the Tsholofelo WDS and sanitary sewer (SS) in Gaborone, Botswana. The results indicate that three-objective climate change counteractive WSSs are more desirable than two-objective WSSs. Solutions obtained considering WDS demand or the WDS only excluding the corresponding SS would undesirably impact the hydraulics and SS upgrade requirements and vice versa. [ABSTRACT FROM AUTHOR]

Wadis, an Arabic term referring to a wadi, in the Eastern Desert of Egypt have undergone rapid unsustainable development in areas vulnerable to flash flooding and water scarcity. To reduce the risk of damage and loss of life from flash floods to a wadi's new residents, the priority is to develop mitigation strategies with distributed (watershed scale) or concentrated (localized) mitigation structures to promote sustainable development. The focus of this study is to develop a new approach that will help in assessing various flood mitigation scenarios in Wadi Abadi in the Eastern Desert of Egypt. The proposed approach considers the limited data availability in the wadi system and utilizes spatial analysis and an in-house developed distributed hydrological model, Hydrological River Basin Environmental Assessment Model (Hydro-BEAM), upgraded with a reservoir routing module. Sensitivity analysis of the key Hydro-BEAM model parameters indicated that the most significant parameters controlling the wadi flood peaks are soil thickness and porosity, runoff coefficient, subsurface layer outlet coefficient, and channel roughness. Digital Elevation Model (DEM) data and satellite imagery were utilized to propose the locations and derive design characteristics of the mitigation structures. The mitigation strategies evaluated in this study resulted in a peak flood reduction percentage of 90% and 86% for the distributed and concentrated dam scenarios, respectively. The results show that a group of distributed dams could outperform a single concentrated dam when flood mitigation and water resources management aspects are considered in the wadi region, where the distributed dams scenario has 600% more protected area and 21% more reservoir volume than the concentrated scenario (i.e., use of one dam). However, the concentrated dam scenario may have advantages due to the cost of construction and operations. The proposed approach can assess the flood risk reduction due to different mitigation measures and provide strategies for development and planning in wadi regions. [ABSTRACT FROM AUTHOR]

The article discusses the need for proper guidance on climate change adaptation and mitigation in coastal cities. It states the barriers in implementing climate change risk management strategies into action. It mentions measures to address the coastal settlements adaptation needs including creating estimates of cities to be affected by climate change, evaluate the cost of adaptation, and policies for environmental protection funding agencies.

As climate change mitigation becomes pervasive on all spatial scales, mitigation options related to urban spatial planning and behavioral change become increasingly important. Because transport energy consumption seems to scale inversely with population density, increased attention focuses on the role of urban form. This study specifically analyzes the importance of population density for the reduction of urban greenhouse gas emissions in Europe. For this, drivers of both carbon dioxide () emissions from transport (for 134 cities) and total urban greenhouse gas emissions (eq emissions) of 62 cities across Europe are investigated. Results indicate that population density is not, per se, a strong determinant of greenhouse gas emissions in European cities. Crucially, the spatial scale of the analysis matters and national influences modulate eq emissions in the analyzed urban areas. Results show that greenhouse gas emissions of European urbanites increase significantly with decreasing household sizes and increasing personal wealth. Although the results are bound by data quality, it is assumed that the relative similarity of European cities is also leading to a lesser degree of importance of population density with respect to climate change mitigation. The results further encourage more thorough analyses of the role of household size and personal wealth for effective mitigation of climate change, additional spatially explicit econometric studies, and detailed, city-specific causal models of urban areas. [ABSTRACT FROM AUTHOR]