Many practical issues arise when dealing with solid waste management, and there are also environmental effects to be considered. Selecting landfill sites requires extra care with respect to many factors such as the environment, health hazards for people, and the cost of transportation. Furthermore, cities have their own rules, methods, and practices for managing and selecting the best locations for collecting solid waste. In this research, multi-criteria decision analysis (MCDA) was presented and used to evaluate the appropriateness of and suggest the best locations for landfill sites in Najran, KSA. Some remote sensing data and the ArcGIS software were used to prepare nine thematic layers, including drainage density, groundwater depth, land use, soil type, road network, surface elevation, surface slope, distance from residential areas, and distance from protected areas. To evaluate the layer weightings, a questionnaire with pairwise comparisons was distributed among experts and analyzed using the analytical hierarchy process (AHP) and fuzzy set technique. The one-factor-at-a-time (OFAT) sensitivity test was conducted to test the sensitivity of the evaluated weightings. A landfill suitability index (LSI) map was created using raster calculator tools and divided into five classes: limited suitability (LSI value 1.39–2.49), least suitable (2.50–3.03), relatively suitable (3.04–3.48), suitable (3.49–3.91), and most suitable (3.92–4.66). According to the statistical analysis, 18.0% and 18.2% of the total area were within the most suitable and suitable landfill regions, while 21.2%, 14.9%, and 9.5% accounted for relatively suitable, least suitable, and limited suitability areas, respectively. The employed technique and its findings can provide an appropriate guideline to assist the municipality of Najran city, regional planners, and decision-makers in selecting an optimal landfill site in the future. This study also presented some recommendations to enhance the suitability map of landfill sites in Najran city.

The city of Jeddah experienced a severe flood in 2020, resulting in loss of life and damage to property. In such scenarios, a flood forecasting model can play a crucial role in predicting flood events and minimizing their impact on communities. The proposed study aims to evaluate the performance of machine learning algorithms in predicting floods and non-flood regions, including Gradient Boosting, Extreme Gradient Boosting, AdaBoosting Gradient, Random Forest, and the Light Gradient Boosting Machine, using the dataset from Jeddah City, Saudi Arabia. This study identified fourteen continuous parameters and various classification variables to assess the correlation between these variables and flooding incidents in the analyzed region. The performance of the proposed algorithms was measured using classification matrices and regression matrices. The highest accuracy (86%) was achieved by the Random Forest classifier, and the lowest error rate (0.06) was found with the Gradient Boosting regressor machine. The performance of other algorithms was also exceptional compared to existing literature. The results of the study suggest that the application of these machine learning algorithms can significantly enhance flood prediction accuracy, enabling various industries and sectors to make more informed decisions.

Energy consumption in the building sector accounts for a large percentage of global energy consumption. For this reason, it is essential to take action to minimize this destructive consumption and promote energy conservation practices within the building sector. A Zero Energy Building (ZEB) concept has been proven as a viable technique for improving energy efficiency in various climatic conditions. This concept can minimize the environmental impact of buildings and helping to advance sustainable development in the construction industry. Worldwide, the ZEB is of the utmost importance to meet sustainability development goals in the built environment. The building sector in the Kingdom of Saudi Arabia (KSA) consumes about 75% of total electrical energy. KSA has experienced an unprecedented energy consumption in the last decade. This is due to the country’s rapid population growth and urbanization, which in turn put more pressures on the kingdom’s natural resources. However, KSA is committed to promote energy efficiency and renewable energy technologies to achieve the goals of sustainability development, as part of its Vision 2030. This paper therefore explores various green building solutions, especially in hot-arid regions, with the aim of reaching ZEB, and at the same time minimizing potential adverse environmental impacts. In order to verify proposed solutions, energy simulation software (Integrated Environmental Solution-IES) is used, along with reviews of related work. The major finding of this paper reveals that several green building concepts are crucial to the design and operation of a building in hot dry region, including thermal mass; daylight; natural ventilation; cavity wall; double-glazing and solar panels (PV). Bear in mind that the operation of a building has to be powered by a Building Management System (BMS). This paper also proposes an auxiliary holistic framework that explains how green practices such as Zero Energy Buildings (ZEBs) can be achievable in Saudi Arabia with no harm to its local environment.

In hot and humid climates, a significant part of the energy is used to cool the building. There are several ways to reduce this air conditioning load, but one standout is through the selection and design of the right building envelope and its components. The thermal characteristics of the building envelope, in particular the thermal resistance of the insulation used, have an impact on the thermal and energy performance of building structures. Thermal conductivity, which indicates the ability of heat to move through a material given a temperature difference, is the primary factor affecting the performance of a thermal insulation material. Both temperature and humidity changes can affect a material’s thermal conductivity value, which can then change. In fact, due to the fluctuating ambient air temperature and solar radiation, thermal insulation in buildings is susceptible to significant and continuous temperature variations. Thermal insulation used in building walls and roofs helps to reduce the energy demand of the building. It improves thermal comfort and, if used correctly, reduces the operational cost of the building. The present study has focused on the effects of location and insulation material on the energy performance of a residential building by considering five climatic locations in the Kingdom of Saudi Arabia (KSA). Five commonly used insulation materials with different thermal characteristics, namely polyurethane board (PU), expanded polystyrene (EPS), glass wool (GW), urea-formaldehyde foam (UFF), and expanded perlite (EP), were analyzed under various climatic zones as per the Saudi Building Code 601/602. The selected cities were categorized based on cooling degree days (CDD) and outdoor dry bulb temperature (DBT) as hot, very hot, and extremely hot climatic zones. Insulation improves thermal comfort and, if used correctly, reduces running costs. Experiments were conducted to determine the thermal conductivity, and the energy simulation was performed by employing IES-VE software for various insulation options. The findings indicate that the location has a significant impact on the energy performance of the insulating materials. The energy saving potential of polyurethane board (PU) insulation is more attractive in cities with higher DBTs and CDDs than in cities with lower DBTs and CDDs. The benefit of installing insulation ranged from a 2 to 14% decrease in energy demand for the climate zones studied. The sensitivity analysis showed that the energy saving potential of the insulation materials is sensitive to the set-point temperature (ST) band.

In the modern era, population and economic growth have accelerated urban sprawl in Saudi Arabia. This has placed tremendous pressure on the country’s natural resources, including water, energy, and raw materials. Hence, the conventional means of expanding the built environment is no longer appropriate, as it has been found to be one of major causes of climate change and global warming. In the early 1970s, the principles of sustainable development emerged in developed countries, in order to remedy this global issue. During this period, Saudi Arabia experienced dramatic development in all of its industries, but the principles of sustainable development were, to a large degree, overlooked. However, there is now an ambitious Vision 2030 for Saudi Arabia, one of the purposes of which is to promote greater sustainability in the country. This study seeks to assist decision makers to identify the challenges and opportunities of the current Saudi practices of city design, and their related operational aspects, and to enable the adoption of effective measures for implementing sustainable development principles. Employing an ethnographic research methodology, the fieldwork concerned includes a public perception survey, followed by a site inspection, in order to develop an insider’s view of the current level of sustainable practice in the city of Najran. A public survey is distributed to well-informed citizens, with the goal of obtaining their insights, and to assess their willingness to embrace green city practices. This is followed by a site inspection visit that seeks to obtain in-depth information regarding site design and operational practices. A checklist of sustainable criteria is adapted from well-known systems. The major outcomes of the study reveal that many challenges are encountered the application of green city principles. The paper offers effective approaches and strategic actions for overcoming these challenges.