Background: Reservoir sedimentation poses a significant challenge to water resource sustainability, as it reduces storage capacity, compromises hydraulic performance, and shortens the operational lifespan of dams. In Pakistan, many reservoirs face accelerated sediment accumulation due to steep catchment slopes and intensive land use, yet limited research has focused on the role of auxiliary dams in mitigating these effects. Objectives: This study aimed to assess the environmental impact of the Auxiliary Kandar Dam on extending the lifespan of the Main Reservoir in District Kohat, Khyber Pakhtunkhwa. It sought to quantify sediment deposition, evaluate trapping efficiencies, and model future storage scenarios under different auxiliary dam construction timelines. The research addressed a key knowledge gap regarding how auxiliary dam construction can optimize sediment retention and improve reservoir sustainability in semi-arid regions. Methods: A detailed grid survey was conducted to determine the storage capacities of both reservoirs, with volumetric and spatial analyses performed using SURFER software. Sediment yield estimations were calculated through the HR Wallingford Sediment Yield Prediction Model (WSYPM). Field observations, hydrological data, and chronological sediment records were integrated to validate trapping efficiencies and predict future capacity loss scenarios. Results: The initial capacities of the Main and Auxiliary Dams were 1,000,365 m3 and 1,994,974 m3, respectively. Over nine years, the Auxiliary Dam accumulated 196,654 m3 of sediment, resulting in a 9% loss in storage capacity. The Main Dam exhibited a trapping efficiency of 90.48%, which declined with a decreasing inflow ratio from 0.508 to 0.194. Within six years, approximately 175,501 m3 of sediment were deposited in the Main Dam, causing a 61.78% reduction in total storage capacity over 41 years. The observed sedimentation patterns closely matched WSYPM predictions. Importantly, the construction of the Auxiliary Dam in 2014 extended the Main Dam's effective lifespan by 34 years (2022 – 2056). Modelling suggested that additional auxiliary structures in 2016 or 2022 could further prolong the lifespan by 80 years (2022 – 2102) or 68 years (2022 – 2090), respectively, while a proposed left Auxiliary Dam (2025) would extend it by 66 years (2022 – 2088), yielding an overall operational duration of 107 years (1972 – 2079). Conclusion: The findings confirm that the construction of the Auxiliary Kandar Dam significantly reduced sediment inflow into the Main Reservoir, effectively extending its operational lifespan and ensuring sustainable water storage for the region. The study successfully demonstrates, for the first time in this geographic context, the quantitative relationship between auxiliary dam placement and sediment reduction efficiency.

Background: With the fast expansion of the social economy and construction industry, environmental pollution, ecological deterioration, and other challenges are becoming more and more serious. The construction industry is a significant contributor to environmental pollution, generating 40% of total solid waste in developed countries and accounting for 30% of global greenhouse gas emissions. Eco-friendly measures must be adopted to design and create environmentally responsible buildings that consume fewer resources throughout their existence. Green construction technologies may be used as an effective technique for implementing sustainability in the construction sector. This growing emphasis on carbon reduction may explain the heightened public awareness and interest in the development of low-carbon buildings. Objectives: The objective of this study is to investigate the benefits and application of green and low-carbon technology in developing countries such as China (Chongqing), where construction activities are primarily performed by Chinese companies and Chinese stakeholders. Our primary target is to find sustainable factors that encourages public to employ green and low-carbon building technologies. Considering above facts, the proposed study attempts to provide answers to the following questions: which enablers and challenges contribute to the adoption of green and low-carbon building technology; how to assess sustainable green and low-carbon building technology enablers under data uncertainty; how to find an interdependent relationship among the enablers. Methods: A systematic literature review (SLR) offers an overview of the research's scope. In total twenty-eight drivers and fifteen challenges of green and low-carbon building technology and sustainable construction were reported from 91 selected articles, and research questions were assessed and evaluated. Following that, primary data was collected through a two-step process involving a questionnaire survey (analysed using statistical software,) and factor analysis. The sample was collected from registered building companies listed in China's Ministry of Housing (Chongqing). The company's sample size in this study was 100 construction companies out of 400 chosen and 300 contacted persons, consists of professionals who are involve Engineers, truction as stakeholder, Project Managers, Architects, Civil Engineers and local literate people in these companies. Carbon emission values for each category of construction machinery were calculated using a standardized emission factor approach. Results: In total, 27 key enablers were identified through literature review and added to questionnaire to monitor the public response. The highest level of agreement, 40.96%, was recorded for "Optimization in energy and construction materials" (E18), indicating strong support for the incorporation and optimization of energy in construction materials. E18 reflects the most appropriate, sustainable, affordable, and trendy option to achieve green construction that offers little or no repercussions making it most voted enabler. Following E18, the factors representing the most valued enablers are "Enhance return on investment" (E25), "Improve safety and health" (E19), and "Environmentally friendly" (E17), with percentages of 39.36%, 39.10%, and 39.89%, respectively. The major challenges were mentioned as "affordability" and "lack of public demand" for green and smart buildings that produced same value of 38.30% highly agreed response. "Lack of knowledge and understanding" of green and low-carbon construction practices also marked as significant challenge with voted value 36.17% strongly agreed response, expressed a relatively low degree of disagreement. Mixed opinions were expressed regarding the "lack of client awareness". The most significant is Tire loader from Shovel and horizontal transport machinery carbon emitting 245.60 Kg/work, Self-raising tower crane from Hoisting and vertical lifting machinery emitting 201.32 Kg/work and grader from Compaction and pavement equipment with total emission 142.75 Kg/work. There is a scarcity of data on the carbon emissions of nonroad construction equipment and the relevant carbon emissions factors of the equipment. Conclusion: Government support, including building regulations, planning policies, and financial incentives such as subsidies and tax breaks was found to be a primary enabler, while limited stakeholder awareness and low market demand were major barriers. The study contributes new scientific knowledge by revealing nuanced interactions between enablers and challenges that previous research had not fully explored, particularly in the context of urban construction landscape of the study area.