Hydropower projects play a significant role in sustainable energy generation and infrastructure development. However, the successful execution of such projects is often challenged by technical, managerial, financial, environmental, and organizational factors. Understanding these factors is essential for improving project performance and minimizing the risk of project failure. The present study aims to identify, evaluate, and rank the critical success and failure factors affecting hydropower projects. A comprehensive review of literature was conducted to identify major factors influencing project outcomes. Data were collected through a structured questionnaire survey administered to professionals associated with hydropower projects, including project managers, construction managers, engineers, consultants, and contractors. The collected responses were analyzed using the Relative Importance Index (RII) method to determine the significance of individual factors. The analysis revealed that project manager's experience, contractor's experience, leadership capability, effective site management, design team expertise, availability of construction materials, and site conditions are among the most influential factors contributing to project success. Conversely, inadequate planning, poor coordination among stakeholders, financial constraints, resource shortages, and environmental uncertainties were identified as major causes of project failure. The findings of this study provide valuable insights for project owners, consultants, contractors, and policymakers in developing effective strategies for enhancing the performance and sustainability of hydropower projects. The study also establishes a framework for future research on project success assessment and risk management in the hydropower sector.

Keywords: Hydropower Projects, Critical Success Factors, Project Failure Factors, Relative Importance Index (RII), Project Performance, Construction Management, Risk Assessment.