Natural hazards are recurring processes that often disrupt community stability and pose risks to the future well-being of people. In the Pyrenees, extreme events such as floods, rockfalls, landslides, and snow avalanches have repeatedly affected transport corridors and human settlements. Addressing these challenges in the future requires a transition toward implementing Ecosystem-based Disaster Risk Reduction (Eco-DRR) strategies and sustainable land use practices. However, little is known about the long-term reliability of these approaches. Here, we present a life-cycle analysis of a catchment with over a century of experience in implementing Eco-DRR strategies—Los Arañones—designed to protect the International Railway Station of Canfranc (Spain-France) from snow avalanches and torrential floods. The Eco-DRR implemented in Los Arañones consisted of two different strategies (i) at short term, innovative nature-based design dikes; and (ii) at long term, systematic reforestation of hill slopes. By employing a multi-disciplinary approach that includes climatology, geomorphology, engineering, tree-ring analysis, and modeling, we assess the past, present, and future trajectories of snow avalanches and floods in a catchment where forest engineers have implemented these measures since the early 20th century. Our analysis suggests that these century-old infrastructures still provide effective protection for infrastructure, although maintenance costs to ensure their reliability have increased. Additionally, our findings highlight differences in effectiveness and efficiency due to process changes driven by climate change stressors. We also introduce an initial system designed to monitor the stability of 100-year-old check dams. This case study offers valuable insights for implementing similar solutions in other mountain regions worldwide while providing a foundation for further monitoring and evaluation of such systems.