Core Viewpoint - The construction of Jinan Metro Line 4 prioritizes the protection of the local spring ecosystem while addressing urban congestion, making it the world's first metro line built near a sensitive spring area [2][6][24]. Group 1: Metro Line Overview - Jinan Metro Line 4 is the first metro line in the world to be constructed near a sensitive spring area and runs beneath the busiest road in the city, aiming to alleviate traffic congestion [2][12]. - The line spans 40.3 kilometers with 33 stations, connecting key urban areas and enhancing public transportation options [21][26]. Group 2: Environmental Considerations - The design philosophy emphasizes "avoiding and elevating" to protect the spring water, with the metro line planned to bypass sensitive areas and minimize impact on groundwater flow [6][14]. - The station at Quancheng Park is designed to be partially above ground to protect the underground water, making it the shallowest station on the line [6][11]. Group 3: Innovative Technologies - Advanced water recharge technology has been implemented, allowing for efficient management of groundwater during construction, with a focus on maintaining water quality [15][20]. - The construction utilized innovative materials that prevent water leakage and allow for the free flow of groundwater, ensuring the integrity of the spring ecosystem [23][24]. Group 4: Monitoring and Future Plans - Continuous monitoring of groundwater levels is established with over 200 monitoring points along the metro line to ensure the health of the spring ecosystem [24]. - The line is set to open by the end of the year, fulfilling the community's desire for a harmonious coexistence of urban transit and natural springs [26].