Core Viewpoint - The successful operation of three new metro lines in Jinan highlights the city's innovative approach to balancing urban development with ecological preservation, particularly in protecting its famous springs while constructing the metro system [2][9]. Group 1: Metro Line Construction and Challenges - The construction of Jinan's metro lines, particularly Line 4, faced significant geological challenges due to the city's unique topography, which includes mountains to the south and rivers to the north, along with underground springs [3]. - Advanced geological survey techniques were developed to ensure that the construction of the metro would not adversely affect the spring water flow, with a focus on high-precision identification of water pathways [4][5]. - The construction process involved innovative strategies such as the "avoidance and elevation" principle, which ensured that the metro lines bypassed sensitive water recharge areas and maintained a safe distance from the main water flow channels [6][8]. Group 2: Technological Innovations and Monitoring - The integration of real-time monitoring technologies has allowed for precise tracking of water levels and quality, significantly enhancing the management of underground water resources [7]. - A data center was established to collect and analyze over 80 years of geological data, which supports both metro construction and ongoing spring water protection efforts [7][8]. - The development of new technologies for groundwater diversion and in-situ water recharge has been successfully applied at critical metro stations, helping to restore the original groundwater flow patterns post-construction [6][8]. Group 3: Regulatory and Environmental Protection Measures - Jinan has implemented a comprehensive legal framework for spring protection, expanding from the protection of spring outlets to include entire recharge areas and associated water systems [8]. - The city emphasizes a multi-faceted approach to spring protection, combining legal, scientific, and ecological strategies to ensure sustainable water resources while accommodating urban growth [9]. - The ongoing efforts to protect the springs, even during peak construction periods, have resulted in maintaining historically high water levels, demonstrating the effectiveness of the city's protective measures [9].