Urban Subarea: Rivers and Subarea Development—Evolution of the Landscape Character Along the Qinhuai River in Nanjing City

This Chapter investigates the landscape character of urban subareas shaped by the Qinhuai River in Nanjing, examining river-driven spatial development at the subarea scale. As a major river system integrated into the urban fabric through long-term hydraulic modification, the Qinhuai River provided a fundamental landscape framework for the formation and differentiation of water-oriented urban subareas. From the perspective of landscape architecture and urban morphology, this chapter elucidates the multiple functions of the river system, including water management, transportation, spatial organization, and environmental regulation, and their role in structuring subarea landscapes. Methodologically, the study combines historical analysis with spatial interpretation to examine the interaction between natural hydrological conditions, artificial water infrastructure, and urban form during key historical periods, particularly the Six Dynasties (222–589 CE) and the Ming-Qing Period (1368–1912 CE). The analysis demonstrates that the Qinhuai River functioned not merely as an infrastructural corridor, but as a persistent generator of landscape space, shaping subarea structure, landscape character, and patterns of urban life. The long-term continuity and transformation of river-based landscape structures reveal how water systems sustained urban development at the subarea scale, providing a critical foundation for understanding river-oriented landscape formation in traditional Chinese cities and complementing subsequent discussions at canal and basin scales.