Planning and Empirical Analysis of Ancient Rivers and Lake Conservation Systems in Beijing

ZHOU Kunpeng; WANG Chongchen; QIN Hongling; SHANG Junhui

doi:10.3969/j.issn.1000-0232.2023.12.002

Abstract：Beijing is a city with a long history of water management.The development of the capital always involves water governance,development and utilization,thus contributing to brilliant hydraulic civilization.The ancient river and lake water conservation system in Beijing is the main factor contributing to the hydraulic civilization,which reflects the wisdom of the designers. The planning and empirical methods used in the historic river and lake conservation systems in Beijing,and their significance to contemporary urban ecology were analyzed.First,the spatial planning and developmental changes of the historic water conservation system in Beijing during Jin,Yuan,Ming and Qing dynasties were analyzed from the perspective of water conservation,and functional design.The findings suggest that that water conservation strategy in ancient times was based on a multi-functional pattern meeting the urban needs.Second,the hierarchical planning,diversion and storage mechanism,and the lock-dam water storage system of historic rivers and lakes in Beijing were explored from the perspective of internal regulation and storage of water.The operational mechanism entailed regulation of water resources.Third,the internal connection,storage space and node design of ancient urban rivers,lakes and channels in Beijing were explored from the perspective of urban rainstorm drainage and storage,which revealed the unique planning and design adopted.Finally,the planning,design,construction and technical methods of historic river water diversion and drainage were investigated from the perspective of water conservation engineering,which suggested a low level of technology used to build the river channels. Thus,the historic river and lake water conservation system in Beijing can be summarized as follows.First,it was characterized by a multi-functional pattern based on water source development,moat construction,water transport planning,and river-lake connection according to the urban developmental needs under all dynasties.Hence,the water conservation system comprising interconnected water sources,rivers,reservoirs and moat was built to meet multiple needs,such as urban water supply,transport,defense,landscape,and drainage.Second,a stable regulation and storage mechanism comprising upstream water supply and storage area centered at Kunming Lake,a midstream water-use and storage area centered at Shichahai and Taiye pond,and a downstream drainage and transport area at Tonghui and Bahe Rivers was constructed.Further,a scientific water storage mechanism was developed by establishing several dams and gates.Finally,an orderly river and lake conservation system was built via hierarchical impoundment and guidance of lakes and dams.Third,substantial rainstorm storage and drainage capacity was ensured by linking urban open channels,underground channels,canals,water moats,and Bahe and Tonghui Rivers,suggesting extensive capacity for urban water storage.The water storage-drainage design at the water conservation nodes including the Forbidden City,Tuancheng and Summer Palace was based on scientific principles.The urban flood pressure was relieved effectively by connecting rivers,lakes and channels,and the huge water regulation and storage space.Fourth,cost-effective smart water conservation engineering designs in harmony with nature were adopted using low-cost technology.The engineering designs included low weir diversion design of Liling Weir,the cross-river confluence of Jingshui River,the C-shaped curve and spill dam of Baifu Wengshan River,and the curved ring water storage of Beiyun River.Such smart low-technology designs facilitated the development of water conservation systems in Beijing. The historic river and lake conservation system in Beijing is attributed to water governance,management and utilization over thousands of years.Its value is manifested by multi-functional water conservation,stable regulation and storage mechanism,strong flood storage and drainage capacity,and smart water conservation engineering design.The core concept is to fully comply with natural terrain as well as river and lake environment.The core method entailed scientific design of"water resource regulation,diversion,storage and drainage"based on natural laws.It is based on the concept of man-nature harmony and simple engineering wisdom,which is reflected in current urban ecological construction.It provides unique concepts and facilitates the optimization of modern urban water conservation system,sponge city construction and water resource management,including multiple values and goals,and multi-level flood regulation and storage.It ensures interconnected storage and drainage spaces.It also contributes to diverse ideas and methods such as bending and low-technology engineering construction for contemporary urban water resource development,channel planning,and water recycling.