Sangyuanwei Polder Embankment System is one of the largest polder embankment projects of ancient China. It is located in Foshan City, Guangdong Province, in the Pearl River Delta. In the south subtropical marine monsoon climate zone, it has a warm climate and annual average precipitation of 1,620mm. Sangyuanwei Polder Embankment System has a circumference of 83.86km and covers an area of 265.4km². Surrounded by the Xijiang River, the mainstream of the Pearl River, and the Beijiang River, a tributary of the Pearl River, it is greatly vulnerable to floods, tides from the two rivers and typhoons. Sangyuanwei Polder Embankment System was first built in the early 12th century of the Northern Song Dynasty (AD 960–1127) and enclosed at the end of the 14^th century. Its construction ushered in the history of large-scale agricultural development in the Pearl River Delta. It is a milestone in the development of irrigation agriculture in the Pearl River Delta and it now still provides basic water conservancy guarantee for the regional social development. Sangyuanwei Polder Embankment System, with a history of more than 900 years, is not only an important historical witness to the water conservancy development in the Pearl River Delta region and the social and cultural development of Foshan area but also an important witness to the expansion and southward shift of Eastern China Economic Zone.

History

Sangyuanwei Polder Embankment System was first built between Chongning period and Daguan period (1102–1110) during the reign of Emperor Huizong of Song, more than 900 years ago. After the Mid-Tang Dynasty (AD 618–907), the continuous wars in the North led to the continuous southward migration of the population in the Central Plains, which promoted the agricultural development in the areas south of the Yangtze River, Zhejiang, Fujian and the Pearl River basin. At the beginning of the 12th century, polder embankments and Jizan Embankment were built along the Xijiang and Beijiang rivers of the Pearl River, with a height of about 1 to 2 meters. In the Yuan Dynasty (1271–1368), the embankment was further raised and thickened, with a height of about 4 meters. The Ganzhuxi area is the lowest in the whole System. Due to the influence of reclamation and natural deposition of sediment, the problems of poor drainage, flood and tidal backflow gradually appeared in Ganzhuxi area in the 14th century and the place was known as a “Flowing-Back Port”. In the 29th year of Hongwu period in the Ming Dynasty (1396), Chen Bomin, a native of Jiujiangbao, led the local people to close up the port, and Sangyuanwei Polder Embankment System was enclosed. With the increase of population, to prevent flood, the levees were further heightened and the levee line was extended in the Ming Dynasty (1368–1644). In addition, many small embankments were built in each village, and sluices were built to control the water volume. In the 17th century, Sangyuanwei Polder Embankment System had become a complete water conservancy project system including embankments, watercourse system, gate system for flood and tide control, irrigation and drainage, and water transport.

In the 59th year of Qianlong reign of the Qing Dynasty (1794), initiated by Wen Rushi, a native of Longshan County in Shunde, the General Administration of Sangyuanwei Polder Embankment System was established jointly by the gentry of 14 villages within the Embankment. The General Administration was responsible for organizing the maintenance and management of the water conservancy projects in the whole polder and compiling Annals of Sangyuanwei Polder Embankment System. This marked the beginning of the unified management and maintenance of Sangyuanwei Polder Embankment System as an integrated regional water conservancy project. The concept, scope, irrigation system and management system of Sangyuanwei were established for the first time. By the end of the Qing Dynasty, Sangyuanwei Polder Embankment System had become the “first fertile farmland in the surrounding provinces” and the “largest production base of grains in eastern Guangdong” with “a circumference of over 50km, hundreds of thousands of households and more than 1,000 hectares of agricultural mulberry fields”, and became one of the largest water conservancy projects in ancient times.

In 1915, the flood of the Pearl River broke the Jizan Embankment and the eastern and western embankments of the System, which promoted the further improvement of the engineering standard of the project. The Shihankou, Longjiang and Gejiao water gates built successively from 1925 to 1926 were made of reinforced concrete materials, which improved the control capacity. In the 1950s, Sangyuanwei Polder Embankment System and Qiaobei Polder were merged, known as Qiao-Sang Polder. At present, the overall flood control standard of Sangyuanwei Polder Embankment System has been raised from less than 10-year return period to more than 50-year return period, and the current irrigation area is 4,133ha. The historical pattern and cultural texture of Sangyuanwei water conservancy project are still intact.

Irrigation System

Sangyuanwei Polder irrigation and drainage system mainly includes three parts: embankments, watercourse irrigation and drainage system, and watergate control work. The perimeter of the whole polder is 83.86km, surrounded by the northern hills and Jizan Embankment, Xijiang Embankment, Dongjiang Embankment and Ganzhuxi Embankment, which together form the flood control barrier of the whole area. The total length of the project is 64.84km. The watercourses within the Embankment crisscrossed, forming a perfect irrigation and drainage canal network. Within the Embankment, there are 57 watercourses of historical value, with a total length of 281.21km, including 14 main watercourses with a total length of 75.91km. The control work of Sangyuanwei Polder Embankment System is called “dou”, actually water gate that can control water diversion, drainage and water transport. Most of the gates are culvert gates. Some of them use “herringbone” wooden gates, which can automatically open for drainage when the water level at waterlogging sites is high and close to block the tide automatically when the external tide or flood water level is high. Some of the water gates are also engraved with water rules for quantitative control. The water system within the Embankment is connected with the outside water through the gates on embankments, and the water level difference between the two rivers due to the difference in the degree of tidal bore patency is used to draw water into and drain water out of the polder. At present, within the Embankment, there are 63 ancient gates of historical value. Shen Fu of the Qing Dynasty vividly described the irrigation mechanism of Sangyuanwei Polder Embankment System in his Six Chapters of a Floating Life: “Each field had a number and was surrounded by a high embankment to protect it from the tides. The dykes all had sluices that could be opened or shut with gates. If the fields were dry the gates could be opened at high tide to irrigate them, and when they were flooded the gates could be raised at low tide to drain.” In history, rice and mulberry fish pond were the main agricultural products within the Embankment and the current irrigation area is 4,133ha.

In addition, there are 60 building facilities related to water conservancy management and water deity worship and 20 water conservancy inscriptions within the Embankment. The water conservancy documents and archives are well preserved and inherited. They witness the history and value of Sangyuanwei Polder Embankment System and also form an important part of Sangyuanwei Polder Embankment System irrigation project heritage.

Water Heritage

Sangyuanwei Polder Embankment System was first built more than 900 years ago, between Chongning period and Daguan period (1102–1110) during the reign of Emperor Huizong of Song. It was enclosed in the 29th year of Hongwu period in the Ming Dynasty (1396) over 600 years ago.

The type: Sangyuanwei Polder Embankment System is an irrigation and drainage work of embankment or polder in the river delta. With its specific engineering types including embankments, irrigation and drainage canals, water gates, Sangyuanwei Polder Embankment System is a complex irrigation and drainage system.

It represents a milestone/turning points in the development of irrigated agriculture.

The construction of Sangyuanwei Polder Embankment System not only ushered in the history of large-scale agricultural development in the Pearl River Delta but also witnessed the historical process of the expansion and southward shift of Eastern China Economic Zone. It is a milestone in the development of irrigated agriculture in the Pearl River Delta.

It was ahead of its times in terms of construction techniques and dimensions.

Sangyuanwei Polder Embankment System is 83.86km in length and the enclosed area is 265.4km². The irrigation area reached more than 13,333ha in history. It took the lead in its time in terms of scale. 

It has made an outstanding contribution to enhancing food production and rural prosperity.

Sangyuanwei Polder Embankment System irrigated more than 13,333ha of farmland in history, and its current irrigated area is 4,133ha. In addition to rice and other grain plantings within the Embankment, mulberry fish pond and other agricultural operation modes are also developed, making Sangyuanwei Polder Embankment System one of the areas with the most developed agricultural economy in the Pearl River Delta and providing water conservancy guarantee for rural prosperity.

It contributed to the evolution of efficient and contemporary engineering theories and practices.

The concept of regional “overall enclosing” for flood control represented by Sangyuanwei Polder Embankment System has been popularized and developed in modern urban or regional flood control practice. The recycling agriculture mode of a mulberry fish pond within the Embankment is of great enlightenment and reference value for the contemporary agricultural development and ecological progress.

It is an example of attention to environmental aspects in its design and construction.

The planning and design of Sangyuanwei Polder Embankment System fully reflect the overall coordination of water environment contradictions such as flood control, tide blocking, irrigation and waterlogged farmland draining, realizes the change, optimization and maintenance of the living environment, ecological environment and production environment in the enclosed area, and has good ecological environment effect.

It bears the stamp of a cultural tradition or a civilization of past the past.

In the long-term construction and operation process, Sangyuanwei Polder Embankment System and its water conservancy features have had a profound impact on the production and life, folk activities and folk worship in the enclosed area. For example, the characteristics typical of the waterside areas south of the Five Ridges, the Dragon Boat Race and the old and diverse activities of water deity worship all endow Sangyuanwei Polder Embankment System—an irrigation project—with distinctive traditional cultural characteristics.

Engineering utility vis-à-vis designed utility

Since its completion, Sangyuanwei Polder Embankment System has been playing an irreplaceable role in regional flood control, irrigation and drainage, tide blocking and other respects. It also played a role in water transport in history. In the Qing Dynasty, the area of farmland irrigated by Sangyuanwei Polder Embankment System was about 6,666ha. In the 1990s, the area of irrigated farmland reached more than 13,333ha. At present, Sangyuanwei Polder Embankment System is still contributing to the flood control and drainage safety of 265.4 km² of land, ensuring the irrigation and water supply of 4,133ha of farmland, and maintaining the production and living of nearly 900,000 people in the area.

Present State of Conservation

Sangyuanwei Polder Embankment System is a water conservancy project still in use today. Its protection and maintenance is jointly done by the water conservancy departments of Foshan City, Nanhai District and Shunde District, including the protection and management of embankments, watercourse systems and water gates to ensure the safety of the project structure and the regional flood control and drainage according to the current laws, regulations, rules and various normative documents concerning water conservancy projects. Among the ancient water gates of Sangyuanwei Polder Embankment System, there are now three historical and cultural sites under the protection of Foshan Municipality and four historical and cultural sites protected at the district level, whose protection and management are done by the cultural relics protection department according to the relevant laws and regulations. There are also two famous historical and cultural towns, four historical and cultural villages and five historical and cultural blocks. They are also carriers of Sangyuanwei regional culture and they are currently protected by the housing and construction department. In addition, the Sangyuanwei historical and cultural trails including “Songtang Village–Minle Water Gate–Jishui Water Gate–Xiqiao Mountain–He Family Ancestral Hall at Yanqiao–Xiabei Shitang Gate–Tanhua Bridge–Wu Family Courtyard at Jiujiang” have been inscribed on the list of historical and cultural routes of Guangdong Province to be protected and developed for tourism by culture and tourism departments. At present, Foshan Bureau of Water Resources is organizing the compilation of Sangyuanwei Irrigation Project Heritage Protection and Utilization Planning to ensure its protection and management in a systematic, scientific and sustainable way.

Management

In history, the management of Sangyuanwei Polder Embankment System continued the mode of official supervision and civilian repair characterized by an integration of overall management and section management. In the Ming Dynasty, the method of combining “section management by each village” and “building the dike according to the circumstances” was implemented. In the early Qing Dynasty, work stations were set up in each village and in case of major projects, a temporary embankment bureau was established for general management. In the 59th year of Qianlong reign (1794), the autonomous General Administration of Sangyuanwei Polder Embankment System was established, which implemented a three-level management system of General Administration, village and household. From the 2nd year of Jiaqing period (1797) to the 14th year of Daoguang period (1834), government supervision was gradually intensified. Sangyuanwei Administrative Rules were approved and promulgated three times by the governor of Guangzhou, which further clarified and refined the management system and maintenance mechanism, and the government was responsible for inspection, adjudication and supervision. Besides, some individual management systems were also formulated, such as “Regulations for Protection of Sangyuanwei Polder Embankment System” and “General Rules for Saving Sangyuanwei Polder Embankment System”, which refined the rapid response mechanism for emergency rescue. The Board of Sangyuanwei Polder Embankment System was established in 1937 through a democratic election and it was responsible for the management, maintenance, fundraising and flood control construction. Historically, the maintenance cost of Sangyuanwei Polder Embankment System mainly came from the apportionment of farmland in the income area, and also the government's appropriation, social donation, and the income from the operation of public resources.

After 1949, Sangyuanwei Polder Embankment System continued and improved the management system of government and private participation. After the establishment of Qiao-Sang Polder in the 1980s, Sangyuanwei Polder Embankment System was under the management of Nanhai District Office for Qiao-Sang Polder Management. At present, the water conservancy institute of each town and Qiao-Sang Polder Management Office are mainly responsible for the water conservancy construction and management of Sangyuanwei Polder Embankment System.