Songyang county, located in the southwest Zhejiang province of China, is surrounded by mountains and has four distinct seasons, with an average annual precipitation of about 1700 mm. Songyinxi Stream, a first-class tributary of the Oujiang River basin, has a total length of 109.4 km. Running from northwest to southeast, it flows across the entire Songgu Irrigation Scheme. As the largest grain-producing base of the Oujiang River Basin, Songgu Irrigation Scheme has an irrigated area larger than 11,000 ha. As an old Chinese saying goes, “when Songyang county has a bumper harvest, the entire region of Chuzhou City will enjoy sufficient food supply”, which reflects the abundance and prosperity of Songyang.

In 138 BC, a small kingdom called Dong’ou moved northward and relocated at Gushi of Songyang County. Thanks to the excellent irrigation conditions there, some of the Dong’ou army and civilians started land reclamation, transforming Gushi into a place with well-developed agriculture and a thriving market and launching Songyang’s history of agricultural irrigation. Before the period of 1041-1048 in the Northern Song Dynasty, Bairen Weir, also called Qinglong Weir, had been completed on the south bank of the Songyinxi Stream at the foot of Dushan Mountain; the village of Shisandu built two weirs on the Fangxi Stream, irrigating more than 500 ha of farmland; by 1340, Bailong Weir was built in the south of Songyang County, irrigating more than 130 ha of farmland.

During the Song and Yuan Dynasties, the irrigation scheme had gradually taken shape. By the late Ming and early Qing Dynasties, Songyang County was already home to 116 weirs, ranking first among all counties in the Oujiang River basin. The irrigation scheme was improving and increasingly complete, with Songyinxi Stream as its water source, a dense network of weirs and canals, and a sound management system. In ancient times, the people of Songyang took local terrain into consideration when building weirs and canals for water diversion. As a result, sustainability has been achieved, and many ancient weirs are still functioning. Fourteen of them could still be irrigating hundreds of hectares of farmland each. Within the Songgu Irrigation Scheme, there are more than 1000 ancient weirs, and 50 of them were built before the Qing Dynasty. Such great density is of extreme rarity. The canal systems of the irrigation scheme are largely geometric. For instance, the canals of Jinliang Weir are perpendicular to each other and of a clearly graded structure; the Fangxi Weir is built at the source of the stream and has a fan-shaped canal system.

Currently, there are 14 ancient weirs, each irrigating more than 66 ha of land. Springs along the Songyinxi Stream gush out from the mountain valleys and never run dry; in addition, there are more than 1000 wells within the irrigation scheme. Generations of farming have gradually created the proper combination of weirs, canals, ponds and wells, and the orderly scheduling of water storage, diversion, irrigation and drainage. Under such an adaptive irrigation system, with the water storage capacity of ponds, wells and springs, the water use is optimized, and the impact of drought is minimized. The Songgu Irrigation Scheme enjoys a beautiful landscape and thriving agriculture.

With its excellent natural environment and sound irrigation system, it is a major grain-producing base in the southwest Zhejiang province. Meanwhile, it has a long history of tea cultivation and is also the largest green tea market in China. In addition, dried red tobacco leaves, a local speciality, had won the gold medal during the EXPOCOMER 1915 held in Panama City.

Water and irrigation have brought prosperity. Within the irrigation scheme, there are hundreds of well-preserved historic villages which open a window to the idyllic life of the ancient Chinese, giving people a taste of mystery and tranquillity. Weirs, ponds, wells and springs, connected with main and branch canals, form an irrigation system resembling a long vine with melons. Within this system, water diversion, storage, irrigation and drainage are orderly and organized, just as in a modernized water scheme.

The siting of a water scheme has a direct impact on its performance and local social stability. In the Ming Dynasty, Zhou Zongbin adopted the method of the seventy-thirty ratio to select sites for weirs, solving the water distribution conflicts between the south and north banks of the Songyinxi Stream. This is an early application of quantitative analysis in the siting of water projects. Downstream of Fangxi Weir, there is a pool with a giant rock in the shape of buffalo back. By observing how much of the buffalo back is submerged in water, people were able to forecast drought and flood and manage water affairs accordingly. This is the earliest evidence of hydrological monitoring in the Oujiang River basin.

By standardizing the specifications of canals and water intakes, the locals allocated water according to demand and solved water distribution conflicts which had lasted for more than a century. Also written in the historical records are the canal-farmland-combined system for long-standing and coherent management, the establishment of the board of directors for weirs and canals for the purpose of collective leadership, and the water rights management mechanism covering aspects of water use permission and the change and transaction of water right.

To conclude, Songgu Irrigation Scheme was equipped with a finely tuned management system. In the Water Museum of Songyang, there is a collection of 16 notices and several inscriptions left by 16 county magistrates which record the historical facts of the rehabilitation, management, water distribution and water dispute settlement of Fangxi Weir over a period of 555 years, as well as the spirit of water management persistently pursued by local officials and people in the past centuries. With its complete and rich heritage engineering system, vivid and detailed historical records, and brilliant water governance practices, the Songgu Irrigation Scheme is a distinctive living museum of heritage irrigation structures and a model of historic irrigation projects in small and medium basins.

The structure made outstanding contribution to enhancing food production, livelihood opportunities, rural prosperity, and poverty alleviation in a region;

The construction of the Scheme has provided Songyang County with higher productivity in agricultural production. Songyang was a traditional agricultural county in the past. Through improvements made by generations by generations, the Songgu basin has become an area with fertile paddy fields and a dense network of canals and ditches. The subtropical monsoon climate is favourable for rice cultivation. In addition, the residents of Songyang County are hard-working and good at intensive farming. Therefore, the agricultural produce is abundant in the county. It has been the granary of the Lishui region (called Chuzhou in ancient times). Songyang County was a main grain production region in the southwest of Zhejiang Province in ancient times. There was a saying that “Chuzhou will not suffer from hunger once Songyang County has a bumper harvest”. Songyang county was well developed in the economy, commerce and trade. The dock at the south gate of the county was buzzing with merchant ships and boats. The prosperous economy promoted regional population growth. Due to its good living conditions, the county is home to many historical celebrities. Many historic villages have been retained.

The structure was innovative in its ideas at the time of its construction;

The Scheme resembles a long vine with melons: A large number of weirs, ponds, wells and springs are connected by the main and branch canals and ditches, forming an irrigation system resembling a long vine with melons, which is similar to the cotemporary tiered irrigation system. With rotational irrigation and orderly water diversion, storage, irrigation and drainage, the Scheme has realized systematic management, which is a model of systematic engineering of ancient times. Many historic official public notices and announcements concerning water affairs are preserved in the archives of Songyang County. The following map of the river and canal system records the flow direction of No.2 Fangxi Weir and the locations of several dozens of small reservoirs and culverts.

The structure contributed to the evolution of efficient and contemporary engineering theories and practices;

Scientific weir design: Qinglong Weir is not parallel to the flow direction of the water. It is skewly positioned relative to the flow direction. Due to geological and economic restraints, this kind of weir design is a solution to many problems. With limited upstream water head, fixed canal width and the purpose of reducing energy loss, a skewly positioned weir could effectively increase the weir discharge. Due to the limited canal width, the weir top axis is oblique to the flow direction, so the length of the overflow front increases. Under a fixed flow rate, when the head decreases or stays stable, the flow capacity of the weir increases.

The adoption of the skew weir design could help flush away sediment in front of the weir when the water level is low, preventing or at least reducing siltation. The construction of a skew weir in the river could increase the discharge flow over the weir and the uniformity of the discharge flow running through the cross-section of the river, and thus stabilize the watercourse near the weir.

Scientific design of water allocation and diversion: The siting of a water scheme has a direct impact on its performance and local social stability. In the Ming Dynasty, Zhou Zongbin adopted the method of the seventy-thirty ratio to select sites for weirs, solving the water distribution conflicts between the south and north banks of the Songyinxi Stream. This is an early application of quantitative analysis in the siting of water projects.

The structure is an example of attention to environmental aspects in its design and construction;

Historically, the Scheme was constructed with locally available and eco-friendly materials such as bamboo and pebbles. The weirs and small reservoirs constructed have created an excellent water ecosystem and promoted biological diversity.

The structure bears the stamp of a cultural tradition or a civilization of past;

The history of the Songgu Irrigation Scheme exceeds 100 years (dating back to the 2nd century BC). The Scheme is composed of water diversion structures such as weirs, canal systems, water storage structures, etc. Its engineering form remains basically unchanged till today.

Songyang County is home to many historic figures well-known for their contribution to water governance. Many of the popular traditional songs of Songyang County are about irrigation. Within the Scheme, there are 75 historic villages built in the Ming and Qing Dynasties. Such a good status of preservation is rare in China. In the ancestral halls of the villages, there are many records of irrigation and water diversion in the genealogical books. Visitors here could enjoy the fun of local folk culture.

Engineering utility vis-à-vis designed utility

As early as before the period of 420-489, the locals of Songyang County had built weirs and dams on the mainstream of Songyinxi Stream for farmland irrigation. Initially, the building materials were wood, bamboo and stones. During the Song and Ming Dynasties (960-1644), the weirs were built with rocks. Such a building method is still used today in some places. At the same time, the local people made full use of the high-lying deep pools of the rivers to carry out weir-free water diverting for irrigation almost a thousand years ago. Some water inlets were equipped with gates for drought and flood control.

Qinglong Weir is also called Bairen Weir or Hejia Weir. Its initial construction time is unknown. According to the Annals of Songyang County, its records date back to the Qingli period of the Northern Song Dynasty (1041-1048). The original location was close to the foot of Mount Bairen. It was moved to the location 400 meters west of Mount Bairen in the winter of 1594, at the confluent point with the source of Zhuxi Stream. The weir was damaged by a flood in the Qingli period (1041-1521) of the Song Dynasty and restored in the Zhengde period (1506-1521) of the Ming Dynasty and damaged again later. It was reconstructed twice in the Wanli period during the Ming Dynasty (1573-1620).

Qinglong weir was constructed on the riverbed of the main stream of Songyinxi Stream near the entrance of Silingxia Village. The water was diverted from the main stream of Songyinxi Stream, flowing east bound through Dushanjiao, Wayaotou, Shuinan, Qinglong, Chengxu and Hengshan villages to Huangkengyuan, and then into the main stream of Songyinxi Stream at Tabuxia Village. The canal is 7 km long, irrigating more than 180 ha of farmland.

Bailong Weir was first built in 1356 with a donation from Zhou Hanjie, a resident of Songyang County. The weir is located in the Hangchuantou section of Songyinxi Stream, 1.5 km away from Xiping Town. The weir was initially constructed with bamboo cages filled with gravel. Sitting on the northern bank of Songyixi Stream, the weir diverts water from the west to the east. The water flew through the road-leaved forest at Hanhchuantou and the densely populated south gate of the county, then passed by the east gate to Xiangnong and Baisha villages, and then flowed back into Songyinxi Stream. Bailong Weir irrigated more than 60 ha of farmland along its canal and provided water for domestic use and firefighting.

Jinliang Weir is also known as Xuangong Dam or Jingliang Weir. The initial time of construction is unknown. The earliest record found is from 1340. The weir is located on Songyinxi Stream at the position north of Xiaoshi village of Zhaitan Township, 8.5 km away from the county town. The water was diverted through the weir by dam-free means from the main stream of Songyinxi Stream. The water inlet was built at the south margin of the Niududong pool. By making use of the natural condition of the deep pool on the main stream and the stream course of Songyinxi Stream, the water flew naturally and steadily. The main canal is 4.5 km long, irrigating 213 ha of farmland in 8 villages and providing water for domestic use. The following statements were recorded in the Annals of Songyang County published in the period of the Republic of China: “Jinliang Weir, located in 15th du (the local word for village), 10 km west of the county town, irrigates 400 ha. It was damaged in early 1340; the then county magistrate presided over the reconstruction, resuming its function and benefits for villagers. The name Xuangong Dam is to commemorate this local official.”

Wuyang Weir is also known as Shimenzhen. The initial time of construction is unknown. The earliest record dates back to 1847. The weir is on Songyinxi Stream near Shimen village of Wangsong street community. According to the record in the stone inscription “Notes on Shimenzhen”, in the process of construction, the beneficiary village (Huanggongdu Village) downstream borrowed land for the construction of the project from the non-beneficiary village (Shimen Village). Borrowing land to build canals reflects not only the wisdom of the local people in the process of water governance but also their solidarity and determination on this matter.

Fangxi Weir was a project jointly constructed and shared by the 13th du and 14th du in the Songgu plain of Songyang County. It dates back to the Northern Song Dynasty (960-1127). Fangxi Weir, located at the source of a tributary of Songyinxi Stream in 13th du, has two weirs. Weir No. 1 is 58 m long, and its main canal is 2.5 km long. Weir No.2 is 90 m downstream from Weir No.1. It is 70 m long, and the main canal is 9.5 km long. The weirs were constructed with stones and rocks. Fangxi Weir irrigates the farmland of Xinxing Town and Zhangxi Town with a total area of 604 ha. They also provide water for domestic and ecological uses. The extant cultural heritages of Fangxi Weir include 18 original public notices and announcements on water affairs issued by the magistrates of Songyang County from 1530 to 1883, 1 ancient map of the canal system, and two stone inscriptions.

In May (the lunar calendar) of 1592, Songyinxi Stream experienced serious flooding. More than 900 meters of embankments were damaged, destroying several hectares of farmland and many houses near the Stream. In June of the same year, the magistrate of the county inspected the site and instructed the villages concerned to share the cost of reconstruction according to the size of their farmland. Later the embankments were restored. This fact was recorded and carved on a stone. This is the beginning of the written record on the water governance of Songyinxi Stream.

According to local documents, in 1681, the embankments on the right side of Lixi Village were damaged in many places by the flood. It was restored in the same year by raising funds from the locals. In 1835, Tang Jinghe, the county magistrate, organized donations and built embankments of several hundreds of meters outside of the Jichuan Gate in the south of the county town. In the early Guangxu period (1875-1908), Chi’an Village built embankments along the Stream and planted willow trees for embankment protection.

In 1914, several hundreds of meters of embankments were built in Gushi and Xiajie. In 1948, Shuinan village was eroded by the flood. Zhu Gengsheng, the then magistrate, initiated the construction of hundreds of meters of new embankments. However, there were no records of river dredging before the foundation of the People’s Republic of China in 1949.

Since 1949, the major weirs have been restored or reinforced gradually with new construction materials.

Present State of Conservation

The Water Conservancy Bureau of Songyang is in charge of managing and operating the functioning facilities of the Songgu Irrigation Scheme. The facilities enjoy good operation and maintenance conditions. An independent museum has been constructed to store and display the numerous cultural heritages such as historical stone inscriptions, historical project structures, official public notices and announcements, etc. Many signboards and protection instruction boards are also set up within the Scheme area to guide visitors. Currently, there are a few challenges concerning the conservation of the Scheme.

Management

The weirs of the Scheme have been managed by democratically elected weir chiefs who then set up boards of directors. One board of directors has 7-8 representatives of the benefiting villagers. The management team is in charge of the weir and canal repair and maintenance, maintaining daily water use orders, recruiting villagers for maintenance and repair work, and collecting water fees.

All the important water conservancy projects in the history of Songyang had charters and regulations on water use and water distribution, which were carved in stones. Any behaviours breaching the rules or violating the regulations were regarded as immoral or illegal by the residents of the county and thus subject to public condemnation and punishment by the government. The rules and regulations on water use and water distribution in Songyang County have a long history and excellent tradition. They were applied to most of the projects to regulate water distribution for the sake of fairness. Its good management system has ensured the sound operation of the Scheme for more than two thousand years, making it a model of sustainability.