Situated between the Huai and the Yangtze Rivers, the Irrigation System features hilly terrain, and is dotted with tens of thousands of ponds, storing over 80 million m3 of water. Within the System, ponds and polders are connected by the canal network, performing the combined functions of dispatching, storage, and irrigation, and smoothing out the impact of fluctuating rainfall and water use demand.

Headworks:  Drawing water from Longshushui River (today’s Hangbu River), it irrigated more than 5,333ha of farmland. The water intake had a sluice which measured “3.33 meters deep and 2.67 meters wide.” A bridge named “Nüer” was built on the sluice, and the exact year when the bridge was destroyed is unknown.

Wuyang Weir: Extending about 5 kilometers, the ruins of Wuyang Weir lie within the boundaries of three towns of Ganchahe, Hekou and Kongji. Wuyang Weir was built by Liu Xin in the early period of the Western Han Dynasty, when it irrigated more than 667 ha of farmland. After the founding of the People’s Republic of China in 1949, Wuyang Weir was expanded for many times before it was incorporated into the Hangbei Trunk Canal Project, becoming a branch canal irrigating more than 667 ha of farmland.

Caoze Weir: Extending about 7.5 kilometers, the ruins of Caoze Weir are located in today’s Chengguan Town, Kongji Town and Gucheng Township. Originally built by Liu Xin in the early period of the Western Han Dynasty, Caoze Weir was used to irrigate more than 1,333 ha of farmland.  After the founding of the People’s Republic of China in 1949, the embankment was built along the former watercourse of Longshushui River, and culvert and sluice were reconstructed at the mouth of Caoze Weir. Later Caoze Weir was incorporated into the Hangbei Trunk Canal Project, and the former watercourse of Caoze Weir is used for drainage of water only.

Ponds: There were ten famous ponds in Shucheng County: Jiulong Pond, Nan Pond, Daguan Pond, Liuchong Pond, Beishan Pond, Zhuoshan Pond, Chunqiu Pond, Wuya Pond, Jinbo Pond and Chenshan Pond. After the founding of the People’s Republic of China in 1949, especially following the completion of the conveyance system of Longhekou Reservoir in 1961, most of the above ponds are incorporated into the Pishihang Irrigation Project. Apart from these 10 major ponds, there were 17,246 other ponds of different sizes, with a total storage capacity of 80 million cubic meters. Since 1980, the water surface has decreased with smaller storage capacity since some of them were turned into farmland while some others were silted up.

Canal network: If Hangbu River can be compared to an artery, the densely distributed canal networks are like capillary systems that string ponds, earth embankments, fields and polders. Hangbu River runs across Qimenyan Village northward for 1.5 kilometers. In Qimenyan Village, gurgling water flows in a large number of thousand-year-old canals that are covered by lush grass and woods on both sides.

Qimenyan Irrigation System stands on the middle reaches of the Hangbu River in Shucheng County of Anhui Province, China. It was first built 2223 years ago by Liu Xin, the nephew of Liu Bang (256 BC/247 BC-195 BC, the first emperor of the Western Han Dynasty).

Standing on the eastern slope of the Dabie Mountain and between the Huai and Yangtze Rivers, Shucheng County has complex topography. Its mountainous areas are prone to flash floods, the hilly areas susceptible to droughts, and the plains vulnerable to waterlogging. And it is the Shumenyan Irrigation System that has helped maintain stable yields through effective water diversion, storage, and distribution, despite weather-related disasters.

During the Xuande Period (1426-1435) of the Ming Dynasty, the county magistrate Liu Xian issued water use regulations for Qimenyan, stipulating that villagers living by the five major ponds in the upstream could use water for irrigation from April to July of the traditional Chinese calendar, and water use was banned in the upstream during the rest of the year so that the ten major ponds downstream could store water for future irrigation. Still in use in the first half of the 20th century, such a water use mechanism had helped distribute water in a fairer way between the up-and downstream.

Taking into consideration its topographic features, the Irrigation System has been able to smooth out the fluctuating water demand and maintain stable water supply by adopting rotational irrigation and allowing the ponds downstream to store water during the off season.

Taking advantage of the hilly terrain that slopes downward towards the northeast and the force of the Hangbu River as it flows out of the valley, Qimenyan Irrigation System has adopted water regulating technologies and management approaches that suit the local conditions. As a vital part of the Pishihang Irrigation Project, the System has sustainably brought the region economic prosperity, social stability, and thriving cultures.

Qimenyan Irrigation System has undergone drastic changes over the past 2,200 years. After the founding of the People’s Republic of China in 1949, the large-scale repair and extension project of Qimenyan Irrigation System was started in November 1951, which increased the irrigated area to 6493ha. Established in 1954, the Management Office of Qimenyan Irrigation System is responsible for reinforcing maintenance and management of the irrigation system. The irrigated area was further increased to 10,000ha in 1957. The Longhekou Reservoir was built on the upper reaches of Hangbu River in 1958. After1965, the Shulu trunk canal was built on the south of Qimenyan Irrigation System, and Hangpi trunk canal was built on the north. Since then, the Qimenyan Irrigation System was incorporated into the conveyance system of Hangpi trunk canal, becoming part of the Pishihang Project well-known both at home and abroad.

As an ancient water conservancy project, Qimenyan Irrigation System displays the planning thoughts that stayed ahead of the time. Taking advantage of the hilly terrain that slopes downward towards the northeast and the force of the Hangbu River as it flows out of the valley, the System creates a scientifically designed and reasonably laid out waterway that runs through Shucheng County between the Yangtze and Huai Rivers. The waterway in which water flows from southwest to northeast along the natural terrain forms part of a gravity irrigation system. Other important achievements in the planning of Qimenyan Irrigation System are reflected in the canal line planning. Generally the canal line planning is required to fully take into account the terrain conditions, proceed along certain contour lines, maintain proper bottom slope for transporting water, satisfy the controlled water level elevation in gravity irrigation, and reasonably arrange ponds, with the aim to ensure the maximum area of irrigation.

The natural ponds and marshes in large numbers in wetland were fully used in constructing the irrigation system. When connected, these ponds not only serve as water-storage reservoirs, but also as canals. They are used to store excessive rainwater during the rainstorm and water rising period, thus mitigating the flood that would threaten people in the downstream areas. A powerful water regulating mechanism is gradually put in place. Such a mechanism, coupled with a rotational irrigation system and organically coordinated with nodes of the System, displays fundamental thoughts of system engineering.

The construction of Qimenyan Irrigation System resolved problems caused by flood and drought in the irrigated areas, and increased grain outputs. The area benefitted by Qimenyan Irrigation System was the hometown of well-known educator Wen Weng (187–110 BC) and militarist Zhou Yu(AD 175–210), providing indirect evidence that Qimenyan Irrigation System guaranteed the regional food security. According to historical record, as early as the 13th Century, the government built granaries in Shucheng County to relieve the famines caused by disasters in the nearby region.

Situated between the Huai and the Yangtze Rivers, Qimenyan Irrigated System is dotted with tens of thousands of ponds. Within the System, these ponds and polders are connected by the canal network, forming a large-scale wetland water regulation and reuse system.

The region where Shucheng County is situated lies between the southern and northern regions of China in terms of precipitation. Water collected in ponds can be used when rainwater is in short supply. The volume of the water regulated by ponds can just satisfy or slightly more than meet the needs of people in their production and daily life in ordinary years. In other words, the volume of water stored in ponds and the frequency of water storage ensure the balance of water supply. Such a balance is reached by people who have followed the law of nature for thousands of years, and it also crystallizes the wisdom of people who have coordinated production with natural environment.

The construction of the three weirs of Qimen Irrigation System was started by Liu Xin, Marquis Gengjie in the Western Han Dynasty (206 BC–AD 25). The three weirs were rebuilt and dredged on a large scale twice by Liu Fu, a prefectural governor in the Eastern Han Dynasty (AD 25–220) and Liu Xian, a county magistrate in the Ming Dynasty (1368–1644). Such deeds were historically called “Three Officials Surnamed Liu” building water conservancy projects. A memorial temple of “Three Officials Surnamed Liu” was built at the mouth of weir, with a tablet set up to record the deeds accomplished by three officials. According to General Records of Anhui, “In the year of 200, military general Cao Cao (155 BC–AD 220) ordered Liu Fu to guard Hefei in the capacity of prefectural governor. Liu Fu had garrison troops open up wasteland for cultivation of food grains. He also ordered troops to rebuild the Qimen weirs originally built by Liu Xin based on ruins. The rebuilt weirs irrigated 1,500 ha of cultivated land, greatly benefiting the local people.”

During the period from 1426 to 1436, county magistrate Liu Xian had a dam built at the mouth of Longwang Marsh to channel water into various weirs. A total of 15 marshes were formed following the end of the project. The first five marshes, with Baoziwan being the last one, are called the “upper five marshes”, and the rest ten the “lower ten marshes”. Such a layout laid the basic foundation of Qimenyan Irrigation System.

After the founding of the People’s Republic of China in 1949, the management office of Qimenyan Irrigation System was established. As the conditions for channeling water gradually deteriorated, the water intake of Qimenyan was moved upstream for two kilometers, where a dam was built to channel water. Starting from the original water intake downstream, a five-kilometer-long trunk canal was built along the mountain, and it has been used since then.

The heritages of the ancient Qimenyan Irrigation System are severely affected by high-speed economic development. In recent years, fully leveraging its advantages in traffic location, Shucheng County explores its distinctive and advantageous resources, seizes upon the opportunities brought by the implementation of the national strategy of integrated development of Yangtze River Delta, actively gets itself involved in the development of Hefei Metropolitan Area, and persists in developing industry to boost its overall strength. To this end, a large number of new infrastructure construction projects are in full swing. In the process of large-scale demolition and construction, however, the irrigation systems that have been used since ancient times are destroyed or threatened to be destroyed, some of which are abolished, and some others are even leveled to the ground and submerged to the bottom of water.