Zhou Enlai grew up in the Huai River drainage basin, and he knew what the river could do. The Huai had flooded catastrophically for as long as anyone could remember, drowning crops and communities across the North China Plain with a regularity that felt less like natural disaster than divine punishment. In 1950, the flooding was particularly devastating, and the Premier -- despite China being newly founded and already engaged in the Korean War -- insisted that the canal project proceed. The nation could not afford it. Zhou argued that the people of the Huai River basin could not afford to wait.
Construction began on November 2, 1951, and was completed by May 1952 -- seven months to build 168 kilometers of canal from Gaoliangjian on Hongze Lake to the artificial estuary of Biandan Harbour on the coast. More than 1,190,000 civilian workers participated, moving earth by hand and by cart across the flat terrain of northern Jiangsu. The scale was staggering even by the standards of Chinese water engineering, a tradition that had produced the Grand Canal and countless levees over millennia. Chairman Mao Zedong had personally instructed the relevant departments to develop a water conservancy plan; Zhou Enlai held the planning conferences, approved the final design proposed by Li Baohua of the Ministry of Water Resources, and pushed it into execution.
The North Jiangsu Main Irrigation Canal -- commonly called the Subei Canal -- does not operate in isolation. It forms one side of a quadrangle of waterways that together constitute an integrated irrigation and flood control system. The Grand Canal crosses the Subei Canal in the western part of northern Jiangsu, functioning as the "west main canal." The Chuanchang River intersects from the south to form the "east main canal." The Tongyang Canal connects the starting and ending points of the system as the "south main canal." Together, these four channels link the inland rivers of northern Jiangsu into a network that can move water where it is needed, drain it where there is too much, and distribute it across 1,720,000 hectares of farmland.
The canal's original incarnation was built between 1934 and 1937 to divert the Huai River's floodwaters, but in 1938 the Japanese military destroyed key dams, causing the Yellow River to redirect into the Huai's channel. The resulting devastation was immense -- the region flooded catastrophically, and the original canal was largely destroyed. The Yellow River, known historically as "China's Sorrow" for its unpredictable floods and the silt that earned it the nickname "Flowing Mud," had once again altered the landscape of northern Jiangsu. The postwar reconstruction faced not just the physical destruction but also the hydrological chaos that the wartime dam destruction had caused, requiring engineers to redesign a system for a river system that no longer behaved as it had a decade earlier.
The completed canal serves multiple purposes beyond irrigation. Designed to transfer water at 5,000 cubic meters per second, it functions as a major flood relief channel for the lower Huai River. A parallel drainage canal on the north side handles overflow at 800 cubic meters per second. The system includes the Gaoliangjian intake sluice, the Funing Waist Gate, the Liuduo tidal sluice, 36 culverts, two flood-release sluices, and four road bridges. Hydroelectric generators and ship locks at Gaoliangjian and elsewhere provide power generation and navigation capabilities. From Hongze Lake to the sea, the canal carries water that irrigates fields, generates electricity, floats barges, and -- most critically -- prevents the kind of catastrophic flooding that Zhou Enlai remembered from his childhood and refused to accept as inevitable.
Located at 34.11°N, 120.32°E in northern Jiangsu Province. The canal is visible from altitude as a straight, engineered waterway running roughly east-west across the flat North China Plain from Hongze Lake to the coast. It intersects with the Grand Canal and other major waterways. Nearest major airport: Yancheng Nanyang International Airport (ZSYN/YNZ), approximately 60 km to the south. At 5,000-10,000 feet AGL, the canal and its network of intersecting waterways form a distinctive grid pattern across the agricultural landscape.