The Grand Canal was renovated almost in its entirety between 1411 and 1415 during the Ming dynasty (1368–1644).
A magistrate of Jining, Shandong sent a memorandum to the throne of the Yongle Emperor protesting the current inefficient means of transporting 4,000,000 dan (428,000,000 liters) of grain a year by means of transferring it along several different rivers and canals in barge types that went from deep to shallow after the Huai River, and then transferred back onto deep barges once the shipment of grain reached the Yellow River.
Chinese engineers built a dam to divert the Wen River to the southwest in order to feed 60% of its water north into the Grand Canal, with the remainder going south.
By the year 600, there were major build ups of silt on the bottom of the Hong Gou canal, obstructing river barges whose drafts were too deep for its waters.
The chief engineer of the Sui dynasty, Yuwen Kai, advised the dredging of a new canal that would run parallel to the existing canal, diverging from it at Chenliu (Yanzhou).
The new canal was to pass not Xuzhou but Suzhou, to avoid connecting with the Si River, and instead make a direct connection with the Huai River just west of Lake Hongze.
With the recorded labor of five million men and women under the supervision of Ma Shumou, the first major section of the Grand Canal was completed in the year 605 called the Bian Qu.
Because most of the city’s traffic goes along the Canal rather than across it, only one bridge crossed the canal until the 19th century, the Rialto Bridge.
There are currently three more bridges, the Ponte degli Scalzi, the Ponte dell’Accademia, and the recent, controversial Ponte della Costituzione, designed by Santiago Calatrava, connecting the train station to Piazzale Roma, one of the few places in Venice where buses and cars can enter.
As was usual in the past, people can still take a ferry ride across the canal at several points by standing up on the deck of a simple gondola called a traghetto, although this service is less common than even a decade ago.
More public buildings were built along the Canal at Rialto: palaces for commercial and financial Benches (Palazzo dei Camerlenghi and Palazzo dei Dieci Savi, rebuilt after 1514 fire) and a mint.
In 1181 Nicolò Barattieri constructed a pontoon bridge connecting Rialto to Mercerie area, which was later replaced by a wooden bridge with shops on it. Warehouses for flour and salt were more peripheral.
From Grand Canal Dock it passes through Ringsend and then traverses the southside, delineating the northern extremities of Ballsbridge, Ranelagh, Rathmines, Harolds Cross and Crumlin.
This section is the Circular Line and has seven locks.
At Inchicore can be seen the path of the original main line to the Grand Canal Harbour, the City Basin (reservoir) and Guinness brewery. Most of the route of this line now runs alongside the Red Luas Line.