regulating submerged walls on both sides would be as high as low-water level so as to give a free passage of the water over the top at flood tide. This will serve the purpose of carrying back the silt from the sea when the tide comes in, thus to reclaim the shallow spaces inclosed behind the walls on both sides of the river more quickly than otherwise. The new channel formed by these two parallel walls would likely be deeper than the present South Channel outside the Whangpoo, which is forty to fifty feet deep because the velocity of the current will be greater than the present one, due to the concentration of three channels into one. Furthermore, the depth would be more uniform and stable than at present. Although the regulating walls end at the five-fathom line, the momentum of the current would continue beyond that point, and so would cut into the deep water outside. This would serve the double purpose of draining the Yangtze Estuary as well as keeping open the approach to Shanghai.
b. From Whangpoo Junction to Kiangyin
This part of the channel of the Yangtze River is most irregular and changeable. The widest part is over ten miles while the Kiangyin Narrow is only but three-quarters of a mile. The depth of the channel at the open part is from five to ten fathoms while that of Kiangyin Narrow is twenty fathoms. Judging by the depth of the water at this point a width of one and a half miles must be provided for the channel in order to
