What was used to guide the flow of the canal water over rivers?

In most cases, the engineered works will have a series of dams and locks that create reservoirs of low speed current flow. These reservoirs are referred to as slack water levels, often just called levels.

answer; eliminate parking problems in cities, because a car took up only half as much space as a horse and buggy;

bro these r easy u may have to do them urself bro. lol jk the answer is two for nimber one, and for question number two sahel boi xd have fun get rekt m8