Rivers!

through the constuction - water is flowing through the canals
by the construction - seems as if water flow is affected by the construction. not sure if water is flowing through or outside

D doesn't have subject in the clause following 'but'.

Following construction would be correct to convey the intended meaning, which is "rivers flow originally into st. Lawrence, but redirected.

Original:

(D) Rivers, originally flowing into the St. Lawrence by way of Lake Michigan, but having been redirected by the construction of

Modified:
(D) Rivers were originally flowing into the St. Lawrence by way of Lake Michigan, but have been redirected by the construction of

E is very concise to convey this same idea:

(E) Rivers, originally flowing into the St. Lawrence by way of Lake Michigan, have been redirected through the construction of:

My question is regarding choice E
Rivers, originally flowing into the St. Lawrence by way of Lake Michigan, have been redirected through the construction of canals so that the water now empties into the Mississippi by way of the Illinois River

is usage of flowing(verbing) here correct?
How to justify that it takes the timeframe of the main clause, which is in present perfect

To me the meaning is redirection and flowing took place at the same time.
What am i missing here?

aflaam wrote:My question is regarding choice E
Rivers, originally flowing into the St. Lawrence by way of Lake Michigan, have been redirected through the construction of canals so that the water now empties into the Mississippi by way of the Illinois River

is usage of flowing(verbing) here correct?
How to justify that it takes the timeframe of the main clause, which is in present perfect

To me the meaning is redirection and flowing took place at the same time.
What am i missing here?

"Originally flowing" is a participial phrase used to modify "rivers." "Flowing" functions as an adjective rather than a verb. And an adjective, depending on how it's modified, can apply to different time frames. Consider a simple case. "The short basketball player has been selected to the team." (The player was short when he was selected. "short" = adjective.) Vs. "The formerly short basketball player has been selected to the team." (The player was no longer short when he was selected. The adverb "formerly" indicates that the player was no longer "short" when the action took place.)

Same idea here. "Rivers, flowing into the St. Lawrence, have been redirected." In this case, the adjectival phrase "flowing into the St. Lawrence" applies to the rivers at the same time they were redirected. This is the case you had mind. However, if we write, "Rivers, originally flowing into the St. Lawrence, have been redirected," we've communicated that the rivers were originally flowing into the St. Lawrence, but have since been redirected. The adverb "originally" modifies the time frame of when the rivers were "flowing into the St. Lawrence."