The flow modification system 21, wherein {HEAD ~ the original prefabricated brace} and the additional prefabricated brace are secured together with {TAIL ~ at least one other prefabricated brace} similar to the original prefabricated brace in a configuration enclosing at least three sides of a region of the channel 
secured together with
The flow modification system 21 , wherein { HEAD ~ the original prefabricated brace } and the additional prefabricated brace are secured together with { TAIL ~ at least one other prefabricated brace } similar to the original prefabricated brace in a configuration enclosing at least three sides of a region of the channel
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH