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