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