The flow modifier modifies the flow of water by creating a weir, by diverting the flow of water, by reinforcing the channel bank, by creating a favorable habitat for plant life, or by {HEAD ~ some combination} of {TAIL ~ these effects} 
of
The flow modifier modifies the flow of water by creating a weir , by diverting the flow of water , by reinforcing the channel bank , by creating a favorable habitat for plant life , or by { HEAD ~ some combination } of { TAIL ~ these effects }
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 OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL