Thus, holes need not be dug into the channel bed 20, and the channel bed 20 is minimally disturbed, so {HEAD ~ that erosion} is not caused by {TAIL ~ the installation} of posts 50 
Thus , holes need not be dug into the channel bed 20 , and the channel bed 20 is minimally disturbed , so { HEAD ~ that erosion } is not caused by { TAIL ~ the installation } of posts 50
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 REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH