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