Here, a relatively low variation in {TAIL ~ water level} would indicate the presence of {HEAD ~ a siphonic phenomemon} 
Here , a relatively low variation in { TAIL ~ water level } would indicate the presence of { HEAD ~ a siphonic phenomemon }
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD