providing a source of water for flowing through a floway, said water containing a quantity of pollutants and having a pH lower than a pH of precipitation of said pollutants on {HEAD ~ entry} into {TAIL ~ said floway} 
providing a source of water for flowing through a floway , said water containing a quantity of pollutants and having a pH lower than a pH of precipitation of said pollutants on { HEAD ~ entry } into { TAIL ~ said floway }
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 REL TAIL TAIL TAIL TAIL TAIL TAIL