Water level offsets H_offset to be subtracted from measured level in order to
get the water level above the plume: H = H_raw - H_offset. H is then used to
calculate Q by using the relationship given by H_Q_Table
Water level offsets H_offset to be subtracted from measured level in order to
get the water level above the plume: H = H_raw - H_offset. H is then used to
calculate Q by using the relationship given by H_Q_Table