476
M. Pettine . L. Patrolecco . S. Capri
30'
12°
30'
13°
30'
14°
30'
45°
30'
44°
Fig. 22.2. Location of the study area. In the Po River, only the Pila station is shown; the other
(Pontelagoscuro) is upstream of the river stretch plotted. In the NA system, the two investigated frontal
regions, one in the north (N) and the other in the south (S), are shown
the arithmetic means of the concentrations and discharges; (c) the product of discharge-weighted concentrations and the mean annual discharge; and (d) the sum of
the products of daily discharge and concentration resulting from the concentration
vs. flow equation, extended to a whole year. Methods a and b, which use the arithmetic
mean of instantaneous loads or arithmetic means of concentrations and discharges,
give equal weight to each pair of variables. This may introduce a major bias in calcu-