Environmental Engineering Reference
In-Depth Information
Conductivity (µS)
547
542
433
Turbidity (NTU)
11
18
25
SW2
pH
7.9
7.0
7.3
T (ºC)
21
23
23
Conductivity (µS)
580
529
470
Turbidity (NTU)
8
33
21
SW3
pH
*
7.4
*
T (ºC)
20
21
22
Conductivity (µS)
*
602
*
Turbidity (NTU)
6
11
14
*-Data not collected due to technical fault.
compared with the values for February. All statistically significant values within each
sampling location are denominated by different letters on the corresponding figures.
Spatial variations, reflecting the impact of the farm area during each distinct season,
were tested for a tatistically significant difference by comparing the results for the control
point SW
1
with SW
2
and SW
3
separately. Statistically significant values within each
season are denominated by different numbers. The averaged results for the whole period
of study are presented in Table 8.4 and are compared with the present recommended
limits for safe environmental water quality characteristics.
4.4.1 Nutrients
Variations of TKN (Fig. 8.7a) and TP (Fig. 8.7b) have a similar pattern. TKN seasonal
variation at SW
1
shows significant differences (aa, bb, cc) for all three seasons. In
February, the pollutant concentrations are much lower compared to the ones in October
and November. This indicates to the presence of river pollution upstream the control
point, which is pronounced only during the dry season due to the relatively low base flow
in the River. At SW
2
there was no significant difference between October and November
observations, but in February the concentrations were significantly lower. At SW
3
the
seasonal variation was very pronounced (ff, gg, hh), showing a peak in October, which is
reduced in November, reaching very low values in February. Spatial variations during
October are significant for all three points (1, 2 and 3) and are of a larger magnitude with
respect to SW
3
, indicating to a considerable impact of this part of the farm area,
contributed to the Little Marimba River.
In November, significant difference was found only between SW
1
and SW
2
(4 and 5),
indicating to a relatively low impact from the portion of the farm draining into the
Marimba River. During the wet season, no impact from the farm area was found.
