Seasonal Changes and Spatial Variation in Water Quality of a Large Young Tropical Reservoir and Its Downstream River

Table 6

Mean difference of in situ and ex situ water quality parameters between the intake point of the dam at 10 m (Station 5) and its downstream river (Station 6) during wet and dry seasons ().

Parameter	Wet season		Dry season
	Mean difference	p value	Mean difference	p value
In situ
pH	−0.03	0.469	+0.01	0.288
Turbidity, FNU	+60.9	0.000	+46.7	0.000
Ex situ
Chl a, µg/L	+0.28	0.013	−0.02	0.755
TSS,  mg/L	+4.67	0.011	+13.03	0.000
BOD5,  mg/L	+1.26	0.000	−1.53	0.000
-N,  mg/L	+0.003	0.001	+0.000	0.374
-N,  mg/L	+0.003	0.631	−0.000	0.374
OKN,  mg/L	+0.08	0.000	+0.05	0.000
SRP, µg/L	+3.2	0.157	−10.5	0.007
TP, µg/L	+10.5	0.189	+115.7	0.002

The positive value of mean difference indicates that the parameter studied is higher in the downstream river whereas the negative value indicates that the parameter studied is lower in the downstream river.