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

Table 5

Summary of the mean and standard deviation of the in situ and ex situ water quality parameters in the downstream river of the Bakun Dam (Station 6) and the mean difference of the parameters between the wet and dry seasons ().

Parameter	Wet season	Dry season	Mean difference	p value
In situ
Temperature, °C			−2.1	0.000
DO,  mg/L			+6.81	0.000
pH			+0.2	0.001
Turbidity, FNU			−36.67	0.000
Ex situ
Chl a, µg/L			+0.12	0.179
TSS,  mg/L			−16.7	0.011
BOD5,  mg/L			+2.60	0.000
-N,  mg/L			+0.006	0.009
-N,  mg/L			+0.014	0.115
OKN,  mg/L			+0.01	0.057
SRP, µg/L			−24.1	0.008
TP, µg/L			−287.2	0.001

The positive value of mean difference indicates that the parameter studied is higher during the wet season whereas the negative value indicates that the parameter studied is higher during the dry season.