Physicochemical Characteristics of River Water Downstream of a Large Tropical Hydroelectric Dam

Table 2

Mean difference in water quality parameters between closed and opened spillway when the Bakun hydroelectric dam is in operation ().

Parameters	Mean difference	value
pH	0.4	0.057
DO, mg/L	−4.8	0.001
Turbidity, NTU	−19.0	0.001
TS, mg/L	1.3	0.019
BOD5, mg/L	−0.5	0.028
COD, mg/L	26.4	0.001
TAN, mg/L	−0.065	0.001
TP, μg/L	−114.7	0.001

Positive value of mean difference indicates water quality parameter was higher during closed spillway, whereas negative value indicates water quality parameter was higher during opened spillway of the Bakun hydroelectric dam. The significant difference at value ≤ 0.05 was indicated in bold.