Effects of Opened and Closed Spillway Operations of a Large Tropical Hydroelectric Dam on the Water Quality of the Downstream River

Table 3

Mean and standard deviation of the water quality parameters in the Rajang River during opened and closed spillways.

Parameters	Opened spillway	Closed spillway
Temperature (°C)	27.40 ± 0.00^a	27.48 ± 0.00^b
pH	6.42 ± 0.00^a	6.12 ± 0.00^b
DO (mg/L)	8.60 ± 0.00^a	4.46 ± 0.00^b
Turbidity (NTU)	71.08 ± 0.35^a	98.83 ± 0.87^b
TSS (mg/L)	47.14 ± 1.44^a	66.79 ± 3.84^b
COD (mg/L)	111.11 ± 7.21^a	91.02 ± 12.39^b
NH3-N (mg/L)	0.22 ± 0.04^a	0.24 ± 0.03^a
NO3-N (mg/L)	0.080 ± 0.010^a	0.019 ± 0.004^b
NO2-N (mg/L)	0.004 ± 0.001^a	0.003 ± 0.000^b

Means in the same row with the same letters are not significantly different ().