Table 3. Physical environment parameters at the sampling sites (mean±standard deviation)

Site	Substrate(%)*					Water velocity (cm/sec)	Water depth (cm)	Water temperature (℃)	Altitude (m)
	B	C	P	G	S
St. 1	16	31	29	14	11	32.3±7.9	24.1±13.5	13.0±2.6	267
St. 2	16	30	23	16	16	39.1±2.1	15.2±5.4	15.0±2.8	202
St. 3	21	32	25	6	16	55.1±1.4	15.0±5.7	16.7±1.9	119
St. 4	0	18	24	23	35	40.3±12.7	15.2±4.0	17.7±3.3	113
St. 5	9	35	28	6	22	42.2±16.9	21.3±4.5	18.6±5.8	111
St. 6	16	36	33	6	9	52.1±6.3	28.6±5.7	18.0±4.8	82

B: Boulder (>256mm), C: Cobble (64∼256mm), P: Pebble (16∼64mm), G: Gravel (2∼16mm), S: Sand and silt(≤ 2mm).