Table 6. Expected stream temperature (M7DAMT), riffle embeddedness conditions (REI), and young trout biomass (YTB) associated with 30- vs. 15-m average riparian buffer widths along the stream network above a given stream segment. M7DAMT and YTB were calculated for cool, intermediate, and warm summers using the three sets of regression coefficients derived for Eq. 3 and across the elevation range where young trout were observed. REI values were calculated for the range of maximum reach velocities where young trout were observed. YTB was calculated with the average maximum reach depth for sites with young trout (0.68 m).

         

Variable Gradient(s) 30-m buffer width 15-m buffer width Expected change
M7DAMT Cool (2003) M7DAMT increase
488 m 20.3 21.9 1.6
578 m 19.3 20.9
740 m 17.5 19.1
Intermediate (2001)
488 m 21.4 23.6 2.2
578 m 20.3 22.5
740 m 18.4 20.6
Warm (2002)
488 m 21.9 24.2 2.3
578 m 20.9 23.3
740 m 19.0 21.3
Riffle Max reach velocity REI increase
Embeddedness 0.04 41.4 45.6 ~4.2
Index (REI) 0.8 39.3 43.4
1.0 38.2 42.4
1.2 37.1 41.3
1.6 35.0 39.2
Young trout Cool (2003) % YTB reduction
biomass (YTB) 488 m 6.62 1.26 81
578 m 12.68 2.41
740 m 40.87 7.75
Intermediate (2001)
488 m 4.12 0.53 87
578 m 8.70 1.12
740 m 33.37 4.31
Warm (2002)
488 m 2.30 0.28 88
578 m 4.61 0.55
740 m 16.07 1.92