1. Q=r*DA As you move down a watershed, the drainage area increases and the discharge increases x4x4 x3x3 x2x2 x1x1 Since Q ↑ as DA↑ downstream and Q=w*v*d Then d, w, and v all tend to increase downstream as WA increases. x1x1 x3x3 x4x4 x2x2 Stream cross-section w=nQ a v=pQ b d=qQ c n*p*q=1 a+b+c=1

2. Q=wvd=(nQ a )*(pQ b )*(qQ c )=npqQ a+b+c which can only be true if npq=a+b+c=1 rDA=wvd=(n(rDA) a )*(p(rDA) b )*(q(rDA) c ) So that w=nrDA a, v=prDA b, and d=qrDA c We can also write w,v and d as functions of DA since Q=rDA These relationships can tell us how the width, velocity and depth of a river will change as its discharge increases or decreases.

3. Drainage Area (km 2 ) 10 1.0 100 o o o o o o o o Slope =0.55 Width (m) 1 101001000 0 1 2 Log 10 width 0 123 Log 10 Drainage Area Log w =0.23 + 0.55 Log DA w= 1.7DA 0.55 How stream width increases with Drainage Area in the Upper Oldman R W DA

4. Drainage Area (km 2 ) o o o o Slope of depth line=0.25 o o o o o Slope velocity line =0.2 Depth m 1.0 0.1 1.0 Velocity m/sec o o o o o o o 1 101001000 v=0.24 DA 0.2 d=0.22 DA 0.25 The exponents for width, velocity and depth add up to 1 How stream velocity and depth increase with drainage area in the Upper Oldman R

5. Drainage Area (km 2 ) Mean velocity (m/s) v= 0.24 DA 0.2 The bell curves rising out of the plane of the graph depict the variability of the river’s flow regime at a series of points along the drainage—the bell curves get wider toward the right, illustrating the increasing range of variability downstream

6. Proportion < given velocity 1.2 m/s 1.0 m/s 0.8 m/s 0.6 m/s 0.2m/s 0.4m/s The distance between these two lines represents the proportion of the river with velocity between 0.8 – 1.0 m/s at the point where DA = 1000 km 2 Drainage area (km 2 )

7. 10 20 30 50 40 5001500100020002500 o o o o o o o o o o o o o o o o o o 0.6-1m /sec adult trout 0.2-0.6m/sec juvenile trout 0-0.2m/sec trout fry % of habitat Drainage area (km 2 ) o o o o >1m/s very large adults Low velocity habitats predominate in the upstream sections and medium and high velocity habitats become more predominant downstream