Slope Area N Value Confirmation

Using USGS methods for computing N values and confirming with a critical depth flow value.

USGS review of slope areas:
Computation of Manning's n=0.39 * S^0.38 * R^-0.16
for slopes>10ft/mile

2-Xsec Slope Area:
Quick 2 xsec velocity head difference Q1*V2/V1 with increased velocity head downstream at x2.
other wise Snew=(H + delta hv)/L as delta V^2/2g If expanding use 1/2 delta hv.

2-Xsec Slope Area:
English Q=1.49*A*R^0.667*S^0.5/n
a=area, r=Wtop/Wetted_Perimeter, g=32.2
Computation of Manning's n=0.39 * S^0.38 * R^-0.16 for slopes>10ft/mile
K=a*r^2/3 * 1.486/n
hv-V^2/2g
Step1: S=H/L
Step2: Q=(K1*K2*S)^0.5
Step3: V1=Q/A1 and V2=Q/A2
Step3: dhv=(V1^2-V2^2)/2g
Step4: S=(H+dhv)/L or expanding S=(H+.5*dhv)/L
Step5: Qfinal=(K1*K2*S)^0.5