Question

A field survey yielded the channel cross-section data given on the next page. Calculate the cross section area of the active channel (i.e., the part that has water flowing) and determine the discharge rate. Assume the average velocity in the channel is 1.3 ft/s. Assume a Manning’s roughness coefficient of 0.04 and slope=0.0021

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Red Butte Creek, Sunnyside Park Cross-section 3 Station (ft) Elevation (ft) Notes 2.2 3.2 5.2 8.4 12.6 13.2 14.3 20.6 4678.45 4676.85 4676.1 4675.45 4675 4675.65 4676.1 4676.45 4678.45 LB WS TW WS RB LB= Left bank WS= Water surface TW= Thalweg RB -Right bank

Answer 1

Assume Recn -Channel P) 0.002 B14 B +2 1- 2/ 2 1.3 0021 O.04 วเ 22/3 0002) 213 12 :347 Chunnel sentinn Crosseetim data hoh pmotided

2 B12H B14 8+2 H 多 21 0.04 213 0.0021 213 12 1 1t347 4t 20876 not prouided