Homework SourseA water stage elevation gauge is located at River Station cr
A water stage elevation gauge is located at River Station cross-section 1.0 which has measured the Water Surface Elevation to be 1505.0 ft for the 100-year storm. Based on this WSEL, the following information was already determined for you for cross-section 1.0:
Column 3: Computed WSEL = 1505 ft
Column 4: A = 596 ft2
Column 5: R = 3.25 ft
Column 6: You calculate
Column 7: You estimate Manning\'s n for main channel
Column 8: You calculate
Next, use the value of flow (Q) that you determined in the last homework (Q= 3,088 ft3/s), to complete Columns 15 and 16.
Then, compute the Water Surface Elevation (WSEL) for cross-section 2.0. For your first trial, use an assumed WSEL = 1509.89 ft and A = 342.24 ft2 and R = 3.20ft and a reach length of L= 450 ft. Determine the computed WSEL. It may not be within +/- 0.05 ft of your assumed WSEL of 1509.89 ft. STOP here. The purpose of this exercise is to appreciate the time and effort required for multiple iterations.
Solution
we assumed n = 0.03
| cross section | WSEL assumed | WSELcomputed | A | R | R2/3 | V2/2g | slope | hl | V | wetted perimiter |
| 1 | 1505 | 1505.41 | 596 | 3.25 | 2.194 | 0.4168 ft | 2,26 * 10-3 | 0.4144 | 5.1812 | 183.38 |
| 2 | 1509.89 | 1511.85 | 342.24 | 3.2 | 4.715 | 1.2639 ft | 1.48 * 10-3 | 0.666 | 9.022 | 106.93 |
