Part A
Presentation of the Part A results has 5% of total mark, this includes naming of the files.
1. Measurements carried out on the uniform flow of water in a long trapezoidal 12.0 m wide channel and of bed slope 0.2% revealed that at a depth of flow of 3.2 m, the discharge of water was 50 m3/s. Assuming the side slopes (z) of 1.5, estimate the discharge of water when the depth is 4.4 m using Manning equation.
2. A concrete-lined trapezoidal channel has a bed width of 10 m, side slopes 6 horizontal to 1 vertical, a bed slope 1 in 1000 and the Manning roughness coefficient of 0.035. Calculate the discharge of uniform flow when the flow depth range varies from 0 to 2.4 m. (Weighting 5%) Show the results in a table (See below example) and a graph (x=Discharge, y= Depth).
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Y
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T
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A
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P
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R
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Q
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(m)
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0
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0.2
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0.4
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0.6
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0.8
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1.0
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1.2
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1.4
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1.6
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1.8
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2.0
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2.2
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2.4
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3. A rectangular channel 8 m wide laid to a mild bed slope of 0.001 conveys a discharge of
16 m3/s at a uniform flow depth of 2.5 m.
a) Determine the critical depth
b) Show Energy vs. Depth graph
4. Culvert Design: As part of a railway upgrade, an existing Reinforced Concrete Box Culvert (RCBC) is going to be upgraded. As hydraulic designer of this project you are required to assess the existing culvert arrangement and then assess proposed culvert arrangement to provide adequate maximum allowable headwater upstream and check for maximum allowable downstream velocity. The railway has to have 1 in 100 AEP flood immunity and the foundation of the railway has to have 1 in 50 AEP flood immunity.
Givens:
The peak 1 in 100 AEP (Q100) and 1 in 50 AEP (Q50) flows are 43.6 m3/s 36.9 m3/s, respectively. The existing culvert is 2@1500×3000 mm RCBC (Height = 1500 mm, Span = 3000 mm). The culvert's downstream material is unknown. The top of the railway elevation is 18.68 mAHD (elevation in metres with respect to the Australian Height Datum). Top of the formation is 0.738 m lower than the top of the railway elevation.
Assume Manning's roughness value of 0.012.
The rest of the other required data is provided in Table 1 below, but if you think any data is missing, assume a value and document the assumption.
Required parameters (existing and proposed):
Do existing and proposed culverts perform as inlet control or outlet control?
What is the maximum Q50 and Q100 allowable headwater for existing and proposed scenarios?
What is the culvert slope for each scenario?
What is the outlet velocity for each scenario?
You may use provided MS Excel calculation sheet to for assistance. The correct use of culvert design nomographs are essential to get the correct answer.
Part B
You are required to perform a hydraulic assessment on Newham Creek, a tributary for Bulimba Creek in Brisbane. The provided model includes basic data for surveyed and interpolated cross sections.
Scenarios to be modelled are:
Base scenario (No Structure)
Developed scenario (With Structures)
This means you need to run the model with and without structures. Add inflows and all the structures data provided in "Required_Data.xlsx" into this model. Remember you have to have a separate geometry file for base and developed scenarios but the inflow files are going to be the same for both scenarios. You need to have two HEC-RAS Plans, name them properly for easy and better understanding. You have to choose events jun-83 and jul 88 for one file, May 81 and Apr 84 for second file, and May 80 and june 83 for third file.
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Event
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May-80
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May-81
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Jun-83
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Apr-84
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Jul-88
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The Boundary condition is as below:
The upstream boundary condition is critical depth.
The downstream boundary condition is known water surface elevation as described in Table 3.
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Event
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Downstream water surface Elevation (mAHD)
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May-80
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10.09
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May-81
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11.09
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Jun-83
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10.56
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Apr-84
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11.42
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Jul-88
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10.30
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Please refer to "Required_Data.xlsx" for all other information necessary to perform the hydraulic impact assessment. Creating two required plans with understandable plan names covers 35% weighting of mark.
Please note that you have to add structures (Bridges, Culverts and Levees) into the model according to the provided data. If you find any required data missing, please assume a value and make a note of it in your submission file.
Estimate the water level at each cross-section for each scenario.
https://www.dropbox.com/s/6hv3kanwsqijgdo/eddy_homework.zip?dl=0