Surface Water Hydrology Paper
Surface Water Hydrology Paper
All instructions are given in the document, calculations must be perfect where you can then discuss about calculations. Graphs and tables must be added. The report is under the Australian guidelines. It is also mentioned in the report to use the basin according to my student ID, therefore, X=1, which means you would have to do calculations against Basin 1. That was to clear it for you. Furthermore, a software is required to
complete the project, which I have linked below, where you can download and complete the last few steps.
https://www.hec.usace.army.mil/software/hechms/downloads.aspx
Thank you for your help in last paper, you answered the question accurately. I will refer you to my friends.
Surface Water Hydrology Project Brief
(Session 2, 2020)
Project background
In this project, you are required to prepare hydrologic analysis of block of land planned for development (see attached map – based on your student number as explained above). The purpose is to satisfy regulatory requirements and get necessary approvals (from hydraulic and hydrologic perspectives) for development. You will need to collect necessary data (as formulated below) using ARR Vol 2 to construct rainfall patterns and the Bureau of Meteorology site (http://www.bom.gov.au/water/designRainfalls/ifd/index.shtml). Perform detailed hydrologic and hydraulic analyses of the basin before and after the proposed development. Discuss, in detail, the actions you propose so that the regulatory agencies’ requirements are met. You will need to perform analyses by using the basic principles you’ve learnt in Surface Water Hydrology (300983), Hydraulics (300765) and Fluid Mechanics (300762). You will also need to confirm reliability of your results by using the software packages HECHMS.
The submission must be in the form of a technical report following the formulated steps given below with a brief introduction to the problem, methodology used, your findings, recommendations, and references + all maps/drawings. It is to be typed using Times New Roman size 12 font and double spaced.
You will need to submit your report, all associated (Microsoft Excel) spreadsheets and all HECHMS files.
Please refer the learning guide for marking criteria.
Make justifiable and meaningful engineering assumptions, where necessary.
Please use the basins provided according to followings:
Basin 1 if 0 ≤ X ≤ 3; Use AEP 5% 3hr storm duration
Basin 2 if 3 ˂ X ≤ 7; Use AEP 1% 3hr storm duration
Basin 3 if X > 7; Use AEP 10% 3hr storm duration
For example, use Basin 2, AEP 1% 3hr storm duration for X = 7 if your student ID is 12345678.
Student ID: 19412317
Basin 1 (3 subbasins)
Centroid of Basin 1 is as follows: Lattitude = 31.073⁰ South Longitude = 151.275⁰ East Note: 1 and outlet are outlets of three Subbasins
Use the scale shown in the figure to estimate the areas

Basin 2 (3 Subbasins) Centroid of Basin 1 is as follows: Lattitude = 31.075⁰ South Longitude = 150.810⁰ East Note: 1 and outlet are outlets of three Subbasins
Use the scale shown in the figure to estimate the areas

Step 1: Physical parameters estimation
Using the scale provided in basin delineation, estimate (an approximate estimation will be enough) the area of each subbasin, compute the total area of the basin and estimate the channel length.
Step 2: Rainfall hyetograph construction
Use the Bureau of Meteorology web site (http://www.bom.gov.au) to generate the IFD curves for your catchment. Use the 2016 IFD and the latitude and longitude stated in the figures (for your basin) to generate IFD information for your site. Use % AEP as allocated above and 3hr storm for further analysis. Include both IFD table and IFD curves in your report.
Generate total rainfall hyetograph for the storm generated in above step (you need to use ARR Data Hub web site, https://data.arr–software.org/). Include total rainfall hyetograph, both table and histogram in your report.
Step 3: Rainfall Excess hyetograph construction
Now use initial and continuing loss model to construct rainfall excess hyetograph. You need to extract the initial and constant loss values from the ARR Data Hub web site. Make necessary adjustments, if required. You will need to explain how you achieved your result and include this in your report. Graphical representation suffices here.
For postdevelopment condition, assume that both the initial loss and continuing loss will be reduced by 50% for the subbasin you’re proposing to develop. Remember you’re developing only one of the three subbasins; therefore, loss values and rainfall excess will change only for one subbasin.
Step 4: Desired duration unit hydrograph construction
You will be generating a desired unit hydrographs for your subcatchments using the 5minute unit hydrograph for a basin given in the table below and making reasonable assumptions as follows:
Use of spreadsheet is required to save time, as the process involves repetitive computations. You will need to include your spreadsheet.
A 5minute unit hydrograph for a basin of 750 hectares is given in the table below.
Time (min)  0  5  10  15  20  25 
Discharge(m^{3}/s)  0  0.85  1.95  3.55  4.31  3.65 
Time (min)  30  35  40  45  50  55 
Discharge(m^{3}/s)  2.95  2.15  1.59  1.15  0.85  0.65 
Time (min)  60  65  70  75  80  85 
Discharge(m^{3}/s)  0.45  0.35  0.25  0.2  0.1  0 
Compute ordinates of desired unit hydrographs for your subbasins using above 5minute unit hydrograph. Consider using the basin area as a scaling factor. For example, if your subbasin area is 350 hectares then consider multiplying those ordinates from above table by 0.5.
Note: You will need to construct up to three unit hydrographs depending upon the size of subbasins.
You will need to explain the process you followed in your report. Make sure to verify your results by checking volumes after each computation.
Step 5: Storm hydrograph computation
Construct storm hydrograph for each subbasin using rainfall excess (step 3) and respective Δthr unit hydrographs generated above in step 4. The constructed hydrographs are the responses at the outlet of each subbasins under the existing conditions.
Step 6: Network diagram construction, routing through channel(s) and computation of hydrograph at the outlet of the whole basin.
Construct the hydrologic network to show connectivity of subbasins, channels and reservoirs (if any).
You will require to extract channel properties for routing the hydrographs through channels using Muskingum routing method. For this, assume the following.
Use weighting factor, x = 0.3
Use average channel velocity 1.1 m/s to estimate average flow velocity in the channel. Use this average flow velocity to estimate travel time constant, K.
Use these values of x & K to route relevant hydrographs through respective channel(s) and compute the hydrograph at the outlet of the basin.
This completes generation of predevelopment hydrograph at the basin outlet.
Step 7: Construction of Postdevelopment hydrographs
Consider developing one of the subbasins by proposing the following:
Both initial loss and continuing loss will be reduced by 50%. 5minute unithydrograph will have the following characteristics.
 Peak discharge will increase by 30%
 Time to peak will decrease by 15%
 Time base will decrease by 25%
Use the above adjustments to scale and generate meaningful postdevelopment 5min unit hydrograph. You will have to ensure that the volume balance works out. This may require a few iterations.
You will then need to construct Δt hr unit hydrograph (postdevelopment) for the subbasin being developed and use this to generate postdevelopment response from the basin.
Step 8: Comparison of Pre and Postdevelopment hydrographs
Now compare the predevelopment and postdevelopment hydrographs. Present your results in graphical form and present salient values in a tabular form. Analyse and discuss your results.
Next, propose a solution that will ensure that the peak of the postdevelopment hydrograph at the outlet does not exceed the peak of the predevelopment hydrograph at the outlet. You may have to design a reservoir incorporating outlet structures to achieve this. If you’re to use this approach, you will need to route the postdevelopment hydrograph through the reservoir.
You will need to discuss your strategy, provide the size of the reservoir and the details of outlet structures in your report.
Step 9: Use of HECHMS to verify your results
This is the last step. You will use HECHMS (ver. 4.3) to verify your results. You will need to include all HECHMS files in your submission.
Best Wishes!
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