Assignment Brief – Part 1

Scenario:

As part of the ongoing development of a large regional town, a drinking water network needs to be analysed and expanded (Part A). In addition, the stormwater design and subsequent flood risk needs to be established (Part B).

Submission:

There are two submission events for this assignment:

Part A Submission Requirements:

• A brief report (max page count = 6 pages) as a single PDF file – submitted to turnitin

• Your EPAnet model (.net) file – uploaded to the Bb submission page

Part B Submission Requirements:

• A brief report (max page count = 12 pages) as a single PDF file

For both reports, the file should have standard (25.4mm) margins, minimum font size 11. The maximum page count includes any appendices, contents page and/or cover page, but excludes references. Scanned hand calculations, where deemed appropriate, should be neat and clear, and properly signposted (defining variables, equations and solutions where needed).  Diagrams must be numbered, clearly captioned and appropriately referenced in text. Written text should be accurate and succinct, with minimal ambiguity or inaccuracy.

Failing to meet the submission requirements detailed above will result in a lower mark being awarded than that suggested by the rubrics given in the assignment.

Late Submission Penalty:

Late submissions will be have 5% removed if submitted from 1 minute to 24 hours after the deadline. Beyond this, an additional 10% is removed per additional day the assignment is overdue.  An assessment more than seven (7) calendar days overdue will not be marked and will receive 0%.

Learning Outcomes:

This submission assesses the following unit learning outcomes:

2. Design and evaluate the hydrologic principles associated with water resources engineering

3. Analyse, appraise and design water distribution networks using a variety of industry appropriate methods    

Assessment criteria and marking distribution and Engineers Australia competencies addressed The total assessment mark awarded is made up of the marks awarded to each element within the assignment brief. Weightings and marks are given for each section.

Each item of the assessment aligns with certain EA competenciesto be demonstrated. Other competencies may be demonstrated by completion of the task in addition to those noted.

Part A (35% of Assignment, Due 22^nd April)

An urban area, shown in Figure 1, has some of a water network already built. The condition of the PE pipes can be assumed to be very good, and the steel pipes are known to have a roughness of 0.1mm.

The network is fed by a gravity main 10km to a tank (Tank 1), from which the water is pumped into the network by a variable speed pump (Pump 1). The reservoir has a water age of 8 hours. Due to the complexities of modelling a variable speed pump in EPAnet, the approach taken should be to characterise the pump by a single point pump curve of (150Ls^‐1, 30m), followed by a pressure reducing valve with a maximum pressure of 35m. The tank has a reduced level of 8m, with a 2m maximum depth and a 22m diameter.

Figure 1 ‐ Existing Water Supply Network

The network demands are shown in Table 1. The flows are split into domestic and industrial flows, where domestic values 𝑄 given are averages of the daily demand, and industrial values 𝑄 are peak flow requirements. All nodes shown in Table 1 have a reduced level of 10m.

Table 1 ‐ Network Node Demands (L/s)

The network will need to be expanded by including the following large demand nodes. The new nodes will have a demand depending on your student numbers, as shown in Table 2 – New Network Node Demands (L/s)Table 2. You should ignore the greyed out nodes for your student numbers combination.

Table 2 – New Network Node Demands (L/s)

Tasks:

1. Using the EPANET model (available on Bb), identify the issues with the current network, given the expected service provisions are:

i. Minimum pressure head of 13m at the nodes (for all times)

ii. Maximum pressure head of 35m at the nodes (for all times)

iii. Maximum water age at the nodes of 30hrs

Although the parameters of the network are correct (pipe, nodal values, etc.), the model settings may need to be adjusted to obtain an accurate model output.

2. Develop the network to include the required nodes in Table 2 and to overcome any of the issues found in Task 1. You should aim to minimise alterations to the current network but can replace or remove pipes if needed.

No additional source is available, but other tanks can be added to the network if deemed appropriate. You cannot change the pump / pressure reducing valve settings, but may install additional pump(s) using the same combination.

3. The client is worried about the possibility that Tank 1 may be contaminated with some toxin. Model the water toxicity (for your finished network in Task 2) at the nodes, if the tank contains 100mg/L of toxin. You may assume that the source is not contaminated, nor is there any initial toxin in the pipe network. Guidelines prohibit a level above 0.2mg/L in the water supply.

The EPANET (.NET) file for Task3 must be uploaded as part of your submission.

Important Note:

It is vital that you use the same node labels as in Figure 1. The accuracy of your report depends on

the values provided against nodes being labelled the same as nodes in the figure.                      

Ref:2023AHHJV

Part B (65% of Assignment, Due 6^th May)

A small airport is being constructed in an undeveloped area. The schematic of the area is shown in

Figure 2. The drainage from this airport needs to be designed.

Figure 2 ‐ Schematic of Development

The requirements for the development are that all the impervious surfaces (apron, runway, and building) is to be collected into a retention basin located in the schematic shown (the basin lines up with the South end of the runway). This basin will drain into a river.

The terminal building sheds water from the South to the North edge. Downpipes are spaced every 30m. The capacity of the roof gutters and downpipes (roof plumbing) are outside the scope of this design.

The concrete apron has surface drains spaced according to Table 3, with one of the drains aligned exactly in the centre of the apron.

The runway must shed across its width, and can drain to a swale on one or both sides. The entire site slopes according to the gradient in Table 3, sloping from North to South. You should assume that the runway will follow the site gradient.

Both the runway and the apron are sealed concrete.

Ref:2023AHHJV

Table 3 ‐ Site Details

Tasks:

4. Design the drainage layout for the site. You will need to choose direction, size (diameter) and gradient of any pipe(s). The cross‐section of the swale(s) parallel to the runway will also need to be designed. Gradients and sizes should be calculated for this task for a 20% AEP storm.

5. Design the retention pond and outlet structures to ensure that all duration storms (of a 20% AEP) are able to be maintained on site with a maximum discharge as seen in Table 3.

The outlet structure should consist of a single orifice (rectangular or circular) with invert level at the permanent storage level, and an overflow weir provided at a higher elevation. You should specify these levels relative to the reduced level of the southern end of the runway (which is the lowest drained point on the site).

You will need to use hydrological modelling (e.g. Modified PULS), and produce graphs of peak discharge vs. storm duration and water quality volume vs. storm duration for all 20% AEP storms.

Ref:2023AHHJV

As part of the planning for the airport, the client needs to present a flood study for the river that the airport drains into. The local authority are worried about a storm event causing flooding of a critical road – where the river passes under the road through a culvert. You need to model this storm to determine if the road is at risk of overtopping.

Figure 3 – Sketch of River and Drain (NOT TO SCALE)

The cross section of the river and the drain are constant and can be seen in Figure 4. The drain can be considered as a straight channel. The river has a constant gradient of 0.2%, and the drain has a constant gradient of 0.8%. The junction between the drain and the river is such that the bank station (top left point) is equal for the river and the drain. The roughness of all the river channel beds can be considered as 0.030 and the drain as 0.035.

The culvert should be considered a ‘tapered inlet throat’ rectangular culvert which is approximately 25m long and has a roughness of 0.05.

Distances and gradient of the river and drain are given in Table 4.

Table 4 ‐ Dimensions of river and drain (in m) and gradient (unitless)

Figure 4 ‐ Shape of River, Drain and Culvert

Tasks:

6. The Annual Maxima historical flow rate in the river is uploaded to Blackboard (the file is listed in Table 5). You must analyse this flow rate record and demonstrate an appropriately chosen and fitted probability distribution. Having fitted the appropriate distribution, you must determine the flow rates that can be expected in the extreme flow environments of 20% AEP, 10% AEP and 1% AEP.

Table 5 ‐ File name for Stream Flow data

7. You must develop a model of the river. Using your solutions to Tasks 5 and 6, you must develop a HEC‐RAS (or similar) model that can predict the maximum water height (Headwater and Tailwater) and the time this occurs after the start of the storm at the culvert. You can assume that the river runs at a constant flow rate for the duration of the model, and the drain will vary as per the solution to Task 5 (if completing this assessment as an individual, us the sample data on Bb).

You should produce at least 1 graph showing the water height and flow rates plotted against time for the 20% AEP storm event. Higher marks will also need to consider the 10% AEP and 1% AEP storms. You will also need to explain how you modelled this, briefly documenting key decisions and identifying any assumptions, limitations, etc.

Ref:2023AHHJV

[1] If working as an individual, sum the last 2 digits of the ID number.