Water Resources Engineering

Task(s)

Task-1: Mini project

The aim is to design a separate sewer system (foul sewer + Storm Sewer) to drain area of el Khuwir City. Urban layout plan with topographic level is provided for each student. The study area involves mainly residential buildings. Population and sub-area will be specified for each student.

Guidelines for mini project

The sewer system is designed for “gravity flow”. Pumping stations should be avoided as much as possible. All pipes are circular and made of concrete. Sewer mains shall be aligned in streets. Manholes are provided at heads of runs, at locations where there is changes in direction, changes in gradient, changes in size, at major junctions with other sewers and at every 90 meter intervals.

The sewers are of commercially available sizes (155; 205; 255; 305; ….)

Part I: Foul sewer system design

1. Preliminary horizontal layout

Sketch system layout (horizontal alignment):

• locate pipes so all potential users can readily connect into the system

• try to locate pipes perpendicular to contours

• try to follow natural drainage patterns (show direction of flow on the layout)

• locate manholes as per specifications.

• Identify the outfall of the sewer system

1. Preliminary breakdown in section

• Slice layout in section and give name each of section using nomenclature FS1, FS2, …

• Fill following table 1 that gives characteristic of each sewer section

Table 1 : section characteristics

If the natural slope is not matching specification, assume a slope of 1.3%. Avoid as much as possible pumping in the system.

1. Estimation of quantities of wastewater generated

• Count number of residence and assume that each residence has a population of 2 + (last digit of student number)

• Estimate future population P for each residence taking population growth rate as 2% and design period of 25 years

• Estimate dry weather flow DWF at the end of the design life of the project. Domestic water consumption per head L = 200 + (two last digit of student number) liter/head/day. Infiltration I = 1%.

• Calculate quantities of wastewater generated by each residence (in liter/day) and maximum flow foe each section.

• Generate calculation in the following table 2.

Table 2: Wastewater production

1. Hydraulic design

• Calculate full section flow (in m3/s) using Manning formula: QFS=24,935 * I1/2 * D8/3

• Generate calculation in the following table 3.

• Check self-cleaning condition for each pipe section

Table 3 : Design computation for foul sewer system

Part II: Storm sewer system design

1. Preliminary horizontal layout

Sketch system layout (horizontal alignment) :

• locate pipes

• Assume a common slope for all pipes. Take I =1.3%

• locate manholes as per specifications

• Identify the outfall of the sewer system

1. Preliminary breakdown in section and catchment area delimitation

• Slice layout in section and give name each of section using nomenclature SS1, SS2, …

• Demarcate and name catchment area drained by each section. Calculate area referring to the given scale on the map.

• Fill following table 4 that gives characteristic of each sewer section

Table 4 : section and catchment area

1. Estimation of runoff flows

For each catchment area, flow should be determined using rational method. Impermeability coefficient C is taken 0.5. Entry time to the pipe is the same for all section Te= 6 min.

• Calculate runoff flow for each section. Fill the table 5 below.

Table 5: Runoff flows

1. Hydraulic design

• Calculate full section flow (in m3/s) using Manning formula: QFS=24,935 * I1/2 * D8/3

• Generate calculation in the following table 6.

• Check self-cleaning condition for each pipe section

Table 6 : Design computation for Storm sewer system

1. Vertical profile of pipe

On a graph sheet, report the vertical profile of one selected pipe from horizontal layout. The depth of cover is 2 meters, pipe wall thickness is 50 mm. Follow the procedure below:

1. Plot ground surface elevations, working backwards

2. Sketch invert and crown

3. Line 1: Locate the invert of the upper end of the pipe

Upper Invert Elevation=Ground surface – depth of cover – pipe wall thickness – pipe diameter.

Lower Invert Elevation= Upper Invert Elevation-(Slope of sewer)x(Length of sewer)

1. Check: Depth of Cover Adequate/ Not adequate?

If Depth of Cover is not adequate / too shallow

Two alternatives:

(1) Repeat with a lower invert elevation, or

(2) A steeper slope

Marking scheme for the Report

Write a detailed report summarizing the design task- Foul sewer system and storm sewer system. The report should contain the following

Guidelines for the Report

• Different set of data for sewer design will be given to each student. Data used should be highlighted in the report.

• Report should contain list of contents, list of tables and figures, nomenclature.

• Tables and Figures should be with Captions and References.

• Layouts prepared by student should be attached in the report in the appropriate part. Urban layout plan should be attached in the appendix

• One design calculation should be written and explained clearly in the report. Results of calculation should be summarized in tables given above accordingly.

Task-2: Summative Class Assessment [Weightage 20%]

• Class assessment on the topic ‘Stream flow measurement and application’ will be conducted during the 8th teaching week with prior announcement.

• If a student does not attend the assessment and fail to produce a genuine reason, no replacement assessment will be scheduled for him/her and ZERO mark will be awarded for that assignment.

Marking scheme

Instructions

1. Plagiarism is a serious offence. In case of any plagiarism detected, penalty will be imposed leading to zero mark. Policy and guidelines for dealing with plagiarism and malpractice in examination can be viewed by clicking:

http://portal.cce.edu.om/member/contentdetails.aspx?id=490

1. The course work shall be subject to plagiarism software check.

2. Course work should be submitted on time. College guidelines on late submission of coursework can be viewed by clicking: http://portal.cce.edu.om/member/contentdetails.aspx?id=565

3. Course work should be submitted with an appropriate cover page, which can be obtained from the departmental assistant at the department.

4. Name, student identification and title of the course work to be written clearly and legibly on the cover page.

5. The completed course work is to be submitted to the departmental assistant on or before the deadline and record your name, date of submission and signature in the book with the departmental assistant.

6. For online submission of course work, pdf file with appropriate cover page mentioning name of student, student number and title of the course work should be uploaded using the submission link created and made available by the module leader.

Referencing

Harvard Referencing (CCE Style) First Edition 2013 should be followed for both in-text and listing references. This downloadable document can be found in our CCE portal at: http://portal.cce.edu.om/member/contentdetails.aspx?cid=628

Note:

Student ID: 150405