Design of storm_water_sewage_system _sample

Design of Storm water drainage system

Submitted by:Date:

Table of Contents

1. Abstract...........................................................................................................................................2

2. Introduction....................................................................................................................................2

3. Project description:.........................................................................................................................3

3.1. Purpose of the project..............................................................................................................3

3.2. The area covered by the project:..............................................................................................4

3.3. The location of the area:..........................................................................................................4

3.4. The size and population covered by the project:......................................................................4

3.5. The importance and land-use of the area:................................................................................4

4. Drainage network............................................................................................................................5

4.1. The Project Horizon:................................................................................................................5

4.2. Topography of the area:..........................................................................................................5

4.3. Flow of drainage (Gravity Drainage):.......................................................................................6

4.4. General description of the network:.......................................................................................6

5. Design Criteria:................................................................................................................................8

5.1. Discharge timetd:....................................................................................................................8

5.2. Runoff coefficients:................................................................................................................10

5.3. Hydraulic Design:...................................................................................................................11

5.4. Manholes Spacing:................................................................................................................11

5.5. Kerbs and pavements:...........................................................................................................11

5.6. Calculations:..........................................................................................................................12

5.6.1.Runoff Flow:...................................................................................................................12

5.6.2.Diameter of the pipe:....................................................................................................14

5.6.3.Intensity Duration Frequency (IDF) curve......................................................................17

6. Bibliography..................................................................................................................................19

1

AbstractStorm water is the water that is collected due to the rainfall, snowfall and melting of ice. This

water gets evaporated, absorbed in the ground and may be get carried or flown away to the

rivers, streams, lakes and other such water bodies that are nearby.

There should be proper disposal of the storm water that cannot be used or treated for these

purposes through a sufficient and effective drainage system. It also refers to handling of the

accumulated and storm water in such a way that it does not possess any hazard to the

community in the future. Accumulation of the storm water also poses a huge threat of

outbreak of diseases due to the dirt, germs and dangerous insects that may arise in these

water. This may lead to a very bad condition and health to the people in these communities

and make the entire locality disease prone (Schmitt, Thomas, & Ettrich, Analysis and

modeling of flooding in urban drainage systems., 2004). Therefore, it has to be ensured that

the sewer system that is adopted is sufficient enough to save the community from such

outbreaks and contribute towards the cleanliness of the city.

IntroductionStorm water drain refers to the system which is designed and adopted to drain the excess

water from the various areas of the city and other streets that gets occupied or logged due to

the improper drainage facility (Schmitt, Thomas, & Ettrich, Analysis and modeling of

flooding in urban drainage systems., 2004).

This kind of storm drain does not create much problem in the natural landscapes like hills and

forests as they get absorbed by the thick soil present there along with their absorption by the

plants and the trees present there. But, these storm drain can pose a very serious problem in

the urban areas where they do not get enough soil as well as plants and trees to absorb it

(Walsh, Fletcher, & Ladson, 2005).

It poses the two kinds of major problems for the city and they are flooding of such water on

being accumulated in large quantities and the other issue is the threat of water pollution that

can be created by excessive storage of these unabsorbed storm water. Accumulation of this

water in the streets of the city, sidewalks on the streets, roofs of the houses and throughout

the parking lots needs to be managed before it tends to create any of the problems mentioned

above. Thereby, it is important to channelize these water before it poses as a threat to the

environment around (Adams & Papa, 2000).

2

Availability of water for commercial and consumption purpose is also on the increase in the

urban areas due to meagre amount of natural water resources available in the cities. There is a

huge scarcity of water that can be used for the household purposes in the cities. However,

through proper management and channelization of the water available into the resources can

provide a solution to these shortage (Mays, 2001). These involves proper treatment of the

water that is led into the water resources like lakes, rivers and other such pure water

resources.

Project description:

There are various things and researches that we are going to cover in our project. They are

listed below along with the description of the elements related to it:

Purpose of the project

The purpose of the project is to design a sewer system for the Um Suqeim locality in

Dubai situated in United Arab Emirates (UAE).These sewer system will help to channelize

the storm water that gets collected in the locality and poses various threats to the community

in terms of various health hazards. This sewer system will tend to provide drainage in order

to prevent floating of water which leads to various problems like damaging and cracking of

the streets, water pollution due to the accumulation and contamination of such water and a

huge amount of traffic jams. These system will target to channelize the storm water that gets

collected and accumulated in the city lanes, parking lots and other such areas. This will help

the community to overcome the problem of water logging due to heavy rainfall or any other

potential consequences of water logging (Walsh, Fletcher, & Ladson, 2005). Water

management is required in these community to ensure the smooth flow of operations,

vehicles and people across the road within the community that will be achieved by this

system of sewer water treatment. This area is very much famous for the tourists due the

things it has to offer to the world. Hence, a proper drainage system will ensure the cleanliness

of the region and will help in increase in tourist revenue of the region.

The area covered by the project:

The size of the locality that has been selected is around 7 sq. kms. It has the major

part of the land used for residential and habitation purposes. With an approx. population of

17000 people, this area serves to be the locality for a community that has been developed and

flourished in Dubai since a long time. The area is a part of the locality that is situated to the

west of Dubai. The region is affected by accumulation of water near the roads due to the

3

design of sewer system that consists mainly of manholes. The area that is to be covered

comes under the Jumeirah beach’s coastline (Fleming, 2000).

The location of the area:

Umm Suqeim is situated in the western part of Dubai and follows the Jumeirah

beach’s coastline. It has Jumeirah towards the north, Al Sufouh towards the south and the

west side is covered by Al Safa, Umm Al Sheif and Al Manara. Umm Suqeim consists of

three subdivisions: Umm Suqeim 1, Umm Suqeim 2 and Umm Suqeim 3. Al Manara road

separates Umm Suqeim 1and Umm Suqeim 2. Umm Suqeim 2 and Umm Suqeim 3 is

separated by Al Thanya Road (Fleming, 2000).

The size and population covered by the project:

The community is situated to the east of Dubai and is spread over a region of 7

sq.kms. It has a population of around 17000 people. The density of the people is only around

2400 people/km which is very large. Hence, there is a lot of space that is available for the

storm eater to be accumulated if not taken care of at the right time. There is a huge scope for

improve in infrastructure due to the available land that is largely habited by the people

(Fleming, 2000). There is huge space for the infrastructure amenities like roads and parking

lanes that are available that need to be provided with the proper slope or design to ensure that

water does not get logged in. In this region, there are exclusive places which involve hot

tourist locations of Dubai.

The importance and land-use of the area:

The area is residential and recreational and hence needs to be taken care of because it

poses the threat of improper accumulation of the water resources in the lanes, parking lots

and other such areas which are near to the houses where people stay. Hence, it is of utmost

importance to channelize this water to avoid the health hazards that may arise due to the

pollution created by the storm water (Bryan, 1972). The proper execution of the system

developed for the evacuation and management of storm water into the nearby disposal source

creates cleanliness on the streets and ensures a healthy environment to live in for the

community. It also helps to eradicate the water that has been released or accumulated by the

industries that occupy a very small portion of this locality (Fleming, 2000). These area serves

to be extremely dense and hence has to be taken special care of due to the revenue that it

generates for the Dubai government and the livelihood of the people in this region. Emirates

4

international school, Suqeim enormous Public Park, super exotic and luxurious Burj- al –

Arab hotel, exclusive Jumeirah hotel and Wild Wadi Water Park.

Drainage networkThe Project Horizon:

The area is designed for approximately 20-25 years and in the future if the horizon is

needed to be enlarged it will require further modifications and maintenance. The area is

mostly residential and it is divided to 6 major blocks as we can see in the picture. The

community has human habitation spread in large numbers over a small area and hence

provides a limited opportunity to utilize more and more space for the construction of the

system (Walsh, Fletcher, & Ladson, 2005). There is a selected area which is to be considered

while analysing the community and developing the sewer system. The area which is to be

considered is shown in the image. The direction of the Sewer system is taken as ranging from

the elevation in the east towards the lower areas near the coast in the west.

Topography of the area:This area has a drainage with pumps and has man holes along the pavement s with

kerbs for the drainage of the water through the surface of the road. It has a slope from 80-75

and this will depend on the gravity and the direction of the water that flows in through the

surface. This, therefore, will support the flow of water starting from the point shown in the

map on the right extreme down corner. The area is divided at various places by the changes in

the lanes and street and it has man holes created to absorb the surface water that is being

accumulated on the surface along these roads (Walsh, Fletcher, & Ladson, 2005). The

topography of the area has exactly seven contour lines and the first top contour line has an

elevation of 80 m and the last one on the bottom has an elevation of 75 m. Along with the

design of the man holes, there has to be proper design which ensures that sufficient number

of kerb, that is, stone edging or pavement created at the corner of the roads and parking lanes

to ensure that the water level does not rise above a particular level and does gets carried away

in a systematic and smooth way (Adams & Papa, 2000). The construction of kerbs and stone

pavements should be followed by appropriate gutters and grills at the side of the road to carry

the flow from the side of the road that does not get carried in the man holes.

5

Flow of drainage (Gravity Drainage):The path which is selected for the sewer system is such that it will provide enough

scope for the water to flow across the surface by virtue of its gravity from an elevation to a

reduced height. This is obtained by proper channelization of the route through which the

storm water will flow. This type of drainage helps to use the force of gravity to ensure

smooth flow of the storm water to the disposal or other resources through the city roads

without much external pressure or pumps required. The use of pumps will be limited because

the water will seep through the gutters at the corner and the man holes present at the centre

(Schmitt, Thomas, & Ettrich, Analysis and modeling of flooding in urban drainage systems.,

2004). The force of gravity will be utilized by beginning from a point or a junction at the east

corner of the locality and gradually moving up in the west direction. It has few changes in the

direction which involve moving down the street and going across the lane across the

community. The drainage system takes the advantage of the geographical slopes that are

observed in these region to be considered (Archdeacon, 2005). The west side gradually opens

to the sea coast and hence is very easily obtainable from the flow of the storm water point of

view in the slope.

General description of the network:The route which is to be created for the storm water to flow through the road is shown

in yellow line. The route consists of specific lines and track that is to be followed as observed

in the figure. There are various junction points developed throughout the network. It is at

these junctions that the route will take a turn or change its course from the system (Schmitt,

Thomas, & Ettrich, Analysis and modeling of flooding in urban drainage systems., 2004). So,

special care needs to be taken while designing and developing these junctions as there are

maximum chances of water getting logged at such corners or it may also tend to change its

direction which is also not desirable. Hence, proper care needs to be taken at this places

which have the maximum scope of error or distortion of the storm water (Adams & Papa,

2000).

The drainage system is designed to take in any rate of flow in the area starting from the east

towards the west throughout the 6 blocks. The lines that go from west to east collect the

storm water from the 3 blocks in the east direction and the drainage system can collect water

from the whole 3 blocks in this area. This water is then graduated towards the inclination in

the west direction. It is also observed that proper track and path of this water is specified so

6

as to avoid the jamming on the roads and places which are having high value from tourist

point of view.

The design and the channelizing of the pipes through the sewer system is made such that they

tend to face least number of obstacles over the surface while carrying the storm water to its

disposal or desired place (Mays, 2001). There has also been terms that are to be taken care of

while developing the design of the sewer system so as to make sure that it does not affect the

working and flow of operations in this region. The lines that are to be provided are designed

and developed after considering the topography of the region as discussed earlier. The points

that are at a greater height from the sea level, that is, which are at an elevation are first

determined. It is then followed by deriving its course for the flow of the water through the

pipes. It involves considering the points that are gradually towards the west and are

comparatively at a lower height from the sea level as compared to the points in the east

(Schmitt, Thomas, & Ettrich, Analysis and modeling of flooding in urban drainage systems.,

2004).

The construction of kerbs along the pavements is also to be made in such a way that it

provides sufficient space for the utilization of roads and the lanes for other purposes. Thus, it

must be made sure that optimum utilization of space is carried out. This will not only help in

saving space but also provide a scope and setup for infrastructural facilities and other

recreational activities. The tourism can also be worked upon for the saved region and

contribute towards its increase that would ultimately benefit the government.

7

Design Criteria:The design of the sewer system is to be made by considering various parameters and

elements that tend to affect the development of the project. Designing elements are to be

defined and at the same time determined for a specific set of variables (Mays, 2001). These

parameters are explained and derived below:

Discharge timet d: It refers to the time that is required by the flow to get across the pipe through different point

of time. The estimation and the figures that are used here are taken as per the Municipality

specifications and the norms that are mentioned and followed by them (Schmitt, Thomas,& Ettrich, Analysis and modeling of flooding in urban drainage systems,2004). The number of years that is to be considered is ranging from 2 years to 100 years

considering the feasibility of the project with respect to the flow and the rate of flow. In the

table shown below, we have obtained the relationship between the rates of flow of storm

water at different Return period (T) for a given discharge time duration given byt d.

8

The results that are obtained from the table show that the flow rate depends on the area and

intensity of the storm water that is flowing through it. The duration or the Return period (T) is

independent of the material of the pipe but depends on the area of the pipe through which it

flows. This can be obtained by calculating the discharge across the pipes for a specific

amount of time. The flow of the pipes is measured and obtained at an interval of few years.

The amount of the flow that gets fluctuated is to be observed from the table (Adams & Papa,

2000). The table also provides guidelines on the discharge that will be obtained by a specific

dimension of pipe over a period of years. The runoff coefficients of these pipes are to be

taken into consideration to develop the pipes design in details.

9

Runoff coefficients:It refers to the surface friction factors that the different material possess. The co – efficient of

the run off tend to determine the intensity and smoothness of the flow of the water across it.

The run off coefficients also tend to help to make an estimation of the life of the pipe that

would be able to sustain the flow of sewer across it for a particular period of time. The

coefficients help to understand the friction that the pipes will undergo when the sewer water

drain flows through it (Schmitt, Thomas, & Ettrich, Analysis and modeling offlooding in urban drainage systems, 2004).

The coefficients value also tend to provide the calculation with an edge to carry the necessary steps and analysis to design the pipe for the project purpose on the basis of the strength of the materials that are shown in the table below.

10

Hydraulic Design:The most affectively factor in the project is the velocity of water in the pipes that depend mostly in the slope of the pipe used. The minimum range is 1.35m/s and the maximum is 2.85m/s. the hydraulic design of the structure tends to provide with the strength and reliability of the design and calculation in terms of the life of the pipes. The hydraulic design helps in better understanding of the features that are to be considered while designing the sewer drain. It also involves developing elements and parameters that will help to ensure that the project will be able to sustain the different hurdles and obstacles that are offered by the nature (Harremoves & Rauch, 1996). The effectiveness of the hydraulic design will provide the confirmation of the life and safety of the project and thereby, of the people in contact with it. The characteristic feature of the hydraulic design id the strength which the material will offer when it is performing a task.

Manholes Spacing:It is observed that approximately minimum value of a manhole spacing is of 200mm to 250mm and the maximum is around 1200mm. The manhole space varies depending on the slope from north to south and from west to east. The selection of the sites and location for construction of man holes needs to be made by considering parameters that are related to the area, locality, density and design of the road pavements above the surface(Schmitt, Thomas, & Ettrich, Analysis and modeling of flooding in urbandrainage systems, 2004). It also helps to determine the path through which the pipelines will be crossing across the man holes and serve as a guide to provide them the course. The design of the man holes should utilize optimum availability of free surface on its side and this will ensure that timely drain of water along the roadside is done.

Kerbs and pavements:The kerbs are gutter like structures made along the pavements of the road at the corner along its surface. The construction of the kerbs along

11

the corners of the roads should be made such that it can take sufficient amount of water through it and this would thereby reduce the load on the sewer pipe. The alignment of the pavements should be made such that it is in the direction of the slope that is existing in the region (Schmitt,Thomas, & Ettrich, Analysis and modeling of flooding in urban drainagesystems, 2004). Hence, hardly, any force or external device will be required to drain the water along the surface. The allocation of space and its utilization on the road surface is made such that it does destroy the look of the infrastructure above and at the same time helps to drain the storm water efficiently throughout the surface.

Calculations:There are various variables that are to be determined during the design and analysis of the

storm drain project. They are as follows:

Runoff Flow:The flow of the water or any other liquid while it is running or flowing is termed as the run

off flow. The run off is measured in terms of m3/hr and the unit is same as that of any other

flow of liquid along a surface. The run off is measured by the following way:

Rational method is used to calculate the runoff flow; which is

Q=CiA

Where;

Q=The water flow rate(m3/hr ) C=Runoff coefficient

I=Rainfall intensity (mm/hr ) A=Drainagearea(m2)

12

There are six main blocks through which the flow is carried out. Here, we are going to

observe the flow calculations of lines 1, 2, 3 and 5 during the discharge across the surface.

The areas of the pipes A is determined and taken accordingly.

o Runoff across the Line 1A:

C1=0.35 I 1=0.055m /hr A1=14200m2

Q1=0.35×0.055×14200=348.2m3/hr .


C2=0.35 I 2=0.065m /hr A2=15200m2

Q2=0.35×0.065×15200+348.2=690.4m3/hr .


C3=0.35 I 3=0.065m /hr A3=5200m2

Q3=0.35×0.065×5200+1035.6=1179m3 /hr .


C5=0.4 I 5=0.065m /hr A5=6900m2

Q5=0.35×0.065×6900+1179+1037.4=2471m3/hr

Here for the proper and precise estimation of the run off, we are going to measure it twice for

the same pipes to ensure that any kind of error is not made in making the dimension of the

pipe.

13

o Runoff across the Line 1B:

C1=0.35 I 1=0.08m /hr A1=14200m2

Q1=0.35×0.08×14200=372.6m3/hr .


C2=0.35 I 2=0.08m /hr A2=15200m2

Q2=0.35×0.08×15200+372.6=743.2m3/hr .


C3=0.35 I 3=0.08m /hr A3=5300m2

Q3=0.35×0.08×5300+1108.8=1370m3 /hr .


C5=0.35 I 5=0.08m /hr A5=6800m2

Q5=0.35×0.08×6800+1260+1117.2=2574.8m3/hr .

Diameter of the pipe:The diameter of the pipe through which the storm water is going to flow is to be determined

and this is done by the following formula (Harremoves & Rauch, 1996):

14

D=(Q×4×n×4

23

π ×S0.5 )38

D=Diameter∈(m) n=coeffiecient of roughness

S=Slope(m /m) Q=water flow(m3 /s)

o Diameter of the pipe in Line 1A:

Q1=0.085m3/s n=0.023 S1=0.006

D1=(Q×4×n×4

23

π ×S0.5 )38=¿ ( 0.085×4×0.023×4

23

π ×0.0060.5 )38=0.321m

Selected pipe ¿0.35m=350mm


Q2=0.192m3/s n=0.023 S2=0.006

D2=(Q×4×n×4

23

π ×S0.5 )38=¿ ( 0.192×4×0.023×4

23

π×0.0060.5 )38=0.431m



Q3=0.325m3

sn=0.014 S3=0.0023

D3=(Q×4×n×4

23

π ×S0.5 )38=¿ ( 0.325×4×0.014×4

23

π ×0.00230.5 )38=062m


15


Q5=0.6615m3/s n=0.013 S5=0.0015

D5=(Q×4×n×4

23

π ×S0.5 )38=¿ ( 0.6615×4×0.013×4

23

π ×0.00150.5 )38=0.88m


Here, to avoid any kind of error we will be calculating diameter of the pipe twice.

o Diameter of the pipe in Line 1B:

Q1=0.102m3/s n=0.013 S1=0.005

D1=(Q×4×n×4

23

π ×S0.5 )38=¿ ( 0.102×4×0.013×4

23

π ×0.0050.5 )38=0.348m



Q2=0.205m3/s n=0.013 S2=0.0058

D2=(Q×4×n×4

23

π ×S0.5 )38=¿ ( 0.205×4×0.013×4

23

π ×0.00580.5 )38=0.440m



Q3=0.4m3/s n=0.013 S3=0.002

D3=(Q×4×n×4

23

π ×S0.5 )38=¿ ( 0.4×4×0.013×4

23

π ×0.0020.5 )38=0.690m


16


Q5=0.712m3/s n=0.013 S5=0.00133

D5=(Q×4×n×4

23

π ×S0.5 )38=¿ ( 0.712×4×0.013×4

23

π ×0.001330.5 )38=0.925m


The runoff for the pipes considered and their diameters thus obtained help to provide the

estimation and design of the sewer pipe that would be required for the storm drain along the

surface following the slope.

The calculations are tabulated as shown below:

Line

No.

Flow (Q)

(m3/hr)

Pipe Size

Calculated (mm)

Pipe size

Selected (mm)

1 343.2 341 350

2 690.4 442 450

3 1179 481 500

4 2471 727.2948523 750

5 2561 841.2 900

17

6 2875 872 900

7 2998 912 950

Intensity Duration Frequency (IDF) curveThis is the frequency intensity that is measured against the duration of the rainfall and is

observed for a period of 15 years. The main focus of this relationship is to observe the

intensity of rainfall within a particular region and at the same time also focus on the side

effects that it produces on the storm water drain system.

18

BibliographyAdams, B. J., & Papa, F. (2000). Urban Stormwater Management Planning With Analytical

Probabilistic Models. West Sussex : John Wiley & Sons .

Archdeacon, W. (2005). Standard Guidelines for the Design, Installation, and Operation \& Maintenance of Urban Subsurface Drainage and Urban Stormwater Systems, .

19

Bryan, E. (1972). QUALITY OF STORMWATER DRAINAGE FROM URBAN LAND1. . Wiley Online Library.

Fleming, C. (2000). Coastal management (1st ed.). London: : Thomas Telford.

Harremoves, P., & Rauch, W. (1996). Integrated design and analysis of drainage systems, including sewers, treatment plant and receiving waters. Journal Of Hydraulic Research, 815--826.

Mays, L. W. (2001). Stormwater Collection Systems Design Handbook: V. 1.

Schmitt, T., Thomas, M., & Ettrich, N. (2004). Analysis and modeling of flooding in urban drainage systems. Journal Of Hydrology,, 300--311.

Schmitt, T., Thomas, M., & Ettrich, N. (2004). Analysis and modeling of flooding in urban drainage systems. Journal Of Hydrology, 300--311.

Walsh, C., Fletcher, T., & Ladson, A. (2005). Stream restoration in urban catchments through redesigning stormwater systems: looking to the catchment to save the stream. . Journal Of The North American Benthological Society, , 690--705.

20

Design of storm_water_sewage_system _sample

Education

Transcript of Design of storm_water_sewage_system _sample