lift irrigation scheme - uma maheshwar reddy...

EXTENSIVE SURVEY PROJECT

DEPARTMENT OF CIVIL ENGINEERING R.V.C.E, BANGALORE 1

1. INTRODUCTION

This extensive survey project is conducted to acquire a practical

knowledge and application of theory and over come the difficulties that

could arise in field during surveying. We also learn the use of different

survey instrument and to develop the team spirit at work. It also helps to

develop the confidence in handling of survey project. We conducted survey

for a new tank project, Highway project, water supply scheme and sewerage

project. This survey is conducted at S.S Ghati located at Honnenahalli

which is 56 Km away from Bangalore.

1.1 Objects of Extensive Survey Camp:

In order to acquire a sound knowledge of both theory and in practical

way and also the difficulties that could arise during surveying.

The object of this survey project is as follows:-

1. To impart training in the use of survey instruments and to acquire a

comprehensive idea of the project.

2. To train the students under difficult and realistic situation of the

surveying project.

3. To develop team spirit in practical work.

4. To impart confidence in the management of the survey project.



1.2 Technical aspects of a project:

The design and construction of any project such as dam, road

alignment requires a thorough investigation of the site as regards to its

stability and feasibility. The preliminary investigation starts from the

reconnaissance work, study of top sheets, proposal of alternate sites etc.

The second stage work of investigation includes the survey work at the

site in order to collect the data necessary for the design of project elements,

preparation of drawings, estimates etc. the office work is confined to the

designs, drawings and estimates of the project.

1.3 Historical background of the place:

The famous Sri.Ghati Subramanya temple is located at the limit of

Honnenahalli of Doddaballapura taluk, Bangalore district. It is 56 km. away

from Bangalore with good transportation facilities from all round the corners

of the state

The temple comes under the jurisdiction of Muzrai of Revenue

department. The temple is an ancient one, which is believed to be 80 years

old. The famous cart festival including cattle fair is also held every year.

2.0 STUDY OF TOPO SHEET

This sheet gives the topographical features of the locality like

alignment of a railway line, roadway, streams and its distributaries and

permanent structures located in that locality. This map helps in selecting the

site for a new tank and also gives clear picture of transportation to the

proposed area in proposed site for the transportation of men and material for

their construction. From this we can know the approximate catchment area

of site. This map has to be study before reconnaissance survey.



2.1 Calculation of yield at site.

The catchment area of proposed New Tank determined from the toposheet is

14 Km2.

The rainfall of a bad year is always taken as 2/3 of mean amount of rainfall.

Average annual rainfall for Doddaballapur area from Meteorological

department data is 80 cms.

Bad year rainfall is 2/3 of 80cm = 53cms.

Runoff coefficient is usually assumed as 15 % to 20%

Assuming as 20%

Annual Yield = 20 x 53cm = 10.6 cms

100

Yield from catchment (14X106) x 10.6 cum/year

100

= 1.48 X 106 cum/year.



3.0 INTRODUCTION FOR IRRIGATION

Irrigation may be defined as the process of artificially supplying water

to soil for rising crops. India is basically an agricultural country and its

economy depends to a great extent on the agricultural output. Water is

evidently the most vital element in the plant life. Water is normally supplied

to the plants by nature through rains.

However, the total rainfall in a particular area may be either

insufficient or ill timed. In order to get the maximum yield, it is essential to

supply the optimum quantity of water and to maintain correct timing of

watering. This is possible only through a systematic irrigation system that

is Collecting water during the periods of excess rainfall and releasing it to

the crop as and when required.

The need for irrigation can be summarized in the following four points:

Less rainfall:

When the total rainfall is less than that needed for the crop, artificial

supply of water is necessary. In such a case, irrigation system should be

developed at the place where more water is available and then, the means to

convey water to the area where there is deficiency.

Non-uniform rainfall:

The rainfall in a particular area may not be uniform throughout the

crop period. During the early periods of the crop rains may be there, but no

water may be available at the end, with the result, that either, the yield may

be less or the crop may wither. But the accumulated or stored water during

the excess rainfall period may be supplied to the crop during the period

when there may be no rainfall, but there is a need for watering.



Commercial crop with additional water:

The rainfall in a particular area may be just sufficient to raise the

usual crops, but more water may be necessary for raising commercial or

cash crops, in addition to increasing the annual output by adopting multiple

cropping patterns distributed throughout the year.

Controlled water supply:

By constructing a proper distribution system, the yield of crop may be

increased. Application of water to the soil by modern methods of irrigation

serves the following purpose:

It adds water to the soil to supply moisture essential for the plant

growth.

It washes out all diluted salts in the soil.

It reduces the hazard of soil piping.

3.1 BASIC PRINCIPLES OF IRRIGATION

Duty:

Duty represents the irrigating capacity of a unit of water. It is the

relation between the area of a crop irrigated and the quantity of irrigation

water required during the entire period of growth of that crop.

For example, if 3 cumecs of water supply is required for a crop sown

in an area of 5100 hectares, the duty of irrigation water will be 5100/3 =

1700 hectares/cumec, and the discharge of 3 cumecs will be required

throughout the base period.



Delta:

Delta is the total depth of water required by a crop during the entire

period from the day of sowing to harvesting.

For example, if a crop requires about 12 watering at an interval of 10

days and a water depth of 10 cm in every watering then the delta for that

crop will be 12x10 = 120 cm = 1.2 m. If the area under that crop is A

hectares, the total quantity will be 1.2 x A = 1.2A hectare-meters in a period

of 120 days.

Crop period:

Crop period is the time, in days, that a crop takes from the instant of

its sowing to its harvesting.

Base period:

Base period for a crop refers to the whole period of cultivation from

the time of first watering for sowing the crop, to the last watering before

harvesting.

The duty of water is reckoned in the following four ways:

By the number of hectares that 1 cumec of water can irrigate during

the base period, i.e., 1700 hectares per cumecs.

By total depth of water, i.e., 1.20 meters.

By number of hectares that can be irrigated by a million cubic meter

of stored water. This system is also used for tank irrigation.

By the number of hectare meters expended per hectare irrigated. This

is also used in tank irrigation.



Relation between duty (D), delta (D) and base period (B) in metric

system

Let there be a crop of base period b days. Let one cumec of water be

applied to this crop on the field for B days.

Now, the volume of water applied to this crop during B days (V)

V = (1x60x60x24)m3

= 86,400 (cubic meter)

By definition of duty (D), one cubic meter supplied for B days matures D

hectares of land.

Therefore this quantity of water (V) matures D hectares of land or 104 D

square meters of area.

Total depth of water applied on this land

= Volume/Area

= 86,400 B/104 D meters

= 8.64 B/D meters

By definition, this total depth of water is called delta (D).

Therefore

D = 8.64 B/D meters

Or

D = 864 B/D cm.

Where, D is in cm or m, B in days, and D is duty in hectares/cumec.



Cultivable commanded area:

The gross commanded area also contains unfertile barren land,

alkaline soil, local ponds, villages and other areas as habitation. These areas

are known as uncultivable areas. The remaining area on which crops can

be grown satisfactorily is known as cultivable commanded area. The

cultivable commanded area can be further classified as cultivable cultivated

area and cultivable uncultivated area.

Gross commended area:

An area is usually divided into a number of watersheds and drainage

valleys. The canal usually runs on the watershed and water can flow from

it, on both side, due to gravitational action only up-to drainage boundaries.

Thus in a particular area lying under the canal system, the irrigation can be

done only up-to the drainage boundaries, which can be commanded or

irrigated by a canal system.

Cultivable commanded area:

The gross commanded area also contains unfertile barren land,

alkaline soil, local ponds, villages and other areas as habitation. These areas

are known as uncultivable areas. The remaining area on which crops

growth, including water consumed by accompanying week growth.

Gross commanded area:

An area is usually divided into a number of watersheds and drainage

valleys. The canal usually runs on the watershed and water can flow from

it, on both sides, due to gravitational action only up-to drainage boundaries.

Thus in a particular area lying under the canal system, the irrigation can be

done only up-to the drainage boundaries. The gross commanded area is

thus the total area lying between drainage boundaries, which can be

commanded or irrigated by a canal system.



Consumptive use:

Consumptive use of water by a crop is the depth of water by a crop is

the depth of water consumed by evaporation & transpiration during the crop

growth, including water consumed by accompanying weed growth.

3.2 INVESTIGATION FOR A NEW TANK PROJECT

The design and construction of any dam whether earthen masonry or

concrete has to be preceded by a thorough investigation to select the most

suitable and economical site. The thoroughness of the investigation depends

upon the size of the project.

3.3 PRELIMINARY INVESTIGATION

Before taking up a detailed survey of project, it is essential to carry out

considerable reconnaissance work. The topo sheet study of the probable

project area gives possible sites in that area and the catchment area of the

site. This reconnaissance survey was carried out by us the day before we

started the actual survey. During this survey, we decided the site for the

construction of bund, weir & canal alignment. Using chain or tape rough

data regarding the level and the length of the dam are collected. The

preliminary investigation should include.

1. A rough levelling work to give the topography of the site.

2. A study of the rocky out crop and a few boring is done to note the nature

of the foundation.

3. Availability of construction materials such as Earth and good quarry etc.

4. Nature and extent of land, roads, bridges, etc. that would be submerged by

the construction of the dam.

5. Benefit the dam would give to the people.

6. Collection of hydrological data like rainfall, floods discharge etc.

7. Facility for discharging the floodwater.



Keeping the above points in view, a thorough study was done were the final

choice of the site was made.

3.4 FACTORS CONSIDERED FOR SELECTION OF SITE FOR EARTHEN

DAM.

The following topography and geological features affects the selection of site

for earthen dam.

1. The water storage should be largest for the minimum possible height and

length. The site should be located in a narrow valley.

2. Good impervious strata [foundation] should be available at moderate

depth.

3. Good and suitable basin should be available.

4. Material for construction should be available locally.

5. There should be suitable site available for waste weir.

6. Value of the property and land likely to be submerged by the proposed dam

should be sufficiently low in comparison with the benefit expected from the

project.

7. Dam should be accessible in all season.

8. Overall cost of construction and maintenance is to be taken into

After selection the site, final and precise investigation was carried out. In the

present survey work it was assumed that a choice of site was made and the

type of dam to be constructed is of earthen dam, with this assumption the

detailed survey were carried out which includes.

A. Longitudinal and cross section along the centre line of the bund.

B. Block levels at the waste weir site.

C. Water spread contours.



3.5 FLY LEVELLING

It is one type of method to determine the R.L of required point. This

levelling work is carried from the nearby permanent B.M for example from a

railway station or other permanent structure. In this project we established

T.B.M near the bund.

The field work is carried as follows:

1. Set the levels near the P.B.M and carry out temporary adjustment.

2. Keep staff on permanent B.M and take readings and enter it as back sight

in the field book.

3. Take intermediate points towards the direction of required point is reached.

4. If the staff is invisible shift the level and note down the last reading as fore

sight, after shifting the level and temporary adjustment take readings of that

point and note down it as back sight.

5. Continue this procedure until the required point is reached.

6. The R.L of the point is determine by using these formula

1. P.C= P.B.M +B.S

2. R.L = P.C-I.S or P.C-F.S



3.6 LONGITUDINAL SECTIONS & CROSS SECTIONS ALONG THE

PROPOSED CENTRE LINE OF THE TANK BUND:

Object: -

To obtain the Profile of the valley along the assumed center line of the

dam.

To estimate the quantity of earthwork for the proposed construction of

the bund the following points should be considered:-

TOP WIDTH

Top width of earth dam should be sufficient to keep the seepage line

well within the body of dam. It should withstand earthquake and wave

action. For small dams, top width is generally governed by minimum road

way requirements.

Top width of earth dam can be selected as per the following

recommendations.

1. T = 0.2 x Z+3 for very low dams (<15 m)

2. T = 0.55 x (Sqrt Z) + 0.2 x Z for height less than 30m

3. T = 1.65 x (Sqrt (Z + 1.5) for height greater than 30m.

where Z is the max height of dam in metres.

T = 0.55 x (Sqrt Z) + 0.2 x Z

= 0.55 x (Sqrt 21.80) + 0.2 x 21.80

= 6.973m say 7.0 m



FREE BOARD:-

Free board of an earth dam is the height provided above MWL/FRL

upto TBL in order to prevent over topping of water due to wave action.

“Minimum free board” is defined as vertical distance between max reservoir

level and top of dam. The vertical distance between full reservoir level and

top of dam is called “Normal free board”.

The Minimum height of free board for wave action is 1.5hw where hw =

max.ht. of wave.

The wave height (hw ) in meters can be calculated according to

1. Molitor’ s formulae (British Practice)

hw metres = 0.032 x Sqrt (V x F) + 0.763 – 0.271 x sqrt (Sqrt (F))

where F is fetch in kms and F<32 Kms

Fetch is defined as the longest unobstructed distance for wind to blow from

one edge of reservoir up to the dam on u/s side of the dam. (Fetch can be

measured from capacity contour sheet) V is wind velocity in kms/hr.

(The max wind velocity in any area is 60 kmph according to meteorological

data)

1. Molitor’s formula

hw = 0.032 x sqrt (v x F)+0.763-0.271 x sqrt (sqrt(F))

where F = fetch in kms and F<32kms

F = 0.32km

v = 40kmph

hw = 0.673m

( hw )max = 1.5 x 0.673

= 1.01 m so provide FB=1M



Earth dams are classified into following.

1. Homogenous earth dam: A purely homogeneous earth dam is composed

of single kind of material {Exclusive of the slope protection}.Shown below

is a typical cross-section of a purely homogeneous type earth dam.

2. Zoned embankment type earth dam: It is the one in which the dam is

made up of more than one material. The most common type of a rolled

earth dam section is that in which a central impervious core is flanked by

zones of material considerably more pervious. Shown below is a typical

cross-section of a Zoned Embankment type earth dam.

h

h/3

CORE

(IMPERVIOUS)

RIP RAP

TRANSITION

FILTER

ROCK TOE



3. Diaphragm Embankment type: This is a modification over the

homogeneous embankment type, in which the bulk of the embankment is

constructed of pervious material and a thin diaphragm of impermeable

materials is provided to check the seepage. The diaphragm may be of

impervious soils, cement concrete, bituminous concrete, or any other

material, and may be placed either at the centre of the section as a

central vertical core, or at the upstream face as a blanket. Shown below

is a typical cross-section of a Diaphragm Embankment type earth dam.

IMPERVIOUS

DIAPHRAGM

PERVIOUS FOUNDATION



RECOMMENDED SLOPES FOR SMALL HOMOGENEOUS EARTHFILL DAMS

ON STABLE FOUNDATION:

Cas

e

Type Purpose Soil

Classificati

on

Upstream

Slope

Downstream

slope

1) Homogene

ous or

Modified

Homogene

ous

Detention

or Storage

GW GP SW

SP

GC GM SC

SM

CL ML

CH MH

Previous

2.5:1

3:1

3.5:1

Not suitable

2:1

2.5:1

2.5:1

2) Modified

Homogene

ous

Storage GW GP SW

SP

GC GM SC

SM

CL ML

CH MH

Previous

3:1

3.5:1

4:1

Not suitable

2:1

2.5:1

2.5:1



RECOMMENDED SLOPES FOR SMALL ZONED EARTHFILL DAMS ON

STABLE FOUNDTION:

Cas

e

Type Purpos

e

Shell Material

Classification

Core Materials

Classification

U/s

slope

D/s

slope

A Zoned

with

“Minim

um”

Any Not critical,

rock-fill;

GW,GP,SW,SP

Not critical GC,

GM, SC, SM, CL,

ML, CH, MH

2:1 2:1

B Zoned

with

“Maxim

um”

Core 1

Detenti

on OR

Storage

Not critical,

rock-fill:

GW,GP,SW,SP

GC,GM,

SC,SM, CL,ML,

CH,MH

2:1

2.25:1

2.5:1

3:1

2:1

2.25:1

2.5:1

1:1

C Zoned

with

“Maxim

um”

Core1

Storage Not critical,

rock-fill,

GW,GP,

SW,SP

GC,GM

SC,SM

CL,ML

CH,MH

2.5:1

2.5:1

3.0:1

3.5:1

2:1

2.25:1

2.5:1

3.0:1

Note; 1. Minimum and maximum size cores shown in Fig:

2. CL and IH soils are not recommended for major portions of the

cores of earth fill dams Pt soils are unsuitable.

Though any one of the tables can be used for preliminary selection of

the bund section the current practice has been in favour of Strange’s table.



Core (Hearting): Core or Hearting is clay type of material provided mainly to

prevent seepage through the body of the dam. The different types of clay silt

for suitability of construction or core is provided in Table No.1 under the

heading “Rolled Earth Dams.”

Rip Rap or u/s Revetment is coarse material placed on the embankment

to prevent erosion of soil is termed “Rip Rap”

Rip Rap is of two types

1. Dumped

2. Placed (also called “Pitching”)

The minimum weight of each rock for rip rap is calculated by using

Iribarren – Hudson formula.

33

33'

)1()(

SSinCos

hSKW

W= Minimum weight of Rock to be placed on rip rap in kN.

K’= A coefficient taken = 0.02

= Specific weight of water =9.81 kN/m3

S= Specific gravity of rip rap material ( 2.45 to 2.2)

= Coefficient of friction of rip rap material (1 to 1.1)

h= effective wave height in meters, calculated using Sverdup –Munk formula

h= 0.0045 x F 0.423 x U1.154

F= fetch in kilometer, U =wind velocity in kilometer per hour

β= Angle of u/s slope made with horizontal.

RIP rap is placed in layers. The innermost is the “cushion“acts as filter to

prevent washing of the soil in the shell zone. It also prevents sinking of the

coarse rock into the softened surface of the shell.



The following table gives the dimension of riprap as a function of wave

height.

Max. Wave

height

Minimum rip

rap Thickness

Min thickness of cushion

Fine Thickness

0 to 1.5 300mm 150mm 150mm

1.5 to 3.0 150mm 150mm 150mm

> 3.0m 600mm 150mm 150mm

Cut off wall

When river bed is having thick stratum of sand, an impermeable

structure is constructed within the stratum to reduce seepage through the

foundation.

There are two types of cut off wall:

1) If the bottom of the cut off wall permeates into the impermeable layer then cut off is called positive cut off wall. This type has the advantage of

reducing seepage loss, but the disadvantage of increasing neutral stress due to water thus decreasing the factor of safety of slope – stability on u/s side.

2) If the bottom of cut off wall does not permeate into loose stratum completely, cut off is called “ Partial cut off wall”

The Minimum bottom width of cut off wall is 4m, side of at least 1:1 or

flatter slope may be provided in case of overburden. ½:1 or ¼:1 may be

provided in soft rock and hard rock respectively. It also prevents seepage,

erosion, and mass, instability, boiling and piping.

Internal drainage system:

The drainage system consists of two components.

a) Protective filter which is in contact with core. b) The conduits, which collect & dispose off seepage water.



Minimum thickness of protective filter is provided as follows

Rock toe/ toe drain

The toe drain is placed at D/s side toe of each dam. In small dams

only drains are provided. In large dams embankment will be saturated

below the phreatic line. And tow drain acts as a disposal zone of the

drainage water. Its height varies from 5% of dam height (above tail water

level), with external drainage system, to as much on 20% in small dams

with no internal drains. The Rock toe designed like protective filter except

for the gravel zone. The top width of rock toe will have the dimension same

as of berm.

Filter Material Thickness for given head (M)

0 to 22m 22 to 46m 46 to 92m

Fine sand 150mm 300mm 450 mm

Coarse sand 200 mm 450 mm 650 mm

Gravel 300mm 600 mm 750mm



3.7 WATER SPREAD CONTOUR:

This survey is necessary to draw the capacity contours by the help of

witch the storage levels of the tank are fixed. This can be carried out by the

following methods.

1. One set of levels is taken along the course of the river on the up stream

and another set at right angle to it at the widest region and counters are

interpolated.

2. The F T L counter is traced directly and cross section at suitable intervals

are taken across this until F T L on the other side is reached. The lowest

point of main valley is met and the contours’ are interpolated

3. The entire water spread is covered by block leveling and any number of

contours is interpolated.

Of the above three methods the third method is most accurate but it is

tedious. Any of the above methods may be adopted depending upon the

degree of the accuracy required and the size of the project.

Calculation of the storage capacity of reservoir:

Areas of successive contours are measured using planimeter or by

constructing squares.

If A1, A2, A3 … An, are the areas of successive contours, H being the

contour interval, then by Prismoidal rule. The storage capacity can be

calculated.

Using Prismoidal rule

V= .......)(2......)(4)(3

7536421 AAAAAAAnAH

cubic meter.

A = in sqm.



CAPACITY OF RESERVOIR BETWEEN RL'S-793.000 & RL'S-808 (F.T.L)

V=H/3((A1+An)+4(A2+A4+A6+...)+2(A3+A5+A7+...))

H/3 0.333333333

(A1+An) 17.02498046

4(A2+A4+A6+...) 173.222217

2(A3+A5+A7+...) 67.210416

858192.04 cum

85.82 ha-m

3.8 BLOCK LEVELS AT THE WASTE WEIR SITE.

WASTE-WEIR: Similarly, as in case of all dam reservoir projects, tanks are

provided with arrangements for spilling away the excess water that may enter

in to the tank, to avoid over–topping of the tank bund. These escape

arrangements may be in the form of a surplus escape weir or waste weir,

provided in the body or at one end of the tank bund. The weir is a masonry

weir with its top level equal to the Full tank level (F.T.P). When the tank is full

up to its FTL and extra water comes in and discharges over the waste weir.

The capacity of the weir is so designed that the water level in the tanks does

not exceed the maximum water level (M.W.L). The top of the bund will be kept

at a level so as to provide suitable freeboard this M.W.L.

A detailed survey at the waste weir site is necessary to design the body wall of

waste weir, the approach and draft channel and other protective works and to

arrive at the cost of their work. In choosing the site for waste weir the

following points must be borne in mind:-

1. A saddle disconnected from the tank bund is the best site for a surplus

work.

2. The natural ground surface at the weir site should be approximately at

F.T.L.



3. The height of body wall must be minimum possible and should be located

as far as possible in cutting.

4. The soil should be hard both at the weir site and along the draft channel.

5. There should be natural diversion to lead the water safely from the bund.

6. Cost of protective work should be minimum.

Design of Surplus Weir or Waste Weir:

Ryve’s formula: Qmax = CM2/3

C: Ryve’s Coefficient = 10.1

M: Catchment area = 14KM2

Discharge Qmax = 58.67 m3/Sec

Assuming it as broad crested weir.

Discharge Q = 1.022 LH3/2

H : Head over the weir = (MWL - FRL) = 1 m

L : Length of weir L= (58.67/1.022) = 57.40m say 60m

3.9 CHANNEL ALIGNMENT



A canal is provided on the downstream side of the bund, taking off

from the sluice points at a gentle bed slope. This is the paths along which

water stored in the tank is supplied to the command area for the purpose of

irrigation.Based on the alignment, canals are classified as:

a) Ridge or watershed canal

b) Side slope canal

c) Contour canal

In contour canals, gravity flow of water is made use of to irrigate the area on

the lower side, down to the valley whereas in ridge canals irrigation is

possible on either sides of the canal.

A contour canal has been provided for the proposed bund. Its alignment is

similar to the figure shown below.



Channel alignment is meant to estimate the cost of the channel and cross

drainage works, and also to determine the gross command area.

The following points were kept in view while aligning the channel.

1) The channel should as far as possible be aligned in a straight line.

2) A channel in embankment is less desirable when compared to a channel

in cutting.

3) A channel should be aligned as a ridge channel wherever possible but

the main channels are usually aligned as contour channels.

4) There should be as few cross drainage work as possible. If cross

drainage is necessary then channel should cross the valley or the river

at a point where the width is least and the foundation soil is good for the

cross drainage works.

5) If there is only one channel, the channel should preferably be aligned on

the flank opposite to the one where the waste weir is located.

Calculation of Ground level for starting channel alignment

Sluice level : 807.000 m

Full supply depth of water : 0.430 m ( According to Channel design)

Free board : 0.320 m (Assumed)

Ground level : 807.750 m @ 0 chainage.

Calculation of actual gross command area:

The area enclosed between center line of bund, the mother valley and the

final alignment is defined as gross command area. This area can be

calculated by using Planimeter or by constructing squares.



Design of Channel Section:

Determination of Irrigable area:

The yield of catchment has been found to be 1.48 X 106 cum

Assuming 10% for evaporation loss and 15 % of conveyance loss i.e., 25% as

total loss in reservoir storage capacity.

Volume of water available for irrigation is = 0.75 X 1.48 X 106 cum

= 1.11 X 106 cum

Assuming average duty of 286 Hectares million cum for mixed crop pattern.

Area that can be irrigated: 1.11 x 106 x 286 hectares

106

= 317.46 Hectares.

Actual canal network provided for an area of 83.09hectares.

Longitudinal slope of channel S= 2392/1

3340 6/1

3/5

Q

f

Hence assumed slope of (1/2000) is correct.

3.10 PARTICULARS AND SALIENT FEATURES OF THE NTP

1. Place of the project Sri Subramanya Ghati

Doddaballpur Taluk,

Bangalore district.

2. Distance from Bangalore 52 Km.

3. Nature of Project New tank Project

4. Type of Bund Earthen Bund.



4.

Earth work required for channel alignment :

Area of channel section = 0.7875 m2.

Length of channel = 330 m.

5. Bund

Length of Bund

Deepest Streambed

T.B.L.

M.W.L.

F.T.L.

Max height of Bund

320 m

792.800m

812.00 m.

811.00 m.

810.000 m.

19.20 m.

6. Length of Weir 60m

7. Capacity contour

85.82 hactare-m.

8. Canal

Length of the Canal

Bed Width

F.S.D.

Free Board

330.00 m

0.300 m.

0.430 m.

0.320 m.



HIGHWAY PROJECT

4.1 HIGHWAY ALIGNMENT:

The positioning or the laying out of the center line of the highway on

the ground is called the alignment. The horizontal alignment includes the

straight path, the horizontal deviations and curves. Changes in gradient

and vertical curves are covered under vertical alignment of roads.

A new road should be aligned very carefully, as improper alignment

would result in one or more of the following disadvantages:

Increase in construction cost

Increase in maintenance cost

Increase in vehicle operation cost

Increase in rate of accidents

Once the road is aligned and constructed, it is not easy to change the

alignment due to increase in cost of adjoining land and construction of

costly structures by the road side.

Hence the importance of careful considerations while finalizing the

alignment of a new road should be overemphasized.

Requirements:

The basic requirements of an ideal alignment between two terminal

stations are that is should be:

Short

Easy

Safe

Economical



4.2 Need for Highway Planning:

In the present era, planning is considered as a pre-requisite before

attempting any development program. This is particularly true for any

engineering work, as planning is the basic need for highway development.

Particularly planning is of great importance when funds available are

limited in contrast to the amount required which would be very high. This is

actually the most important problem that has to be addressed by the

developing countries like India as funds have to be utilized in the best

possible and economic way.

4.3 The objects of highway planning are as follows:

To plan a road network for efficient and safe traffic operation, but at a

minimum cost.

The cost of the construction, maintenance and renewal of pavement

layers and the vehicle operation costs must be given due considerations.

To arrive at a road system and lengths of different categories of roads,

which could provide maximum utility and can be constructed within the

available resources during the plan period under consideration.

To fix up date wise priorities for development of each road link based on

utility as the main criterion for phasing the road development program.

To plan future requirements and improvements of road in view of

anticipated developments.

To work out financing system.

4.4 Factors controlling alignment:

For an alignment to be shortest, it should be straight between the

terminal stations. This is always not possible due to various practical

difficulties such as intermediate obstructions and topography.

A shortest route may have very steep gradients and hence not easy for

vehicle operation. Similarly, there may be construction and maintenance



problems along a route, which may otherwise be short and easy. Roads are

often deviated from the shortest route in order to cater for intermediate

places of importance of obligatory points.

A road which is economical in the initial construction cost need not

necessarily be the most economical in maintenance or in vehicle operation

cost. It may also happen that shortest and easiest route for vehicle

operation may work out to be costliest of the different alternatives from

construction view point. Thus it may be seen that an alignment can seldom

fulfill all the requirements simultaneously hence, a judicial choice is made

considering all the factors

The various factors controlling the alignment of the highway are:

Obligatory points

Traffic

Geometric design

Economics

Other constructions

In hilly areas, additional care has to be given for setting up the

alignment and the factors governing are as follows:

Stability

Drainage

Geometric standards of hill roads

Resisting length

STEPS INVOLVED IN A NEW PROJECT REPORT

Map Study

Reconnaissance Survey

Preliminary Survey

Location of Final Alignment

Detailed Survey



Materials Survey

Design

Earth Work

Pavement Construction

The following points may be kept in mind while aligning any type of

road:

1. Cutting and embankment must be balanced.

2. Curves of larger radius should be used in no case; the radius of curves

should be less than 16m.

3. A flat gradient as far as possible should be used, only when unavoidable

conditions, the ruling gradient has to be given.

4. Super elevation has to be given for all the curves.

5. Transition curves should be provided between curve and a straight

alignment.

6. Vertical curve should be provided whenever the gradient changes.

7. The alignment should be the most economical with economical with

minimum drainage crossing, so it should follow the ridge

GRADIENTS FOR ROADS IN DIFFERENT TERRAINS

Terrain Ruling

Gradient Limiting Gradient

Exceptional gradient

Plain or Rolling 1/30 1/20 1/15

Mountainous & steep terrain with

elevation more than 3000m above MSL

1/20 1/16.7 1/14.3

Step terrain upto 3000m Height above MSL

1/16.7 1/14.3 1/12.5



WIDTH OF ROADWAY FOR VARIOUS CLASSES OF ROADS

SL

No Road classification

Roadways width in meters

Plain & Rolling Terrain

Mountainous & Steep terrain

1 National & State Highway a) Single lane

b) Two lane

12.00

12.00

6.25

8.60

2 Major District Roads

a) Single lane b) Two lanes

9.00 9.00

4.75 --

3 Other District Roads a) Single lane b) Two lanes

c) Village Roads

7.50 9.00

7.50

4.75

--

4.00

DESIGN SPEEDS

Road

Cla

ssific

at

ion

Plain Rolling Mountain Steep

Ru

lin

g

Min

imu

m

Ru

lin

g

Min

imu

m

Ru

lin

g

Min

imu

m

Ru

lin

g

Min

imu

m

NH&SH 100 80 80 65 50 40 40 30

MDR 80 65 65 50 40 30 30 20

ODR 65 50 50 40 30 25 25 20

VR 50 40 40 35 25 20 25 20

MINIMUM RADII OF ROADS

Cla

ssific

ati

on

of

Road Plain Rolling

Mountain Steep

Area Not affected by

snow

Snow bound

area

Area Not affected by

snow

Snow bound

area

Ru

lin

g

Absolu

t

e

Ru

lin

g

Absolu

t

e

Ru

lin

g

Absolu

t

e

Ru

lin

g

Absolu

t

e

Ru

lin

g

Absolu

t

e

Ru

lin

g

Absolu

t

e

NH&SH 360

230

230

155

80 50 90 60 50 30 60 33

MDR 230

155

155

90 50 30 60 33 30 14 33 15

ODR 15

5

90 90 60 30 20 33 23 20 14 23 15

VR 90 60 60 45 20 14 23 15 20 14 23 15



DESIGN OF HORIZONTAL CURVE

While undertaking the initial alignment of the new highway project , it was

required that in the final alignment , we provide a smooth curve between 150

m chainage and 210 m chainage and another curve between 480m chainage

and 540m chainage. we have designed the curve as follows.

e+f= v^2/127 R;

where

e is the maximum super elevation that can be provided which is taken as

0.07,

f is the maximum value of lateral friction which is equal to 0.15,

v is the design speed taken as 40 kmph for other district roads,

R is the radius of curve to be provided.

Curve 1: (360 m to 420 m)

0.22= 40*40/(127*R)

R req= 57.27 m

R Provided = 200m.

L= 104.55 m

O0= 7.27 m O10 = 6.818m O20 = 6.23 m

O30=4.72 m o40=3.180m o50 = 0m



HIGHWAY PROJECT

EARTH WORK CALCULATIONS

Chainage

in m

Filling area in

sqm

Cutting

area in sqm

remarks

0 0.180 0.00 A1

60 0.00 7.87 A2

120 1.32 0.00 A3

180 0.00 1.10 A4

240 0.320 1.89 A5

300 0.00 6.00 A6

360 0.00 5.59 A7

420 3.810 0.00 A8

480 0.00 5.4 A9

540 5.200 0.00 A10

600 3.600 0.00 A11

VOLUME OF EARTH WORK IN FILLING IN 'cum'

V=H/3((A1+An)+4(A2+A4+A6+...)+2(A3+A5+A7+...))

H/3 20

(A1+An) 0.00

4(A2+A4+A6+...) 36.04

2(A3+A5+A7+...) 3.28

872cum



VOLUME OF EARTH WORK IN CUTTING IN 'cum'

V=H/3((A1+An)+4(A2+A4+A6+...)+2(A3+A5+A7+...))

H/3 20

(A1+An) 0.000

4(A2+A4+A6+...) 59.88

2(A3+A5+A7+...) 25.76

1718.2 cum

Balance earth required 846.2 cum

5.0 INTEGRATED ENVIRONMENTAL ENGINEERING PROJECT FOR S.S.

GHATI.

1. Water Supply project:

a) New source project

(b) Augmentation scheme.

c) Water treatment system

d) Pumping system

e) Distribution system.

2. Sewerage project:

a) Sewerage system

b) Sewage Treatment facility.

5.1 WATER SUPPLY PROJECT FOR S.S.GHATI.

DATA:

a) Geological

b) Hydrological

c) Sanitary conditions



d) Topography showing elevations of various points, density of population in

various zones. This map helps in positioning intake works, treatment

plant and type of system to be adopted for conveyance and distribution

of water.

e) Legal data of lands

f) Public opinion.

FACTORS:

Population P 2001, as per census = 4115;

P 2020, assuming an annual increase of 1.9% = 6000.

Per capita requirement: 175 lpcd is to be provided as per Indian standards.

Q required=(6000 x 175)/(1000*24*60*60) = 0.0122 cumecs

Assuming a peak factor of 3

Max. flow = 0.0122*3=0.0365 cumecs =3153.6 m3/day

Proposing slow sand filter & chlorination for the treatment of water.

Slow sand filters are designed for 100-200 lit/hr/m2

Assuming 150 lit/hr/m2

Water surface area of filter = rateFiltration

Q max

= 2876150

6.3153m

Propose 4 units of filter each of area 219 m2.

Assuming L/B ratio of 2.0

The dimensions of each filter:

L x B = 219

2B x B = 219

B = 10.46 m, say

B = 11.0 m, L = 22 m



Providing filter sand depth of 1 m, gravel depth varying from 30-75 cm say

50 cm, 50 cm free board and water depth of 1 m.

Therefore Total depth = 1+1+0.5+0.5 = 3.0 m

Design of pump capacity

c

WQHBHP

75 where W= 1000 kg/m3(unit weight of water)

Q = discharge m3/sec H = Head in m

c = combined efficiency of pump and motor =

pxm = 80%

Friction loss (hf) = flv2

2gd

= flQ2

12.1 d5

= ( 0.01 x 884 x 9460.82)

(12.1 x .2255)

hf = 15.19 m

‘Q’ for 8 hours pumping will be maximum flow rate x 3.

Providing a pipe of 22.5 cm & adding 10% minor loss due to valves.

‘H’ = Suction head (3m) + Delivery head (13.12 m) + Friction loss (hf) = 4.316

m + 3.0 m

= 23.436 m

BHP = (1000 x 5043 x 23.436)

(75 x .8)

BHP = 7.6 KW



6.0 ABBREVIATIONS:

P.B.M : Permanent Bench Mark

T.B.M : Temporary Bench Mark

R.L : Reduced Level

P.C : Plane of Collimation

B.S : Back sight

I.S : Intermediate Sight

F.S : Fore sight

T.B.L : Tank bund level

M.W.L : Maximum water level

F.T.L : Full Tank Level

F.S.L : Full Supply Level

lift irrigation scheme - uma maheshwar reddy...

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