IS 5497: Guide for topographical surveys for river valley projects

2008·6.1 MB·English

by  Bureau of Indian Standards

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IS 5497 (2008): Guide for topographical surveys for river
valley projects [WRD 5: Gelogical Investigation and
Subsurface Exploration]
“!ान $ एक न’ भारत का +नम-ण”
Satyanarayan Gangaram Pitroda
““IInnvveenntt aa NNeeww IInnddiiaa UUssiinngg KKnnoowwlleeddggee””
“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता हहहहै””ै”
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“Knowledge is such a treasure which cannot be stolen”

IS5497 :2008

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Indian Standard
GUIDE TO TOPOGRAPHICAL SURVEYS FOR
RIVER VALLEY PROJECTS
( Second Revision)
res07.060
OBIS 2008
BUREAU OF IND IAN STANDARDS
MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
NEWDELHI 110002
November 2008 PriceGroup4
Geological Investigationsand SubsurfaceExplorationSectionalCommittee, WRD05
FOREWORD
This Indian Standard (Second Revision) was adopted by the Bureau ofIndian Standards, after the draft
finalized by the Geological Investigations and Subsurface Exploration Sectional Committee, had been
approved bythe WaterResources DivisionCouncil.
Thisstandardwas first published in 1969andrevised in 1983. Inthe first revision, specificationsregarding
scaleofmapsfordifferentsurveys had been modified to reflect current practice. Provisions regardingriver
survey, flood survey and command area development survey had been added. In this revision contour
intervals for different types ofsurveys have been incorporated and modified where needed. Subjective
detailsaboutthe individual surveyingmethods havebeen deletedasthey are readilyavailableinallstandard
text-books on surveying, Geodesy, Photogrammetry and Cartography or departmental handbooks ofthe
SurveyofIndia.
Topographical survey forms a very important and vital activity for river valley projects. Any river valley
project to beplanned and constructed is to be based on certain basic facts and figures. The process of
collection ofthese facts and figures istermed as investigation ingeneral.The first requisiteofinvestigation
is to carry out topographical survey and prepare maps which are graphical representation of land.
Topographical survey enables presentation ofa picture ofthe terrain in the form ofmaps, which provide
important and accurate data about topography and other characteristics of the area. These accurate data
assistinformulation ofcorrectplans fordevelopmentofriver valley projectsforharnessingand utilizingthe
country'swaterresources. Thecost ofsurveyingandmapping isonly aminorfraction ofthetotal cost ofthe
projectandwhenundertakenatinitialstagewillsavealotofinfructuous expenditurearisingoutofincomplete
or faulty data.
Ithasbeenassumed intheformulationofthisIndian Standardthattheexecutionofitsprovisionsisentrusted
toappropriatelyqualifiedand experiencedpeople, for whose guidance ithas been formulated.
Forthepurposeofdecidingwhetheraparticularrequirementofthisstandardiscompliedwith,thefinalvalue,
observed or calculated, expressing the result ofa test, shall be rounded offin accordance with IS2 : 1960
'Rulesforroundingoffnumerical values (revised)'. Thenumberofsignificantplacesretainedintherounded
otTvalue should bethe same as that ofthe specified value inthis standard.
IS5497:1008
Indian Standard
GUIDE TO TOPOGRAPHICAL SURVEYS FOR
RIVER VALLEY PROJECTS
( Second Revision)
I SCOPE distance. These are further divided intotwogroups,
namely M.D.M. (Microwave distance measuring
Thisstandard lays down the general principles and
instruments)andE.O.D.M.(Electro-opticaldistance
guidelines fortopographicalsurveys connected with
measuring instruments). M.D.M. instruments use
arivervalleyproject.
microwaves ascarrierwhile E.O.D.M. instruments
uselightor infra-red rays.
2 REFERENCES
Thestandards listedbelowcontain provisions which 3.5 Height- Theheightofapointabovemeansea
through reference in this text constitute provisions level isthe length ofthe vertical between the mean
of this standard. At the time of publication, the sea-level surface and the point.
editions indicated were valid. All standards are
3.6 Latitude- The latitudeofaplace istheangle
subject to revision and parties to agreements based
between the direction ofa plumb line at the place
on these standards are encouraged to investigate
and the plane ofthe equator. It is marked N or S
the possibility ofapplying the most recent editions
according to the place being north or south ofthe
ofthestandards indicated below:
equator.
ISNo. Title NOTE - If earth is assumed a perfect sphere of
homogenous density the plumb line shall pass through
5510:1969 Guide for soil survey for river
the centre of sphere.
valley projects
3.7 Longitude - The longitude ofa place is the
15686:2006 Recommendations for angle betweenafixed reference meridian called the
preparation of geological and
primeorfirstmeridianandthemeridianoftheplace.
geotechnicalmapsforrivervalley
Longitude ismeasured from00 to 1800 eastward or
projects westwardandismarked°EoroW.
3 TERMINOLOGY 3.8 MeanSea-Level-Meansea-levelistheaverage
elevationofthe seawater level which isdetermined
For the purpose of this standard the following
by continuous observation ofthe varying level of
definitions shall apply.
thesea foras longatimeas possible.
3.1 AbsoluteOrientation- Theprocess bywhich
3.9 Pbotogrammetry -The science and art of
an adjoining pair of relatively oriented aerial
obtaining reliable measurements by means of
photographs are broughtto correct horizontal scale
photography.
andvertical datum.
3.10 Photographic Interpretation - The art of
3.2 Azimuth- The azimuth ofa body istheangle
examining photographic images for the purpose of
betweentheobserver'smeridian andthegreat circle
identifying objectsandjudgingtheir significance.
(vertical circle) through the body and the zenith of
the observer.
3.11 RelativeOrientation- Theprocessbywhich
two successive aerial photographs having common
NOTE - The meridian of an observer is the great
circle passing through the poles. the zenith and the overlap isbroughttomutualgeometricalrelationship
nadir. betweenthemselves,whichexistedatthetimeoftheir
exposure.
3.3 Diapositive- Apositive printofaphotograph
prepared onfilmorglass transparency. 3.12 Stereopair- Twophotographswithsufficient
overlap andconsequentduplicationofdetailtomake
3.4 ElectromagneticDistanceMeasuring(E.D.M.)
possible stereoscopicexaminationofanobjectoran
Instruments- These arethe instruments basedon
areacommonto both.
electro-magnetic waves for precise measurement of
IS5497:2008
b) Maximumandminimum historical/observed
4 CLASSIFICATION
water level; and
4.1 TypesofSurvey
c) Rapids and rock outcrops, etc.
Topographical surveys required for river valley
projects may be broadly classified under seve.n 4.1.4 The longitudinal section shalI be plottedtoa
important types, namely, river survey, reservoir scaleofI:10000horizontaland I:100vertical.Cross
survey, site survey, command area survey, sections shall be plotted to a scale of I: 2 000
communication survey, flood controland command horizontaland I: 100vertical.
areadevelopmentsurvey.Thesesurveysarerequired
4.2 ReservoirSurvey
indifferent stages ofinvestigation ofa river valley
project. Methods of topographical survey .vary Areservoirsurvey is necessary to providethe basic
depending onthedegree ofaccuracyto beattained, data for calculation ofwater storage capacity of a
extent ofthe project and topography ofthe project reservoir, for indicating the limit of submergence
area(seeIS15686andIS55I0). areas and for locating the topographic depressions
or saddles in the reservoir rim which may cause
4.1.1 RiverSurveys
spiIling or leakage ofthe reservoir. The scale and
Riversurveyscover longitudinalsection (L-Section) contour interval for topographical survey for
andcross-section(X-Section)ofthe river upstream reservoir survey depend on the extent ofthe area
anddownstream ofthe proposed structure. andthe topographyofthe site. Thereservoirsurvey
is made with a view to examining all possible
4.1.2 The L-Section on the upstream side shall
alternativesfor itslocationsandtoeliminatesuchof
extend fromthe axis ofthe structureto the pointup
the proposals which become unsuitable from
towhichtheback watereffect islikely toextend or
considerationsoftechnicalfeasibility,economyand
up to the maximum water level (MWL) + 5 m
practicability. The reservoir survey enables
whichever is more. If any headworks is situated
preparation of a fairly dependable project report
withinthereach, the L-Section shall be taken upto
supported by cost estimates and economic studies.
the headworks. On the downstream side, the
Reservoir survey maps shall be made on scales
L-Sectionshallextend for 10krnfromtheaxisofthe
rangingfrom1:2000to 1:10000withcontour interval
structure or uptothe nearestheadworks, whichever
of I or 2 or 5 m corresponding to natural ground
isless.The levellingofthe L-Section shall be done
slopes less than 10°, 10°_30° and more than 30°
at50mor less intervalsalong the fair weatherdeep
respectively.
channel. ThefolIowing itemsshalIalso beindicated
intheL-Section: 4.3 SiteSurvey
a) Date ofsurvey ofthe particularreach and A site survey is carried out to investigate the
average water level on that day; suitabilityofasite for aparticularstructure,suchas
dam site, power house or tunnel site. A dam site
b) Deep pools and rapids, rock outcrops, etc;
survey should cover a sufficiently large area to
and
include allpossiblelocationsofthemaindam,coffer
c) Maximumhistoricalobservedhighest flood dams,spillways,separateoutletstructures,andother
level(H.F.L.). appurtenances. The scale ofdam site survey maps
may range from I : 500 to I : 1 000, with contour
4.1.3 The X-Section on the upstreamside shall be interval ofImto2m. Powerhousesitesurvey should
takenat200mintervals uptoMWL+5mor Ikmon include an area for possible construction of plant
either side ofthe firm bank, whicheveris less, fora sites, stockpile areas, warehouse, switchyard areas
distance of2 km from the axis of structure and and camp sites. The scale ofmaps may normally be
thereafter at 1 km intervals corresponding to the from 1 :250 to I : 1000. Tunnel site survey maps
length ofthe L-Section. On the downstream side, should be made along possible tunnel alignments
X-SectionshalIbeat200 mintervalsandtaken upto
onscale I: I000to 1:10000,with contourinterval
historical highestflood level +5mon eitherside of of2mto5mandcontourplanofareashall coverthe
firmbankforadistanceof2krnto5kmfromtheaxis
length ofthe tunnel and minimum 300 m on either
ofthe structure depending upon the meandering
side ofthecentreofthe tunnel. The levellingshould
nature ofthe river. AX-Section shalI also be taken
bedone atregularintervalsintoaregularmeshof50
alongtheaxisofthestructure.The levellingshalIbe moreven closerdependingupon the terrain andthe
doneat50 mor less intervals. The following items contour interval should be I or 2 or 5 m
shallalsobeindicatedinthe X-Section:
corresponding to natural ground slopes less than
10°,10°_30°andmorethan30° respectively.
a) Date ofsurvey and the water level on that
day;
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4.4 CommandArea Survey survey ofthe area can be based upon. Theaccuracy
of a detail survey depends on the accuracy of its
The command area isthe area,which is likely to be
network of ground control points and hence the
benefited fromtheriver valleyproject.Thecommand
desiredaccuracyofcontrolsurveyhastobedecided
area survey is very important in order to know
in advance keeping in view the scale, purpose and
beforehand the capability ofthe command area to
topographyofarea.Itisalso essentialtoensurethat
makemaximumuseofthebenefitsoftheriver valley
the control in adjoining river valley projects is
project.Sometimesthecommandarea survey isalso
consistent. Forthis purpose,the control surveysare
necessary to assist in designing the layout ofmain
invariably linked to the national control network
canals anddistributariesfor irrigationpurposes.The
provided bythe Survey ofIndia.
scale ofcommand area survey maps should range
from I : 10000 to I : 15000 and contourinterval of 5.1.1 Two types of ground control points are
0.5 m or I m depending upon the steepness ofthe required for survey,namely, horizontaland vertical
country. Block levelling on 50 m or less grid-basis control points. The horizontal control provides the
shall be done. planimetric position ofacontrol point.The vertical
control provides the altitude or height ofa control
4.5 CommunicationSurvey
point above the mean sea-level.
The movement of construction equipment and
5.2 HorizontalControl
material toaproject construction site will normally
require the construction ofaccess roads, as most Theco-ordinatesofhorizontalcontrolpoints should
project sites are not accessible from existing be fixed either in terms of latitude and longitude
highways.Sometimesbranch lines fromtheexisting expressed in degrees, minutes and seconds or in
railwayroutes willberequired.Existingrailways and rectangular terms in grid metres in northings and
highways running through the reservoir area may eastings relating to predetermined origin and type
have to be relocated where these are liable to be ofprojection.
inundated orsubmerged byareservoir.The surveys
5.2.1 Horizontalcontrol pointsmaybefixedbyone
are required for this purpose and for deciding the
oracombinationofthe followingmethod:
alignmentand gradesofrailwaysand highways. The
surveys forthelocationorrelocationofrailways and a) Dopplersatellitecontrol,
highways are normally performed in consultation
b) Triangulation/E.D.M.trilateration,
with the field survey parties of the railway or
c) Theodolite/E.D.M.traverse:and
highways authorities who should be entrusted with
the determination of specification and survey d) Resection.
instructions.
Of these, the best method for topographical
4.6 FloodControlSurvey operations is a system of accurate triangulation,
whereby undue accumulation oferror is precluded
These surveysare requiredinsome projectareasfor
inthe extensionofthenetwork,andatthesame time
flood control work, that is, for the planning and
limits are settothe intrusionoferror, inthe internal
executionofflood protectionworks.These maps are
details to be surveyed.
preparedon I: 10000or I: 15000scalewithcontour
interval of I or 2 or 5 m corresponding to natural 5.2.2 Triangulation/E.D.M. Trilateration or
groundslopes lessthan 10°, 10°_30°and more than Traverse
30°respectively.
The electronic distance measuring (E.D.M.)
4.7 CommandArea DevelopmentSurvey instrumentsincontrolsurveysoperationsare useful.
In view ofthe accuracy and speed ofoperations of
These are carried out for shaping topography to
these instruments,their useisrecommendedtoavoid
conserve water resources and for an integrated
the laboriousand time consumingmethods oflinear
development to optimise productivity of the area.
measurements by chains. Since these instruments
Scale for such survey maps variesbetween I: I 000
measure distances, they may be used for measuring
to I:5000withcontourinterval of0.5 mor Im.
three sides of a triangle which is known as
trilateration.Theymayalso beusedfortraversingto
5 PROVISIONOF CONTROL
measuretraverse legsinconjunctionwiththeodolite
5.1 ControlSurvey formeasuringangles. E.D.M. trilaterationoftraverse
iscarriedout by the SurveyofIndia.
First ofall, the whole areashouldbe coveredwith a

numberofcarefully determinedgroundcontrol points 5.2.2.1 Accordingto the procedureofobservations,
whichwillformanetworkonwhichtheensuingdetail instrumentsusedandqualityoftriangulationresults,
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IS5497 :2008
a triangulation is classified as primary, secondary points might have been destroyed. Owing to the
andtertiary.Thereareavarietyofelectronicdistance flatness ofthe country the expense oftriangulating
measuring instruments available today which are the intermediate area may be greater and
very useful in control survey operations. This triangulation may take several seasons to carryout.
classification may also be called as first-order, In such cases theodolite traversing is a more
second-order and third-order triangulation. The expedientand economicalmethodofcontrol survey.
primary and secondarytriangulations are termed as Traversingisamore laboriousand atthesametime a
geodetic. The tertiary triangulation is called less accurate method of fixing control points than
topographic.Allgeodeticdata which form the basis triangulationand,therefore,may only be resortedto
of topographical survey are published in in flat ground where buildings, trees, high grass or
triangulation and levelling pamphlets. These haze prevent distant vision.
pamphlets maybeobtainedfromthe SurveyofIndia.
5.2.3.1 The length oftraverse legsare measured by
5.2.2.2 Primarytriangulation isthe highestgradeof chains(Crinolinechains,see Note I )or steel bands
triangulation and isemployed for the determination [Huntershort base(see Note 2)] or subtense bars or
of the shape and figure of the earth and other invar wires or E.D.M. instruments according to the
geodetic investigations. Italso constitutesthe basic accuracyaimedat.
preciseframework for mappingand for powerorder
NOTES
of triangulation. As it is independent ofexternal
checks, all possible precautions and refinements I Crinoline chain isariband ofsteel about 3to Smm
should be taken in the observations and their wide and about 1/2 mm thick. obtainable in lengths of
100 m to 110 m. II is calibrated for its length under
reduction. The length of a base-line in primary
standard conditions oftemperature and pressure. It is
triangulation may be about 8 km to 12 Ianon the
used for direct measurement of distances where the
averageandthesides ofthe trianglesmayrangefrom accuracy desired is of higher standard. The tension
16kmto 50km. The averagetriangulationerror(or applied during field measurements should normally be
the same as that applied during calibration.
the discrepancy between the sum ofthe measured
2 Hunter short base is a short measured base, invented
angles inatriangleand 180"plusthesphericalexcess
by Hunter, consisting of calibrated steel tapes hung in
ofthe triangle) should not be in excess of Is. The
catenary, for commencement or carrying forward of
probable error of computed distance should lie control work by triangulation or traverse. Normally it
between I in50000 to I in 250000. consists of four tapes calibrated under standard
conditions of temperature and pressure. The tapes
5.2.2.3 Secondary triangulation is designed to together with other accessories are easily portable and
connect two primary series and thus furnish points form a convenient base to commence and carry forward
control operations in any type of terrain, particularly
closertogether than those ofprimary triangulation.
bushy and undulating, with meagre existing control
The average triangular error in secondary
points.
triangulation should not exceed 3 s. The probable
errorofcomputed sides should lie between 1in20 5.2.3.2The angles between consecutive traverse
000to Iin50000. legs should be measured by a theodolite set up at
each station in turn. Vertical angles should be
5.2.2.4 Tertiary triangulation is run between the
observed by theodolite from one station to another
stations of the primary and secondary series and
when heights are required. If the position of one
forms the immediate control for topographical
station and the bearingofa traverse line connected
surveys. Theaveragetriangularerrormayrange from
to itare known, then the position ofthe nextandall
3sto 15sand the probableerrorofcomputedsides
succeeding stations may be computed.
mayliebetween 1in5000 to Iin20000.
5.2.3.3The rate ofaccumulationoferrorsintraverse
5.2.2.5 The initial data required for commencing
affectsthe accuracy andshall be kept undercontrol
topographical triangulation in an area ofwhich a
byclosingtraverseson well fixed pointsat bothends
detail survey is contemplated, is a base ofknown
and also by introducing bases and azimuths.
length, an azimuth, latitude, longitude and height
Topographical or tertiary traverse may have an
above meansealevelofonestation.Thetriangulation
accuracyofIin5000providedmorepreciseangular
chain starts from this known base and closes on
and linearmeasurementdevicesare used.
another known base.
5.2.3.4Theobservationofazimuths,eitherfrom sun
5.2.3 Theodolite Traverse
orstars,at frequent intervals,providesadirectcheck
In some stretches of flat country, primary against accumulation of errors of angular
triangulation seriesmay lie over 150 Ianapart, and measurements. These azimuths, as well as the
even whereasecondaryseriesmight have been run bearings from one station to another, should be
to connect them, many of the secondary control computedinthefield.Ifcomparisonrevealsanerror
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I~ intersected points may be computed by means of
largerthan minutesin 12stationsinmaintraverse
the differences in height derived from the vertical
lines the line shall be reobserved. angles and the lengths of the triangle sides. In
5.2.3.5 The most important field check in linear measuring the vertical angles the theodolite should
measurementsistheestablishedcustomofmeasuring beplacedoverthe centremark ofthe station and its
each line twice and comparingthe values.Each line height above the station should be measured. The
should be measured once with a long chain 30 m in triangulation stations should have definite signals
length and a second time with ashort chain 20 m in which should be observed for sighting the cross
length. Thesetwomeasurementsshouldagree within hair when measuring the vertical angle. From the
I in500forchainsand Iin I000 forsteel bands.The known heightofthedistantsignalabovetheground,
measurements ofthe length obtained by the longer the height ofthe triangulation station sighted may
chain shallbeaccepted. InE.D.M.instrumentsfield be computed.
check is obtained by repeat observations.However,
5.3.2.1 The main difficulty in obtaining accurate
the time taken is much less than surface taping and
results inthiskindofworkarises fromtheuncertainty
accuracy achieved isofhigh order.
of the atmospheric refraction. It may be nearly
5.2.3.6 Traverseshouldbecomputed inrectangular eliminatedbytakingreciprocalobservationsbetween
co-ordinatesand referred to an origin. two stations when the refraction issteady. The best
time to observe vertical angles is during the middle
5.2.4 Resection
ofthe day,from 1300 hto 1600 hasthe refraction is
then much less variable than in the morning or late
This method may be adopted to determine the
geographical position of a point on the ground afternoon.
occupied by surveyor, by making observations to
5.3.2.2 Trignometriclevellingmaybeused forfixing
other stations or points of known co-ordinates
verticalcontrol pointswherethe terrain issteepand
without visiting them. This method obviates the
undulating and the contour intervalaimed at is5 m
necessity of visiting or making observations from
ormore.
otherexistingcontrol pointsand stations. When the
observations are made with theodolite, it is termed 5.3.3 Levelling
as 'trigonometrical resection' or 'theodolite
Levellingorthedeterminationofthe relative altitude
resection'. In topographical triangulation, stations
of points on the earth's surface, is an important
mayoccasionallybe fixed by this methodwhen it is
operation; both in acquiring data for the design of
not convenient to visit other stations for making
all classes ofworks and during construction. Like
observations. Ajudicious selection ofthe control
triangulation, depending on its quality, levelling is
pointsisessentialwhileadoptingthismethod.Italso
classified as high precision, secondary, double
involves complicated computations. However,
tertiaryortertiary.
occasionally, it may be necessary to resort to this
method inexploratoryor activeservicework. 5.3.3.1 High precison levelling is carried out to
provide the main vertical framework ofthe country
5.3 VerticalControl
and for the detemination ofthe shape and figure of
5.3.1 Vertical control points are essential to know the earth and other geodetic investigations. It also
thealtitudeofthearea. The heightsofvertical control constitutes the basic precise framework for less
points above mean sea-level may be determined by precise levelling. Secondary and double tertiary
one or combination of the following methods of levellingmaybeusedforestabilishingtheelevations
levelling: ofthecontrollingbenchmarksinthe projectareafor
all subsequent levelling. Tertiary levelling may be
a) Trigonometriclevelling,and usedforprovidingadense networkofvertical control
b) Levelling(spiritlevelling).
points inthe projectarea.
5.3.2 Trigonometric Levelling 5.3.3.2The simplestoperation for levellingconsists
in determination ofthe difference oflevel between
The elevations of triangulation stations may be
two pointsso situatedthat, from one positionofthe
establishedbyobservingthe verticalanglesbetween
instrument,readingsmaybeobtainedonastaffheld
stations and computingthe differences inelevation
successivelyon the two points.Thepreciselocation
trigonometrically. The angles are taken at the time
ofthe instrumentis immaterial, but toeliminatethe
the station isoccupiedfor the purposeofmeasuring
effectsofpossibleinstrumentalerror,refractionand
the horizontal angles. The trigonometricallevelling
curvature effects the two sights should be nearly
shouldstartfromandcloseoncertainpointofknown
equal inlength asmaybejudged.Precisionlevelling
elevation. From the known elevationofthese points
also requires observations for the values ofgravity
the elevations of the triangulation stations and
5