Guidelines Invetigation Major Irrigation Projects 1975

7/30/2019 Guidelines Invetigation Major Irrigation Projects 1975

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GOVERNMENT OF INDIA

CENTRAL WATER COMMISSION

GUI DE L I NE S F OR

INVESTIGA TIONS OFM AJ OR I RRI GATI ON AND

HYDRO-ELECTRIC PROJ ECTS

NEW DELHI AUGUST 1975


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MAJOR IRRIGATION AND HYDRO-ELECTRICPROJECTS


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Water resources development provides the basic infrastruc-ture for the gro'wth of our national economy, and consequently large

investments are being made on projects for the purpose in our

country. Once they are completed, such projects cannot be alteredafter discovery of any shortcomings. Failure of large water retain-

ing structures will lead to heavy loss of life, besides enormous

. monetary losses. There is' need, therefore, for comprehensive in-vestigations and planning of new projects.

Unlike buildings, roads or industrial projeets,water re-

sources projects are more complex and their planning involvesmulti-disciplinary activities. Economic demands, agronomic, geolo-

gic, meteorologic, topographic, hydrologic, engineeing and many

other factors all have impact on their preparation and each requires

careful study. It is true that for such highly complex projects, itis not unusual, that, unforeseen factors like unfavourable geological

conditions are actually revealed during construction of heavy struc-

tures. It is however possible by means of adequate investigationsto keep such uncertainties to the minimum.

The Planning Commission have from time to time issued

instructions on the formulation of new projects and laid down

questionnaires which have to accompany new project reports. Inorder to supplement these, the erstwhile Central Water and PowerCommission compiled, in February 1972, guidelines laying down the

minimum investigations of major irrigation and hydroelectric projects

.and sent these to the State Governments. An addendum detailing theinvestigations for irrigation and power channels and allied canal

structures was sent in December 1972.

Due to increases in costs of labour, construction materialsand equipment, the costs of projects are increasing. It is needless

to emphasise that the new projects have to be planned carefully toevolve the most economic means of affording the planned benefits


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and this will be feasible only if comprehensive investigations on thelines indicated in this booklet are carried out.

Environmental considerations are now recelvlng increasing

attention in the planning of projects and guidelines to cover these

aspects were circulated in July 1975.

In view of several requests from project engineers for

copies of these guidelInes, the various communications of theCommission in this regard have been compiled together and printed.

The Central Water Commission would appreciate any sugges-

tions for improvement of this publication.

New Delhi,the 13th August, 1975.

Sd/ -(Y. K. MURTHY)

Chairman

Central \Vater Commission


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Introduction

Topographical Surveys

Geological and Foundati.on Investigations

Meteorological and Hydrological Studies

Pre-Irrigation_ Soil Survey and. Drainage Soil Survey

Special Surveys for Hydro- Electric Project

Construction Material Investigations

Communications

Construction Plap...ning

Environmental Considerations

Appendix I

Appendix II

Appendix III

Appendix IV

Appendix V

Appendix VI

APPENDICES

Map of India showing the principal lithological groups.

Seismic zones of India.

Seismic coefficient for some important towns.

Composition of Inter-disciplinary official body.

. Map of India showing the annual normal rainfall.

Soil Mapof India.


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GUIDELINES FOR INVESTIGATiONS OF MAJORIRRIGATION AND HYDRO-ELECTRIC PROJECTS

. In order to ensure preparation of sound and economical

projects. it is necessary' to have thorough and systematic investiga-tions. The investigations should include the study of various alter-

natives regarding the layout of the scheme as a whole and also de-

tails -of alternatives considered for the type and location of variousfeatures. of the project. The fi~al alternative recommended should

be fully justified recording the reasons f9r its choice as againstthe others. The minimum surveys and investigations necessary for

the purpose are of the following nine types:

8. Collection of relevant data for drawing out programme

of construction including coffer dam construction.

9. Hydraulic model studies for setting the important

features of the project.

General and broad requirements with regard to each of theabove type of investigations' are set-forth hereunder.


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1.1 Surveys for preparation of plans should be carried out of

the area covering the dam site, the reservoir area and other project

features. Property surveys should be done for the reservoir area.Adequate number of G.T. S. Bench marks should be got establishedby the Survey of India.

1.2 Survey plans of the project will be prepared and exhibited

to cater. to requirements as indicated below:

i) The dam site topographical survey plans sl'!5mldcover an

area sufficient to accommodate all possible arrangem~nts of the pro-jects (dam, spillway, outlet works, diversion works etc.). For a

large structure, a scale of 1/1000 with contours at intervals of 2m.

would be adequate. Unless otherwise necessary, the plan will coveran area at least upto about 200 m. upstream and 400 m. downstreainof the dam site and extend well beyond the abutments.

ii) The reservoir submergence plans may be prepared to

scale of 1/ 15000 with contours at intervale v(2 m to 3 m depending

upon the size of the reservoir. Area capacity curves and tables

will be prepared to an elevation high enough to allow for the antici-

pated maximum reservoir level.

iii) The command area survey plans may be to a scale of

1/15000 with contour intervals of 0.5 m.

iv) For a barrage structure, detailed survey maps will

cover the area under the barrage and appurtenant works (guide banks),

head regulators, road and rail approaches, site for colony etc. The'.plan may be to a scale of 1/4000 with levels in a 30 m. grid.

(v) River surveys in a length of about 10 km. upstream

and 10 km. downstream of the diversion structure will be carriedout. On the basis of this survey, an L-Section 'of the river will be

prepared. Cross-sections will be taken 30C m apart, extending

sufficiently above the H. F. L.

vi) Along the canals alignment, L-Secti-on should be pre-

pared with levels at 50 m. intervals and cross-section 100 m apart

extending to 100 m on either side of the centre lin~$ of the canals.


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The longitudinal sections should show the soils that will be met within the canals excavation.

vii) Surveys connected with cross-drainage works shouldinclude L-Section and cross-sections of the drains, along with de-

tails of catchment areas, high flood discharges, observed H.F. L.

along with canal data at the point of crossing.

viii) For the location of power station, the survey plan

should cover an area sufficient to include alternative station layoutsand should give contours at intervals of 5 m. Low Water level,

maximum. observed flood level, rock outcrops, sand shoals, etc.

where the plant is to be, on the bank of the river, will be indicated

therein.

ix) L-Sections covering power channels, penstocks and

tailrace channels should be prepared. The .L-Section should givelevels at 50 m. inte1..~valsand should show log of boroholes at

points recommended by the geologist of Geological Survey of India.

Cross-Sections should also be taken at 100 m. intervals extendingsufficiently on both sides.

x) For tunnels, longitudinal sections along tunnel alignment

and contour plan with 50 m intervals covering about 100 m on either

side of the alignment and also upto contours corresponding to tunnel

grade, if applicable, indicating location of adits.

Xi.) For surge tank contour plan of surge tank area at 5 m

contour intervals.

xii) For underground power house, .contour plan at 1 in

4000 showing contour intervals at 15 m covering location of accesstunnels, tailrace tunnel, and switchyard.

2..1 A resume should be prepared for the regional geology.

Geological sections to show k"TIownand interpreted sub-surfaceconditions should be prepared. A geological map appended' to this

note gives the general pattern of geological strata met with in

various places of the country (Appendix 1).


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2.2 Seismic conditions of the region should be investigated with

reference to the geological map of the vicinity. For the purpose of

determining the seismic co-efficients the country is divided into five

zones as given in the map (Appendix II).

2.2.1 Unless otherwise stated, horizontal seismic coefficient for

static design in different zones shall be taken as follows (see 2.2.3).

V

IV

III

II

I

Horizontal Seismic coefficient h

0. 08

0. 05

0. 04

0. 02

0. 01

For detailed "design practice, please refer to 1.S. Code

No. 4362 of 1967 and its subsequent amendments BDC (39) (1968)

which is under print.

VALUES OF "B" FOR DIFFERENT SOIL FOUNDATION

SYSTEM

S1. rType of soil I Bearirig

No. 'mainly consti- IPiles

'tuting the I resting

'foundation Ion soil, Type I

Ior RaftIfound-, ation

1 '2 3

Value of "B" forI Friction I Isolated

I Piles, I Footings

I Combined I without

I or Isola- I the Beams

I ted ReC I or Unrein-

I footings I. forcedI with the I strip

I beams I foundations 1

4 5

Well

I foundation

i) Type I Rock

or Hard Soils

ii) Type II Me-dium Soils

iii) Type III Soft

Soils


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2. 2.2 The seismic coefficients according to 2"2. 1 for some impor-tant towns and cities are given in Appendix III.

2.2.3 Buildings provided for accommodating essential services

which will be of post earthquake importance, such as hospitals,

emergency relief stores, foodgrain storage structures, waterworks,

water towers and power stations shall be designed for one and. halftimes the seismic coefficient given in 2.2. 1 or one and a half times

the F-values specified in Appendix of Revised 1.S. 1. Code of Prac-

tice for Earthquake Resistance Construction of Building.

2.2.4 The vertical seismic coefficient where applicable may be

taken as half of the horizontal seismic coefficient as indicated in2.2. 1.

The design seismic coefficient should ~egot confirmed fromthe standing committee set up for the purpose by the Ministry of Irri-

gation and Power and composition of the Committee is enclosed in

Appendix IV.

Evaluation of seismic status of faults and thrusts and collec-

tion and maintenance of seismological data both in pre-constructionas well as post construction stages of river valley projects are of

vital importance because of safety reasons. Recommendations givenin 1.S.1. Code No. 4967-1968 for seismic instrumentation for River

Valley Projects may be used for investigation of seismicity of site

for any project besides river valley projects, if the situation and

the magnitude of the project justifies so.

2.4 Geological investigations should ,be carried out for determin-

ing the water tightness of the proposed reservoir, presence or other-

wise of solution channels. sink holes, etc. and the existing and poten-

tial slide areas. The survey should also include an assessment of

valuable mineral deposits in the reservoir and existing and potential

slide areas.


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i) Boreholes at a minimum spacing of 150 m all along the

dam alignment should be drilled to a depth equal to the height of the

dam at the location of the hole or 5ill below bedrock whichever ismore. The method of drilling adopted should be specified. Bore-hole logs for soil strata must be in accordance with 1.S.1. Unified

classification system.

ii) In situ permeability tests in all the boreholes should

be carried out at various depths of hole.

iii) For cohesive materials, at least one undisturbed

sample for each soil stratum met with shall be tested for in-situ

density and natural moisture content as well as for shear para-

meters in triaxial shear with pore pressure measurements under

saturated condition. Degree of compaction of the foundation ma-terial in terms of Proctor density for the material in each stratum

will be determined.

iv) Where the foundation. material is cohesionless, the

relative density of the material will be determined at various depths,

extending upto a depth equal to the height of the dam or to rock

whichever is higher.

Masonry I Concrete Dams

) i) Exploratory holes andlor drifts should cover the entirefoundation and abutment area of the dam including energy dissipation

structure. The location, spacing and depth of holes shall be de-cided in consultation with an engineering geologist of the Geological

Survey of India.

ii) Description and logs of exploration should include

ground elevation at the hole, location coordinates and sufficiently

detailed remarks regarding the nature and type of rocks, geologicalstructure, water loss etc. for a clear interpretation of the founda-

tion conditions.

iii) Contours of bed rock and geological structure of found-

ation strata should be presented.


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iv) Location and thickness of weathered, altered or other-

wise softened zones and their characteristics and the structural

weaknesses and discontinuities shall be investigated.

v) Tests for significant engineering properties of founda-

tion rock such as density, absorption, permeability, shear compres-

sive strength and strain characteristic (including the effect of mois-ture content) should be done and data presented. Where the type

andt or structure of rock is such that its competency to ensure the

stability of the dam"against a sliding failure is in doubt, necessary

in-situ shear tests should be done and data presented.

Barrages tWeirs

i) Along the proposed alignment of the barrage, explora-

tory holes spaced 150 m apart should "be put to determine soil

profile upto a depth of 30 m below average bed level on permeable

strata. Where sheet rock is met earlier, the depth of drill holesmay be taken 3 m in rock. .

ii) Samples of soil obtained from bore holes should be

tested for properties as set forth under items 6.4.2.

Water Conductor System

i) The L-Section of the water conductor system from intake

structure to tail-race should be given. In power channel portion,

trial pits to adequate depth be put in at suitable intervals so as to

indicate all changes of strata.

ii) For tunnel, a geological section of the tunnel alignment

and surge shaft and drill holes adequate to establish cover of rock

and important geological features should be given.

i) 2 to 4 drill hole details for the power station area may

be given. The number, location, spacing and depth shall be decidedin consultation with an engineering Geologist of the" Geological Surveyof India.


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include switchyard and alternative plant lay-outs and should give

contours at intervals of 5 m. Low water level maximum observed

flood level, rock out crops, sand shoals etc. at the power house

site will be indicated therein.

iii) Indications of slides and their locations and the possi-

bility of rockfalls in the hill slopes should be explored.

v) For underground power house, a geological sections of

power house, pressure tunnel, access tunnels and switchyard and

sufficient drill holes /drifts to establish the geological features of thesame.

2.5. 6 Irrigat~on and Power Channels and Canal Structures

(a) Plans to be attached

1. Index Plan showing the entire canal system and the whole

scheme.

2. The command area survey plan to a scale of 1/15'000 with

contour intervals of 0.5 m.

3. L-Section:- Along the canal alignments, L-Sections should

be prepared with levels at 50 m. intervals indicating thefollowing details:

vi) Type of 'Canal, nature of soil where the canal ispassing through (by giving test pit or auger hole data


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at about 500 m. intervals), value of In', bed width,

side slopes, full supply depth, freeboard, full supply

discharge, width of bank, L/R, velocity, C.V.R.,

losses etc. for various reaches.

viii) Location and type of cross drainage works with hy-

draulic details, e. g. catchment area, H. F. L., Dis-

char ge etc.' and loss of head provi ded at such C.D.

Works.

. 4. Cross-Sections:- Cross-Sections of canals, at intervals of

100 tn., specially for maximum cutting, maximum filling and

partial cutting-filling, extending to 100 m. on either side of

the centre line of the canal showing the following details,

be given:-

v) Profiles of banks suitably designed providi.ng adequate'

cover over saturation line assumed for the soils in

banking with details of the impervious core if provided.In9pection and non-inspection path details.

vii) For lined canals, details of lining and under-

drainage arrangement behind it conforming tothe relevant 1.S. Codes. .


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(b) Design of Canals: The following data may be given.

1. Trial pit or auger hole data indicating the nature of soil

met with along the alignment of the canal.

2. Transmission losses assumed -ill the main Canal, brancl?-es,

distributaries and minors in the unlined and lined channelsalongwith th,ejustification for their assumption.

3. Cut-off statement showing the details of discharge requiredfrom tail to head considering the requirements of the off-

taking channels and transmission losses etc.

4. Design calculations for adequacy of canal sections adopted

indicating details e. g. formula adopted, values of constants,designed slopes, velocities allowed, C.V. Ratios, F. S.depths, Free Board, bed 'width to depth ratio etc.

(c) Cross Drainage Works: The followin'g information may be

given.

1. L-Section and cross-sections of the drains, along with de-

tails of catchment areas, high flood discharge, observed

H. F. L. alongwith canal data at the point of crossing.

2. Test pit or bore hole data for deciding the. nature of found-ation of structure.

3. At least outline designs and drawings for a few typicalstructures. Designs should include waterway calculationsand other items of hydraulic design.

(d) Distribution system :. The following details may be given:

1. Plan showing alignment of the distribution system -withthe

commanded area of each distributary.

2. Calculation of "Design Discharge 11 of each distributary in-

clusive of transmission losses.


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3.1 On the watershed plan should be shown (a) the prominent

orographic features (b)n~rmal annual isohyets (c) location of rain.

gauge stations in and around the catchment (the source of rainfall

data should be indicated) (d) gauge and discharge sites and (e) inter-

state boundaries. A map of India showing annual normal rainfall is

enclosed as Appendix V.

3.3 Data and frequencies of. heavy rainfall in the catchment and

its neighbourhood should be collected and evaluated. Standard pro-

ject storm or maximum probable storm rainfall depths including

maximisation should be determined.

3.4 Climatic investigation for the project 'command should include

pan-evaporation data where available. If. however. this. is not avail-able. information on the following items may be collected.

4. Mean mon~hly temperature. Maximum and minimum monthly

temperature.sand maximum variation in daily temperatures

for each month should be observed.

3. 5 Ga~ge and discharge observatiolls (preferably by currentmeter) should extend for at least five years at the project site.Observed data for as many years as possible. should be collectedfor the nearest site on the same stream or for adjoining stream(s)with similar catchment characteristics. .)


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3.6 Sediment observations should be carried out for a period of

three years of the suspended load, bed. load and natural soil condi-

tions including catchment characteristics from the point of erosion.

The silt manual by c. S. M. Research Station of cwe may be refer-red to for further details.

3.6.1 Chemical and petrographic analysis of river water may be

examined and report maintained.

3.7 Gauges and discharges during flood occurrence should be ob-

served at short intervals say hourly and survey map of flood marks

of past floods.

ii) Estimation of annual yields and their break up into

monthly, monsoon and non-monsoon run-off.

iii) Actual 10-daily observed run-off pattern for run-off

the river projects.

iv) Estimated yields for reliabilities of 75%, 90% and

100%for irrigation, power and water supply projects

respectively.

v) Working tables for a representative cycle of years to

ascertain the percentage success of the project.

vii) The criteria to be followed in the estimation of design

flood for major and medium dams and other hydraulic

structure, are as follows:-

3.8. 1. 1 Major and medium dams: In the design of spillway for

major and medium projects {with storages more than 50,000 acre

ft.) the maximum probable flood which is the maximum flood for '-;}which there is a reasonable chance of occurring at the site should

be used. The method of estimation of the maxirn,um probable flood

is the one using the unit hydrograph principle and the maximum


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probable storm. The maximum probable storm is an estimate of

the physical upper limit to storm rainfall over a basin. It is ob-

tained from storm studies of all the storms that have occurred in the

region and maximising them for the mechanical efficiency of the

storm in changing water vapour and droplets in the atmosphere intorain and moisture content of the rain-producing air mass involved

in the storms. It has been the practice till now not to attemptmaximisation for mechanical efficiency of the storm due to insuffi-

cient knowledge of this factor; therefore for the present maximisa-

tion for moisture content need only be made.

3.8.1.2 The distribution of storm intensities for small durations

is obtained on the basis of recorded data of self-recording raingaugestations in the concerned catchment or region. The range of maxi-

misation of unit hydrograph peak should be taken between 0 to 50percent based on the discretion and judgement of the hydrologist.

If the unit hydrograph is derived from very heavy floods of con-

siderable volumes then the increase need be of a small order. Butif it is derived from low floods then the increase has to be sub-

stantial.

The rate of infiltration loss should be estimated from the

volume of flood run-off and the corresponding storm rainfall thatcaused the flood etc. and a minimum infiltration rate has to be

adopted.

3.8.1.3 The probability method when applied to derive design

floods for long recurrence intervals several times larger than the

length of data has many limitations. In certain cases. however.

like that of very large catchments where unit hydrograph method is

not applicable and where sufficient long term discharge data is

available. the frequency method may be the only course possible.

In such cases the design flood to be adopted for major structures

should have a frequency of not less than once in 1.000 years.

Where annual flood values of adequate length are available. they

are to be analysed by the Gumbel's method and where the data is

short either partial duration method or regional frequency technique

is to be adopted as a tentative approach and the results verifiedand checked by hydrological approaches.

Sometimes when the flood data is inadequate. frequency

analysis of recorded storms is made and the storms of a particular


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frequency applied to the unit hydrograph to derive the flood; this flood

usually has a return period greater than that of the storm.

3.8. 1.4 While planning there may be some projects where there is

hardly any discharge data available. In such circumstances for

preliminary studies the peak flood may be estimated by empirical

formulae. The empirical formula commonly use? in Central andNorthern India is the Dicken's formula Q = CA3 4 where A is the

catchment area in sq. miles and C is a constant. The constant

C varies widely; and it is subject to individual judgement its value

is of the order of 200 to 400 for plain catchment and 1000 to 2000

in the mountainous region according to catchment characteristics.In South India, Ryv's formula Q = CA3/4 is adopted, t:le value of

C being 450 in flat tracts along coast and it varies widely, being

of the order of 2,800 in the Western Ghat region. In Maharashtra:

Inglis-rbrmula Q = 7000 A and Q = 7000JA are generally

j A+4

used for small and big catchments respectively.

Since the probability method and the empirical approach

have their limitations and would give only the design peak discharge

and not the complete design flood hydrograph, the Commission areof the view that these methods be used provisionally and every effort

should be made to collect the required hydrological data at site and

obtain the design flood by rational methods (e. g. unit hydrograph

method) before the project designs are finalised.

3. 9 In the Case of Barrage and Minor Dams

In the case of permanent barrages, and minor dams withless than 50,000 acre ft. storages, the standard project flood or a

100-year flood, whichever is higher is to be adopted.

The standard project flood may be defined as a hydrograph

representing run off from the standard project storm. The standard

project storm is defined as one which is "reasonably capable" of

occurrence over the basin in question. This is not as definitive as

description as that for probable maximum storm. It may be takengenerally as the largest storm which haf occurred in the region of

the basin during the period of weather records. It is not maximi-

sed for most critical atmospheric conditions but it may be transposed

from an adjacent region to the watershed under consideration.


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3.10 The initial reservoir level before the impact of the spillway

design flood has to be taken as at full reservoir level. In regions

experiencing prolonged floods where storms can occur in quick

succession, design flood preceded or succeeded by a flood of once

in 25 years frequency should be considered. The interval between

these two floods (peak to peak) may be taken as 3 or 5 days accord-

ing to as the region lies in an annual rainfall zone of more than 40I'

or less than 40" respectively.

3.11 To provide for mechanical and other failures, it is neces-sary to assume some gates as inoperative with a maximum of 10 per

cent and minimum of one gate. For this purpose the designer may

be permitted to increase permissible stresses treating it as anextra-ordinary occurrence, like earthquake.

In the Case of Weirs, Aqueducts etc.

For pick-up weirs, a flood of 50-100 years frequency

should be adopted according to its importance and local conditions.

Waterways for canal aqueducts should be prOVided to pass

a 50-100 years flood, but their foundations and freeboard should befor a flood of not less than 100 years return period.

In case of cross drainage works, which carry highways or

railways, waterways provided should also satisfy the respective

standard code of practice of highways or railways.

3.13 Each site is individual in its local conditions, and evalua-

tion of causes and effects. While, therefore, the norms, mentioned

herein above, may be taken as the general guide lines, the hydrolo-

gist, and, the designer would have the discretion to vary the norms,

and the criterion in special cases, where the same are justifiable on

account of assessable and acceptable local conditions; these should

be recorded and have the acceptance of the competent authority.

1. Floods for various return periods where long termflood peak data are available.

II. Distribution of silt load in the reservoir and

estimation of total loss of reservoir space onaccount of silting.


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4.1 On topographical maps. to a scale of about 1/15000 of the

project command area grid squares of about 100 ha. for flat areas

and smaller grids where topography is undulating. should be estab-

lished. Soil map of India is appended at Appendix VI.

4.2 Rapid reconnaissance survey may be carried' out with tra-

verses about 2 km apart. Auger holes and profiles should be takenat the rate of two per sq. km. covering the whole of the commanded

area. Detailed soil survey should then be done for the problem

areas such as those with high water tables. which are saline /alkaliaffected and water-logged or have low permeability. For the prob-

lem area auger holes and profiles should be taken at the rate of oneper sq.km.

4.3 Soil sampling data should be collected upto a depth of about

3 m. Test pit method of sampling may cover about 5 to 10%of the

total command area.

4.4 Observation wells suitably spread over the command area

should be selected and water levels observed during monsoon andnon-monsoon months for about 5 years.

4.5 Location of pits. auger holes and observation wells should

be shown on the topographical map indicated in 4.1 above.


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Water samples should be taken of the surface and ground

water and tested for their quality.

The publication"Tecl:mical series 3-Section I: Soil surveyand land classification", April 1970 published by Union Department

of Food and Agriculture during 1970 may be referred to for detailed

procedure.

4. 7 Soil map of the corn.mand area and a table giving area inhaD for each soil group should be prepared. Area in haD falling

under each land irrigability class using standard land classification.system should be shown. A chart should show the criteria used instandard land irrigability classification with definitions of each land

class.

4.8 C2Eo~pingPattern

i) Present cropping pattern gIvmg area in haD under

different crops now grown with or without irrigationunder each soil group and their present yields should

be surveyed.

ii) Proposed cropping patterns glVlng area in haD under

different crops to be grown rmder different soil groupsand their expected yields should be determined in con-

sultation with the State Agriculture Department.

Duty and delta for each crop being irrigated in the neighbour-ing areas should be studied.

Irrigation Wat~..rReq~rements

Investigations shall be done to determine the irrigation

water requirements at the farm outlets in consultation with the StateAgriculture Department.


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The areas in the commanded areas of the project which

require drainage system must be selected in the first instance.

Accordingly pilot schemes may be framed and carried out after

making necessary investigations. The following measures may be

adopted in above regard:

Training of existing natural drains (nallahs)of water from shrubs, grasses and woods.

of the following operations:

to free the flowThis consists

2. Excavating new drains or regrading existing drains on the

sides of irrigation channels and roads.

3. Land levelling and construction of field drains with proper

slopes duly turfed to avoid erosion.

Design G~iJ~_ri~of the drainage system

Following points may be taken into consideration to determine

the capacity of the drains by the surface and sub-surface flows which

vary from State to State depending on the nature of soil.


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1. Intensity and Frequency of Rainfall

Intensity and frequency of railuall for. the design of drainage

channel may be taken as 'maximum rainfall of 3 da.ys duration. On

economic consideration the maximum intensity ,of rainfall should be

taken as corresponding to only 15 years return. In case of masonry

structures, it should be taken as corresponding to 50 years return.

The infiltration capacities of soils tend to vary from placeto place according to type of soil, land use, season of year, generalclimatic conditions. The infiltration loss rate for the different soils

may be taken as under:

~Arid areas, Rainfalll Semi arid & Sue' IHumid areas

~ upto 40 Cm. ~humid.)Rainfall 40 IRainfall 150 ems.Type ~ I to 150 Cms. I

t Fo- IFarm ~Fal- ~ 1 .70- ~Farml Fal- ~ Fo- IFarmlFal-J rest ILand J low ~rest ILandIlow Irest ILand Ilow

I

,Unit Centimetres/hour

Hilly &Fat

Clay soil. 0. 09 0. 07 0. 05 0. 07 0. 05 0. 04 0. 05 0. 04 0. 05

Clayeyloam or

blackcottonsoil. 0. 17 0. 13 O. 09 0. 13 0. 10 0. 07 0. 09 0. 07 0. 05

Silty

loam orloams. 0. 26 0. 20 0. 14 0. 20 0. 15 0011 0. 14 0. 11 0. 08

Sandy

loam orAlluvium 0. 55 0. 50 0. 20 0. 30 0. 22 0. 15 0. 20 0. 15 O. 12

SandySoils 0. 50 0. 40 0. 30 0. 40 0. 30 0. 20 0. 25 0. 20 0. 15


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3. Permissible depth and duration of submergence

Permissible depth and duration of submergence will vary

from crop to crop. It is considered reasonable to keep the periodof submergence limited to 10 days inclusive of days of precipitation

and depth of submergence limited to 2 ft.

From econOlnic consideration" the construction of drains

may be taken upby designLngfor 50%of the discharge worked out for

the areas.

'!ype of Sche.mes

The ,area requiring drainage system should be divided into

three types.

The areas which have been adversely affected due to rise of

watertable between 0 to L 5 In (0 to 5'). In this case natural

drains ulay be deepened so that 0.5 m to 0.6 m (1!to 2 ft.) depthof the drain is in pervious strata. The total depth of the drain may

vary from 2.5 m to 3 m (8 ft. to 10 ft.). The other artificialdrains Inay be taken 0.45 to 0.6 m (I' to 2') it, the pervious strata.

Some dug wells may also be provided for lowering the watertable.

Type II

In the area where watertable is between 1.5 rn to 3.0 m(5ft. to 10ft.) at present and is likely to rise as time passes.

It is p1"oposed to train the natural drains to the depth of 1.2 m to

1.8 m or upto pervious strata whichever is less and the artificial

drains proposed to be dug along the channels should be to the limitof 1.2 m to 1.8 m or upto the pervious strata whichever. is less. .'

In the area where watertable is below 3.0 m (10 ft.) the

natural drains may be trained to the depth of 1.2 m to 1.8 m or

upto pervious strata 'whichever is less and no artificial drains arerequired to be provided in that area.


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i) Present position of power supply in the region, systemloads, load factor, kWhgenerated per kWinstalled.

ii) Extent of firm power available fromthe scheme andalso from the grid after commissioning of the P1?nt,extent of secondary power etc.

iii) Details of major loads to be served, future peak andenergy demands, anticipated system load factor.

iv) Investigation regarding earth resistivity connectionwith sub-station designs.

v) The survey plan should cover an area sufficient to in-clude switchyard and alternative plant layouts andshould give contour at intervals of 5m. Lowwaterlevel, maximumobserVedflood level, rock outcropssand shoals etc. at the power house site will be indi-

cated therein.

vi) Maximumand minimummonthly temperature andmaximumvariation in daily temperatures for eachmonth shouldbe recorded.

vii) Chemical and petrographic analysis of river watershouldbe carried out and recorded.

6.1 A map showingthe location of the sources of constructionmaterial required withtransport facility to work site should begivenfor rock, coarse andfine aggregates, pozzolans if proposedto be manufactured locally, soil for use in earth dam, dykes etc.

6.2 An estimate of the quantities available at vari


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6.3 Reports on tests carried out on the various constructionmaterials. The test procedures and other details shall be as perthe relevant Indian Standarrls Specifications.

6.4 Following investigations are' to be done for establishingsuitability:

Concrete and Masonry Dams

a) Geological and related characteristics of aggregates,

including:

b) Investigations for the availability of natural and

artificial pozzolona with their characteristics.

i) Petrographic analysis of sand and rock samples;

ii) Grading and .physical tests of ~and and rocksamples to asses s their suitability as construc-tion materials;

a) Plans and sections should be made of the borrow areashowingthe location and logs of test pits spaced about150mapart and demarcating different types of soil.


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v) Triaxial shear tests withpore pressure measure-ments under OMCand saturation conditions

c

;

c) The sand and gravel to be used for filters should betested for suitability ,as for concrete aggregate.

Map(s) should be preparea showingthe followingfacilitiesduring construction and completion phases of the project:

a) Existing andproposed roads, water and rail routeswith information on load and size limitq.tions.

c) Sources for obtainingpower withtransmission linesroutes.


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'Re-routmg of the communication system where existingsystem is disrupted dueto the construction of theProject.

8.1 Planning of river diversion arrangements and investigations

for structures such as cofferdams~ diversion channels~diversiontunnels etc.

8.3 Construction plari.trequirements and plant planning ,vi.thparticular reference to supply of power~water~compressed airand other equipment required for construction.

Theplanning~construction and operation of irrigation hydro-electric /multipurpose projects have conside.rable impact on navigation~fish culture, wild life~recreational aspects and overall ecology ofthe affected regions. Someof these. aspects onthe ecology of theregion as well as the overall environment are irreversible in nature.It is, therefore, necessary that a careful evaluation is made ofthese impacts~ whether goodor bad before the project is undertakenand necessary measures are planned well in advance to mitigate,

wherever feasible~the adverse impacts.

The minimumsurveys and investigations required to be madeare indicatedbelow:-

The construction of dams/barrages may affect the migration

of fish. This aspect has to be examined in consultation with theappropriate department of the State Government and provision offish ladders or other measures, if feasible economically, wouldhave to be considered. Somerestrictions may also have to be


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imposed on fishing in the project areas. Owing to diversion of water

into canals, there may be modification in flow patterns and quantums

along the rivers Ichannels, and their effects on fishing downstream

should also. be evalu:ated.

Measures should be identified to reduce the quantity of the

trash fish and at the same time increase the availabiu.ty of qualityfish in the affected areas.

A survey plan of the areas likely to be submerged constitu-

ting as encroachment on wild life habitat as a result of the proposed

structure should be incorporated in the report. The report should

also indicate the area of reserve forest/wild life sanctuary/n~tionalpark, if any, that may come under sub-mergence as also the esti-

mate of the wild life population in the area proposed to be sub-

merged. The quantum of the forest area used as cover and grass-land used for grazing by animals in the area proposed to be sub-

merged should also be indicated, as also the details of such areas

in the remaining parts of the sanctuary/park. The report should

also discuss whether the area to be submerged is of any special

importance to wild life in their annual/ seasonal migration. Indica-tion should be given of the site of any islands that may be created

due to the formation of the lake as well as of the possibilities of

alternative proposals fqr relocation of the affected wild life in theregion. Wherever necessary, the cost of these should be provided

in the project estimate.

In case the problem of water-logging is serious, the

steps to be taken to mitigate problems due. to water logging shouldbe outlined.

The contents on these matters included in the project reportshould be framed in consultation with the appropriate department ofthe State Government dealing with forest and wild life. .

9.3 Historical and Cultural Repercussions

Sites of great historical and cultural importance should becarefully looked for during the investigations and where such sitescannot be av~ided, a complete inventory of these should be made


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and the aspect discussed in the project report. The report shouldalso deal with the feasibility of shifting such monuments to safe

areas nearby wherever this is feasible, and indicate the cost

thereof.

The project report should indicate

submerged is of outstanding scenic beauty.damage to this amenity of natural heritage

be indicated.

whether the area to be

If so, how best thecan be minimised should

9.4 Other Ecological Factors

Large hydraulic structures will result in modification in the

natural flow patterns of the rivers. The disturbances likely to be

caused to the natural conditions of the river by such modificationsshould be discussed in the report and the protection works, if any,needed to retain the river to its naturality as much as possibleshould be thought out and discussed in the report. Among the as-

pects which would need attention are: the silting/scouring in theriver bed; impact of flood problems; the salinity of the flow in the

river channel and other similar ecological factors.

Hydr~ulic structures provide the scope for augmenting mani-fold the water-based/recreation facilities, including sport fishing.

The project report should include a discussion on the scope of such

development.

The project report should also have a broad qualitative

assessment of the various benefits which would arise from the

implementation of the project, and discuss these in relation to theadverse effects, if any, to the overall ecology of the region by theconstruction of the project.


32/39

ii!!!!E"~'!!!!!:'!"=-~=~-""""='!OW'~~"-:'-;-"'-"'====1t:;O==='===~~==7t"~~~:=~~=8~:~,= . . . . . . , . . . . . . , = = ~ ~ -= ~U ~ ~ ~ - = = ~ = --'w~~~~j--~-~'~-m : f I I

I i

INEHt>,

PRINCiPAL LfTHOLOGlGpL

t'-J D

--'76~

The territorial waters: of t(idj~e::.;:ccnGinto the sea to a dis:t;l rI ce of twelve nautic~ miles

measurEd from thE . app r op ri at e base l ine.


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tND\ASEISMTC. ZONES

5 A Y OF

BENGAL'

, .~Ol!llOfi TA 'k.sfisMJ C> ~;Clt-f:"FFlC'trg '!' < h


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APPENDIX III

SEISMIC COEFFICIENTS FOR SOME IMPORT ANT TOWNS

I IHorizontall I Horizontal

Town t ZoneI

Seismic I Town Zone I SeismicI ICoefficient I ICoefficienti1 h

Agra III 0. 04 Durgapur III 0: - 04

Ahmedabad III 0. 04 Gangtok IV 0. 05

Ajmer I 0. 01 Gauhati V 0. 08

Allahabad II 0. 02 Gaya III 0. 04

Almora IV 0. 05 Gorakhpur IV 0. 05

Ambala IV0. 05

Hyderabad I0. 01

Amritsar IV 0. 05 Imphal V 0. 08

Asansol III 0. 04 Jaipur II 0. 02

Aurangabad I 0. 01 Jamshedpur II 0. 02

Bahraich IV 0. 05 Jhansi I 0. 01

Bangalore I 0. 01 Jodhpur I 0. 01

Barauni IV 0. 05 Jorhat V 0. 08

Bareilly III 0. 04 Jabalpur III 0. 04

Baroda III0. 04

Kanpur III0. 04

Bhatinda III 0. 04 Kathmandu V 0. 08

Bhilai I 0. 01 Kohirria V 0. 08

Bhopal II 0. 02 Kurnool I 0. 01

Bhubneshwar III 0. 04 Lucknow III 0. 04

Bhuj V 0. 08 Ludhiana IV 0. 05

Bikaner III 0. 04 Madras II 0. 02

Bokaro III . 0. 04 Madurai II 0. 02

\Bombay III0. 04

Mandi V0. 08

Budwan III 0. 04 Mangalore III 0. 04

Calcutta III 0. 04 Monghyr _ IV 0. 05

Calicut III 0. 04 Moradabad IV 0. 05

Chandigarh IV 0. 05 Mysore I' 0. 01

Chitradurga I 0. 01 Nagpur II 0. 02

Coimbatore III 0. 04 Nainital IV 0. 05

Cuttack III 0. 04 Nasik III 0. 04

Darbhanga V0. 08

Nellore II0. 02

Darjeeling IV 0. 05 Panjim III 0. 04

Dehradun IV 0. 05 Patiala III 0. 04

Delhi IV 0. 05 Patna IV 0. 05


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I t Horizontal 0 t o HorizontalTown IZone ISeismic I Town I Zone ISeismic

I ICoefficientI I ICoefficient '-h h

Pilibhit IV . 0. 05 Srinagar V 0. 08

Pondicherry II 0. 02 Surat III 0. 04Poona III 0. 04 Tezpur V 0. 08Raipur I 0. 01 Thanjannur II 0. 02Rajkot III 0. 94 Trichunapalli, II 0. 02Ranchi II 0. 02 Trivandrum III 0. 04Roorkee IV 0. 05 Udaipur II 0. 02 . "ROurkela I O. ' 01 Varanasi II 0. 02Sadiya V 0. 08 Vijaywada III 0. 04

Simla IV 0. 05 Visakhapat- II 0. 02Sironj I 0. 01 nam


36/39

No.DW-l1-11(8)!68Government' of India

Ministry of Irrigation and Power

Subject: Allowance for Seismic Forces in the Design of River

Valley Projects, Setting up of a Standing Committee.

After the Koyna earthquake, the necessity has been felt

for a high level inter-disciplinary official body to advise on the de-sign Seismic co-efficients for dams and other structures of Irriga-

tion and Power projects. In consultation with the Ministries of

Tourism and Civil Aviation and Petroleum, Chemicals, Mines and

Metals (Department of Mines and Metals) Standing Committee of

the following composition is hereby constituted:

Member (D&R). Central Water &

Power Commission

Director, Seismology, Indian

,Meteorological Department,

New Delhi

Shri V. S. Krishnaswamy,Director, Engineering Geology,

Division, Geological Survey

of India, Northern Region,Calcutta

The Standing Committee will meet periodically as required

and advise the various authorities on matters referred to it.

Sd/- N.C.Saksena

23. 6. 1969

Joint Secretary to the Govt. of India.


37/39

I ND I A

A N NU A L N ORM A L RA I NF A L L

I ' A R A B I ANSEA

BAYOF

BENGAL

E I 'J > '~ PORT 8LAIR_% (i

-III

~~ ,- (\ ,~0'/I

---------' '\~

\~().~

rJ > ' .711:' I,. .U I

-%'%1>00

~ ~ - T R I V A N D. . . '"

"1l

The territorial waters of lodiaextend into the sea to distance of twelve nautical miles

measured from the appropriate baseline.


38/39

F-----i ,-_ _ 6 ' ~- - - -j 1o~l -i~-- -- 72;' I~_ - - - r - - -! I

III

II 'i.r

iJ 2 .

i, I

- I I II,

ilf

-- - - "i ----.--~.I

_ 92"- - - . --I

INDIASOiL M A P

(

PAKISTAN


39/39

Guidelines Invetigation Major Irrigation Projects 1975

Documents