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है”ह”ह

IS 4410-11-1 (1972): Glossary of terms relating to rivervalley projects, Part 11: Hydrology, Section 1: Generalterms [WRD 3: Ground Water and Related Investigations]

( Reaffirmed 2001 )

I

Rep ' JU 1 )

c 0 •5 - . 1J

IS I 4410 ( Part XI Sec 1 ) • 1972

Indian StandardGLOSSARY OF TERMS RELATING TO

RIVER VALLEY PROJECTSPART XI HYDROLOGY

Section I General Terms

Terminology Relating to River Valley ProjectsSectional C(i,~lmittcc, BDC 46

ChairmanSHill I. P. KAPILA

R~prrsmting

Central ".,',Fd of Irrigation and Power, New Delhi

In personal capacity (.1.1 18 Nau Delhi SouthExtension, Part If, Nrw Dllizi 16)

Geological Survey of India, Calcuttap"bli" \\'urk< Dcpartmcur, GOVLT:JnH'rll of

~lah;\r."hlr3

Beas Designs Organization (Minisfry ot rrngation& Power)

Public Works Department, Government of TamilNadu

( Altrrnat« )Land Reclamation, Irrigation & Power Research

Institute, ArnritsarCentral Water & Power Commission, New DelhiIrrigation Ikpartmen1, Government of Cr'ar

PradeshAlok Udyog Cement Service, New Delhi

Public WMks Department, Government of \Vc,tHell gal

Public Works Department, Government of MadhyaPradesh

SUPElllNTENDING ENGINEER ( DCS,CNS )( Alternnts )

DR R. C. HOON

SUPEIUNTf:.NDIHO ENGINEERDIRECTOR

SHRI R. L. GUPTA

SlJIU M. S.. lAIN'SURI N. V. KUURSALL

CHt!!1' ENGINUR ( bRIGATtON )

SHRI K. C. GIIOSALSHIH A. K. BISWAS ( Alternate)

SHRI N. K. GHOSU

J)UUICToa (HYDROLOGY)5mu N. K. DWIVP.Dl

Members

SHill B. S. BHALLA

SIIRI E. C. SALDANHA (AltuIJale)SIIRI T. S. !\o!URTIiY N:ll;onal Projects Construction Corpr.ration Ltd,

New D,'!:liSHRI K. ~. T.\KF-JA ( Alternaie )

SURI 1\-1. VENKATA RAO

SllRI R. K. S.\IlU

PROF S~llA"JIT SINGH

Public \\'orb Dcpartu.cnt, G"v, rrmcnt of AndhraPrarlrsu

Irrigation & rower Department, Government ofOrissa

Indian lnstitute of Technology, N"", DelhiI. Ccntinued onpage 2 )

INDIAN STANDARDSMANAK BHAVAN. 9 BAHADUR

NEW DELHI

INSTITUTIONSHAH ZAFAR MARG

IS: 4410 (Part XI/Sec 1) .1972

( Continued from page 1 )

MembersDR P. P. SEHGALCoLN. K.SEN

COL I'. MISRA ( Altemat« )SHRl G. S. SIDHU

SHRI M. M. ANAND ( AltertllJte)SOIL CONSI!.RVATION ADVISER

SaRl VIJENDRA SINGH

SHRl D. AJITHA SIMHA,Director ( Civ Engg )

RepresentingUniversity of RoorkeeSurvey of India, Dehra Dun

Irrigation Department, Government of Punjab

Ministry of Food, Agriculture, Community Develop-ment & Co-operation

Irrigation Department, Government of Uttar. Pradesh

Director General, lSI ( E"-~flicio Member)

Secretaries

SHRI K. RAOIIAvENDRAN

Deputy Director (Civ Engg )" lSI

SlIRI S. P. MAGGUSenior Technical Assistant ( eiv Engg), lSI

Panel for Glossary of Terms Relating to Hydrology, BDC 46: Po

Indian Institute of Technology, New Delhi

It~rigatiun Research Institute. RoorkeeCentral Ground Water Board, Faridabadbdian Institute of Technology, New Delhi

ConvenerPROP SARA.NJIT SINGH

M~mbers

SHRI S. BANERJI National Committee for International Hydrologi-cal Decade, New Delhi •

DIRECTOR (HYDROLOGY) Central Water & Power Commission, New DelhiDEPUTY DIRECTOR (HVOfl'lLOOY;

( Alternate)SHRI M. M. LAL KHANNADR K. V. RAGHAVA RAOnR SUBHASH CHANDER

IS: 4410 ( Part XI/Sec 1 ) • 1972

Indian StandardGLOSSARY OF TERMS RELATING TO

RIVER VALLEY PROJECTS

PART XI HYDROLOGY

Sec:tion I General Terms

o. FORE W 0 R D0.1 This Indian Standard (Part XI/Sec I) was adopted by the IndianStandards Institution on 24 February J972, after the draft finalized by theTerminology Relating to River Valley Projects Sectional Committee hadbeen approved by the Civil Engineering Division Council.0.2 A number of Indian Standards has been published covering variousaspects of river valley projects and a large number of similar standards isin the process of formulation. These standards include technical terms,the precise definitions of which are required to avoid ambiguity in theirinterpretation. To achieve this, the Institution is bringing out' IndianStandard Glossary of terms relating to river valley p'·ojeets' (IS: 4410)which is being published in parts. The other parts of this standard so farpublished are given on P 10..0.3 Part XI covers the important field of hydrology which is a separatescience by itself. In view of the vastness of the subject, it is proposed tocover the subject in different sections. Section I covers general terms.Other sections in the series will be the following:

Section 2 Precipitation and run off. Section 3 Infiltration and water losses

Section 4 H ydrographs. Section 5 Floods

Section 6 Ground waterSection 7 Discharge measurementsSection 8 Quality of waters

0.4 In the formulation of this standard due weightage has been given tointernational co-ordination among the standards and practices prevailing indifferent countries in addition to relating it to the practices in the field inthis country. This has been met by deriving assistance from the followingpublications:

UNITED NATIONS. ECONOMIC COMMISSION FOR ASIA AND THE FAREAST. Glossary of hydrologic terms used in Asia and Far East.1956. Bangkok.

3

IS: 4410 ( Part X: Sec 1 ) - 1972

INDIA. INTERNATIONAL COMMISSION ON IRRIGATION AND DRAINAGE.Multilingual technical dictionary on irrigation and drainage,1967.

INDIA. CENTRAL BOARD OP IRRIGATION AND POWER. Glossary ofirrigation and hydro-electric terms and standard notations usedin India, 1954. Manager of Publications, Delhi.

American Society of Civil Engineers. Nomenclature for hydraulics.196~. New York.

0.4.1 All the definitions taken from ( Multilingual Technical Dictionaryon Irrigation and Drainage' are marked with asterisk ( • ) in the standard.

I. SCOPE

1.1 This standard (Part XI/Sec 1) covers definitions of general termsrelating to hydrology.

2. GENERAL TERMS

2.1 Anchor Ice - Ice formed below the surface of a stream or otherbody of water on the stream Led or upon a submerged body or structure.

2.2 Arid - A term applied to regions where precipitation is so deficientin quantity, or occurs at such times, that agriculture is impracticable with­out irrigation.

2.3 Avalaoche--·< A moving mass of debris, snow and ice, sliding rapidlydown a mountain slope.

2.4 Barograph - An instrument designed for automatic recording ofatmospheric pressure. <

2.5 BarOuleter - An instrument for measuring pressure of theatmosphere,

2.6 Brook- A small shallow stream turbulent in character.

2.7 Climatic Cycle - Actual or supposed recurrences of such weatherphenomena as 'Net and dry years, hot and cold years, at more or lessregular intervals, in response to long-range terrestrial and solar influences.

2.8 Climatic Year -- Continuous twelve-month period selected forpresentation of hydrologic and meteorologic data.

2.9 Climatology - It is a subdivision of meteorology which deals withthe average or normal or collective state of the atmosphere over a givenarea within a specified period of time. It implies the study of climate

IS : 4410 ( Part XI/Sec J ) ~ 1972

including the statistical relations, mean values, normals, frequencies,variations and distribution of meteorologic elements.

2.10 Cryology- The science of ice in all its forms, such as snow, ice andhail.

2.11 Drainage Area, Draillage Basiu. Catchment, Catchment Area,Catchment Ba.in, Riv~r Basin* - The area from which ;\ lake,stream or waterway and reservoir receives surface flow which originates asprecipitation.

2.12 Drought- In general an extended period of 'dry weather or aperiod of deficient rainfall that may extend over an indefinite number ofdays, without any set quantitative standard by which to determine thedegree of deficiency needed to constitute a drought. Qualitatively, it maybe denned by its effects, as a dry period sufficient in.length and severity tocause at least partial crop failure.

2.13 Dry Weather Flow· - The flow of water in a stream during thenon-rainy season.

2.14 EfBuent Stream, Gaining Stream - A stream or stretch of streamwhich receives water from ground water in the zone of saturation, Thewater surface of such a stream stands at a lower level than the water tableor piezometric surface of the ground water body from which it receive-swater. Also a stream flowing out of another stream or out of a lake.

2.15 Ephem.eral StrealU - A stream or portion of a stream which flowsonly in direct response to precipitation.

2.16 Frazil lee - Fine spicules of ice found in water too turbulent forthe formation of sheet ice. It forms in supercooled water when the airtemperature is far below freezing. In some cases the number of spiculesper mil is very large and it resembles a mass of snow. Frazil ice mayextend to the bottom of the stream and dam its flow, thus causing propertydamage or stopping water wheels.

2.17 Frost* - A light feathery deposit of ice caused by the condensationof water vapour directly in the crystalline form, on terrestrial objectswhose temperature is below freezing, the process being the same bywhich dew is formed, except that the latter occurs onlv when the temper­ature of the bedewed object is above freezing.

2.18 Geo-hydrology or Ground Water Hydrology - That branch ofhydrology relating to sub-surface or subterranean waters.

2.19 Glade.. - Body of land icc formed from recrystallized snowaccumulated on the ground; may form where annual accretion of snowis greater than ablation by run off and evaporation. There are two

5

IS: 4410 ( Part XI/Sec 1 ).1972

hroad classes:.1) Ice Streams- which form in mountain valleys and move down

slope under gravity; andb) Ice Caps - which cover large land masses and spread out radially

because of great pressures built up by their weight ( see also 2.32 ).

2.20 Glacier Burst- - A sudden release of a volume of water which hasbeen impounded within or by a glacier.

2.21 Glaciometer* - An instrument for measuring glacial motion.

2.22 Head Watera) The water upstream of a structure, andb) The flow in the upper reaches of a stream near its source.

2.23 Humid - Term applied to land or climates where precipitation isadequate in amount and occurs at such times that agriculture can becarried out without irrigation.

2.24 Hydrogeology - That branch of geology relating to effect of wateron earth.

2.25 Hydrography - The science of measuring and analysing the flowof water, precipitation, evaporation, and allied phenomena, Also thescicnr-e of measuring charting and mapping and studying oceans, seas,rivers, and other waters and their marginal land areas.

2.26 Hydrologic Cycle - A phenomena relating to circulation of waterfrom the sea, through the atmosphere to the land, and thence, often withmany delays, back to the sea or ocean through various stages andprocesses, for example, precipitation, interception, run off, infiltration,percolation, ground-water storage, evaporation and transpiration. Alsothe many short circuits of the water that is returned to the atmospherewithout reaching the sea.

2.27 Hydrologic Equation* - The water inventory equation (inflow =outflow ± change in storage) which expresses the basic principle thatduring a given time interval the total inflow to an area .must equal thetotal outflow plus the net change in storage.

NOTE - For any hydrologic system the terms are explained further in 2.27.1, 2.27.2and 2.27.3.

2.27.1 II1Ji?W - This term as implied in the hydrologic equationincludes:

a) precipitation,b) surface inflow,c) water piped or channelled into the area, andd) ground water inflow while considering a ground water body.

6

IS : 4410 ( Part XI/Sec 1 ) • 1972

2.27.2 Outflow - This term incu..des:

a) surface outflow;

b) ground water;c) water piped or channelled out of the area;d) evaporation;

c) transpiration; andf) interception, that is, precipitation intercepted by foliage and

buildings and returned to the atmosphere without reaching theground.

2.27.3 Change in Storage - This term relates to the cumulative change instorage of:

a) ground water,b) soil moisture,c) snow cover,d) surface reservoir water and depression storage, and

e) water temporarily existing on the surface of the ground as flowingwater ( called channel storage if in channels or detention storageif not in channels ).

2.28 Hydrology --I'he applied science concerned with the water of theearth in all its states - their occurrences, distribution and circulationthrough the uncnding hydrologic cycle of:

:1) precipitation,b) consequent run off,c) stream flow,d) infiltration and storage,e) eventual evaporation, andf) reprccipitation.

It is concerned with the physical, chemical and physiological reac­tions of water with the rest of the earth, and its relation to the life of theearth.

2.29 Hydrometeorology -- Meteorology concerned with water in theatmosphere as rain clouds, snow, hail and its effects on surface and/orsubsurface flows, agriculture, etc"

2.30 Hydrometry -- The measurement and analysis of the flow of wateras well as the measurement of the specific gravity of water or suspensionsof finery divided solids in water.

7

IS: 4410 ( Part XI Sec 1 ) • 1972

2.:U Hydrosphere - Aqueous envelope of the earth, including all oceans,lakes, streams, underground waters, ice in all its forms and the aqueousvapour in the atmosphere.

2.32 Ice Cap* -- Perennial cover of ice and snow over an extensive areaof land or sea.

2.33 Influent Stream or Losing Stream - A stream or stretch ofstream which contributes water to the zone of saturation. The watersurface of such stream stands at a higher level than the water table or;:iC'LOmetric surface of the ground water body to which it contributeswater.

2.34 Intermittent Stream - Stream which flows during a season.

2.35 Isobars- - - Lines joining points of equal atmospheric pressure.

2.36 Isotherms or Isothermal Lines· - Lines joining points of equaltemperatures.

2.31 Limnology - That branch of hydrology relating to water of lakesand ponds.

2.38 Meteorology· - That branch of science which deals withatmospheric phenomena and the basic laws that produce and control suchphenomena.

2.39 Pack Ice - A large body of floating pieces of ice moving togetheras a continuous cover or a rugged mass.

2.40 Perennial* - Flowing during all the year, for example, perennialstream, perennial canal.

2.41 Potamology* '- That branch of hydrology which pertains to surfacestreams, the science of rivers.

2.42 Regeneration - Regeneration, as distinct from return flow, is thewater which enters the river ( or stream ) as percolation or seepage throughits bed and banks.

2.43 Return Flow - Return flow is that portion of the w vrer divertedfrom a river or stream which ultimately finds its way back thrnugh surfacerun off ( visible flow) and as percolation or seepage through the bed andbanks ( invisible flow).

Z.44 River - A large stream for conveying water.

2.45 Semi-arid or Sub-arid -- A term applied to an area or climate,neither entirely and nor strictly humid but with a pronounced tendencytowards arid character in which certain types of crops can be grownwithout irrigation.

8

IS , 4410 ( Part XI/Sec 1 ). 1972

2.46 Semi-humid or Sub-humid - Land or climate, neither entirelyarid nor strictly humid, with pronounced tendency towards humidcharacter.

2.47 Sheet Ice - Ice formed on the surtace of water in lakes, ponds, andstreams where the velocity is low. It starts forming near the banks andthen gradually extends towards the centre.

2.48 Slush Ice* - An unfrozen mixture of water and ice.

2.49 Stream - A natural channel for conveying water.

2.50 Torrent* - A stream of water flowing with great velocity or turbu­lence, as during a freshet or down a steep incline.

2.51 Thermograph - An instrument designed for automatic recordingof temperatures.

2.52 Water Year - Continuous twelve-month period selected formaintaining or presenting records of flow, and or use of water or any riversystem.

9

INDIAN STANDARDS

ON

GLOSSARY OF TERMS RELATING TO RIVER VALLEY PROJECTS

IS: 4410 Glossary of terms relating to river valley projectsIS: 4410 (Part I ).1967 Irrigation practiceIS: 4410 ( Part II )-1967 Project planningIS: 4410 (Part III )-1967 River and river trainingIS: 4410 (Part IV )-1967 DrawingsIS: 4410 ( Part V)-1968 CanalsIS: 4410 (Part VI )-1968 ReservoirsIS: 4410 (Part VII )-1968 Engineering geologyIS: 4410 (Part VIn )-1968 Dams and dam sectionsIS: 4410 (Part IX )-1968 Spillways and siphonsIS: 4410 ( Part X )-1969 Civil works of hydro-electric generation system including water

conductorsystem