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IS 14961 (2001): Guidelines for Rain Water Harvesting inHilly Areas by Roof Water Collection System [CED 56: HillArea Development Engineering]

,

IS 14961:2001

Indian Standard

GUIDELINES FOR RAIN WATER HARVESTING INHILLY AREAS BY ROOF WATER

COLLECTION SYSTEM

ICS 13.060.10; 13.060.20

0 BIS 2001

BUREAU OF INDIAN STANDARDSMANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI 110002

July 2001 Price Group 3

_f!-

Hill Area Development Engineering Sectional Committee, CED 56

FOREWORD

This Indian Standard was adopted by the Bureau of Indian Standards, after the draft finalized by the Hill AreaDevelopment Engineering Sectional Committee had been approved by the Civil Engineering Division Council.

In the absence of sustained drinking water sources, rain water collection and storage is one of the effectivemeans to provide drinking water. The term ‘Water Harvesting’ connotes cxdlection and storage of rain waterand also other activities aimed at harvesting surface water, prevention of losses through evaporation and seepage,and all other hydrological studies and engineering interventions aimed at conservation and efficient utilizationof limited water endowment of a physiographic unit such as a watershed or a geomorphic basin.

The water harvesting is affected by:

a) In-situ harvesting,

b) Artificial recharge — methods and structures, and

c) Treatment of catchments for augmenting surface run-off,

h-situ harvesting system is necessary in areas, where (a) rainfall is scanty, andlor (b) water bearing geologicalformations are not available.

In-situ harvesting is affected through natural and artificial sources. Roof water collection system is recommendedas the first option for hill areas and also in arid/semi-arid and coastal areas.

The composition of the technical committee responsible for the forniulation of this standard is given in Annex A.

For the purpose of deciding whether a particular requirement of this standard is complied with, the final value,observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance withIS 2: i 960 ‘Rules for rounding off numerical values (revised’. The number of significant places retained inthe rounded off value should be the same as that of the specified value in this standard.

IS 14961:2001

Indian Standard

.-

GUIDELINES FOR RAIN WATER HARVESTING INHILLY AREAS BY ROOF WATER

COLLECTION SYSTEM

1 SCOPE

This standard covers guidelines for rain waterharvesting in hilly areas by roof water collectionsystem.

2 REFERENCES

The following Indian Standards contain provisionswhich through reference in this text, constituteprovisions of this standard. At the time of publication,the editions indicated were valid. All standards aresubject to revision, and parties to agreement based onthis standard are encouraged to investigate the possi-bility of applying the most recent editions of thestandards given below:

IS No.

277:1992

1239(Part 1): 1990

1254:1991

1536:1989

4984:1995

12701:1996

14243(Part 2): 1995

3 GENERAL

Title

Galvanized steel sheet (plain andcorrugated) @fth revision)Mild steel tubes, tubulars and otherwrought steel fittings: Part 1 Mildsteel tubes (fifth revision)Corrugated aluminium sheet (thirdrevision)Centrit%gally cast (spun) iron pres-sure pipes for water, gas and sewage(first revision)High density polyethylene pipes forwater supply ~ourth revision)Rotational moulded polyethylenewater storage tanks (first revision)Selection and development of site

for buildings in hill areas —Guidelines: Part 2 Selection anddevelopment

Rain water may be harvested in areas, having rainfallof considerable intensity, spread over the larger partof the year, that is, in the hilly areas. Roof watercollection is an ideal solution for water problem wherethere is inadequate ground water supply and surfacesources are either lacking or insignificant. Rainwateris bacteriologically pure, free from organic matter andsoft in nature.

4 ROOF WATER COLLECTION SYSTEM

4.1 In this system roof top forms the catchment.

Typical details of roof water harvesting structures aregiven in Fig. 1 and 2.

4.2 Materials

Although suitable locally available materials of non-corroding, non-rusting, non-absorbent nature arepermissible, for longer life, materials indicated beloware recommended.

4.2.1 Roofing

Galvanized iron sheet (see IS 277), aluminimum sheet(see IS 1254), deleterious glass tibre sheet, concreteclay tiles, slates and other rooting materials. Thatchedroof may be used provided it is covered by water proofsheeting like food grade low density polyethylenefilms.

If the roof is painted, only non-toxic paints be used forpainting the roof. Water collected from roofs paintedwith toxic paints should not be used for drinkingpurposes.

4.2.2 Drain (Gutter)

Galvanized iron sheet (see IS 277), wood, bamboo orreinforced cement concrete gutters.

4.2.3 Down Pipe

Galvanized mild steel pipe [see IS 1239 (Part 1)] castiron pipe (see IS 1536), high density polyethylene pipe(see IS 4984).

4.2.4 Storage Tank

a)

b)

Underground — Masonry or reinforcedcement concrete structure suitably lined withwater proofing materials, high densitypolyethylene tanks (see IS 12701).

Over Grouna7Surface — Galvanized ironsheet (see IS 277), reinforced cementconcrete, plastic/high density polyethylene(see IS 12701) or ferro-cement sheet.

4.3 General Requirements

The following requirements should be considered fordesigning/installing/operating the system, althoughthe choice of the tank depends on locally availablematerials and space available:

a) The tank should be located on slope which isstructurally stable. In case the slope is in the

‘,

1

IS 14961:2001

r ROOF

.._Q-

. . ..

b)

c)

GUTTER

\

MANHOLE + 600 OR600sI 600 WITH COVER

mi M— I -. %s 1 11

100I ,,,,,~ y ‘

4+

~ ‘rr 450

330

k STOP COCK WATER TANK AS PERREQUIREMENT

All dimensions in millimetres and tentative.

Dimensions may be modified depending upon tbe site requirements.

Fm. 1 TYPICALROOF WATER COLLECTIONSTRUCTURES— UNDERGROUND

distress, adequate safety measures betaken before installation of tank [see1S 14243 (Part 2)].

The size of the tank depends upon factors likedaily demand, duration of dry spell, catch-

d)

ment area and rainfall.

The down pipe should be of at least 100 mm

2

diameter with 20 mesh (850 microns) nylonwire screen at the inlet to prevent dry leavesand debris from entering in it. -

Dust, bird droppings, etc, accumulated on theroof during the period of no rain and washedoff with the first rains shall not be allowed toenter the storage tank to contaminate the

,.,

1%,’,

IS 14961:2001

5

I?L-

%

--QLPR------ ------ ----- 1

MANHOLE #$&)mm OR

Y600x 600 mm WITH COVER

+100mm OVERFLOW PIP,

RAIN WATER 25mm BELOW INLET

PIPE 150

r \ ,

7’ ■ J

- I

41

\

STOP COCK * ‘7:

1650

-J+_ .,-,, ‘-‘x” g:%‘

~

‘ ..;.

zDRAIN PIPE WITH

STOP COCK

ROOF

1

EiF-+100mm

RAIN WATER ILPIPE

All dimensions in millimetres and tentative.

Dimensions may be modified depending upon the site requirements.

FIG. 2 TYPICALROOF WATER COLLECTIONSTRUCTURES— OVERGROUND

water. This can be prevented by two methods:

1) Simple diversion of foul water, and

2) Installation of foul flush system.

Under method (l), the down pipe is movedaway fi-omthe inlet of the storage tank initiallyduring the rains, until clean water flows. Undermethod (2), storage provision for initial rainshould be kept in a pipe. These are cleanedafter each heavy rain. These are providedbetween down pipe and the storage tank.

e) Filter materials such as gravel, sand, orcoconut, palm or betalnut fibre, etc, shouldbe used as filter media.

f) Underground storage tanks should be suitablylined with water proofing material andpreferably have a hand pump installed forwithdrawal of water, Their top shall remainat least 300 mm above the ground.

g) The bottom of surface tank should be placedlittle higher than the ground level on a raised

“i

1L ;,

3

._Q_

IS 14961:2001

platform. Anoutlet pipe should be fixed atthe bottom of the tank to facilitate cleaningof the tank. A tap should be provided forwithdrawing water.

h) The following provisions shall be made:

1) a manhole of 600 mm x 600 mm squareor 600 mm dia with cover,

2) Vent pipeloverflow pipe (with screen) of100 mm dia, and

3) Drain pipe at bottom.

j) Before the tank is put into use it should bethoroughly cleaned and disinfected with a

k)

suitable disinfectant such as chlorine,bleaching powder, potassium permangnate.Since the water shall remain stored for quitea long time, periodical disinfection of storedwater is essential to prevent growth ofpathogenic bacteria.

In order to avoid any instability to slopes,excess and after use water should be drainedto the nearest nullah or any natural drains ordisposed through a properly designed outletsystem.

ANNEX A

(Foreword)

COMMITTEE COMPOSITION

Hill Area Development Engineering Sectional Committee, CED 56

Chairman

DR M. N. VILADKAR

Professor, Department of Civil Engineering,

Members

SHRSSHEKHNAZIRAHMEDSm R.C. LAKHERA

DRA. K. CHAMPATDLAY(Alternate)

CHAIRMAN-CUM-MANAGINGDRECtOR

Stmr B. B. KUMAR (Alternate)

CHIEFENGINEER(DAM DESIGN)

SUPERINTENDINGENGINEER(TEHRIDAM DESSGN

CIRCLE)(Alternate)

Ssmr S. S. KHINDA

SHRI JASPRAKASH(Alferrrate)DEPUTYDMECTORGENERAL

SHIOARUNKUMARSHARMA(Alternate)

Drrwcrok HCD (N&W)

DIRECTOR(SARDARSAROVAR)(Alternate)

DR R.K. DIJBEY

DR D. S. UPAOHYAY(Aherrzate)

SHRIT.N.GUPTASrmrJ. K. PRASAD(Alternate)

Mu V. N. PANDAY

SrsrGM.S. BIST(Alternate)

SW B. C. BORTHAKUR

Smr’U. C. BORA (Alternate)

SrsmBHANUPRAKASH

SW SANJAYAGRAWAL(Alternate)

University of Roorkee,

Roorkee -247667

Representing

Public Works Department Jammu & Kashmir

Indian Institute of Remote Sensin~ Debra Dun

National Buildings Construction Corporation, New Delhi

Uttar Pradesh Irrigation DesignOrganization,Roorkee

Ministry of Surface Trrmspo~ New Delhi

Indian Roads Congress, New Delhi

Central Water Commission, New Delhi

Indian Meteorological Departrnentj New Delhi

BuildMig Materials&Technology Promotion Council, New Delhi

Forest Survey of India, Debra Dun

Regional Research Laboratory, Jorhat

Ministry of Railways, New Delhi

.

I

(Continued onpage 5)

4

.

IS 14961:2001

(Continuedfiom page 4)

Members

%ru Knmr KUMAR

.%a R. S. RAWAL (Alternate) ‘

PROFA. K. MAITRAPROFARVINDKRISHAN(Alternate)

DR S. K. SHARMA

DR PRADEEPKUMAR (Alternate)

Smrr P. L. NARULA

Smu S. DASGUPTA(Alternate)Sma K.K.Mmu

SkuuT.V.K.SRIVASTAVA(Alternate)

SssssD. P. PRAOHAN

%5150. P. YAOAV

DRKISHOREKW (Alternate)DRK.S. MOPROFG. RAkfASW~

DR P. C. JAIN(Ahernate 1)

DR S. K, GHOSH(Akernate II)

SrmrBHOOPSINGH

%0 SURASPRAKASH

Smu R. D. SINGH

DR SUDHIRKumsr (Akernate)

DE+J%TOR

ADVISER(Alierrrate)%rraL.mrmm Smrm so~

SswaA.K. SOMDR M, NEELMEGAM

Smu K. MANI(Alternate)SUPERINTENDINGSURVEYOROF Wosuw (NZ)

SURVEYOROFWows - I (NZ) (Alternate)SHRIv. S(103H

Smu R. K. SOFAYA(Akernate)Wru S. C. TIWARI

SW S. K. BABBAR

SHRIK. VENKATACHALAM(Alternate)

DRN. S. VIRDHi

DK R. L. SHARMA

SrrrrrS, K. JAIN,

Director (Civ Engg)

Representing

G.B. Pant Institute of Himalayan Environment and Development, Almora

School of Planning and Architecture, New Delhi

Central Building Research Institute, Roorkee

Geological Survey of Indiaj Kolkata

Engineer-in-Chiefs Branch, Army Headquarters, New Delhl

Sikkim Hill Area Development Board, Gangtok

Central Road Research Institute, New Delhi

Indian Institute of Technology, New Delhi

University of Roorkee, Roorkee

Department of Science and Technology, New Delhi

Directorate General Border Roads, New Delhi

National Institute of Hydrology, Roorkee

North-Eastern Regional Institute of Water and Land Management, Assam

Public Works Department, Shimla

Central Mining Research Institute, Dharrbad

Structural Engineering Research Centre, Chennai

Central Public Works Departmen4 New Delhi

Housing & Urban Development Corporation, New Delhi

U.P. Hill Area Development Board, Lucknow

Central Soil & Material Research Station, New Delhi

Wadia Institute of Himalayan Geology, Debra Dun

Regional Engineering College, Hamirpur

Director General, BIS (E-w@cio Member)

Member-Secretary

Ssca D. K. AGRAWAL

Joint Director (Civ Engg), BIS

5

Bureau of Indian Standards

4_u-

BIS is a statutory institution established under the Bureau of Indian Standards Act, 1986 to promoteharmonious development of the activities of standardization, marking and quality certification of goodsand attending to connected matters in the country.

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Review of Indian Standards

Amendments are issued to standards as the need arises on the basis of comments. Standards are also reviewedperiodically; a standard along with amendments is reaffirmed when such review indicates that no changes areneeded; if the review indicates that changes are needed, it is taken up for revision. Users of Indian Standardsshould ascertain that they are in possession of the latest amendments or edition by referring to the latest issue of‘BIS Catalogue’ and ‘Standards: Monthly Additions’.

This Indian Standard has been developed from Doc : No. CED 56 (5532),4

Amendments Issued Since Publication

Amend No. Date of Issue Text Affected

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