Fundamentals of Rain Water Harvesting

Vishal BhanushaliEureka Forbes Institute of Environment

May 06, 2009

Vision Living an unpolluted life

is our children’s birthright.

Launched in 2000

Air Pollution

Ground Water Pollution

What is the need for harvesting rain water ?

Water in Urban Space …

Municipal water deficit

City

MumbaiDelhiKolkataChennaiBangloreHyderabad

Need

4000383022583000840956

Shortfall

10308806901050135186

Shortfall %

253030351619

Water in Urban Space …

Municipal water deficit

City

IndoreBhopalLucknowJaipurJabalpurVaizag

Need

318335560349239305

Shortfall

1347012031394.5146

Shortfall %

422121894048

RURAL INDIA IS SCREAMING FOR WATER!

‘Water now precedes roti, kapda, aur makan’

2/3rds of the country has been declared drought prone

90,000 villages declared ‘no source villages’- no source within 7 km radius

Rajendra Singh, Tarun Bharat Sangh

 

Can Bore Wells Help ?

June 2004 – Musampally village Nalgonda DistrictAndhra Pradesh

Population 3000Land 2000 acresBore wells 6000

No typing mistake – There are 2 bore wells per person In this village. More than 85 % never struck water.Others dried up soon after drilling

The Bore wells have worsened the matters

Instead of reducing scarcity, they are increasing it.

We have seen bore wells - 1500 ft deep and drying

Big dams and diversion canals are making down stream older river courses dry

The Bore Wells and The Big Dams

are the real culprits

Ural Sea in Russia Dried by AgricultureAnd Industry

?

There is certainly need for doing everything

possible for conserving water

Where can we learn about water harvesting ?

What are the basic rules?

The Fundamentals ?

Any Degrees, Diplomas ?

Foreign Universities ?

?

It is available every where

In the most pure form

It is free

Yet

There is scarcity

Water Learning Points

There was no water supply department in India till the British Government made one

… Till the British Government had to make one

Ancient India was Prosperous because of Ponds and Lakes Made and Managed by People

Thus achieving water security, irrigation, flood control and food security

Wise Water Management of our ancestors

Modified from Stephen Lemcke, 2002

Modified from Stephen Lemcke, 2002

Modified from Stephen Lemcke, 2002

Varuna

Ganga

Assi

Source - Stephen Lemcke, e-mail: slemcke@sai.uni-heidelberg.de

Marine forts have sweet water

Water Learning Points

Corresponding mainland water is brackish

Water Learning Points

Hill Forts Have Water

Lower lands may not have water

Are these Miracles ?

No !

There are rational explanations

Which can be put to good use

Water Learning Points

Through a well the harvested water is used

Fort walls, Temple and surroundings collect rain water that is stored in a huge pond.

Marine forts have sweet water

Jalashayanam Vishnu Temple … Mahabalipuram

Note the Rock paved surfaceAnd drain channels as well as The large rain water retaining Cistern probably used as rain gauge

Rameshwaram TempleNote the gaps inFoundation and the Sweet water reflecting the shrine

Water Learning Points

Hill Forts Have Water

Lower lands may not have water

Water Learning Points

Fortress walls help to hold micro-water table created by a pondWells give the bounty in usable form

Hill Forts Have Water

Nature offers us Nature offers us our most important needs our most important needs

Nature offers us Nature offers us our most important needs our most important needs

- free of chargefree of charge

Rain Water is one such thingRain Water is one such thingIt is Water – in its purest form It is Water – in its purest form

We only need to harvest itWe only need to harvest it

WHAT is Rainwater Harvesting?

Activity of capturing the rain and storing it for direct use or recharging into the groundwater.

Simply.. catching rain where it falls and using it.

What is the need for harvesting rain water ?

A natural resource presently wastedA natural resource presently wasted Prevents ground water depletionPrevents ground water depletion A good supplement to piped waterA good supplement to piped water Positive cost benefit ratioPositive cost benefit ratio Relatively pollution freeRelatively pollution free Water conservation & self-dependenceWater conservation & self-dependence

Any person planning to build a house Any person planning to build a house An independent plot owner.An independent plot owner. Persons in apartments Persons in apartments Industries, Institutions and factoriesIndustries, Institutions and factories People who are purchasing water for People who are purchasing water for

domestic usedomestic use

Who can harvest rooftop rainwater?

In short, everywhere ……the potential for rainwater harvesting is huge

How Much One Can harvest Rainwater ?

Vol RWH =A x R x C

A=Area

R= Rainfall in meters

C=Runoff coefficient

An example A =100 m2

R = 2000 millimeters C = 0.85

RWH = 1,70,000 litres

Catchments details: Area, type and nature

Sr.No Catchment Area

(sq m)

Collection co-efficient (%)

1. Roof – flat/slope 80-90

2. Paved area

Driveway/courtyard, roads

60-70

3 Unpaved area

Lawns, garden, playground

20-30

WHAT is Rooftop Rainwater Harvesting?

CollectionCollection FiltrationFiltration StorageStorage UsageUsage RechargeRecharge

• Daily Harvesting

Possible in rain forests or areas with prolonged rainy season

Collect daily – Use

Use when available

Types of Rain Water Harvesting – 1

During Rainy season, Drinking water needs of 35-house villageare met by a simple saree based rainwater harvesting system.(Pic: Shree Padre)

Simplest Rain Water harvesting – Use when available

• Harvesting for future use

Necessary where availability is not through out the year

Collect during rains – Store – Use

Storage can be in

2.1 - Tanks

2.2 - Soil strata

Types of Rain Water Harvesting – 2

• Harvesting for future use - Storage in Tanks

Used in havelis of Rajasthan/Kutcch for centuries

Replicated in Moral Re-armament Centre and Ion Exchange Guest house in Panchgani

Roof acts as catchment area.

Under ground Storage tanks act as collection devices.

Usage by fetching from the tank as per need

Types of Rain Water Harvesting – 2.1

Clean Roof

Haveli

Storage tank in the Raised Plinth

Harvesting for Future Use – Storage in TanksUsed in Rajasthan and Kutch

• Harvesting for future use - Storage in Soil

Roof as well as open areas act as catchment surfaces.

Inter particular spaces in soil / rocks are used for storing water.

Water is channeled to structures made for enhanced percolation of the harvested rain water into soil layers

Usage – through Dug wells or bore wells

Types of Rain Water Harvesting – 2.2

Simple Ground Water Recharge Pit

Terrace

Building

Use through well/Bore well

Permeable strata

Subsoil water

Ground water

Harvesting for Future Use – Storage in Soil Strata-IRecharge Pit Method

Recharge PitWith a deeper shaft

Terrace

Building

Use through well/Bore well

Impermeable strata

Subsoil water

Ground water

Harvesting for Future Use – Storage in Soil Strata-IRecharge Pit Type 2

TerraceBuilding

Recharge through well Use through well/bore well

Harvesting for Future Use – Storage in Soil Strata - IIRecharge through Dug well

Subsoil water

Ground water

TerraceBuilding

Recharge through bore well Use through bore well

Ground water

Harvesting for Future Use – Storage in Soil Strata - IIIRecharge through Bore well

Improved Ground water

Harvesting for Future Use – Storage in Soil Strata - IVRecharge through trenches

TerraceBuilding

Recharge through soil Use through well/bore well

Ground water

Harvesting for Future Use – Storage in Soil Strata - VImproving permeability of pavement

• Site Specific

• Slopes

• Geo-morphology

• Space availability

• Usage pattern

• End use specific

Selection of Rain Water Harvesting Structures

If you want to harvest rain water in industrial setting

Take care not to mix it in any way with toxic chemicals, industrial effluents, sewage etc

Allow first flush rain water to go out of the collection system

What is the precaution needed

RAINWATER COLLECTION POND

POND WITH PLASTIC LINING

One Success Story :Aachal Avichal Chanchal

• Situated at Yari Road, Andheri West

• Area prone to flooding

• YET THEY DID NOT FLOOD ON

26th July 2005

• Featured on Doordarshan / BBC

Sunshine CHS, Andheri (E)

• Storm water drainage Rainwater harvesting

Borewell recharge through storm water drainage

List of Societies/Institutes

Wishing all of you Abundance of Pure Air

Clean waterHealthy Food

Yours Ecofriendly,

For

Eureka Forbes Institute of Environment

Vishal Bhanushali – 9869145017

Vishal.b@eurekaforbes.com

Wishing All of you abundance of

Clean Air Pure Water

Healthy Food And

Healthy Body & Rich Soul