rain water harvesting, 21

8/7/2019 Rain Water Harvesting, 21

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Presented by:

J S Swati

Guided by:

Prof. Sanjeev Kadam

Environment management



R

ain

Harvesting

Water



What is rain water harvesting?

Why should the rain water be harvested?

Global Population Growth

Constant growth in the population

Natural resources are getting exploited beyond their limits

Meeting the needs of the growing population is necessary

Demographic shifts due to migration i.e growing urbanization

T he Global Water Crisis

Rapid growth in industrialization, urbanization, agricultural

intensification and water-intensive lifestyles

Lack of access to a safe sanitization system



Not depending on the upper stream of the water resources

To avoid the problem of siltation

Availability of water during the times of less rainsDue to urbanization the rain water is not getting stored



Advantages of RWH

Rainwater harvesting systems can provide water at or near the point

where water is needed or used

Rainwater is relatively clean and the quality is usually acceptable for

many purposes with little or even no treatment

The physical and chemical properties of rainwater are usually superior

to sources of groundwater that may have been subjected to

contamination.

RWH acts as supplement to the existing water resources

RWH provides water supply in the times of emergencies

RWH technologies are flexible and can meet almost any requirements

Construction operation & maintenance of RWH is not labor intensive



Rain Water Harvesting

RWH is in existence since ancient times

During ancient period the

Roman villas were designed to take the

advantage of the rain water

The very simple technique of collecting water via jars, pots, roof tops &

simple gutters were used



Considerations in utilizing the rain water

Catchment surface: (roof tops or land) materials which are commonly

used are corrugated, aluminum and galvanized iron, concrete, fiberglassshingles, tiles, slates, etc, non toxic materials or paints should be

avoided

Conveyance system:

Transferring rain water from the catchment surface to storage tanks

Done by connecting one or more pipes to the collection devices

Materials used: Plastic or PVC or other inert substances

Filtering the rain water should be emphasized

Storage tanks:

Should be located below or above the ground level & should be made

up of inert material

Precautions are to be taken so that the contaminations should not

enter the tank



Extraction systems: (e.g., taps/faucets, pumps)

This system should not contaminate the stored waterThe confusion between the normal pipes and the pipes for rain water

should be avoided

Calculations for the required storage is also important



Some of the systems for RWH

Simple roof water collection systems

Larger systems for educational institutions, stadiums, airports: Water

can be collected from roofs & grounds of institutes, stored in

underground reservoirs & then treated for non potable usage

Roof water collection systems: In high-rise buildings in urbanized areas

roofs can be designed for catchment purposes & collected water can be

kept for non potable uses.



Collection of storm water in urbanized catchments : Collection of

water in ponds/reservoirs etc.Water can get contaminated due to

pollution in urban areas, hence water pollution control cost can be

considerable

Land surface catchments: Simple way of collecting the rain water. Can

be done by retaining the flows of flood. There is a possibility of high rate

of water loss due to infiltration. This technique is mainly used foragricultural purposes



Some of the Disadvantages of RWH:During a prolonged drought, the storage tank may dry up.

Maintenance of rainwater harvesting systems, and the quality of

collected water,can be difficult for users.

Rainwater storage tanks may take up valuable space

Some development costs of larger rainwater catchment system

may be too high



Few examples of RWH & utilization across the world:

Tokyo, Japan:

water is collected from the arena of 8400 sq feet roof top for non potable purpose

Berlin Germany

Singapore

Thailand

IndonesiaBangladesh

China

Africa

Tanzania

USA

Generally used for fire fighting drills, air conditioning, toilet flushing,

garden watering, watering green areas,



THANK YOU

rain water harvesting, 21

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