Seminar on : RAIN WATER HARVESTING

Presented by: Vivekanand. S.Murashillin Xth b Roll no:24 subject : science

RAIN WATER HARVESTING

SAVE WATER:RAIN WATER HARVESTING

WHAT IS RAIN WATER HARVESTINGRainwater harvesting is the accumulating and storing of rainwater for reuse before it reaches the aquifer. 

The principle of collecting and using precipitation from a catchments surface

WHY RAIN WATER HARVESTINGSurface water is inadequate to meet our demand

and we have to depend on ground water.To arrest ground water decline and augment

ground water tableTo beneficiate water quality in aquifersTo conserve surface water runoff during

monsoonTo reduce soil erosionDue to rapid urbanization, infiltration of rain

water into the sub-soil has decreased drastically and recharging of ground water has diminished.

RAIN WATER PATTERN IN INDIATotal annual rainfall in India: 400 million

hectare-meters (area x height)India’s area: 329 million hectaresIf evenly spread, average height: 1.28mActual distribution:

Highly skewed area-wiseThar desert receives less than 200mm annually,

while Cherrapunji receives 11,400mmBut almost every part of India receives at least

100mm annuallyKey: even 100mm annual rainfall

sufficient if harvested properly and where it falls

RAIN WATER HARVESTING TECHNIQUES :Roof top rainwater harvesting.

Surface runoff harvesting .        

ELEMENTS OF ROOFTOP RWHCATCHMENT

COUNDITS

FILTERS

STORAGE FACILITY

METHODS OF ROOFTOP RWHStorage of direct use

Recharging ground water aquifer - Recharging dug wells - Recharging pits - Recharging tube well

SURFACE RUNOFF HARVESTING

Harvesting of surface runoff and storage of the same into reservoirs such as water pans makes it available for use when required.

In this method of collectingrainwater for irrigation, water flowing along the ground during the rains will be collected to a tank below the surface of the ground..

TRADITIONAL RWH STRUCTUREBAWODI:Traditional step wells are calledvavadi in Gujarat, or baoris orbavadis in Rajasthan and northern India.

They were secular structures fromwhich everyone could draw water.

Most of them are defunct today.

JOHADSA johad is a crescent-shaped bund which is built across a sloping catchment to capture the surface water before it runs off.

Water accumulating in the johad percolates in the soil to augment the groundwater. The groundwater then can be used when there is no rainfall.

USES OF RAINWATER HARVESTING

Domestic Use

Agricultural Use

Increase groundwater supplies

POTENTIAL OF RWH

Impacts on downstream flows.Reduce soil erosion.Increase the crop production.Increase infiltration and groundwater

recharge.Improve food & economic security.

ADVANTAGEIt uses local construction materials and labor.Sources of energy are not needed to operate

the systems. The owner/user can easily maintain the

systems. The water is convenient and accessible;

valuable time and effort are saved in collecting and/or hauling water.

 It provides a supply of water to meet future agricultural needs.

RWH: A NOBLE GOAL

A COMMON RESPONSIBILITY

Thank You