welcomePRESENTATION

RAIN WATER HARVESTINGON

PREPARED BY

prashanth Halemane.

RAIN WATER HARVESTING

A NOBLE GOAL

A COMMON RESPONSIBILITY

WHAT IS RAIN WATER HARVESTING

Rainwater 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 HARVESTING :Surface 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 RWH

Storage of direct use

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

SURFACE RUNOFF HARVESTINGHarvesting 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 collecting rainwater 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 called vavadi in Gujarat, or baoris or bavadis in Rajasthan and northern India.

They were secular structures from which 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.

Kunds Covered underground tank,

developed primarily for tackling drinking water problems.

Usually constructed with local materials or cement, kunds were more prevalent in regions where groundwater is saline.

Before the onset of rains every year, meticulous care was taken to clean up the catchment of the kunds.

Cattle grazing and entry with shoes into the catchment area of the kunds was strictly prohibited.

The proximity of a kund to the house or village saved time and effort in searching for drinking water.

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

FOR

ATTENTION

Special thanks to my group..

1.Prashanth Halemane2.Vinay Vihari…………...