description of rainwater harvesting techniques

1. Vigyan Ashram Pabal

2.  No maintainence and electricity required
 Less time required for implementation
 Water available from rain is free from bacteria
 Safe and pure drinking water available
 Less cost involved in implementation

4.  Domestic
This type also known as rooftop rainwater
harvesting.
Water is collected from rooftop into storage
tanks for each family
 Community
This involve larger catchments for collecting
water runoff like reservoirs , village ponds

5.  Diversion
Rainwater collected is diverted to storage
through pipes
 Filtration
Rainwater is filtered to remove impurities like
dried leaves,dust, bird dropping etc
 Storage
Water collected from rooftop is stored in tank

6.  Following Image describes Rainwater
harvesting techniques

7.  Planning and design of water harvesting
Water harvesting Potential = Rainfall(mm) x
Collection efficiency x rooftop or catchment
area
This is explained in next slide

8. Example
A building having 100 sq meter rooftop area
Rainfall = 600 mm per year(0.6 meter)
Assume that collecting efficiency is 70 % due to
leakage etc
Volume of water harvested = 0.6x100x0.7
= 42 cubic meter/42000 liter per year

9.  Catchment/Collection
 Drain Pipes
 Down Pipes
 Gutters
 First Flush pipe
 Filter Unit
 Collection unit
 Pumping Unit

10.  Rooftop water harvesting
 Percolation tanks
 Contour trenching and nala bunds
 Khadin , Johad in dry regions of Rajasthan
 Bandharas or bundings on river in
Maharashtra
 Kuls in glacier region of Himachal
 Saza kuva or jointly owned wells in Aravali
region of Rajasthan