Rain water harvesting is very ancient technique of rain water storage & management.

In rainwater harvesting rainwater collected and stored for various usage like farming drinking and domestic purpose.

Some of rainwater harvesting technique like madakas, surangs and tankas.

Madakas

It found in Kerala and Karnataka, it is natural occurring depression of large area with high terrain on three side where rainwater from surrounding slops accumulated this water and it rainwater catch by help of bund built on fourth side.

Surangs

Surangs is less known form of rainwater harvesting mostly use in Kerala. In this method cave or tunnel excavated in hard soil form from which water seeps out of tunnel and flow out in open pond. It is very narrow about 2 ft and long around 100 ft to 200 ft air vent provided at distance of 30 to 50 ft. which will also use for fetch water from tunnel.

Tankas

Tankas is widely use rooftop rainwater harvesting system in Gujarat .Tanka is large storage under ground storage tank. capcity of tank around 20 KL to 30 KL water from roof collected with help of copper channel called rainwater gutter attached to roof.

Vav

Vav is also used in Gujarat as specially it is found in forts in that step well designed and rainwater from surrounding area enter in vav by seepage or trenches. On very old Va with filtration system exist in Junagadh Fort

Storage area of rainwater in Baudh Cave Junagadh

Sand stone filtration system in Baudh cave Junagadh

Water Channels in Baudh Cave Junagadh

Step well (Vav) Adalaj

Ranki Vav (Patan)