Eleven states in the country are hit by drought this year. And, ironically, almost all states face the problem of water logging during monsoon. What if we can stop the surface run off and use this water to recharge the ground water and increase the water table? That’s what rainwater harvesting is all about. It means catching and holding rain where it falls and using it later.

A dried bore-well, a row of soak pits or a tank (below the ground), are all that you need. The open spaces such as rooftops, grounds can be used as catchment (surface to catch rain).

According to central ground water board, out of the total geographical area of 3,287,263 sq km of the country, an area of 448,760 sq km has been identified suitable for artificial recharge.

Check storage status of 91 storage reservoirs of the country


Facts about rainwater harvesting
 

• Allahabad became first city in north India to promote rainwater harvesting through surcharges in the house tax. The rule gives a two percent rebate in house tax in the buildings with rainwater harvesting systems. But if the houses have no such systems, additional surcharges can be imposed and house tax gets increased.

• All government departments, PSUs and institutions buildings must have rainwater harvesting system.

• In Delhi, rainwater harvesting mandatory in all institutions and residential colonies in notified areas (South and southwest Delhi and adjoining areas like Faridabad, Gurgaon and Ghaziabad). The CGWA has also banned digging of tube wells in many areas.

• Some states provide subsidy to farmers who practice rainwater harvesting.

• In Germany, they collect rain taxes for the amount of impervious surface cover on a property that generates runoff directed to the local storm sewer. READ more here

 Why it is important
 

• According to central ground water board, ground water levels have declined both in hard rocks and alluvial areas. Areas most hit by the excessive extraction are in the states of Rajasthan, Gujarat, Tamil Nadu, Punjab, Delhi and Haryana. See state-wise availability of ground water here
   

• Traditional water harvesting methods, which worked best in arid and semi-arid areas are either missing or have been abandoned.

• In  some  parts  of  the  country  like  Rajasthan,  Gujarat,  Haryana  and  Delhi,  the  in-storage or static ground water resources are also limited and depletion in ground water level is resulting in ground water drought scenario.

• In many cities, ground water is contaminated due to over application  of  fertilisers  and  pesticides,  indiscriminate  disposal  of  effluents  from industries  and  urban  sewerage.

• Surface water (rivers) cannot be used throughout the year as many rivers dry up during summers.

• Ground water abstraction structures have increased from 58,75,909 in 1982 to 1,85,03,267 in 2001. The water has to be replenished at the same rate as it is being extracted.

 Learning from the past

The history of rainwater harvesting systems dates back to 1st century BC.
 

• The Satavahanas (1st Century BC) introduced brick and ring wells for extraction of water.

• During Pandya, Chera and Chola dynasties, lake and well irrigation techniques were developed on a large scale. Large dams were built across Cauvery and Vaigai rivers.

• Large-scale construction of tanks (Tataka) for  harvesting  rainwater  was  also  done  during  this period  in  Tamil  Nadu.  The Chola period  (985-1205  A.D)  witnessed  the  introduction of  advanced  irrigation  systems,  which  brought  about  prosperity  in  the  Deccan  region.

• The Rajput dynasty (1000-1200 AD) promoted irrigation works in northern India. The 647 sq km Bhopal Lake was built under King Bhoja.

• In eastern India, Pal and Sen Kings (760-1100 A.D) built a number of large tanks and lakes in their kingdoms.

• Rajtarangini of Kalhana gives a detailed account of irrigation systems developed in the 12th century in Kashmir.

• In  the  Medieval  period, Mohammad  Bin  Tughlaq  (1325-1351  A.D.)  encouraged the farmers to build their own rainwater harvesting systems and wells.

•  Feroze Shah Tughlaq (1351-1388  A.D.)  built  the  Western Yamuna Canal  in  1355  to  extend irrigation  facilities  in  the  dry  land  tracts  of  the  present-day  Haryana  and  Rajasthan.

• Emperor Shahjahan built many canals, prominent among them being the Bari Doab or the Hasli Canal. Under the rule of Rangila Muhammad Shah, the Eastern Yamuna Canal was built to irrigate large tracts in Uttar Pradesh.

• The Vijaynagar Kings (1336-1548 AD)  in  the  south  took  keen  interest  in  building large  and  small  storage  tanks.

Here's how states are enforcing rainwater harvesting