Everything you need to know about rainwater harvesting
Rains are barely a few weeks away and it is time to take a look at rainwater harvesting which helps will help in tackling water woes.
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.
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
State/ Union Territory
Under Chapter 3, Section 17(1) of the ‘Andhra Pradesh Water, Land and Tree Act, 2002’ stipulates mandatory provision to construct rainwater harvesting structures at new and existing constructions for all residential, commercial and other premises and open space having area of not less than 200 sq. m. in the stipulated period, failing which the authority may get such rain water harvesting structures constructed and recover the cost incurred along with the penalty as may be prescribed. Municipal Administration and Urban Development have notified that all Group Housing Schemes shall be provided with required facilities and infrastructure for conservation and harvesting of rainwater. Municipal Administration and Urban Development Department vide G.O. No. 185 dated May 5, 2001 have been assigned responsibilities and made special efforts to conserve rain water through rain water harvesting structures in urban environs. Municipal Corporation of Hyderabad, surrounding Municipalities and Panchayats have been made responsible for construction of rain water harvesting pits.
Roof Top Rain Water Harvesting made mandatory by amending building byelaws.
Roof Top Rainwater Harvesting made mandatory for 100 sq m and above by Guwahati Development Authority through including provision in building byelaws.
Enacted “The Bihar Ground Water (Regulation and Control of Development and Management) Act, 2006. Chapter-III (Clause 18) of the Act stipulates provision of roof top rainwater harvesting structures in the building plan in an area of 1000 sq m or more while according approval for construction by the Municipal Corporation / other local bodies.
The Nagar Palika Nigam, Raipur has made it mandatory to adopt the roof top rainwater harvesting having roof top area more than 500 sq ft.
Government of Goa has made rainwater harvesting mandatory for residential complexes including apartments on plot areas of 2000 sqm & above and for industrial units on plot areas of 10,000 sqm & above. PWD, Goa has been asked to take up rainwater harvesting structure for Government buildings.
Metropolitan areas have notified rules under which no new building plan is approved in absence of rainwater harvesting structures.
Rainwater harvesting has been made mandatory by Haryana Urban Development Authority vide notification dated 31st October, 2001 and 13th December, 2002 respectively.
Installation of rainwater harvesting system has been made mandatory for all buildings to be constructed in urban areas of the State and no building plan without rain water harvesting system can be approved. Construction of rainwater harvesting system has also been made mandatory for all schools, Government buildings and Rest Houses, upcoming industries, bus stands etc.
Ranchi Regional Development Authority amended building byelaws in November, 2006 and made adoption of rainwater harvesting and recharge well mandatory for multi-dwelling and commercial units.
Amended Rules of Bangalore Water Supply and Sewerage Board which provide for mandatory provision of rainwater harvesting structures by every owner with area of 2400 sq.ft and above, or every owner who proposes to construct new buildings with site area more than 1200 sq. ft.
An amendment was made in Kerala Municipality Building Rules, 1999 incorporating rainwater harvesting arrangements.
Incorporated mandatory provision for rainwater harvesting in the M.P. Bhumi Vikas Niyam (1984), Rule 78 (4) makes it mandatory to provide for rainwater harvesting in all houses of more than 140 sq.m.
Launched rain water recharge scheme named “Shivkalin Pani Sathawan Yojana” (Shivkalin Water Recharge Scheme) in the State from 2002. Under this scheme, drinking water sources are strengthened by recharging rainwater through different water harvesting structures. This scheme is implemented in rural areas. In urban areas, keeping in view the constraint of the available space, provision has been made in the Development Control Rules to make provision of rainwater harvesting scheme in Greater Mumbai Municipal Corporation Area and other Municipal areas of the State.
Roof Top Rainwater Harvesting made mandatory for buildings above 100 sq.m area.
The State Government has made provision for roof top rainwater compulsory for all new Government buildings.
The Odisha Legislative Assembly has already passed a bill during 2012 on “Ground Water(Regulation, Development & Management)for the state of Odisha. The bill contains provisions for roof top rain water harvesting and artificial recharge for buildings, particularly in urban and peri-urban areas of the State.
Department of Local Government have amended and notified the building byelaws and have made mandatory Rainwater Harvesting System in all buildings above 200 sq. yards. The same has been adopted by all Urban Local Bodies of the State. Punjab Urban Development Authority has also made provision of rainwater harvesting mandatory in all institutional buildings while approving building plans as well as licensed colonies developed by private promoters.
Provision of rainwater harvesting made mandatory in respect of plots having more than 300 sq m area in Nagar Nigam/ Nagar Parishad/ Nagar Palika area and notification in this respect issued vide letter dated 16.01.2006 by the Local Self Department.
Springshed development has been made by Rural Development Department, Sikkim for augmentation of drinking water supply in rural areas.
It is mandatory for all the existing and new buildings to provide rainwater harvesting facilities under Municipal laws. It has also been made mandatory to include roof top rainwater harvesting structures in the plan of the building itself for accordance of approval by the relevant Competent Authority.
As per Tripura Building Rules, 2004, water harvesting is mandatory in all new buildings having plinth area more than 300 sq m for all types of uses and in group housing of any size.
Rainwater Harvesting made mandatory for all new housing schemes/ plots/ buildings/ Group housing schemes with separate network of pipes for combined Rainwater Harvesting/ Recharging system. In Government Buildings (both new as well as old), installation of rainwater harvesting structures has been made mandatory. For housing schemes of 20 acres and above, it is mandatory to develop ponds/ water bodies in 5% of the total proposed area.
The Government (Awas Evam Shahari Vikas) made rules for compulsory installation of rainwater harvesting system and directed to adopt rules in building byelaws vide order dated 15.11.2003. Accordingly, all the Development Authorities have made partial amendments in the prevalent House Building and Development byelaws/ Regulation.
Government has notified ‘The West Bengal Municipal (Building) Rules, 2007’ and vide its rule No. 168 (13), Part – XII has made rainwater harvesting mandatory for all buildings.
Andaman and Nicobar Islands
In UT of Andaman & Nicobar Islands, rooftop rainwater harvesting has been made mandatory in Port Blair Town.
UT Administration has made installation of rainwater harvesting system mandatory for all buildings (existing and new) located on plot of one kanal and above to recharge ground water.
Dadar, Nagar & Haveli
Roof Top Rain Water Harvesting made mandatory as per Development and Control Rules (Amendments Rules 2009) in all types of buildings, which are constructed in an area of 1000 sq m and above.
Daman & Diu
Daman Municipal Building Model Byelaws and Zoning Regulation, 2002 exists which have provision for construction of sump-well for recharge of ground water. The UT Administration has issued instructions to the local PWD for construction of roof top rainwater harvesting structures. Administration has also advised the local bodies such as Municipality & District Panchayats to make provision for construction of roof top rainwater harvesting structures.
Roof top rain water harvesting made mandatory for building having area of 100 sq m and above by amending building byelaws. Registrar Cooperative Societies has advised all Group Housing Societies to adopt rainwater harvesting in their premises. Requested all Government departments to adopt rainwater harvesting and waste water recycling system. NDMC, MCD, DDA, PWD sanctioning plan by including rainwater harvesting in their buildings.
Made provision of rainwater harvesting mandatory in residential, offices, public buildings, commercial buildings, educational and health institutions and industrial buildings vide Govt. Order Dated 19.3.2010.