“Water is the basis of all that is good in life. The most beautiful things happen to us because water provides us with vigor” [Rigveda X-30-10 to 12]
Man realized the importance of water very early. All the ancient civilizations flourished near the rivers like the Indus and the Nile. Water is the main element for all activities including agriculture which provides us food. Life on this planet evolved because of water. Nature has supported life with this precious commodity. With an increasing population and industrialization the demand for water has increased beyond imagination. This has led to an exploitation of natural resources and the ground water levels are decreasing at an alarming rate. People have realized that some serious action has to be taken to prevent this beautiful planet turning into a desert.
Water management is a vast topic, which includes a list of related subjects. Broadly speaking this can be summarized under these headings-
Water conservation
Water recharging
Water recycling
Restoration of water bodies
This has to be on two levels - micro and macro - where individuals and the country have to work together.
Water management through the ages
India has a rich tradition of water management through the ages. From the Vedic period people realized the importance of water and the need for its conservation. With the development of other allied sciences such as astronomy, agriculture, horticulture and mathematics a system of rain forecasting was developed.
The available water was divided into three broad categories namely
Rainwater
Surface water
Ground water
Rainwater was used for agriculture and drinking purposes. It was also harvested and stored in tanks. Tank irrigation is mentioned in the Ramayana and Mahabharta. There are records of lakes and tanks constructed by rulers in different parts of India. A lake was constructed by the king Bhoj Parmar at Bhopal in 11th century AD.
Groundwater currents were identified with the help of the surrounding flora and fauna. Wells were dug on these spots. A detailed analysis of surrounding vegetation to find ground water is given in Lokopakara, a Kannada manuscript written in 1025 AD written by Chavundaraya. It is interesting to find the ancient civilization studied nature in such detail. The manuscript contains a lot of information about where to find water and the various types of water available. Surface water consisted of rivers lakes and ponds. Four types of water reservoirs were in use.
Tanks which were filled with water from external sources
Tanks which used internal springs as sources
Ponds and pools which filled with rainwater
Dams constructed on rivers
Tank irrigation-Tanks both natural and manmade were in use from the ancient period.
In the modern period the demand for water has increased tremendously. Water is needed for drinking, for irrigation and for industries. This has lead to over exploitation of water resources. The digging of bore wells and the use of underground water has depleted the underground water tables. Rainwater harvesting is a practical answer to these problems, which saves money and provides a long-term solution. This is also an energy efficient solution.
What is Rain water harvesting?
The annual precipitation in India is about 4000 cubic km, most of which is received in the southwest monsoon season. In simple terms rain water harvesting is a system to collect and store rain water. The practice is about 4000 years old [Mayers, 1975]. This can be done in two ways. Firstly by catching water at the ground level and secondly by recharging the underground water tables. Through the ages this happened naturally and still does in open fields and in villages. In the cities however, the rainwater flows from rooftops and other areas to the streets where it collects and floods the roads. The concrete structures and the tar pathways do not let the water seep into the ground.
Methods to harvest rainwater
Independent dwellings or multistoried apartments have rooftops that can be easily used as water catching structures. The rainwater has to be brought down by using closed PVC pipes from the rooftops and directed towards a bore-well or a sump. A baby well can also be constructed for this purpose. There is a three-stage filtration system to ensure that the suspended particles are removed. .This filtration system is made of sand brick jelly and broken bricks.
Another type of rainwater harvesting module is to have the surrounding water flow to the gate of the house and let it collect there. A concrete slab with holes is installed at the place covering a 2-3 feet deep pit. This is then connected to a baby well with pipes, which allow the water to flow into the well.
Cost of constructing rainwater harvesting system
This varies from place to place. For a single dwelling it is in the range of Rs 2000-5000 and for a group of 25 flats it is about Rs 60,000 to Rs 80,000 in Chennai. In Delhi and Mumbai the costs are doubled.
Benefits of rainwater harvesting system
The benefits of this system are experienced on different levels–
Individual level
Community level
Ecological level
At the individual level this is a very cost-effective solution, which fulfills water demands in times of need. It provides self sufficiency to an individual.
At the community level it ends the water woes, which sometimes result in fights and quarrels. This also controls water floods in cities at the time of a downpour. It provides water for drinking and irrigation and reduces the cost for public distribution of water.
At the ecological level the system of rainwater harvesting does not create any imbalances .This is a safe option which gives a sustainable water solution. It is a cheap alternative, which saves energy and human efforts required for large projects. This can be used to recharge and restore water bodies and maintain the ground water tables.
List of some NGOs working in this field
There are a number of NGOs working in this field all over India. This issue needs the involvement of individuals and government organizations in a well planned manner. Here is a list-
[1] Akash Ganga Trust –Chennai
[2] BAIF-PuneMaharashtra-Narayan Hegde
[3] Development alternatives Delhi-Dr Ashok Khosala
[4] DHAN Foundation-Madurai Tamilnadu
[5] KRG Rainwater harvesting foundation
[6] MF-Morarka Foundation-Jaipur Rajasthan-Mukesh Gupta
[7] SMSF-S.M.Sehgal Foundation-Gurgaon Haryana-Dr. Suri Sehgal
[8] Tarun Bharat Sangh in Alwar Rajasthan-Rajender Singh
Tank irrigation system
This system had been in vogue in India through the ages. With the advent of large irrigation works and without enough support from the government the tank irrigation system is not in much use. The existing tank structures are also not in use because of poor maintenance and because people have started cultivating on these lands.
Tank irrigation is an important method of storing water. A detailed analysis and study of the existing tank structures and their catchment capacity has to be carried out. In this regard the space borne multi spectral data can play a major role. This can also help in identifying new sites for construction of rainwater harvesting projects. The tank irrigation system should be revived with support from the government for proper maintenance and desiltation of tanks.
According to Agarwal[2001] “Traditional water harvesting systems being simple and sustainable need to be respected and maintained. They carry a lot of historical significance besides contemporary relevance.”
The need is to develop a sustainable water management system. This means that the system should be such that the water needs of the present times are met without creating ecological imbalances in the future. Traditional and modern techniques along with scientific developments can provide a practical solution. The society as a whole should actively participate in these activities.
References
The following books from Asian Agri History Foundation Secunderabad, Andhra Pradesh
www.agri-history.org
[1] Krishi Parashara [Agriculture by Prashara] English translation of Sanskrit manuscript
[2] Vishwavallabha[Dear to the World: The science of Plant Life] English translation of Sanskrit manuscript
[3] Vrikshayurveda[The science of Plant Life by Surpala] English translation of Sanskrit manuscript
[4] Lokopakara [For the Benefit of People] English translation of a 11th century Kannada manuscript
[5] htpp://akash-ganga-rwh.com
[6] Agarwal.A 2001 Drought? Try Capturing the Rain Brief Paper for Members of Parliament and State Legislature. Centre for Science and Environment, New Delhi,India 16pp
[7] Restoration Of Ancient Irrigation Tanks:A Remote Sensing Prospective-R. S. Dwivedi and K.V.Ramana National Remote Sensing Agency Department of Space, Government of India Balanagar Hyderabad 500037
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