Contrary to belief, rainwater harvesting is not costly
Mathematically speaking, rain water harvesting (RWH) reduces the flow of rainwater to the oceans. It is nothing but to check the flow of rainwater and store it in convenient places using appropriate technology, which can be used for agriculture, gardening or drinking purpose. The water collected through harvesting can be directed to borewells so as to recharge the the ground water level. Rainwater harvesting is not new, it is in our culture and tradition and we are doing it since ancient times. Housing societies can easily calculate how much rainwater their roofs can collect by measuring the terrace in square metre and multiplying it by 0.5 cubic metre of rain. For example, if you tell people that your rooftop is capable of collecting 1 lakh litre of water in a season, people find it acceptable and are ready to invest in the harvesting system. The misunderstanding is that is a costly procedure. This water can be used for many purposes besides recharging the borewells and also for drinking purpose if it is filtered.
—Praveen Saptarshi, professor, Sustainability Management, INSEARCH
RWH is a viable option when groundwater level is decreasing
Rainwater harvesting is important for city like Pune. Today, no one actually knows that how much groundwater is being extracted through borewells in the city. Through the construction policy, PMC has made it mandatory for all the housing societies and commercial premises to have the rainwater harvesting system. However, on the other hand, it has also been made compulsory for these societies to have borewells. When we talk about groundwater, we have to consider the aquifers. The groundwater is not an unlimited supply of water, it has its limitations. It is also not necessary that the water percolates into the ground. What is happening right now is that we are drilling borewells without knowing if the groundwater is actually available or not. It is important to know that the aquifers of the ground are absorbing water or not. Using water from rainwater harvesting for watering gardens or drinking purposes is not being done because it becomes a costly affair.
—Siddharth Patil, researcher, Advanced Centre for Water Resources Development and Management
Recycling water in urban areas is the need of the hour
Artificial water harvesting is required because, the natural process of harvesting is being obstructed in the city due to concretisation. The natural recharging of groundwater is blocked by altering the earth’s surface by asphalting, concretisation and construction. For example, when any road is blocked for repairs, we create a bypass for the traffic to flow. However, we are not doing the same when we are blocking the natural harvesting process of rainwater. Few years back, there was news that in Delhi, due to asphalting the roads and over-concretisation, all the borewells in the city had gone dry. Rainwater harvesting is important because trees get water that percolates into the ground. On Senapati Bapat Road, the borewells in most of the housing societies have run dry because there is no room left for natural harvesting. However, besides rainwater harvesting, it is also important to recycle water in urban areas. I have restored to rainwater harvesting in my garden because if we recharge the groundwater, the trees will get water and remain alive and green.
—Prakash Joglekar, environmentalist
Our streams and rivers should not be reduced in size
Due to concretisation and encroachment, natural rainwater harvesting is not taking place and groundwater is getting depleted on a larger scale. We have to ensure that we have our streams and rivers in their natural sizes, with no interventions being carried out by the civic and private bodies. The stormwater drain system designed in our city are all obsolete. Soil is the fastest absorber of water and if we plant trees along the side of the roads, water can be easily absorbed into the ground. It is the best way of stormwater harvesting. We have to redesign our stormwater drain system — they have already been given to the PMC more than two years back. Making rainwater harvesting mandatory for all housing societies is a good step. However, while implementing the system, the builders have to consider the water carrying capacity of each area and then decide what kind of tenement density should be allowed.
—Anupam Saraph, future designer and environmental
New residential complexes have resorted to rainwater harvesting
Rain water harvesting is the need of the hour. The demand for water is increasing with urbanisation and crowding of the cities. There are a lot of residential complexes, especially the new ones, that have taken up rainwater harvesting. As the water cost is increasing and the natural sources are getting polluted and depleted, the industries too, are realising the need for conserving and tapping rainwater in their premises. The government laws are one of the reasons why companies are opting for installing the rainwater harvesting system. However, they are also doing this to improve their brand name and earning a goodwill from their customers. In the past few years, there has been an increase in the number of commercial complexes such as offices, hospitals and educational institutions that have taken up rain water harvesting project and are benefited from it.
—Nishant Tambade, consultant on RWH