SRIDHAR D IYER
India is blessed with two monsoon seasons because of a unique wind system. There is the ‘summer’ monsoon between June and September and occurs because of South West moist-bearing winds from the Indian Ocean, during which period Goa receives ample rainfall.
The other is the ‘winter’ or ‘retreating’ monsoon, between October and December, due to the moisture brought by North East winds from the Bay of Bengal. This monsoon has an insignificant effect on Goa.
Despite these two monsoons much of the time, and in several States, there is an acute shortage of water. People in remote areas walk kilometres to fetch water for their daily use and in urban areas people get limited or irregular water supply due to poor water management, misplaced priorities, pilferage etc.
Furthermore, filling of wetlands and lakes to construct infrastructure and buildings hamper the percolation of rain water which in turn leads to flooding and wastage.
Water conservation experts propose several ways to collect, store, save and share water such as by river linking, recycling, rainwater harvesting (RWH), limiting consumption amongst others.
All these methods are of different scales but doable by the government and by the people. Interlinking of rivers are in the offing so as to ease the water situation while the other measures are implemented in different degrees but more needs to be done.
RWH involves collecting the rainwater that flows on the ground and from the roof in an underground or ground-mounted tank.
Rainwater Harvesting
RWH involves collecting the rainwater that flows on the ground and from the roof in an underground or ground-mounted tank. There are various ways to store and/or treat the collected rainwater.
- Using PVC or GI pipes, channelise the rainwater that falls on the ground and from the roof into a cement or plastic tank. Use this water for washrooms, gardening, and for washing of utensils and vehicles.
- To remove the impurities, pass the collected water through sediment filters. The filtered water could be passed through carbon, chlorine and if necessary ultra-violet media and this treated water could be stored and utilised for drinking and cooking.
- An underground storage tank of plastic or cement with connecting pipes and filters.
- Lay pipes from the roof and recharge the borewells.
The cost and size of the RWH system could be as low as Rs 15,000 or a few lakhs depending on factors such as for individual houses, societies with several flats, whether to be built for an existing or new building.
The cost and size of the RWH system could be as low as Rs 15,000 or a few lakhs depending on factors such as for individual houses, societies with several flats, whether to be built for an existing or new building.
The cost could reduce if RWH is built during the construction stage of a building. In industrial estates there could be a common RWH so that the expenses could be shared by the establishments.
Installing a RWH system is not rocket science and could be done by watching YouTube videos and with the help of an experienced plumber. Alternatively, guidance could be sought from the Public Works Department (PWD) and Department of Water Resources (DWR).
Installing a RWH system is not rocket science and could be done by watching YouTube videos and with the help of an experienced plumber.
RWH Scenario in Goa
Goa, with an area of 3,702 sq km and a population of about 17 lakhs and annually crores of floating population and tourists, has its share of water problems.
This is even though Goa receives an average rainfall of 100 inches (250 cm) and has no major industries that are water-guzzlers. Goa has seven dams and reservoirs: Selaulim 7,324 acres, Anjunem 625 acres, Chapoli 272 acres, Amthane 168 acres, Panchawadi 131 acres, Gaunem and Tillari.
These are insufficient to store the copious rainwater and leads to immense run-off into the rivers and the Arabian Sea.
During the summer, the water level in the dams quickly depletes and people depend on water tankers. Incidentally, even during peak monsoon some places do not receive tap water.
The Goa government had notified a policy on rainwater harvesting with subsidies in 2008 and through an amendment the subsidies were substantially increased.
The policy includes water management techniques, collection of rainwater and recharging of groundwater and borewell and RWH pits. The policy necessitates RWH in residences (including apartments), commercial complexes and industrial units that are built on plots of 2,000 sq m, 1,500 sq m and 10,000 sq m and above, respectively.
The Goa government had notified a policy on rainwater harvesting with subsidies in 2008 and through an amendment the subsidies were substantially increased.
The policy may be difficult to apply in existing buildings due to lack of space, and presence of septic tanks, soak pits and drainage pipes that could hinder RWH.
Most times, builders seek approvals for release of water connections after completing the projects. To stop this practice, in November 2023 the PWD was to notify that the builders must obtain water availability certificate for domestic and other purposes before starting the projects.
The PWD should insist that builders have RWH to reduce the dependency on PWD, water tankers that may be tapping (legally and illegally) and depleting the groundwater.
This would help the PWD to confirm the quantum of potable water available, i.e. minimum, partial or full to a building. Builders would be penalised if they failed to obtain the certificate and need to pay twice the applicable water charges for 10 years.
The builders need to meet the shortfall through their own arrangements. The PWD should insist that builders have RWH to reduce the dependency on PWD, water tankers that may be tapping (legally and illegally) and depleting the groundwater.
In addition, TCP could insist that new dwellings, malls, government and private office buildings have to show RWH in the approval plans.
In addition, TCP could insist that new dwellings, malls, government and private office buildings have to show RWH in the approval plans.
When lakhs of people have insufficient water for basic uses, it is sad to see swimming pools within private residences and gated complexes. The water is mostly from the PWD or from water tankers.
To conserve water, firstly the government should not permit pools in private residences when a corporation pool exists close-by. Secondly, water for the pool could be sourced through RWH facility.
On June 5, 2022 (World Environment Day), former Environment Minister Nilesh Cabral had lamented that only a few people have installed solar panels despite Goa government’s insistence and subsidies.
Similar is the case for RWH. The reasons being, firstly the people are put-off by the initial high cost involved in constructing RWH facility vis-à-vis the conventional methods of laying pipelines for PWD water.
But with subsidies and savings on water bills, one can over a period of time recover the investments and dependence on PWD and reduce expenses in procuring water tankers.
People are put-off by the initial high cost involved in constructing RWH facility vis-à-vis the conventional methods of laying pipelines for PWD water.
Secondly, people baulk due to the time involved and clearances required for RWH. To offset these concerns, TCP, PWD and DWR could work in tandem and frame simple guidelines to implement RWH.
The RWH Policy (Amendment) 2022 had already informed that the State issuing permissions/licenses for building constructions should immediately amend the bye-laws to conform with the policy.
The RWH Policy (Amendment) 2022 had already informed that the State issuing permissions/licenses for building constructions should immediately amend the bye-laws to conform with the policy.
The approvals should be fast-tracked through a one-window clearance to help the builders and individuals to install RWH.
Priority could be given to those who need permissions and forego subsidies, while for others subsidies could be released within three months after an official inspection of the RWH unit. OC should be withheld if the RWH units are absent or not as the approved plans.
Globally the demand for water will grow by 40 per cent by 2050, and 25 per cent of people will reside in countries with inadequate access to clean water.
It is the need of the hour to conserve and use water and in this RWH plays a pivotal role. As it is said, “The next world war could be for water,” since it is postulated that globally the demand for water will grow by 40 per cent by 2050, and 25 per cent of people will reside in countries with inadequate access to clean water.
(Sridhar D Iyer, a marine geologist, retired as Chief Scientist from CSIR-National Institute of Oceanography, Goa)