RAIN WATER HARVESTING IN GLN RESIDENCY, CHROMEPET
There is a steep rise in number of families living in Apartments especially in Sub urban areas with high number of dwelling units in one apartment complex. However all such apartment complexes are facing shortage of water during summer . There are cases where few of the apartments rely completely on water tankers to meet even the domestic requirement. GLN Residency, Vaishnava College Road, Chrompet is one such apartment complex with 136 dwelling units and initially relied on water supplied from bore wells. After a year as the occupancy rate got increased, and also yield from most of the bore wells reduced and virtuallystopped it also started depending on the water tankers for the supply of water recalled Mr. Anantha Narayanan, President of Association. At one point of time we need to spend around 1.75 lakhs per month during peak summer month for the purchase of Water.
Water tankers arrival and distribution of water inside the complex is always a painful experience. Lots of heated arguments normally happen for water stoppage of few minutes and distribution amongst different blocks. Neighbours also object water tankers as they block traffic for couple of hours during unloading of water. At this stage Association members came together and started to discuss ways to come out of this situation said M.Raju, Secretary of Association.
It all started once we have noticed water coming out from one of the existing RWH pit intended to collect roof top water and that particular area is flooded very often, and this water ran off to drain. That meant we are not collecting rain water and wasting precious water and on another hand suffering from water scarcity. That is a triggering point for the Association and thereafterwe have started going through various articles regarding Rain water harvesting in newspapers & magazines. Asssociation Members followed up and sought advice from Rain Centre, Chennai a NGO which has spearheaded the cause of rain water harvesting in Chennai successfully. Dr.Sekar Raghavan, Head – Rain Centre along with Mr. Ganesan visited the complex and advised collection of surface water also which runs off during rain along with water which is falling on roof and getting directed to recharge pits. On further inspection , it was found the recharge pits provided are insufficient to hold the water and their design of sand, marble and blue metal is not suitable for Chrompet type clayey soil area. Hence it wasdecided to modifiy the existing recharge wells with cement rings and dig new recharge pits for collection of Surface Water.
Speed Breaker Location Identification – Critical to success
GLN Residency has built in a vast area of 4 acres and collects lots of surface water during rainly season. This water normally goes as waste and runs off to road. To prevent runoff , it was decided to construct speed breakers at various vantage points which prevents water runoff and helps to stop the water in addition to their primary function of vehicle speed restriction. The surface water pits are located near speed breaker so as to collect water accumulated near speed breakers. To summarise each speed breaker acts as a check dam for stopping water, then the water is diverted to a recharge pit by natural gradient / flow/gravity.
By stroke of luck, one spell of rain during Augut 2015 helped us identify the location of Recharge wells and Speed Breakers . A plan was made to dug wells in a phased manner as families were already shelling out around Rs.1200 per month for purchase of water through tankers. Last year alone we spent around Rs.8.75 Lacs for water tanker alone and this for a large scale apartment like us having 136 dwelling units, will be a substantial monthly outgo in addition to maintenance said Mr. K. Balaji, Treasurer of Association.
It was indeed tough task to make Owners / Residentsunderstand the need of additional RWH structures & improvement in the existing structures as we require initial amount to execute the same. There are questions being raised to the extent that Guarantee is being sought to supply water even during summer without water tanker. Association has handled all the Owners / Residents patiently and made them understand the needof such RWH structures. Ultimately without the co-operation from all the Owners & Residents this feat could not
be achieved. We collected Rs.1200 per flat towardscharges of constructing the recharge pits and the Builder was kind enough to build speed breakers at vantage locations recollects Mr. Anand and Ganesh Kumar, Joint secretaries of Association.
Benefits – Success Story:
After installation of RWH structures, we awaited eagerly for rain to come and you won’t believe even when it rains at midnight after 12 till 2 am we used to roam around the apartment to see how effective the RWH structures are location wise reveals Mr. Riaz, Vaitheeswaran, Siva Shankar & G. Karthik Members of Association. While major focus will be usually more on collecting rain water from Roof top in apartments, much water is also wasted as surface runoff during monsoon period. With Growing water crisis in city and sub-urban areas, it is need of the hour to harness rainwater around buildings. Given the average rainfall of 1200mm in the city nearly 113 litres of rain water can be collected in 1 sqft of land per year. Even if only 60% of rainwater percolates in a plot measuring 2400sqft nearly 1.62 lakh litres can be recharged per year. If we could be able to do it in each of the apartment, then we could be able to improve the water table substantially
and do not rely on water tankers. With excess rains during last year, the ground water got recharged sufficiently and this year till date we have not purchased any water tankers reveals Mr. Gunasekaran Mr. Swaminathan and Mr. Rajaguru, elder members of the association. Also water quality is also improved sufficiently the TDS coming down from 1700 to around 900 TDS levels now and is potable.
The benefits of RWH done at GLN Residency , also helped nearly around 100 families in the neighborhoodas the water table in the entire area was increased due to the efforts of association. Now the association is taking up the cause of RWH with neighborhood houses and apartments so that the benefits spread to the entire