Don’t miss the story of the construction of rainwater tanks in villages around Bangalore : Bringing home rain
If you are interested in getting the full version of the movie (18 min.), please ask the rainwater club
Archive for October, 2006
Bangalore is situated on a large plateau, in a semi arid area. Its water comes from a hundred kilometers away. Big pipes bring seven hundred and fifty millions liters a day from the river Cauvery. And still many people have not enough water in this city of 6 millions inhabitants.
We believe that using the rainwater is a part of a more sustainable solution for water supply and also flood problems in Bangalore.For example the rain that falls on the 1249 sq km of our city if converted to daily water would clock 3000 million litres per day. If we harvest or recharge 45% of this water it would be good enough for a populace of 7 million.
The rainwater can be directly stored in tanks or led into the aquifers through open wells.
That is why we would like to involve a maximum of Bangaloreans in the process of rediscovery and reuse of open wells for both recharging groundwater and water supply.
We want to do it through a study of the groundwater.
We will ask for every people that owns an open well to call us and give us some data about it (is it still used or not, what is the level of water in the dry and rainy season…). We will use that contact with people to sensitize them and show through succesful recent case studies how efficient can be an open well when it is well managed. We will send them a simple manual and encourage them to contact us again if they feel they need help.
Through this enquiry, we will have a better knowledge of the water issues in the city. We will map the datas collected (localization of open wells, borewells, rainwater harvesting systems, and the level of groundwater in all the places). This will help us to give some tools to even more people who want to be part of the water solution in our city.
In many parts of India, people are also confronted to this problem of contaminated groundwater .
This excess of fluor in the groundwater occurs through a natural phenomenon.
Some ways to face this problem is to consume directly rainwater wich avoid you to use this groundwater. We can also practice artificial groundwater recharge through rainwater harvesting in order to dilute the fluor in the water.
If you are building a new house, you have to know that water harvesting and water re-use are cost effective and well integrated systems when designed alltogether with the house. Here is a great example of a beautiful and eco-friendly house in Bangalore. The house harvest the rain falling on its terrace through iron chains. The ferrocement filter placed in the entrance, the sight and song of the rain running in the chains please every visitor. The water is after led into a sump tank, noticeable only through its small door. This minimal system allow the house to harvest
more than 60 000 liters of rainwater every year.
At the back of the house, a 25 liters tank has been built at the first floor level,on the external wall. Connected with the exit pipe of the washing machine placed on that same floor, this grey water will run by gravity to flush the ground level toilet.
Let’s meditate on these simple tips that change our wasting houses to smart houses !
Jane was here as our guest at the Rainwater Club. We managed to hijack her from a vacation in South India and the good person she is, she gave us two wonderful days of knowledge.
Jane’s study on school children drinking rainwater and mains water and the gastro enteritis case they have is special. She shared the study with us at Arghyam (www.arghyam.org) . Basically children in South Australia are not particularly higher suseptible to gastro enteritis even though they drink rainwater.
very informative. On the second day Jane joined us in a visit to Kurubura kunte , the village where every household has a rainwater tank. She talked to Venamma and a lot of children. Then we went to see some beautiful Persian wheel still in operation in a town called Kolar. Jane met Thamanna -91- and still going strong and we saw the beautiful village up on th hills. Of course she had to get us some good Australian wine for the trip.
Thanks Dr Jane Heyworth, Perth Australia. Hope to see you in Sydney for the IRCSA conference on rainwater.
Last week, the NGO Samvada in Yelahanka (Bangalore) put its house in the hands of 16 young people from rural areas of all Karnataka. Looking for job opportunities, they want to work on water issues. Thus Samvada, with the help of the Rainwater Club, suggested them to learn how to built a rainwater harvesting system. After mesuring the roof area (127 m²) and the size of the existing tank (8000 liters), they have implemented in the house a new PVC pipes system from the roof to the sump tank, passing through a drum sand-filter. One day work and Rs 3000 have been necessary for them to learn how building such a system for an existing house, and allow Samvada to store 90 000 liters of rainwater every year ! So when will you be ready to put such a simple but effective system in your own house ?
Big questions arise when it comes to rainwater quality. Is it potable? Is there not acid rain? Will it not ‘spoil’ if kept for some days? What about worms? Is it not too soft without minerals? Do we not get a cold if we drink rainwater?
The experts too are a bit confusing on this front.Here is my take.
In all cases check rainwater for potability before consuming. The precautionary principle applies with rainwater too. If in doubt don’t. Our checks seem to suggest that except for Maximum Possible number (MPN), which suggests a bit of bacteria but not of the faecal kind, all other parameters permit drinking. We drink the rain and enjoy it BUT we take care to keep the catchment clean and the filters and the storage tank too.
What do you think?
Tommorrow we do a workshop for the Engineers of the Bangalore Water Supply and Sewerage Board (BWSSB) on rainwater harvesting. This is perhaps more in the nature of awareness building. It will be a nice challenge to win converts here and then will it become a movement in our fair city? Questions questions.