Rain Water Harvesting for every home/apartment

This post is for everyone in India who wants to implement a rain water harvest in their homes but don't know how to do go about the same.

First the definition: Rain water harvesting means of storing rainwater for useful purposes - like drinking, washing, gardening etc. instead of just letting all the rain water run off into the storm drain (in other words the road next to your house).

Motivating factors: If you are asking why I and you should invest in rain water harvest, basically it is for us to do a bit for the nature and reduce our own water expenses. According to some theories, the next world war is going to be fought over water. Water is becoming more and more scarce, your ground water level is constantly droping and what better way than using some of the water which falls right on your house to offset some of your domestic demands? There are other advantages too. You will prevent rainwater runoffs causing road erosions (I mean what is left of as a road - I bet your city doesn't have a good storm drain), your water bills will reduce, your health could improve - the water you harvested is probably more clean than the one supplied by the corporation/municipality(at least you are in-charge of quality of the water). While using ground water (say from borewell), there is a risk of "Radon" exposure. Radon is a radioactive gas found mostly in deep wells. The amount of radon depends on various factors - rock makeup, depth, region etc. However, it is a common notion that radon exposure increases with older wells (as the water level goes down). I'm no geologist. But my guess, if you implement rain water harvesting/re-charge of borewells, it is going to minimize your exposure to radon (in case you have a borewell).

If you have a little more money and are little enterprising, you could let excess rain water which you cannot use, to recharge your ground water as well - by diverting the water into the borewell which you dug at the time of constructing the house and kept on sucking water for construction as well as present consumption.

According to some statistics, in Bangalore, in a 60 X 40 site if you harvest rain water without wasting a single drop in the entire year, the water so harvested is sufficient to take care of 100 families with 4 members in each for an entire year. With that statistic(okay take it with a pinch of salt), if you own a house (of whatever dimension) and do not harvest rain water, and continue to cry about your water woes, first blame yourselves then the city corporation.

Ok, enough preaching, now some practical ways of implementing rain water harvesting.

The next sections will discuss a few designs, techniques to implement rain water harvest at homes/apartments with an option to recharge ground water as well.

1. Simple with Syntex (Plastic) tanks.





The simplest technique involves diverting your rain water pipe(s) to a single location, running the water through a filter (sponge, wads of clothes) and collecting the water in a drum/storage. You could use two metal grids at the top of the barrel and wedge the filter (sponge/cloth) between the two. You could also cover the filter with a cover if you desire so.

Excess water beyond your storage capacity would get wasted and run off like it did before you implemented this system. However, this is better than doing nothing. It might at least provide you with enough water to wash clothes, your car or pet during rainy season.
2. Large Storage with dirty water outlet



This idea is a little more complex and a more engineered (needs plumber's assistance). In Idea #1, it assumes the barrel can be easily portable and cleaned. For example, the first rains could bring in lots of dirt and you may not want to use it. In case you have a large storage(like a sump), discarding the water you collected from first rain with silt and dirt from your unclean terrace may be a pain. In this design, install a run off valve at a level lower than the intake of the sump. During summer, before the first rains come, keep the dirty water run off valve open. After the first few rains, close the valve and start collecting and using the rain water.
Again a filter at the top of sump intake is assumed - this could be a layer of sponges wedged between two metal grid/grill. The dirt accumulated on top of the filter will automatically run off through the excess water runoff pipe - if they are of floating type. Once in a while you can access the filter and remove any sediments (like soil, pebbles) caught in the filter - or even replace it say once in a year. You could also put a mesh/filter at the top of the terrace where the water gets into the piping.
Make sure there is free flow of water in this system. If there is blockage at the excess runoff, water may accumulate in the pipeline and start collecting over your terrace as well.. Not a bad idea if your terrace is 100% leak proof - it will serve as a reservoir!!. However, in most cases, given the quality of construction you could afford and also due to ethics of your contractor, this may not happen. You will mostly develop few damp spots in your terrace if you are not careful in ensuring free flow of water.
Also, make sure your sump is well insulated from external elements (like the street drain overflowing) and creating a feed into your sump during flood conditions. A valve on the excess water run-off is not a bad idea in such cases to prevent 'feedback'.
3. Storage/Rain water recharge
As a variant of Option #2 above, move the excess water runoff pipe below the filter and connect it to a borewell shaft or open well (if you have one). As simple as that ! In case you had a borewell which did not give you the desired yield, try recharging it - make something out of the money that got sunk.

4. Green design (for new constructions)

• At the time of working with your architect, let him know that you are going to do rain water harvesting (to take care of natural incline of the terrain).
• While reviewing the plumbing lines, ask your architect where the run off of sewage is vs rain water run off (corresponding ducts). Ideally, they should be on different sides of the house (for easy maintenance, prevention of contamination etc.).
• Construct a sump for rain water collection (optional).
• Construct a sink pit 10 feet deep, 4 feet wide(dia). If you have a borewell in your house, the sink pit can be around the borewell. Remove the casing, sorround the bore duct piping with nylon mesh. Lay a layer (2 feet) of large gravel, 1 feet of medium size gravel, 1 feet of char coal (to absorb odor), 2 feet of sand leaving 4 feet of clearance for rain water recharging. The depths, layers could be different depending on the catchment area and other practical limits. At the top of the sink pit, leave a excess discharge outlet to the storm drain, where normally rain water would flow without rain water harvesting.
  

From my personal experience, rain water harvesting works. When my new house was constructed, a borewell was dug and hit source of water at 169 feet depth. I insisted with my architect to implement a rain water harvesting plan. After impelementing a sink pit around the bore well, spending around 25,000 rupees extra, I was wondering if it was really worth the trouble. After couple of years, during a maintenance work with the borewell submersible pump, I discovered the water depth had improved. Instead of reaching water at 169 feet, it was now available at 50 feet depth.

Small Idea for Bangalore's Big Transportation problems

I dropped my uncle near Devegowda Petrol bunk - the plan was he would catch a BMTC bus going towards Vijayanagar, if he couldn't get a bus at this hour (8.00 pm), I was planning to drop him in my two wheeler. There were lots of private buses, vans travelling in that direction and picking willing passengers (for a fee of course). Even my uncle got into a van after unsuccessfully enquiring a few, which were heading in a different direction.
After he left and I came home, I'm now just wondering.... Even though what these private operators were doing wasn't entirely "legal", I thought they were doing had great "customer value". At this hour, the options for commuters were either to wait a long time (or eternally) for a BMTC bus OR pay an exhorbitant amount to Auto rickshaw driver OR take the above third approach for a nominal fee - higher than BMTC perhaps, but certainly lower than an Auto, however much less congested than a BMTC bus.

Now I'm thinking, why can't this paradigm be extended for all private modes of transport ? say two wheelers, cars, vans, institutional buses (TCS, MindTree) - you name it.
As a nay-sayer, I understand the following objections:
* As a commuter I do not trust the person who is giving a ride - what if he kidnaps me or something like that?
* Is this guy a safe driver? What if he drives rash and I get into an accident or something?
* Is this really legal? Will a cop stop this transport and penalize me for not using BMTC or an Auto?

I think the above apprehensions are real. In fact, some of them are also reasons why good-samiritan-private transport owners don't want to car pool/bike pool/van pool with total strangers since "security" is a big concern for them as well. Also, from a lift giver's (pooler) perspective, there is no tangible "reward" for offering a service. If he accepts money, it probably is an illegal transaction (private transport owners cannot indulge in commercial transaction unless they have a yellow board - something like that). Bigger is the worry of being car-jacked or getting into unwanted situations with a bunch of strangers masquerading as lift takers.

However, if there was a mechanism for
* validating the identity of the lift taker(poolee) by the giver (pooler),
* validating the identity of the lift giver(pooler) by the taker (poolee),
* a transactional record created somewhere for audit/security,
* some form of reward was in place - say top ten poolers in city of Bangalore gets gift vouchers in Forum Mall for Month January (or fuel vouchers in petrol bunk),
* some payment mechanism is also in place for poolee (of course you need money to run the above show and give rewards !!!),

imagine what would happen to Bangalore roads :-
1) Crowd in Bangalore BMTC would go down.
2) Auto rickshaw drivers will certainly go crazy - because the number of commuters enquiring them to take somewhere, where the auto drivers obviously do not want to go at the first place, will go down. I know it will hurt their ego - it is the duty of every auto-commuter to enquire if the auto driver is willing. They have the right to sit in their autos, nod their head negatively or even ignore you - go nowhere for eternity. Yeah, they will go if the commuter wants to go right next door of the auto driver's house at one and half times the meter.... I'm digressing, enough of auto bashing...
3) Commuters get to behave more responsibly as a community member - I think we are increasingly becoming intolerant traffic society - Every 'single' driver on the road wants to own the entire road to himself and no one should overtake him/her from the right, from the left. At the next traffic crossing, irrespective of whether the driver sees red, green or yellow, he always have the right of way - if he sees enough space to squeeze his vehicle. On the other hand, if we are driving with fellow passengers - be it family, friends or even strangers, I have a gut feeling, we will all be lot more responsible.

So, after reading this rather long prelude, you are probably asking, "OK, Mr. I got your reason, What is your bloody small IDEA?"

Well here it is:
Create a public-private partnership firm, a Non-profit (or small profit) organization of some sort where swipable photo-id transport credit cards are given to poolees. Poolers could have card swipe readers attached to their cell phones. A centralized service (SMS/Cell phone based) keeps track of pooler/poolee transactions. Poolers get transport credits - based on number of lifts given, distance of lift or a combination of both - encashable as vouchers/coupons if meets the criteria. Poolees charge their transport credit cards when they run out of enough units - by paying money - either through internet or their own registered cell phones. Poolers have stickers on their transports identifying them as valid "service providers" - they also could have a photo id issued by the same organization. Bigger vehicles could even display destination where heading to.

There are some legal, liability,technical, financial aspects that need to be taken care of. I think that is a technicality that can be resolved by putting like minded brains together (lawyers, transport officers, MBAs, IT professionals, sponsors).

Any takers?

-dheera.