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Open Drains Versus Point of Source Infiltration

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Written By RKCHARI - 20 September, 2009

Bangalore BWSSB Analysis sewerage sewage Others education

Open Drains
Point of Source Infiltration
Contamination of rivers creeks, wetland & oceans
Maintains Hydrological integrity og natural water systems
Causes urban flooding
Prevents urban flooding and preserves pure water to be recycled
Depletion of flora and fauna
Maintains healthy flora and fauna
Causes erosion and sediment migration
Promotes soil stability
Uncontrollable water runoff due to excessive flow
Regulates water movement compatible with nature
Soil contamination and degradation
Promotes healthy soil
Causes air pollution
Purifies air
Creates thermal pollution (depletion of ozone layer) and consequent global warming
Eliminates thermal pollution at ground level, regenerates ozone layer and regulates planet temperature
Causes disease infection
Promotes healthy atmosphere
Causes global water contamination
Achieves global water purification
Creates anaerobic conditions which cause oxygen depletion in water and proliferates harmful anaerobic microbial activity
Creates aerobic conditions that oxygenate water and induces aerobic microbial activity
Provides habitat for vermin, snakes, rats and mosquitoes
Eliminates habitat for vermin, snakes and mosquitoes
Creates conditions for human accident and loss of life, particularly of street urchins / children
No possibility of children falling into strong water currents flowing through drains
Tempts urban slum households to dump garbage and even sewage waste
Creates proper civic sense
 The above is an attempt to list out the pros and cons of open drains versus point of source infiltration being presently debated throughout Bangalore after the tragic death of two young children in the last few months.
 
Regards,
Chari

COMMENTS

Excellent comparison of pros and cons

psaram42 - 20 September, 2009 - 12:13

  The points compared are very simple and important yet so difficult for the general public to understand. Many in powers to be refuse to see the obvious as the practice of open drains is there for such a long time almost 2500 years since the Roman Empire times. It is high time that our city of Bangalore takes a lead in abandoning this practice of open drains for the better.

 One point to add perhaps:-

  Point source infiltration widens the existing roads too as the present open drains area can be utilized as nice foot paths!

Some disadvantages too

n - 20 September, 2009 - 18:41

On the infiltration side:

- Higher maintenance cost (though required on a much rarer basis), skilled labour required.

- Higher initial cost. Long-term costs are far more economical (cost to human lives, cleaner etc.)

- Greater learning curve for authorities, requires change in the age-old mindset. This is the most difficult step. Public couldn't care less what happens outside their house. They will welcome it once it becomes apparent that the annual flooding is reduced to a great extent (some flooding will still occur with wastewater drains overflowing with rainwater runoff esp. due to encroachments downstream).

- The screening process needs to be proven and robust (it is).

The above shortcomings are weak and can be easily overcome. There needs to exist strong support for the more modern infiltration system irrespective of who happens to promote it. Very good tabular comparison - all that is needed is graphical/dramatic photos and/or computer-generated graphics to sway the non-technical people as also the decision-makers.

 RKchari Sir,  request you to

thampan - 20 September, 2009 - 19:28

 RKchari Sir, 

request you to kindly clarify a quick doubt 

what is the rate at which the infiltration will take place ? ( how many cubic centi meters of water per second in one infiltrator, dimensions of the infiltrator)

Wanted to calculate the time it would take to clear off a storm burst in bangalore by infiltration.

Responding to Comments

RKCHARI - 21 September, 2009 - 01:34

Dear Psa, n & Thampan garus,

I would like to respond point-wise if I may:

1. Higher maintenance cost - not correct as it requires absolutely no maintenance. It is literally fit it and forget it kind of technology!

2. Higher initial cost - again not true as retention tanks are made of recycled, virgin polypropylene resins which costs much less than concrete or rough granite slabs being presently used in lining three sides of the open drain.

3. Annual flooding will be completely eliminated - not just reduced to a great extent. This technology has been tried and tested in 30 countries worldwide and has been proven for the last 40 years!

4. Unable to fathom what the "screening process" implies. Kindly clarify.

5. I have plenty of dramatic power point presentations and videos that I would love to publicise as much as possible. BBMP and BWSSB authorities have all been more or less shown / covered by us. We need an upsurge of public support in the wake of the authorities not being able to handle tragedies like Abhishek & Vijay.

6. Rate of infiltration - we design the retention tank and what covers it to suit the rainfall - quantity and velocity of actual rainfall basis. So infiltration from road surface to retention tank is alomost instant. Infiltration from retention tanks to ground water table can take as long as it likes since capacity to "hold" water temporarily is made to suit quantum of rainfall arrived at after studying (normally) 100 year's rainfall pattern. We install our infiltration systems absolutely in consonnance with scientific data and it is not a hit and miss system.

7. PSA garu, point about extended road width is definitely additional benefit. We have a matching flo-grid cover which is designed to be pevious and yet strong enough to withstand wear and tear for 50 year! So water gets infiltrated from the sidwalks as well as from road ends and in thhe case of a double road having a median, throughh the median area also.

I hope these clarifications help.

Regards,

Chari

BIAAPA

tsubba - 23 September, 2009 - 14:29

chari gaaru.

unsolicited reco.

have you contacted BIAL? that is an important area. as you might know, there is a serious shortfall water table in the area and they have banned drilling there. there is a lake too just behind bial.

also namma metro could perhaps be interested. bmtc ttmcs etc...

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