Namma
Metro - the biggest clean roof of Bangalore to Harvest Rainwater
Namma
Metro has a potential to harvest around 300 Million Liter RAINWATER every year
Metro
rail infrastructure in Bangalore has created rapid mass transport and also
created one of the largest roofs in public space.
Bangalore
Metro Rail Corporation (BMRC) is one of the urban utilities to have adopted
rainwater harvesting in a massive and practical way. The Metro has made simple
arrangements to catch all the rainwater that falls on its station areas and use
the same for non-potable uses.
The metro Reach 1
to Reach 4 has 44 stations and 33 of them are over ground. The roof are
available in these infrastructures can be of two types.
1. Viaduct with 8.8 meter and
2. Roof of the station above ground
The
stations form a roof area at high density traffic flow and commercial
activities.
The
Viaduct run all along the motor roads and is elevated.
Every
raindrop that falls on Bangalore roads will only go down the drain. But every
drop that falls on the Metro corridor can be harvested. Each of the six
stations on the Metro's operational stretch between MG Road and Byappanahalli
have water tanks of one lakh liter capacity each, to store rainwater.
The
rainwater from the viaduct flows in the direction of the natural gradient as of
the ground / road below. The flow of this water on the top of the viaduct is directed
to the centre and finally reaches the grating at the centre of the pillar.
It
is proposed to harvest roof top rainwater from Stations and Viaduct. The roof
top rainwater from stations is a high volume flow at a busy junction and it is
proposed to channelize this water through underground pipes either under the
road / foot path on inside storm water drain sidewalk. The rainwater pipes
through this underground system is discharged into a system of first flush lock
and filtration system underground at a nearest open space / park / playground /
parking area. The filtered rainwater is temporarily stored in an underground
sump. The stored water will be pumped up and taken for final processing.
Similarly the water collected from the stockyards and rising range of the
station is also tapped / harvested.
The
stored rainwater can be treated at storing or treated on line while pumping.
The rainwater being pure form of water does not have salt and minerals or
chemicals which are undesirable. Treating filtered rainwater is only by
chlorination to remove bacterial contamination.
The
rainwater flowing on the viaduct can be handled in two ways:
1.
Collecting
the discharge from pillars at ground level and laying a trunk line along the
viaduct next to the pillar under the road following the centre of the gradient.
This trunk line leads water to a central location at a park.
2.
Collect
rainwater directly below the grading at the top of the pillars and run a trunk
line in the hollow portion of the viaduct. The pipe will follow the contour and
gradient of the viaduct.
The
trunk line at a suitable point can be drawn out at an intersection at the top
of the pillar and below the Viaduct separate intersections.
Highlights of Rainwater Harvesting @
Namma Metro:
Metro Rail
|
|||
Total length
|
42300
|
m.
|
|
E-W Corridor (Phase-1)
|
18100
|
m.
|
|
N-S Corridor (Phase-2)
|
24200
|
m.
|
|
Width of segments
|
12
|
m.
|
|
Below ground length
|
8822
|
m.
|
|
Above ground length
|
33478
|
m.
|
|
Number of Stations
|
41
|
No.
|
|
Stations above Ground
|
32
|
No.
|
|
Each Station Roof Area
|
4925
|
Sq. m.
|
|
Roof Area-Biyappanahalli Depot
|
48552
|
Sq. m.
|
The above
proposal is only the suggestion from KSCST, IISc, Bangalore.