No more dry spells at DHOBI GHAT.
All
good omens for the dhobi ghat and the residents of Malleshwaram area in
Bangalore.
Of the
many dhobi ghats in Bangalore, the one is Malleswaram is spread over six acres.
It lies in the downstream of Sankey Tank. This dhobi ghat was once a natural
water body. Decades ago, it was converted into a dhobi ghat, where 250-300
workers wash clothes in shifts. Earlier, the sources of water were
streams of the Vrushabavathi River.
With
time, these streams dried up because of the proliferation of open wells and
borewells in the vicinity. Houses and establishments upstream discharged sewage
into the storm water drain which ran right through the dhobi ghat. Left with
little choice, the washer men had to use polluted water, which they collected
in huge ponds. They added hefty quantities of detergents and chemicals into
cement-ring tanks with their bare hands, leaving them vulnerable to burns and
infection. The clothes with chemicals were rinsed in the huge ponds, leaving
the water even more murky and contaminated. The ponds were drained by
unplugging valves at the bottom once in three-four days. The dirty water was
released in to the Vrushabhvathi.
The
dhobi ghat had a huge well, which went dry 20 years ago. The BBMP got four
borewells dug 18 years ago but all went dry within no time. Water was then
pumped from a public borewell behind Kadu Malleswara Temple in Malleswaram and
piped to dhobi ghat. Fights broke out between the washermen and the local
residents. Soon, even this water yield began to decline.
Distraught,
the dhobis approached Government. Government requested the Senir Scientist A R Shivakumar at KSCST, Indian Institute of Science to come up with a solution.
The
solution
The
dhobi ghat has a steep slope from east to west and north to south. The tanks
are built in the valley at the lowest level. The highest ridge is on the
eastern side and a huge open well is located at this point. As the rainwater
collection area inside the dhobi ghat is not conducive for systematic collection,
it was decided to harvest runoff water from the stormwater drain on 15th
Cross of Malleswaram, starting from Bashyam Circle in Sadashivnagar. The paved
road on 15th Cross has a stormwater drain on either side that
carries rainwater from east to west.
The
upstream stormwater from the stormwater drain on the roadside at the
north-eastern corner of the dhobi ghat is collected with a system of first
flush separator, leaf slide, silt trap and a pebble filter for subsequent
storage. The huge quantity of stormwater is systematically processed.
During
low rainfall and lean flow periods, water in the storm water drain (which
carries pollutants) is not allowed into the water storage system.
During
periods of heavy rainfall and higher flow, the debris, leaf litter and
suspended particles such as plastic covers are allowed over the leaf slide and
relatively cleaner water percolates to silt traps. The silt settles in these
traps and clean water passing through the filter bed is allowed to flow into
the open well in the dhobi ghat which is 60 ft deep.
The
rainwater harvested in this manner is temporarily get stored in the open well
and it also recharges the ground water. The overflow from the well is connected
to 4 underground sumps (of 1 lakh litre capacity each) which are built
strategically in the open space located beside and behind a temple inside the
dhobi ghat. The extra rainwater from one of the underground sumps is allowed to
flow into one of the existing borewells for ground water recharge.
The
stored water from the underground sumps is directly piped, without pumping,
into the wash area as these tanks are located at an elevation.
This
intervention has mitigated the water crisis to a large extent. The 60 ft deep
well, which had gone dry, is now full of water through the year. Two of the
four borewells have been recharged. All good omens for the dhobi ghat and the
residents of the area.