The community cyclone shelters have served well
in saving human lives but death toll continues. These deaths are
caused largely by the reluctance of the people to leave their home
and livestock behind until it is too late to take the (often) long
walk to shelters. Strengthened individual houses with shelters will
remove the causes. Scheme-2, presented here, is a step to future
development and should be treated as an input to a National Reconstruction
Programme. This Scheme will, however, provide “full” protection
only when the Government implements its part as described below.
Land use Plan
A survey should be carried out in the coastal districts
to record the farthest reach of tidal surge and the gradual reduction
of surge height inland. The area along the coast where the surge
height exceeds 3m should be declared a “Red Zone” (RZ) and put permanently
out of bounds for human habitation. People could still use the land
inside the RZ but only for economic purposes, such as farming, cattle
grazing and the like. The band of land that lies immediately on
the coast and is subject to daily tidal action should be forested
to serve as a first line of defence to dissipate the energy of the
wind and the rushing sea during a cyclone. Indigenous mangrove trees
should be preferred for forestation.
Coastal Levee
The line where the surge levels at 3m will be the
location of the second line of defence, a coastal levee. The construction
at this location will cost less than that of an embankment built
closer to the coast. The levee will serve as a strong psychological
barrier and discourage people to build house outside the levee.
The idea should be tested by a socio-economic feasibility before
putting in effect. The concept of this levee, however, will not
be useful in the south for reasons described below.
(i) The innumerable distributaries of the Ganges-Padma-Meghna
river system that flow down to the Bay of Bengal divide the southern
coast into slivers of land. The coastal levees here of necessity
will have to follow the banks of the estuaries to be effective and
thus acquire the shape of polders.
It is not surprising that a system of coastal embankments
was built in the form of a series of polders over a period following
the 1970 cyclone throughout the southern coast of the country. The
polders still exist but many are in disrepair and now of questionable
integrity. The polders should be surveyed and rehabilitated and,
if necessary, raised and upgraded to meet present and forecasted
surge conditions.
(ii) A large section of rural population in the
south is landless. These people have moved to the newly accreted
chars (sandbanks) in search of land and livelihood. They set up
huts on the riverbanks and chars outside the protection of the coastal
embankment with predictable consequence during a tidal surge. These
ultra vulnerable people should be moved to safety and given titles
to homestead lands. A land bank could be created for the landless
by purchasing land in the vicinity of the growth centres (to facilitate
employment opportunities) and establishing cluster villages with
planned resettlement. Government intervention and NGO support will
be critical to the success of such an initiative.
Strengthening House
The Scheme does not propose a large-scale resettlement.
Instead the existing houses will be provided with an elevated “safe
room”, which will be constructed to withstand cyclonic winds at
250 km/hour. Two such rooms could be built contiguously to be shared
by neighbouring families. The twin construction will provide structural
stability and save on construction cost. Each of these safe rooms
will be about 4.80m x 3.60m in plan and will be raised about 3.60m
above ground and provided with a toilet and emergency water supply.
Water will be harvested from the rains, which invariably accompany
a cyclone. The rest of the house will be improved by the owner –
initially strengthening the house by providing stronger supports
and roof and anchoring non-rcc roof against wind uplift. The improvement
could be an incremental undertaking over a period of time as finances
will permit.
Other Measures
a. Each village (50~60 houses) is proposed to be
provided with two power tillers and two thrashers. These should
meet the farming needs and eliminate or reduce the need for keeping
draught-animals.
b. Each village will be provided with a deep set
tube-well for safe potable water.
c. A traditional 3-pitcher
water filter
Traditional
Water Filter
could be provided in each safe room to filter the harvested rainwater.
A plinth level tank will collect the excess rainwater (unfiltered).
d. The villagers will be encouraged to form a Management
Committee, which will raise volunteers from the village and train
them (with the help of an NGO or Disaster Management Bureau) to:
• Maintain the tube-well,
e. People wishing to use the land inside the Red
Zone shall register with and report their going/comings to the Management
Committee in their village. The Committee will organize appropriate
warning and mount, if necessary, search and rescue of the missing,
in the event of an imminent threat of a cyclone or tidal surge.
f. The existing houses within the RZ should be
resettled to a safer area. Adequate inducement should be given to
the people to be displaced to encourage them to move.
g. Cattle shelter could be provided either by constructing
an earth mound or a raised rcc platform on stilts in the village.
The mound will have an edge slope of 1:4. The slope will be planted
with water-tolerant deep-rooted local grass, such as “kash” found
on river banks. The earth-mound/rcc platform will have a flat top
of adequate area with a 1.5m high railing. The platform will additionally
have a flight of wide stairs to the top.
Implementation and Institutional Measures
1. Implementing a successful cyclone protection
programme will require joint effort of the Government, NGOs and
affected people. Motivating the villagers to participate and help
in implementing the programme will be critical to the success of
a reconstruction programme. It is also equally important for the
government to change its policy and attitude towards resettlement
and rehabilitation of the landless and disaster victims. Necessary
institutional reform and administrative framework must follow.
2. Government’s intervention is required for implementing
the survey of the tidal surge, establishing the RZ and construction
and maintenance of the coastal levee/polder. Without an appropriate
legal cover, the establishment and restriction on use of RZ cannot
be enforced. This anticipates drawing up land zoning maps and empowerment
of the district administration for mandatory enforcing of the zoning
in the region.
3. Construction of the safe rooms including the
toilets and the village tube-well is proposed to be carried out
by NGOs and/or private sector initiatives with funds collected for
cyclone recovery. This will likewise include provision of the tillers
and thrashers. Strengthening of the individual house should be the
responsibility of the owner but NGO/Private initiatives could also
be encouraged to assist if the owner lacks the means to do it.
4. The safe rooms will be constructed of rcc frame
and floor/roof. It is important that in designing the safe room
adequate protection against the saline environment is taken and
appropriate materials specified. Adequate compaction must be ensured
in casting concrete members.
The walls of the safe rooms could be built of brick masonry or sun-dried
mud bricks
Mud
Brick
The mixture is molded in a frame and the frame
is removed quickly. After drying a few hours, the bricks are turned
on edge to finish drying. Slow drying (under shade) avoids cracking.
The same mixture to make bricks, less the straw, is used for
mortar. Lime based mortar for the plaster is used to protect against
rain damage.
, if fired bricks are not locally or easily available. A lime-based
rendering
Cement
Lime Render:
Lime Render: 1 part lime putty and 3 parts sand
is another choice for render on abode construction. Lime render,
when it cracks, will self heal – that is, it will close
the small cracks by addition of moisture. Lime is highly caustic
and great care needs to be taken during application; wearing long
sleeved shirt, gloves and safety glasses are recommended.
In both above renders, chicken wire will prevent wrapping.
Ferro-cement: Ferro-cement is made with cement,
sand, water and wire or wire mesh, and if needed, reinforced with
steel wire or steel bars. It is fire proof, earthquake safe and
does not rust, rot or blow down in storm. It has great strength
and economy. The desired shape is built from a multilayered construction
of cement sand mortar (1:4) and chicken wire over a formwork.
The mortar should be laid in layers of no more than 10~12mm thickness
and provided with a layer of chicken wire before laying the next
layer of mortar. The casting is kept moist during hardening to
ensure cement to set and harden. The usual thickness of the finished
construction is 25~50 mm and can be made in-situ or precast. Zinc
coated wire should not be used in the casting.
to the latter wall will protect it against the environment.
5. A strong supervision of construction of the
safe rooms must be provided with proper quality control of the materials
used to ensure durability of the structure against the saline environment.
6. The cost of resettlement of the existing houses
away from the RZ should be borne from the money collected for cyclone
recovery.
About Drawings:
Architect
: Mahbub Haque
Date
: Feb, 2008
Format
: PDF (zip)
Contact
: Email: <bcl@bclgroup.com>
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Layout
Safe Rooms
