1Arc.Boyce A. Odoko 2Olokpo Morgan I.
3Ealefoh Dominic E. 4Onwuka Okechukwu
1Department of Architecture,
National Institute of Construction Technology, Uromi, Edo state.
2,3,4Department of Building
Technology, National Institute of Construction Technology Uromi, Edo State.
Email: odokoarch@yahoo.com
ABSTRACT
Throughout
Nigeria, from small to large cities, surface open channel storm sewage drainage
system is the choice for rain water disposal. Even municipals with flat
terrain, with all constrains in sloping the storm drain, they invest on the
open channel storm drainage system, still. These open channels accumulates
debris, solid materials, some of the solid objects are deposited into the
channels by the city inhabitants. Besides the solid objects, there are also
large deposits of silt and sand that flows into these open drain channels. The
debris, silt and sand deposited into the open drain channels stays there
permanently with no attempt of removing them by the local city authorities. In
effect, you have stagnant water with solid objects, silt and sand deposit in
the open channels, this becomes permanent home for mosquito, frogs and all
types of insects. At some point, the stagnant water generates extreme bad odor,
circulating through the wind around the community. At this point, it has become
environmental pollution issue, a public health problem for the inhabitants.
This is the situation in most Nigerian cities with the surface storm sewage
drainage system. People get infected by malaria every day from mosquito attack,
yet municipal government authorities allow these surface storm sewage drainage
system to stay with stagnant water without cleaning them. Take for example,
Yenagua, the capital city of Bayelsa State, Nigeria, a coastal city with major
flooding problem due to seasonal heavy rain fall. The city’s choice for storm
drain is the surface open storm sewage drainage system. Throughout the city,
wherever there is any storm drainage, it is the open channel storm sewage
drainage system. The city has a flat landscape and therefore, it is almost
impossible to slope the surface storm sewage drainage system to enable the water
drain away into the river and creeks. In addition to this problem, the roads in
the city are constructed and elevated above ground level for the convenience of
the automobile. As a result, there is constant stagnant ground water on both
sides of the roads in the city. These elevated roads seems to imply a
construction that gives preference to the automobile. This is constantly
creating flooding whenever it rains heavy, the rain water backs-up to the
buildings and flows into the river as well. The buildings get flooded time
after time from the heavy rain fall. As it happens in other cities with surface
storm sewage drainage system, the surface storm drainage in Yenagua are
constantly receiving debris, solid objects sometimes from human inhabitants,
depositing them and when heavy rain falls, these solid objects are injected
into the drain channels along with the rain water. Therefore, most of these
surface storm sewage drainage systems are clogged with solid objects with rain
water.
They become
very good home for mosquitos, frogs, snakes and all types of insects. This is a
major health problem and financial cost on the city inhabitants, they facing
with constant malaria infections, due to the presence of the mosquitos. The
stagnant water generates diseases and each time the city inhabitants are
infected with disease, they bear the financial cost for treatment.
When people
get sick, they do not go to work as a result, it reduces work productivity and
subsequently, it lowers the economic base of the city. Therefore, this letting
of debris, solid objects, silt, sand and stagnant water to stay in the surface
storm sewage drainage system must be properly addressed by the local municipal
authorities. They need to periodically clean up the surface drain channels to
avoid the constant environmental pollution in the community. Better yet, they
should invest in underground storm sewage drainage system.
Keywords: Surface Storm Drainage, Open
Channel Drainage, Storm water Overflow, Flooding, Blockage, Debris
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