The city of New Owerri Nigeria is situated on a flat terrain and rainfall pattern is tropical high. The area is the seat of Government of Imo state and is crisscrossed by network of dual carriage roads adjoining exclu...The city of New Owerri Nigeria is situated on a flat terrain and rainfall pattern is tropical high. The area is the seat of Government of Imo state and is crisscrossed by network of dual carriage roads adjoining exclusive housing complexes. The road drainage system comprises open concrete drains on both sides of the cambered asphalt pavement. Much of the area is often flooded after a torrential rainfall and the flood water remains in the drains as long as evaporation permits. A study shows that the scenario is due to a number of factors, amongst which siltation and vegetal growth in the drains, poor drainage outlets are, very gentle terrain and poor maintenance culture. The standing pools of water in the drains sustain massive breeding of mosquitoes which constitute health hazard. Replacement of open concrete drains with properly designed trenches backfilled with permeable earth materials, sand, and overlay of grasses does not only reduce standing time of flood water but completely eliminates stagnant water. The method makes use of enlarged surface area of infiltration provided by the trenchless drain and millions of infiltration channels provided by the grass rootlets.展开更多
文摘The city of New Owerri Nigeria is situated on a flat terrain and rainfall pattern is tropical high. The area is the seat of Government of Imo state and is crisscrossed by network of dual carriage roads adjoining exclusive housing complexes. The road drainage system comprises open concrete drains on both sides of the cambered asphalt pavement. Much of the area is often flooded after a torrential rainfall and the flood water remains in the drains as long as evaporation permits. A study shows that the scenario is due to a number of factors, amongst which siltation and vegetal growth in the drains, poor drainage outlets are, very gentle terrain and poor maintenance culture. The standing pools of water in the drains sustain massive breeding of mosquitoes which constitute health hazard. Replacement of open concrete drains with properly designed trenches backfilled with permeable earth materials, sand, and overlay of grasses does not only reduce standing time of flood water but completely eliminates stagnant water. The method makes use of enlarged surface area of infiltration provided by the trenchless drain and millions of infiltration channels provided by the grass rootlets.
