Silt Management; Flood Control; Peter Aniediabasi John; Ecolegal Nigeria

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ENVIRONMENT & WASTE, BIOTECH PROCESSES, INDUSTRIAL PROCESS DESIGNS, RESOURCE CONSULTANCY

SILT MANAGEMENT AND FLOOD CONTROL

Suggestions & the Ways Forward

Photo by Peter A. John: 2008

Peter Aniediabasi John Environmental Research Consultant - Nigeria

January 2008

--------------ECOLEGAL SERVICES NIGERIA LIMITED---------

SILT MANAGEMENT AND FLOOD CONTROL Poor town planning in most cities in the world today attracts poor allocation of areas for drainages or wastewater channels. In Nigeria this happens to be a major problem because of not only poor planning but illegal disposal of waste in existing drainages, most especially during heavy down pour. Deposition of sand and other earth materials also contributes to the inefficiency of the drainages. Poor engineering designs of roads can be said to be a major reason why flood remains a problem. Full optional design of an advance road construction requires that slabs be placed on the drain system to avoid easy access of materials either mistakenly or deliberately. Slabs such as these, also end up as pedestrian walk ways with aligned kelps to differentiate road limits from safe walk ways. At strategic locations, gauze is fixed to filter materials for safe removal. The culture of having periodic sanitation exercise still remains the best practice in Nigeria, but due to reluctance and an non-availability of disposal spaces, the excavates returns back to the drainage over time. Good percentage of these excavates are made up of sand, stones and more silt. Regular sweeping of roads after daily human traffic and activities most times, end in the drainage. All these activities contribute to the blockage of drainages, thereby resulting to flood. In some cases, there are no provisions for drainages; instead shallow gutters are constructed for very low and sluggish flows. This resultant condition have special impacts on the roads/structures, human activities, waste management and public health. In this case roads and structures face challenges of gradual water seepages into the matrix of the building material, thereby deteriorating the status of the roads and structures. Human activities is also affected, as alternative means will be used, which may not be friendly to the environment. On the area of waste management, water tend to sweep the waste illegally disposed and will encourage more illegal disposal of waste. Sewage may be disposed in some rural areas, which is encouraged by the presence of the flood, with the thought that it would be driven away by the flood water. The greatest challenge will be the compromise on public health. Stagnant drainages inhabit mosquito larva and pupa, prior to maturity. The success of these stages of growth/developmental cycle determines the prevalence of malaria infection. Other pathogens other than Plasmodium survive from humans environmental malpractices. Waste disposal in drainages also causes growth and proliferation of vectors, pathogens such as bacteria, fungi, viruses, micro-nematodes, helminthes and other parasites and can cause disease conditions and most times death. Siltation is a major problem and requires routine evacuation from drainages. In very busy cities, silt recovery from drainages can be a very lucrative exercise. Major construction require excavations of earth materials, which leaves the earth open precipitation containment, thereby causing small to very large pools with almost steady presence pool water on yearly basis. This is another good habitat for vectors, pathogens and illegitimate human activities. With the increase of developmental projects, there is also a tendency of having more excavations to form borrow pits and a resultant pool of water either from precipitation or surface water recharge. It is advisable to re-load excavated sites (borrow pits) with recovered silts from drainages to avoid both pool of water formation and return of silt into drainages (borrow pit rehabilitation program/exercise). This is one practice that can enable the success of Roll Back Malaria in Nigeria. This single and simple practice can enable the achievement of a sound public health condition and a better, safe, habitable and disease-free environment. Periodic sanitation exercise can be a sure way out, with task force to enforce the routine sanitation of our environment. The Government at all levels should also put in place waste management facilities to further improve disposal at right locations. There are several policies and laws made to check human disposal attitude. It does not end at making laws, it goes beyond law and policy making, it requires all it takes for the government to carry out a waste inventory procedure of various cities and towns for the purpose of designing a suitable waste containment facility for each location. The various facts mentioned here are in line with the various developmental policies and program in Nigeria and the Globe at large.Design This is a clear point of risking our healthEnvironme because of unprofessional Project engineering practice, which can be avoided by enforcing standard developmental project designs, with Inappr A below: proper quality control and assessment. See illustration Disease Affected Low

Parasite Displa Low

F

Wast

Block

Increased Threat to Developmental Programs, such as MDGs *Deteriorating

health

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This article clearly states the relationship amongst some neglected factors needed for development. From the environmental point of view developmental programs can be achieved if proper and safe environmental practices are considered. The populace constitutes the work force of any society and they should be considered if any meaningful development is expected. The various goals are achievable, but proper understanding of the synergy is required. It requires proactive and properly projected minds. **This article is solely owned by Ecolegal Nigeria and should not be duplicated or presented anywhere without permission.

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