Posted on | november 4, 2011 | No Comments
Erosion is defined as the mechanical process of wearing or grinding something down like particles washing over it. It can be caused by water, wind, ice and gravity; what is predominant in South East Nigeria is erosion caused by water called gully erosion which is erosion where water accumulates over short periods of time in narrow channels and removes soil from this area. The situation is despicable with some state government in the region calling for federal assistance and certain groups calling for international assistance.
For long or short term solution, development is key; this to me can be achieved gradually or at once when made priority. Since there is a challenge, we have to bring everything that appears to be a solution to table; manual, natural, automatic and artificial methods, this will bring on short long term solutions and long short term solutions, any of these is expedient because of the heavy rainfall predicted this year by meteorologists in Nigeria.
I have first hand information on dirty practices of certain villagers in that region where they pack sand carelessly in front of their buildings to sell. They assume the roadside in front of their building as part of their space; this makes them hire people to pack and transport clayey from there to points where they are sold; good net-profit and happy land owner right? bad for the environment and their safety, they should be censured.
I did my Youth Service somewhere around that region and I saw what environmental challenges was for the people during dry and rainy seasons. It is something we can work out, It is not an impossibility, It is not rocket science, at the level of our development in Nigeria as a nation, we can keep erosion especially in South East Nigeria at bay. Clayey is predominant in South East Nigeria, which has made farming practices there different from other parts of the nation; we can talk of successful farming in South-East Nigeria (SEN), but still growing are solutions towards erosion and environmental matters.
Erosion in SEN mostly occurs during rainy season, it is said to be caused by water, wind and gravity. Solutions from, manual, natural, automatic and artificial will be proffered in this write up; collectively or separately, they can be applied as long or short term solutions.
Manual, just as road contacts are assigned and carried out, manual methods as make shift solutions can be available state wide with interested youth handed pittance to ensure that sloping water channels by roadside head to a local waterway, this means that they are hired to make or adjust water ways.
It requires a design, mustn’t be from professional architectural knowledge; those in charge will have to build channels in accordance with peculiarity of places, such that small channels are directed to medium channels and medium channels to large channels. Unskilled laborers can build these channels for short term use. The channels are so that fast flowing water finds it path to and through them. Overtime as this works, the channels can be constructed, and made permanent as long term solution to erosion especially in those areas.
Natural, erosion has water make way for self, in SEN, such channels remain permanent during rainy season. Already made channels by erosion can be used as small or middle channel where fast-flowing water should be lead from or to medium or large channels.
Currently depleted land parts can be termed active sites for this writing, stress test, age analysis and conformity maybe necessary to see active sites developed to water channels; these checks will help reduce the risk of causing more damages to the environment when working to convert active sites to medium channels. Not expanding active sites but providing wide pipes as channels that lead to medium or directly to large channels will make sense, cost and protraction may not see this come as short-term solution. Spacious places can have such as permanent solution to be active for many years ahead.
Automatic, this is approached from already known channels that fast moving water make when passing through. Large erosion can take better part of clayey streets, especially with sloping topography obtainable in many places. Since the channels are known, and development maybe gradual for affected areas as long term solution; erosion created water channels will be part of the solution. Using water shock, a well sunk barrier to keep less water flow over it and make more water flow against it, to a direction that leads to a medium or large channel created by the government.
Erosion created channels may also be diverted at some point, such that alternate way is made for water flow lead to government made medium or large channels, this will posit quick recovery for the former erosion created channel and avoid further wash away.
One suggestion comes to mind here, Government contractors should install peculiar erosion control facilities during small and large scale infrastructural development in the region. So far we can thumbs up for government in that region, more effort is however required, it is never enough because we have to win this ‘erosion’ that seek to reduce us.
Artificial, the solution to Erosion in Nigeria is Research because South East Nigeria is of large land mass with different topography; varying solutions are required for different parts of the region.
One solution for everywhere will not just serve completely for all places affected; this implies that as solutions are brought and put forth, further solutions applicable to certain places should be welcome.
Having certain vegetable matter, mulch, along some erosion channels may help reduce erosion, this will be applied at certain places especially within cities; building a large catch basin around some area, may help rest fast moving water before evacuation with pipes away, this will make some sense for other parts also, terracing in some other place will reduce erosion in some other parts; adding gypsum to sand in some other area may enrich its chemical composition to help control erosion; gully reshaping and filling, gully floor stabilization and controlling gully heads will help out in many parts. I will briefly explain the last three below, for their relevance for erosion control in South East Nigeria.
Gully reshaping and filling: Gully is used to characterize a kind of erosion that creates a deep ditch cut by running water especially after prolonged downpour,
It can be created when watercourse balance is disturbed by larger than normal water flows. However, gully can be shaped and filled, for this gully size and amount of fill will be put in consideration. Annual crops can be used to provide a quick cover but water will be diverted during the process, not to interfere with crop growth and development. Topsoil from some other place can be stockpiled and spread over erosion exposed areas, these methods and some described above will be used for gully reshaping and filling.
Gully Floor stabilization: weirs from wire netting can support vegetable growth before the rainy season; vegetable weirs and branches of dead shrubs or trees also help to stabilize the gully floor to keep it from remaining a gully or further depletion. Controlling gully heads: diversion from gully head to a medium or large channel will help to maintain or reduce its width, drop structures to allow run-off to drop vertically to a lower level where energy is dissipated before flowing down the watercourse.
There are have been studies, there will be more studies to see that erosion is not a problem anymore in South East Nigeria; respective state ministry of environment will have to do more work, departments in environmental sciences of higher institutions in SEN should get to serious work also. As a matter of responsibility such work especially for 2011 rainy season should start now. The solutions listed above will be studied more and proffered to places where they exactly apply; locals (both young and old) of places facing gully erosion may be handed questionnaires or simply questions (in English or Igbo) on how they think erosion can be controlled.
There should be erosion control offices in communities to act as information source to respective state ministry of environment, these offices will act as a representative of the government towards erosion to the people and vise versa. Addresses and phone numbers will be available for ease when people will to proffer solution towards this; an aged mother may suggest how they worked things out in the 50’s and young schooled lady may have the picture of a design to let out water because of the good knowledge she has of her place. Suggestions as these will be put together to see that erosion is controlled in such places.
Professionals and groups will work together to ensure that all solutions are put to table and applied; badly bashed regions may be the initial focus of the project this year before others. When SEN state ministries of environment have erosion mitigation as precedence, they can request the Federal Ministry of environment in the way their assistance is needed; increased seriousness can have groups from the international community as coterie to have solutions. This is my first writing directed at solutions towards erosion in Nigeria; I hope to put up further writings.
AUTHOR: David Stephen
E-MAIL: Stephen [at] trpns.com