Maduka Nweke, [email protected]
Erosion menace has lived with many people in Nigeria. This has defied all checks by both states and Federal Government. Communal land has been chopped off while many residential buildings have been swallowed and more going in for it. A lot of things happen that help to bring about erosion. Erosion happens whenever soil and rocks become displaced usually as a result of water, wind or geological shifts. The process happens naturally, and soil erosion is largely responsible for the unique contours of the planet. So knowing fully all these natural disaster prone areas and still developed your property there, then you will not cry if your property is washed away or eroded by gully or flood.
But soil erosion can also be an unnatural process. Excessive land development and agriculture can accelerate the pace of soil erosion. Widespread deforestation removes the complex root systems that hold soil in place. In addition to stabilization, these roots also absorb water, helping to maintain consistent, subterranean moisture levels. Eliminating this vegetation allows soil and water to move more easily. Worse still, the ground contracts and expands unpredictably, loosening even more soil. Left unchecked, this erosion can lead to landslides, floods and severe property damage to area homes. Foundation failure is one of the most common (and costly) results of soil erosion. As a homeowner, what actionable steps can you take to prevent erosion from damaging your property’s foundation? There are a lot of steps in that direction. First of all, you must not build your house in soft soil otherwise you will be courting trouble for yourself. Again if you build on a sloppy ground, you must make sure the land is sticky to withstand denudation.
Anambra State has been an example of states where erosion has wreaked havoc in people’s homes. The extent of damage by erosion in the state is better imagined than beheld. More than 15 local governments in Anambra State are really prone to erosion menace. Many communities have called the state government’s attention to the devastation of their areas by erosion. In the case of Anambra State, some town unions mostly affected while calling on the state government to expedite action on the erosion control, also said pockets of gully erosion has already built up at Ula and Eziagulu villages in Ekwulobia presently. Despite this fact, various villages are doing a lot in controlling the menace of gully erosion by constructing new catchment pits and de-silting existing ones. A lot of warnings have also gone to the villagers to desist from pouring refuse into water channels. Some of these warnings are yielding dividends as town union earmarked fines against culprits. There is every need to educate people on your he use of land, because a larger percentage of the environmental challenges we are suffering today are man-made.
We cannot blame everything on nature. What is happening to the climate today was caused by man. During the inspection of Community Secondary School Obosi erosion site, Mrs Sharon Ikeazor current Minister of State for environment bemoaned the devastating impact of gully erosion on the school and assured that urgent steps must be taken to address the situation. She said that the disruption of education by erosion should not be tolerated. She said that gone are the days when erosion will be disrupting education and people keep quiet. There is urgent need to declare a state of emergency on erosion in Nigeria. Although, her statement is not anything different from various government agencies’ pronouncements. Many a time, it is not enough to make pronouncements, action they say speaks louder than words. For this to be done, government must consolidate its efforts and make it fast too otherwise, the control will outstretch the control is state resources. It is not enough to say what we are going to do differently this time around is to sustain intervention, rather let the intervention start immediately. There was an intervention on an erosion site in 2017, and it has given way because it was not sustained. It will give way because sustainable remediation was not carried out.
A recent visit to two of the communities currently being ravaged by erosion; Oko and Nanka in Orumba North Local Government of Anambra State showed that residents are still fleeing their houses for fear that they may cave in any moment. In Nanka, an indigene of the community and an elder, Mr. Okorie Nwawo said that the gullies in Isiakpuenu Village of Ifite Nanka are older than him, even though he is over 70 years of age. He added that the gullies were not as big as they are today when he was a growing boy. He however recalled that from the time he was a boy, he and his parents had to abandon their residence for fear that it may cave into the gullies, and relocated to another land, where they built their house. But since then, the same language, the same strategy and the same method is being adopted. Promises and promises all the way. Although, Nwawo praised the federal government for the job it is doing at the gullies, using Rhino Maritime and Construction Company, he said better work would have been done, and timely too, if the company did not stop work on the site for some years as a result of non-mobilisation of the contractor by the federal government. This, again indicates that government is only politicizing policies at the expense of human lives. Any serious government should not wait until erosion start wrecking havoc before they start to control it. Erosion control is most necessary because it stops small potholes from developing into gullies.
The purpose of gully control is not so much erosion control as an attempt to limit the effects of erosion which is taking place upstream from the gully. Of course, existing gullies should be prevented from developing further. What measures are taken to prevent or control the process of gully formation depends on the size of the gully and the area to be drained (the amount of water to be diverged). First of all we try to check the amount of water coming into the gully by protecting the soil upstream or even by diverging the water. The velocity of the water in the gully also has to be checked so that it doesn’t scour out further. Smaller gullies can be kept in check by the farmers themselves as follows: As far as possible the water is kept in the middle of the gully so that the walls cannot be undermined. In shallow gullies small dams with an overflow can be laid out with rubble, twigs, stones and wire bolsters. The water can then ooze through these fairly open constructions whereas any transported silt is held back upstream. In this way the longitudinal slope is reduced and with it the flow velocity too. If available, wire netting supported by wooden posts, can be used for smaller gullies.
Protection of the head of the gully can be done by protecting the soil with broken stone, rubble, twigs or similar material. It is also advisable to keep the area around the head of the gully planted up with trees or a tuft forming crop, for example vetiver grass. To prevent trampling by cattle (sometimes even the direct cause of gully formation) preventive measures should be taken by making a good fence (thorny hedge for example). By leading the water along the lower parts of the land you must be sure that water actually comes into the gully.