Dr. Akintola Omigbodun is an expert in flood management. In this interview, he says the floods ravaging many states in Nigeria are avoidable. Omigbodun, who fielded questions from Vanguard editors during a visit to the media house, last week, also deplores the Ministry of Water Resources' handling of the crisis and warns that there are grave dangers ahead for Lagos and Ogun states should the water in Oyan Dam not be properly managed.
You are an expert on environmental issues, particularly flooding. What got the flooding story in Nigeria started and was it avoidable?
There is a dam across the River Benue in Cameroon called Lagdo Dam. This dam is about 40meters high. Its storage capacity is about half of what is found in Kainji Lake Dam. And at full flow, if equipment was installed in it, it could possibly generate 700 megawatts of electricity. But the equipment is limited and is only generating about 20 megawatts.
They are also supposed to have an irrigation scheme in that dam. The result is that the dam is storing a huge amount of water and is not being used for any purpose. In the event of so much rainfall like what we have now, the people around the dam would become terrified that it might be overtopped. So the authorities release additional water from the dam.
What we get now is a lot more than what we would get. If there was no dam, the water will continue to flow day in day out. But when you put a dam, you are controlling the flow of water; when you now suddenly release the water because you are afraid your dam will overtop, then it will result to releasing much water. The Lagdo Dam has been flooding every year, just that this year is exceptional. Communities in Cameroon are also flooded. There is a town called Garua; every year, that place is flooded. But in order to save Nigeria, the Cameroonian government should lower their operational level, otherwise, every year, most Nigerian communities will continue to be flooded.
Can we know more about this operational level that you want the Cameroonian authorities to lower?
What really happened was that they opened the gate of their dam. The actual water released from that dam from 1992 to 2002 showed that they opened a number of gates at higher percentages. Floods are associated with rainfall, water courses, streams, rivers, dams and reservoirs where water behind dams are stored. Rainfall is natural while dams and their reservoirs are hand made and are therefore subject to human control. Dam owners and operators are expected to exercise control over the water behind their dams such that in years of heavy rainfall and for singular rainfall events, water passing through the dams does not damage infrastructure or create floods. Earthquakes are natural events and, when they occur in certain regions, there is considerable damage to buildings and other social infrastructure. However, in some areas such as Tokyo in Japan, Los Angeles and San Francisco in the United States, buildings are designed to withstand earthquakes. Damage from natural occurrences can be limited through appropriate human action. For example, the Netherlands has over two-thirds of its economy and half its population below sea level. The Netherlands has about 350km of coastline on the North Sea and major rivers, the Rhine, the Meuse and the Scheldt passing through on their way to the North Sea. The Netherlands has an active coastal and river flood management programme to keep the country flood-proof and maintain its prosperity.
Our experience in Nigeria suggests that dam operators should prepare for heavy rainfall within the next 20 years and for singular rainfall events leading to exceptional floods within the next 35years.
Is there a nexus between the Dam in Cameroon, and the River Benue and the flooding of the Oyan Dam?
There is no physical connection. What we have is operational connection. They (Cameroon) are storing a lot of water in the lake and they are not doing much with it. And when the water is much, they release it and the released water causes flooding.
If they release it in small quantity, it would not have effect, but when they release the water in large quantity, it results to flooding. The Osun River is not in any way connected to the Ogun River or the Niger. That tells you that there is no physical connection. I am hoping that government will live up to expectations. I have personally involved the Ministry of Environment and I must say that I am disappointed with their level of involvement in the crisis. They are just being arrogant.
The Minister of Water Resources has not lived up to expectation and I have met with the Director of Water Resources and I could not get him to do anything. I have also written to the Attorney General of the Federation on the Oyan Dam, so that they can do something about it. We must understand that the dams are designed to have spillways and the spillways guide the release of water. The people are suffering as a result of the flooding and government has to rise to the challenges posed by the flood.
We have River Ogun which starts in Oyo North. And there is a dam in Iseyin. That dam is about 47meters high. There is also a tributary of the Ogun River which also has a dam.
At the moment, the Okere Dam is not gated. There is no gate and water flows over. The dam is supposed to provide irrigation and also generate power. What is important is that the dam is supposed to provide water for Iseyin and environs. Following the non-utilisation of the dam for various purposes, there is huge storage of water. All the things that caused the flooding in Lagos and Ogun are under the control of Ogun River Basin Authority. They should manage the dams in such a way that we do not have flood in the areas of their mandate. We are about to be flooded again like what happened in 2010 and 2011.
I have had experience of the floods along the River Ogun in Ogun State and Lagos State in 2007, 2010 and 2011. The flood path is over 27km long and is up to 4km wide in places. The flood level in 2010 was 0.5m higher than the level of 2007. The River Ogun system has two major dams, the Okere Gorge Dam on the River Ogun at Okere Village 28km north east of Iseyin in Oyo State and the Oyan Dam located about 20km northwest of Abeokuta on the River Oyan, a tributary of the River Ogun.
The Okere Gorge Dam is ungated while the Oyan Dam is gated. The Federal Ministry of Water Resources has been asked to direct that the freeboard in the reservoir behind Oyan Dam should be increased by 4meters as an interim measure pending appropriate studies and a construction programme along the River Ogun from Oyan Dam to Lagos flood plains. Put simply, the floods now taking place yearly at Isheri North, the Lagos wetlands communities and parts of Ogun State and the River Oyan Dam were not built on the River Oyan respectively, floods will occur in the Lagos flood plains within the intervals of 10years and 25years.
With the construction of both dams, floods should no longer occur in the Lagos flood plains if both dams are being operated in accordance with their designs. In the exceptional situation, floods may occur once in 50 years.
For the months of August, September, October for years 1992 to 2002, it was only in August 1993 that there was water release. Presently, exceptional release of water takes place yearly in August, September and October. This was observed in 2007, 20010 and 2011. A greater part of the area covered by flood water in 2007 qualified to be included in the disaster area as opposed to the flood plains of the River Ogun. For example, a newspaper published on Friday, November 4, 2011 that the Itowolo Community Primary School Ikorodu started experiencing flood in 2007. The report indicated that the community was founded over 200 years ago and the community never experienced flood until 2007. Further, when the school was established 30years previously, there was no sign that the school would be affected by water.
Why does flood incidence wreaks so much havoc in the face of the existence of River Basin Authorities? Does it mean that the River Basins are no longer working?
The law establishing River Basin Development Authorities all over Nigeria, which is the River Basins Development Authorities, RBDAs, Act Chapter R9 Laws of the Federation of Nigeria 2004, required RBDAs to control floods in their areas of operations. Under section 4(1) of this Act, part of the functions of the RBDAs is to undertake comprehensive development of both surface and underground water resources for multi-purpose use with particular emphasis on the provision of irrigation infrastructure and the control of floods and erosion and for watershed management. The river basin is also established to construct, operate and maintain dams, dykes, wells, boreholes, irrigation and drainage systems, and other works necessary for the achievement of the authority's functions and handover to be cultivated under irrigation scheme to the farmers.
However, they have not been performing their functions well. Even though the Ogun River Basin Authority is responsible for what we are experiencing here in Lagos, we are not taking them to court because of my not pleasant experiences in Nigeria's judicial system. The truth is that the flood in Lagos and some parts of Ogun State is entirely avoidable.
It is regrettable that the river basins are not working. For example, when I met the General Manager of Sokoto River Basin Authority, he told me that he only had three qualified staff to work with. Why should the government continue to award new contracts to build new dams, when they have not properly managed the ones they have?
Some have attributed this flooding disaster to climate change. Do you in anyway see climate change as a factor?
We should not be talking of climate change and sea level rise as the cause of the flooding because they are measurable. What the New York City panel on climate change said was that the figures of rainfall analysis from 1970 to 2000 indicated that rainfall and snow will only be ten percent different from 1970 to 2000. The rainfall in 1991 for Abeokuta and Iseyin in 1990 was higher than what we have today. People who are doing research on climate change have come up that there are variations in the rate of rainfall in West Africa. That implies that there are years of low rainfall and years of high rainfall change have variables that are measurable. What is needed to be done in the case of Oyan Dam is to lower the operational level by 4 meters.
What can be done proactively to forestall further damages by flood?
The best thing is for the government to perform its functions. I don't think the government is deaf to newspaper publications, even if they are deaf to letters, because I have written in the past and present on how to avoid the present damages that the flood is unleashing all over the country. What we are saying is that they should take correct measures so that we don't experience this kind of disaster again, because the chances of occurring again are real. The water we are seeing in the Niger Delta is River Niger and Benue water, because there is exceptional rainfall in Kainji and Lagdo Dams.
They were forced to release water. In River Benue, for instance, they wait for the water to be so much high before they release it. Government should realise that they are losing economically to the flooding. It affects our GDP and well-being.
My message is that the losses we are encountering as a result of the flood is avoidable. Definitely the flood would unleash food crisis on the nation, because farmers would lose their crops to the flood. We experienced a similar thing in Sokoto in 2010 when the Goronyo Dam wreaked havoc. The same thing will happen as a result of this year's disaster, especially for those that planted by the river side.
BY CHARLES KUMOLU@allafrica.com
what impact does hydropower have on the andes?
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