Tuesday, October 19, 2021

Why Flooding Should Be Tackled Aggressively – Nze

Engineer Clement Nze
Engineer Clement Nze

Engineer Clement Nze is the director-general of the Nigeria Hydrological Services Agency (NIHSA). In this interview with NKECHI ISAAC, he restates earlier prediction that as many as 28 states and a high number of local government areas across the `country will either suffer high degree of or severe flooding this season. He identifies population explosion as one of the reasons behind the spike in flooding, urging the desilting of small rivers and regular clearing of drainages to tone down the potential hazards of flooding and mitigate its impact on the country’s economy. The excerpts.

In the past, flooding was not as severe as we have it now, what’s the reason behind the sudden surge in the incidence of flooding in the country?

I will answer this in two or three parts. The issue of flooding has been there for quite some years now. Like the flood disaster in Ibadan, Ogunpaflood disaster, it has been there for a quite a long time but what happens now is that the speed at which information is disseminated is faster within a shorter period of time.

There is heavy traffic of information these days more than ever before. So, whatever happens in any part of the country is quickly disseminated all over the country and globally.

Two, yes there has been aggravated increase of flooding recently because of global warming, heavy industrialization, depletion of the ozone layer, the melting of the icebergs in the Atlantic Ocean and others which have gone a long way to increase the rate of flooding worldwide, not only in Nigeria.

Thirdly, there has been heavy urbanization, in Abuja for instance, the population density has, conservatively, grown more than five times since the creation of the Federal Capital Territory (FCT) in the 1990s. In the face of this influx, we still need to meet one of the basic needs of man, one of them is shelter. And in meeting this need there is so much encroachment on the land, the land is not elastic, while the population is increasing with distortion of the town planning laws, this sees people building on the flood plains. Another issue is human waste, by this I mean solid waste being disposed indiscriminately, blocking the waterways or the natural flood plains. So, these are a few of the reasons why we have increased flooding.

For instance, using Abuja as a case study, so many estates are springing up in the city and there is no environmental or social impact assessment study carried out. Before you can put any structure in an environment you have to study it and predict how the new structure will affect the land. Up till now the estates are being developed without any ESIA or any report, as a result of that nobody presents the flood vulnerability studies of the environment before thousands of buildings are built in a place chosen as an estate site.

Nature has provided for everything. If you do proper delineation, flood vulnerability mapping, it will tell you this is where the flood will pass when it comes.

There is also the issue of the return interval of flood, this means the length of years it will take for a particular flood magnitude to reoccur. Maybe it has not occurred yet and you go and build a house there, in 10- or 20-years’ time when the flood returns and finds out its foot path has been encroached upon it will destroy everything on that path.

These are some of the issues that have accelerated flooding in the recent past.

You identified population explosion as one of the issues causing rampant flooding. The United Nations has predicted the country would be among top 3 largest with a projected population of over 400 million people by 2050. How can the nation manage this massive population to reduce flooding incidences?

This has put enormous burden on government and individuals. The popular adage ‘if you fail to plan you plan to fail’ comes into play here. By this I mean that having gotten this information it behoves on government at all levels to begin to prepare and do proper delineation. Like we are in FCT, with the size of the city that is already inhabited there is still a large expanse of land within Abuja, the issue is that there is heavy concentration within the city centre and then the suburbs are not being planned.

So, government, through the relevant authorities should plan at the federal, state and local government levels to ensure that we will be able to contain the UN population projection. To make proper planning, there should be delineation of spaces within the states. If you go to more developed climes you will see a lot of high-rise buildings which reduce the number of spaces needed for building, government should also consider that. You have more people living in small space because it has so many floors.

Engineer Clement Nze

We are about to enter the peak of the rainy season, what projection has the agency made about flooding in the states and the FCT?

On May 6, 2021, the agency made public its prediction for the 2021 annual flood outlook (AFO). The Minister of Water Resources, Engr. Suleiman Adamu, made the public presentation with over 190 people present and other online participants. The meeting had high level of government participation with relevant commissioners in attendance both physically and online.

In the prediction we said that about 121 local government areas cutting across 28 states of Nigeria will face severe flooding and another 302 LGAs which cut across the entire country will suffer high degree of flooding but not like the first set.

The peak of flooding in Nigeria is usually between the months of July, August, September and early parts of October. There was a period of dry spell in the month of June and even late May, and we keep drumming it into the ears of Nigerians that nobody should go home and rest, that the floods are yet to come and we are expecting that as we step into the month of July the rainy season will step up with attendant flooding. So, the states should be prepared. Letters have been written to each of the governors in Nigeria with names of specific LGAs in their own states they should watch out for. The minister has informed the governors and as follow up the agency has done the same to notify the governors who are the custodian of the states. Our role primarily as an agency is that of advisory, we inform you of a projected occurrence, and proffer measures you are expected to take to reduce the impact of flooding. Flooding generally cannot be eliminated as long as there is rainfall, Flood is a potential hazard, however, how you handle it will show whether it will translate to disaster or not. Again, worldwide, flooding issue is a phenomenon which accounts for about 55 per cent of natural disasters.

Which states and LGAs fall within the highly probable flood risk areas?

The highly probable flood risk states include Abia, Akwa-Ibom, Anambra, Bauchi, Bayelsa, Benue, Cross-River, Delta, Ebonyi, Edo, Gombe, Imo, Jigawa, Kaduna, Kano, Kebbi, Kogi, Kwara, Lagos, Nasarawa, Niger, Ogun, Oyo, Rivers, Sokoto, Taraba and Zamfara.

In addition, some coastal states such as Bayelsa, Delta and Lagos are expected to experience coastal flooding due to rise in sea level and tidal surge and this could impact fishing, habitation and coastal transportation. On account of poor drainage systems, flash and urban floods are expected to occur in some locations such as Birnin Kebbi, Sokoto, Kaduna, Gombe, Yola, Makurdi, Abuja, Lafia, Asaba, Port Harcourt, Yenagoa, Lagos, Ibadan, Abeokuta, Benin City, Oshogbo, Ado-Ekiti, Abakaliki, Awka, Nsukka, Calabar, Owerri, Kano, and other major cities.

What were the key recommendations in the letters to the governors in terms of reducing the impact of flooding from moving from hazard to disaster?

One is to ensure that their drainages should be cleaned. For instance, the Abia State governor sequel to the prediction, said he had already mobilized citizens to open up all block drainages in the state as well as construct new ones that will convey any massive flood safely to the relevant rivers.

The issue of cleaning drainages is not a one-off affair, it is an annual event, so long as there is rainfall there will be deposition of debris that has the tendency to block the drainages. So, it should be cleaned annually.

They should also have that political will to remove structures obstructing the free flow of surface runoff, the overland flow during rainfall, especially structures on the floodplains. They should also educate the citizens on how to dispose solid waste. We had sanitary workers in Nigeria in the 60s, we should try something like that to ensure high compliance with proper disposal of solid waste.

Another thing that could be done is desilting of our small rivers within our localities. These are channels that convey flood water to safe places. Some of them have been filled up with sand. Why we may find it difficult to dredge River Niger, River Benue and some other big rivers, there are other small rivers within the cities we can scoop the sand out of them to increase the carrying capacity so the excess flood will flow into those ones. These are some of the measures.

What is the economic impact of flooding on the country’s economy?

In 2020, Kebbi State, the biggest rice producing state in Nigeria lost close to 450 hectares of rice farm and additional 50 hectares of agricultural farm. A similar scenario played out in Jigawa State, Kano, Anambra and Ebonyi states that produce rice too. So, there is a direct relationship between the amount of flooding that occurs in a year and food security.

So, when there is too much flooding in a year so much agricultural lands are lost, farmers may be forced to harvest before time thereby losing a lot economically.

This means farmers will loss so much, their processing capacity for the next farming season will be lost. And then generally, it will give rise to food insecurity in the land. So, there is a direct relationship between flooding and food security. So, the earlier hands are put on deck to minimize flooding the better for us economically and in terms of food security.

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