“It has since been established that while nature may take its natural course in flooding, human activities such as dams’ construction may lead to Flooding if not properly managed.
The perenial Lagos flooding, experts say, could be attributed to many factors such as torrential rainfall, poor drainage system, poor sewage management and disposal, poor urban planning control, deforestation and climate change. All of these factors have combined to make flooding a regular occurrence in most areas of the state, particularly the Ogun River downstream areas, such as Akute, Kara market, Ishasi, Isheri, Ojodu –Abiodun, Ajiliti and Ajegunle Mile 12 axis of the state.
Determined to find a lasting solution to it, the state last week, organised a two-day summit on the “Negative Impacts of Flooding of Ogun River on Adjoining Towns and Villages in Lagos State”. The summit, which held in Alausa, Ikeja, aimed at mitigating the effects of the flooding of Ogun River plains and maximising the benefits derivable from the river basin, which include transportation, fishing/farming, power generation and water supply.
The State Governor, Mr. Akinwunmi Ambode, who spoke through his Commissioner for the Environment, Dr. Babatunde Adejare, said Lagosians along the plains of the Ogun river usually suffer the hardship brought about by the recurrent flooding of the river, owing to the discharge of water from the Oyan Dam, managed by Ogun-Oshun River Basin DevelopmentAuthority (OORBDA).
“Over the years, people in flood plains, especially Ajegunle (Ikorodu), Owode-Elede, Agiliti, Maidan and Itowolo, have been at the receiving end of the flooding of the plains of Ogun River” he said.
According to him, the operational activities of dams, being subject to vagaries of nature, sometimes produce unpleasant consequences to the immediate environment, while human activities, resulting in flagrant abuses of the environment are also contributory factors.
He said: “While the forces of nature can be adapted to, all man-made factors must be adequately dealt with for sustainable environmental renewal,” adding that, to bequeath a sustainable environment to posterity, Lagosians must change their attitude to the environment.
Ambode disclosed that in response to the phenomenon of Flooding, the state had strengthened Flood Early Warning Signs (FEWS) to deliver reliable, timely and effective flood information to the people at an appropriate response time.
As part of measures to relieve the pains of people living along Ogun River plains, Governor Ambode, stressed the commitment of his administration to strengthen the existing relationship with the Ogun-Oshun River Basin Development Authority for effective Dam management.
Ogun-Osun River Basin is located in the Southwestern part of Nigeria, with a land area of 101,802 km2, which is 11 per cent of the total area of the country. The river basin covers Lagos, Ogun, Osun, Oyo and parts of Kwara States. It is drained by two main rivers–Ogun and Oshun, a number of tributaries and smaller rivers, the most important among them are Sasa, Ona, Ibu, Ofiki, Oni, Oyan, Opeki and Yewa.
In his paper presented at the summit entitled: “Some Evidence of Changing Climate and the implications on Flood Events in Nigeria,”Director-General/Chief Executive Officer (CEO), Nigerian Meteorological Agency (NiMET), Professor Sani Abubakar Mashi, agreed that in addition to the changes in weather patterns, Nigeria has also been experiencing extreme weather events in line with the global trend. He said the extent and intensity of the 2012 flood in Nigeria was almost the worst in recent history.
He based his submission on statistics from the National Emergency Management Agency (NEMA), which reported that at least 363 persons were killed; 5,871 people were injured; over 590,000 homes were destroyed and over 2.1 million persons displaced by the flood in 2012. Mashi further said the Post-Disaster Needs Assessment (PDNA) carried out by the World Bank revealed that the losses and damages to infrastructure- transport, electricity, water and sanitation, occasioned by the flood amounted to $398 million. The combined value of the damages and production losses stood at $16.9 billion, representing 1.4 per cent of real gross domestic product (GDP) growth in 2012.
The floods affected 35 out of the 36 states, covering 3,870 communities in 256 Local Government Areas. He said Agriculture ranks among the most vulnerable sectors to extreme weather events. The estimated damage and loss inflicted on the agricultural sector in Nigeria by the 2012 flood, according to him, stood at N481.53 billion, representing 40.6 per cent of the total for the productive sectors.
From the various plenary session and presentations at the summit, it was evident that flooding in Lagos can be attributed to natural and anthropogenic causes. The natural causes include the flat topography, coastal location, low elevation relative to mean sea Level, climate, hydrology, and soil characteristics while anthropogenic causes include haphazard land-use and physical planning.
Besides, Lagos, through its Lagoon and Creeks, receives all the waters from the Ogun and Osun river basins for onward release to the Atlantic Ocean via the Commodore Channel. This, in combination with its small geographic size, and extensive urbanisation make Lagos incredibly vulnerable to flooding. Also is the effect of climate change, which is said to be responsible for the extreme weather events such as floods that the country now experiences.
The summit also noted that the hydrological network within the country are few with insufficient annual financial budgetary support to maintain basic hydrological services and their data collection activities, putting lives and infrastructure at risk and limiting the potential for better and informed decision making. It further noted that flood prevention and management efforts can only be achieved if interdisciplinary and inter-governmental approaches are adopted, and affected communities are sensitised of potential and actual risks in order to induce their pre-cautionary actions, and ature conservation measures adopted.
The Oyan and Ikere Gorge dams, stakeholders agreed, are underutilised assets, especially as regards their hydro-electrical power generation and irrigation potentials, which offer alternative uses of the Ogun and Oshun basins’ waters that should help prevent flooding of downstream communities. They are convinced that the rapid increase in settlement areas, and corresponding decrease in vegetation cover, non-urban land (floodplains) and channel coverage along the Ogun River course in Lagos and Ogun states are the underlying reasons for the flood impacts during heavy rainfall and release of water from Oyan dam in Ogun State.
Arising from the summit, a communique was issued and signed by stakeholders in attendance. Part of it was that: Physical development (housing estates, industrial estates etc) on Ogun River flood plains must be discouraged by both governments of Lagos and Ogun; that Lagos State should strengthen collaboration with the NiMET, OORBDA, Nigeria Hydrological Services Agency (NiHSA) and other relevant MDAs, for early warning systems on Ogun River; all identified stakeholders (Federal Government, Lagos, Ogun, Oyo states and OORBDA) should ensure that both Oyan and Ikere Gorge dams are put to their maximum usage in order to prevent flooding the downstream. Where necessary, new upstream dams, channels, floodwalls, levees, retaining walls and piers, as well as non-structural options such as natural ecosystems, planted degraded wetlands be used as buffers against flood prone areas. All these they said, should be seriously considered as protective measures by the Federal Government; Lagos and Ogun states and that they should liaise with other relevant stakeholders, especially OORBDA to produce flood risk maps, comprehensive flood plain management plans and set up flood management teams for communities at risk. The stakeholders, it was agreed, must adopt Integrated Water Resources Management plan (IWRM), which promotes the co-ordinated development and management of water, land and related resources, in order to maximise the resultant economic and social welfare in an equitable manner without compromising the sustainability of vital ecosystems.
It was also agreed that the Federal and Lagos State, OORBDA and tertiary institutions should facilitate easy access to all relevant data in the public domain from past studies relevant for flood management. Re-afforestation of the flood plains, they said, must be seriously considered for urgent implementation by Lagos and Ogun states, while the Federal Government should partner Lagos State for further studies to better understand the tidal effect of Lagos Lagoon and the Atlantic Ocean on the flood plains.
The OORBDA and the Lagos State Ministry of the Environment, it was recommended, should spearhead the formation of a Technical Committee to work with other states(Ogun, Osun and Oyo) to facilitate regular holding of similar fora. OORBDA, again, should strive to reduce the negative impacts of the Oyan and Ikere Gorge Dams on communities in the Ogun River Basin by followinginternationally acceptable best practices in their reservoir operations.”
Source: The Nation