Oyan dam not responsible for Ogun community floods- O-ORBDA boss

The Managing Director and Chief Executive Officer of the Ogun-Oshun River Basin Development Authority, Adedeji Ashiru, on Wednesday debunked claims that the release of water from Oyan Dam caused perennial flooding in the Isheri axis, a border community between Ogun and Lagos States.

Ashiru emphasised that, contrary to this long-held misconception, residents of Isheri and other communities should be grateful to the Federal Government for constructing Oyan Dam in 1979.

“Without the dam, many of these communities would have been submerged because they are on the floodplain, while some are even below sea level,” he said.

He revealed that the Federal Government plans to construct four additional dams on the Ogun River to control water flow downstream into Abeokuta, Isheri, and other communities to tackle the recurring flooding problem.

Ashiru disclosed this during a briefing at the authority’s headquarters in Abeokuta, Ogun State.

Earlier, on Monday, the state Commissioner for Environment, Ola Oresanya, issued a flood alert urging residents in riverbank and wetland areas, including Akute, Alagbole, Isheri, Magboro, Makogi, Orimerunmu, Iro, Kajola, and parts of Abeokuta such as Lafenwa, Enugada, Adedotun, Iberekodo, Akin-Olugbade, and Ago-Odo, to prepare for possible overflow of the Ogun River from October 20 to November 3.

Oresanya explained that the overflow could result from the controlled release of water from Oyan Dam due to heavy rainfall from northern Nigeria, which increases water volume reaching the dam, compounded by rising tidal levels.

He urged residents to exercise caution and avoid loss of lives and property during the period, advising those in wetlands to move to higher ground.

However, Ashiru insisted that it is not the gradual release of water from Oyan Dam that causes flooding in Isheri or other downstream communities.

“The authority has, for the past five months, been engaging in the gradual release of water from this dam, yet there has been no incident of flooding in any of the communities,” he said.

He explained that flooding is instead caused by the overflow of the Ogun River, which has over 52 tributaries, as well as blocked water channels.

The situation is further complicated because Isheri is on a floodplain and below sea level, making it naturally susceptible to flooding.

He also criticised the historical designation of Isheri for residential purposes without adequate water channelisation and sand filling, unlike developments such as Eko Atlantic City.

“This area should not have, in the first instance, been designated for residential use without adequate water channelisation and sand filling like what was done in Eko Atlantic City before the area was built,” he said.

He further explained, “This Oyan River, which has a dam constructed in it and is gated, flows into the Ogun River. This means that Oyan Dam did not flow directly into the Ogun River because it is being controlled with the help of a dam. However, the Ogun River, without a dam and with over 52 tributaries, flows directly uncontrolled from upstream to downstream.

“It will also interest the public to know that for about six months, Ogun-Oshun River Basin Development Authority has been releasing water systematically on a daily basis without any incident of flooding in Isheri or anywhere downstream of Oyan Dam till today.

“It means that we can come to a safe conclusion that it is not the Oyan Dam that is causing flooding in the Isheri axis and part of Abeokuta. It shows that if flooding occurs in the next couple of days or weeks, which we are not going to shy away from, it could be as a result of heavy downpour as predicted by NIMET.

“If that happens, naturally, there will be flooding in the Isheri axis and the reasons are very simple. You have two rivers: one is controlled by a dam, but the other one, River Ogun, with over 52 tributaries, flows directly downstream into Isheri and other communities and is not gated.

“Oyan Dam actually provides safe haven for the residents of Isheri town. It is also worth noting that Isheri is in a floodplain zone and also below sea level. Definitely, when there is heavy rainfall, there will be a rise in tide; all the tributaries that are not gated will flow into the River Ogun, which will also overflow and then flow into the Isheri axis. This is the only scientific way to explain the flooding at Isheri axis.”

He added, “For instance, Eko Atlantic City was a disaster in the years past but there was an idea that bothered on building an estate in the place. But before constructing the estate, a lot of water channelisation and sand filling were done, the same thing ought to have been done too in Isheri community before the land was sold to the residents of Isheri many years ago. Nothing was done to raise where they built, which is below the sea level and naturally, when there is heavy downpour, there will be flooding.

“This accounts for the year-in, year-out flooding in Isheri and not because of the controlled release of Oyan Dam. The people of Isheri should therefore continue to thank the federal government because if the Oyan Dam had not been constructed, the whole of the community would have been submerged.”

Calling for further collaboration with Lagos, Ogun states, and the federal government to address the flooding challenge, Ashiru said that the 2025 federal budget approved the design of four rivers—Ekisa, Iju, Opeki, and Owo—that flow directly into the Ogun River.

This, he said, is preparatory to constructing additional dams to control their flow and mitigate downstream flooding into Isheri and other communities.