Are Nigeria's floods caused by humans or climate change?

Recent severe flooding has submerged almost half of the northeastern Nigerian city of Maiduguri, Borno State's capital. At least 30 people have been killed, tens of thousands more have been displaced and the flooding has triggered a severe humanitarian crisis.

The United Nations refugee agency in Nigeria said it was the "city's worst flooding in 30 years." 

The governor of Borno State, Babagana Umara Zulum, told DW  that "over a million people in Borno State in northeastern Nigeria have been affected."

But floods are not a new phenomenon to Nigeria. Adaku Echendu, an urban flooding researcher at Queen’s University, Ontario, Canada said, "It is an annual thing. The same story every year."

While government officials say that the floods are climate-driven, urban flood experts like Echendu believe they are considerably influenced by human actions.

What caused the recent flood in northeastern Nigeria?

According to Nigeria's Emergency Response Agency (MENA), the recent flood in Maiduguri occurred because, "one of the spillways of Alau Dam collapsed..."

The Alau Dam is located about 13 miles (20 kilometers) away from the city of Maiduguri. It has capacity to retain 112 million cubic liters of water. The dam was designed to regulate water flow and provide irrigation and drinking water.

Abubakar Monguno, a professor of Geology from the University of Maiduguri, said the flooding was a combination of "high rainfall" and the "collapse of the spillways meant to channel the water."

But for Echendu, the underlying problem runs much deeper.

"The biggest problem of flooding in Nigeria is the lack of infrastructure," Echendu told DW.

Lack maintenance, monitoring and care of the dams

Structures such as the Alau Dam "need proper maintenance" to avoid floods, Monguno said.

A study published by the European Scientific Journal in 2015 that examined the problems of the Alau dam found that, "Alau Dam is not undergoing any form of monitoring to ensure as assessment of the damages it causes on yearly basis."

Echendu argued that while "[studies] have discovered the issues [with the dam] many years ago, they were never fully addressed. And this is despite budget allocation."

Hamzat Lawal, the executive director of Connected Development (CODE), a non-profit that tracks public funds, told DW that the lack of maintenance is linked to fund mismanagement. He said that if the funds meant for the maintenance were used properly, "no house today in Maiduguri would be under water. Even if water was released, the maintenance and surveillance would have allowed the government to prepare."

Similarly, Echendu suggests that "the lack of preparation from the government" and the lack of "maintenance of the infrastructures" are the major contributing factors in this year's flood disaster.

After the most recent flood, CODE wrote in a report that "the over 300 dams in Nigeria are in dire need of maintenance." 

Borno State governor Zulum said in an interview with the BBC that the government aims to "expand the size of Alau Dam," to allow it to contain the increasing water level. 

DW tried to reach the government authority responsible for managing the Alau Dam, but there was no response from them to a request for a comment.

What role did climate change play?

According to Monguno, due to the impact of climate change, "Maiduguri has experienced increased rainfall" which contributed to the flood. 

"Maiduguri experienced over 300mm of rainfall in August. Which was preceded by about 200mm of rainfall in July," Monguno said. 

A study published by International Journal of Environment and Climate Change examining the rainfall trend in Maiduguri found that due to climate change, "notable trends in June and August highlight the necessity for proactive monitoring and adaptation strategies to mitigate potential consequences."

Beyond that, Monguno added that, "a large quantity of silt piled up in the rivers. Which means even if the water isn't as high as this, it is likely to contribute to flooding because the riverbanks have too much quantity of sand in them." 

Nigeria's minister of water resources, Joseph Utsev, made a similar point at a press briefing last week. According to the minister, "Because of climate change, the downpour was in excess, and the rivers could not actually contain the water."

But for Echendu that doesn't tell the whole story. "The authorities are often quick to say its climate change, saying it also happens in the US and Canada. But comparing that is like comparing apples to oranges. That is not the same thing. And we cannot let them hide under the umbrella of climate change."

Blaming the recent flood on climate change, shows a "lack of empathy from the government," said CODE's Lawal. "This is lack of preparedness. I disagree that it is because of excessive rainfall," he added. 

"Yes, climate change is a factor,"  Echendu concluded. "But it is just a small part [of the problem]."  

Building on waterways another major problem

In an interview, Borno State governor Zulum said that another problem is a human factor where "People are building houses right inside waterways."

But Echendu said the authorities are also to blame for that. 

"While people building on waterways makes the situation worse, you will still blame the government because there is lack of control and lack of good urban planning," she said.

Sometimes, she added, simple solutions could solve complex problems. "Raising awareness of people building on waterways will go a long way." 

Edited by: Rob Mudge