I n recent years, water bodies have witnessed unusual transformations, a trend many suspect may be linked to global climate change. The situation, however, has been exacerbated by intensified human activities, which continue to stress the already fragile bodies of water. One practical example of such is the recent sudden drying up of a part of the Ogun River which flows under the Kara Bridge around Ojodu-Berger.
With livestock husbandry as the major source of income in the Kara community, grasslands are supporting far more animals than they can sustain, and the insatiable resource demand and the need to feed a fast-growing population have resulted in massive grassland degradation and devastation of the ecosystem’s water-trapping capabilities.
“We first noticed that plants had grown on the surface of the river on Friday morning and by afternoon, the water couldn’t move freely again. In about two days, the river had completely turned to dry land. Many of us have never seen such happen before,” a resident who identified himself as Mohammed said.
While various activities have since commenced on the ‘dry’ land, experts have however, warned residents to keep off the area for the risks of it opening up unexpectedly. In the past week, people have been seen commuting on the ‘dry’ land and even some go as far as driving motorcycles on the land. Others have turned it to a spiritual ground of some sort.
What actually happened?
According to reports gathered, the Ogun-Osun River Basin Authority had opened the dam a week earlier, and that increased the torrent of the river flow. The plants seen on the river, known as water hyacinth, had flowed with the torrent before forming a mass on the river.
Water hyacinths are very invasive plants which are aggressive in nature. They usually thrive during the rainy season because the salinity of the water. The salt content in the water body is always diluted because of the downpour, and as such, it is the time for them to grow and culture. Each plant can produce thousands of seeds each year and these seeds can remain viable for more than 28 years. They are vigorous growers known to double their population in two weeks.
Speaking with Nigerian Tribune, an environmentalist, Mrs Adeola Oladejo said, “I believe that before the dam was opened, and coupled with the fact that we are in the rainy season, the water hyacinths had cultured down around that area. They weave themselves into a mat and they can cover an entire river space in less than two weeks.
“They can grow to a height of four feet and their root is fibrous in nature. So I believe that had happened before the water was opened. So when the dam was opened, it increased the torrent of the river flow and brought along the entire hyacinth that had cultured along the river to Kara market,” she said.
Why it stopped at Kara market
“Water hyacinths are free-floating perennial aquatic plants. So, naturally, they float on water. However, the two pillars of the bridge at Kara are in the river and that had stopped the hyacinths from flowing, which caused the clogging that we are presently experiencing.
“Water hyacinth often invades water bodies that have been impacted by human activities. When not controlled, they will cover lakes and ponds entirely. This dramatically impacts water flow, blocks sunlight from reaching native aquatic plants and starves the water of oxygen, often killing fishes,” Oladejo explained.
Environmental, economic impacts
Despite various warnings, many still believe that nothing stops them from commuting on the ‘dry’ land, while the residents are lamenting the impact the situation had caused their businesses. Prior to the recent development, the community didn’t have to worry about water supply as the river served as the major water source for them. Now, the water source is suddenly gone. On the other hand, the cattle rearers have resulted to feeding their animals on the ‘dry’ land, no longer worrying about going far away for grazing.
However, environmentalists have warned that the area be sealed off and no form activity should be allowed there at all.
“The river cannot just dry up like that, especially not in the in the rainy season. The occurrence is as a result of anthropogenic activities. Cattle rearers along that bridge often dump dung into this water body and this must have aided the flow of the water hyacinth, causing it block the flow of water. They best thing to do now is for people to leave that place for a while, because once there is two hours consecutive rain or more, flooding will likely occur and the outcome may be uncontrollable,” Mr Biodun Awoyode, an environmentalist, said.
The Ogun State Commissioner for Environment, Mr Bolaji Oyeleye, has also urged people to keep off the area, adding that work has commenced on the excavation of the weed.
“People need to stop commuting on the ‘river’ because it is very dangerous. Water hyacinths harbour dangerous reptiles. For instance, a snake was killed right in front of us on Saturday evening. We have done quite a lot in correcting what has happened and work is still ongoing. We have mobilised a contractor to move to site. who is trying to hoist a barge on the river because the water hyacinths have piled up, it cannot be removed by hand.
“Water hyacinths can be removed in three ways. It could be via mechanised harvesting or through chemicals which kills the hyacinths; however, this is not environmentally healthy. The third approach is biological, which involves conditioning the water. Water hyacinths can be managed, but not eradicated. They are invasive plants which come without notice.
“So we are using the mechanised harvesting method through special equipment. The crane has been on sight since Wednesday and work has commenced on the Kara River,” he said.
These three commonly used control methods depends on the specific conditions of each affected location such as the extent of water hyacinth infestation, regional climate and proximity to human and wildlife.
Reacting to the situation, president of the Africa Ecosystems Based Adaptation for Food Security Assembly (EBAFOSA), Nigerian National Branch, Mr Oyesola James Oluwagbemiga, noted that the situation was an evidence of climate change, which is not peculiar to the river alone.
“There is considerable evidence that climate change is already affecting Africa’s people and its environment. Africa’s six warmest years on record have all occurred since 1987. Lake Chad has shrunk from 26,000 square kilometres in the 1960s to just 1,500 in 2000 and still continues due to prolonged drought and less rainfall.
“The ice caps on Africa’s highest mountains are receding; Mount Kenya has lost 92 per cent of its glaciers in the last 100 years. Besides all these, the impacts of climate change are predicted to affect the livelihoods of Africans in many ways. By 2020 for instance, between 75 and 250 million people are predicted to be exposed to increased water stress due to climate change,” he said.