Continued from Monday, November 11, 2024
This segment of the story opens with the next act of this monstrous environmental crime. The unbelievable plan, bordering on the insane, to build a residential estate on the floodplain of a river with a well-documented history of repeated flood disasters.
A floodplain is a flat or gently sloping area next to a river, stretching from the banks of the river to the base of the enclosing valley, which experiences flooding during periods of high discharge.
As one author puts it: “A floodplain is called a floodplain, because it floods.” I couldn’t have said it better myself!
The whole point of a floodplain is that it absorbs excess water from the river rushing through it, thus reducing the risk of flooding in built up areas.
In recent weeks, workers at the site of the proposed Baywood Estate, have been attempting to sand- fill the swampy area surrounding Agodi with the redder laterite soil.
The reason that area is swampy, is because it is a massive floodplain for the Ogunpa River. It is a popular misconception that sand-filling absorbs water.
It does not. It displaces water.
The pertinent question would be, WHERE will all that water on the Ogunpa River floodplain be displaced to?
Sand-filling a floodplain and then placing concrete structures on it, might deceive an unsuspecting property buyer, but it will not deceive Nature.
What the sandfill does is to reduce the carrying capacity of the floodplain, leading to an increase in flood risk, especially in lower lying neighborhoods.
Dejo Oyelese and Francis Okediji streets and beyond, where some homeowners are still struggling to rebuild after the blast explosion of January 2024, spring to mind.
Downstream, the lower-lying neighbourhoods on either side of the Ogunpa River, channelised or not, will be at very great risk of flooding.
Partly because the floodplain in the murdered Ogunpa Forest Reserve is being tampered with. And partly because there are now several million more gallons of water, released by the deforestation of the Ogunpa River watershed to contend with.
And needless to say, any home built by unscrupulous property developers on the floodplain for the Ogunpa River, will be regularly exposed to flooding events.
Which will eventually impact on the overlying structures, if the floods don’t wash away the homeowners first.
If the property developers had any iota of conscience, they would have first attempted to understand the nature of the river whose floodplain they are now trying frantically to fill. With red laterite soil of all things.
Even in the wide concrete-banked channelized stretches of the river, during a torrential downpour, the Ogunpa River with its high-velocity, extremely turbulent flow, is not a force to be taken lightly.
I dread to think how it will react in its unchannelised state, as it roars through its narrow river channel in the valley of the denuded Ogunpa Forest Reserve, now that its floodplain and watershed forest have been destroyed.
Countries with access to considerably more advanced civic engineering technologies than ours, threw caution to the winds and built on their flood plains.
Now they are complaining about an increase in the incidence of flooding in their cities. And blaming it on climate change.
Let’s see what Baywood Infrastructures Limited and the Oyo State Government authorities are going to blame our flooding incidents on, now that they have uprooted the flood buffer of Ogunpa Forest Reserve and poured more red soil on top of the Ogunpa floodplain.
In the past few months, environmentalists have spoken extensively on the dangers of uprooting over 50 hectares of a forest that slowed down rainwater by absorbing it.
Thus, preventing it from rushing headlong into the Ogunpa River during torrential downpours. But has any of us stopped to consider that we now have an added problem of over 50 hectares of raw red soil, or should I say mud, fully exposed to the elements, with no tree roots to anchor it?
That’s a lot of red soil to leave lying around next to a narrow flood- prone river.
Every time it rains, larger and larger quantities of that red earth are being rapidly eroded and deposited in the Ogunpa River, within the confines of its concrete-walled trench that runs beside Secretariat Road, as it races into downtown Ibadan.
At this section of the Ogunpa River, there will be at least three significant sources of water to contend with.
• The already huge overload of water in the swollen river with no floodplain to absorb it.
• The unprecedented volume of water from the massive storm water run-off, previously captured by 50 hectares of trees.
• An additional contribution of wastewater and effluent from the residential estate itself.
And keep in mind that the water holding capacity of over 50 hectares of trees will be equivalent to the size of a small lake.
Releasing all that water into the high-velocity, flashflood-prone Ogunpa River will be a massive provocation.
I wonder how long it will take, before the notorious Ogunpa River, pushed to the limits of its endurance, decides to remind us that Nature stands supreme, and presents us with another sensational flood disaster.
By Rosalie Ann Modder-Oyefeso, on behalf of The Save Our Green Spaces Group and The Ogunpa Forest Reserve Team
Concluded
