01 The water tower
The mechanism is simple and sits in the neighbouring pillar: it rains enormously here. The coast receives 3,729.9 millimetres a year, and although the figure drops inland it remains a huge volume concentrated between June and September. That water falls on a high plateau and from there it distributes in every direction.
What makes the Fouta Djallon special is not only that it rains but that it holds. The plateau's soils and formations work as natural reservoirs that fill in the wet season and release water through the rest of the year, which is what keeps the rivers flowing once the rain stops.
02 Three rivers and four countries downstream
The list of what rises here is what turns the fact into more than a geographical curiosity. The Niger, which then draws an immense arc through Mali and Niger before reaching the sea in Nigeria. The Senegal, which marks the border between Senegal and Mauritania. The Gambia, which gives a whole country its name and its shape. And smaller courses such as the Corubal.
The river that names the Gambia, the one that separates Senegal from Mauritania and the one that crosses Mali all rise on the same plateau, a day's drive from Conakry.
Put that way, the expression makes sense: what happens in these mountains is felt thousands of kilometres away. Irrigated farming in the Senegal valley, fishing on the inner Niger or the ferries of the Gambia depend, ultimately, on how much water falls and is held on a handful of Guinean plateaus.
03 What it looks like on the ground
It is worth adjusting the mental image, because it does not look like what you expect of a river's source. There is no signposted spring with a plaque and a fountain. What there is is an undulating plateau, high and very extensive, cut by canyons, with wooded slopes and large expanses of bare rock.
Those bare rock surfaces have a local name: bowé, laterite plateaus where barely any grass grows and where water runs across the surface instead of soaking in. They alternate with very green, cultivated valleys. The combination of the two — what holds and what sheds — is precisely the hydrological system the figures are talking about.
04 What to do with this
First, do not go looking for a specific point. Here you do not visit "the source of the Niger" the way you visit a monument: you travel a region, and what you see is waterfalls, canyons, streams and plateaus. The experience is one of landscape and route, not of reaching a sign and taking a photograph.
Second, choose the month with this fact in hand. The same water that makes the Fouta Djallon what it is turns the wet season into a serious logistical problem: between June and September the tracks break up and the streams rise. From December to April the ground is dry and passable, and the waterfalls are still there, with less flow but reachable.
And third, use it to read the whole trip. Conakry presents itself as a coastal capital, cramped and difficult, and it is. But it stands at the foot of the region that supplies water to half of West Africa, and that is why almost everyone who comes to Guinea ends up heading inland. The city is the door; the water is the reason.
