The source of the Nile? That would be Lake Victoria.
Whenever you have high ground with lots of rain or snow falling on it, it is the headwater source of the springs, creeks, and rivers that flow in the valley below.
In the case of the Meuse, the term “source” is a bit of a misnomer. It’s recharged with water along its entire watershed – through groundwater seepage and tributary channels – not just conveying water from some upstream font.
And where the plateau drops into valleys is often where you find some pretty steep crevasses, which from a water supply standpoint are strategic places for building dams.
The Gileppe is one such dam. It is located at the edge of the plateau (of the Hautes Fagnes) meets the valley below, just uphill of the small Belgian city of Eupen. What’s incredible about The Gileppe is not that it is 1 kilometer wide, or 2.5 kilometers thick, or that it has a sculpture of a giant lion that sits at its rim overlooking into the valley below, or that it has a +200 ft tall viewing tower overlooking the reservoir and dam (sadly the viewing tower was closed on Mondays, which was the day we visited): But that it was built in 1867! *
I’m no dam historian – or barrages as they call them in Belgium, but 1867 pre-dates the Hamilton Disston’s inaugural drainage of the untamed Everglades.
Even the dams in Europe are ancient!
* The barrage was enlarged in the early 1970s to its current dimension.