This does not contradict what has been said previously, on the contrary. The most important thing to avoid (with the waste) is that the water does not run off directly to the river or to the sea. And there, there is a lot of progress to be made, both in urbanized and agricultural areas (drainages galore, unstructured and non-filtering soils, uprooting of hedges, filling in wet areas etc ...)
And sanitation!
When they did the remediation, they put gravel around the tubes before recapping. Cows.
At the first rain, well, the lowest house in the village found itself under water.
How did they do it?
Well, it's simple: 500m of trench in a direct field in the river. How to get rid of water simply.
Suddenly all the ponds are dry in the area.