[derealized]

Some countris have mandated >30 meters of green area on each border of rivers. That also helps a lot from what I've seen. Before that, especially with plantations, the crops would go up to the border and that killed the rivers (plus all the agrotoxics would feed more easily into the water).

[dghughes]

My province does it's mainly for the fish. It is called a buffer zone I'm not sure of the dimensions. The province even buys up land from old farms that have fields that used to go right to the water edge.

Even the orientation of furrows helps. Not having them perpendicular to the river the furrows should be parallel.

Even provincial workers cutting trees need to use canola oil for bar oil (bar and the saw chain lubrication).

Farms can have runoff of fertilizer and it can cause fish to die rapidly in large groups aka a "fishkill". The farmer is fined too.

[rewmie]

> Some countris have mandated >30 meters of green area on each border of rivers.

I think this has more to do with flood plain management. Some countries prohibit construction within X meters of the average water level because that's expectedly where water will rise. In some shallow areas municipalities even build parks with no permanent structure because of the high probability those areas will be flooded, and that ensures no life is put at risk and economic damage is limited to whatever infrastructure was placed there (i.e., park benches, public restroom, small public cafe, camping ground, etc.)