The palette
This is one of the few prints in the collection with two real surfaces to work: water, in several arms, and open ground, in two large stretches. So you can set a landscape rather than a diagram. The balance to watch is between the two: if the meadows go too pale they read as blank paper and the whole idea collapses, and if they go too strong they compete with the rivers. Keep them lighter than the water and darker than the sky of the margin.