Inversnaid by Gerard Manley Hopkins - how do the sounds of the words create the movement of water?

Inversnaid by Gerard Manley Hopkins

THIS darksome burn, horseback brown,
His rollrock highroad roaring down,
In coop and in comb the fleece of his foam
Flutes and low to the lake falls home.

A windpuff-bonnet of fáwn-fróth
Turns and twindles over the broth
Of a pool so pitchblack, féll-frówning,
It rounds and rounds Despair to drowning.

Degged with dew, dappled with dew
Are the groins of the braes that the brook treads through,
Wiry heathpacks, flitches of fern,
And the beadbonny ash that sits over the burn.