I remember it now, its runnel filled with autumn leaves, the hornbeams and hazels on its banks, unvisited, unknown, the most wonderful and vivid antiquity I had ever seen.
From the denverpost.com
The river oozes like a huge runnel of dirty metal through a landscape utterly devoid of the romantic crags, arroyos, and heights that signify wildness and natural spectacle to most North Americans.
From the theatlantic.com
If the irrigator neglected to repair his dike or left his runnel open and caused a flood, he had to make good the damage done to his neighbours'crops or be sold with his family to pay the cost.
From the en.wikipedia.org
More examples
Rivulet: a small stream
A stream is a body of water with a current, confined within a bed and stream banks. Depending on its locale or certain characteristics, a stream may be referred to as a branch, brook, beck, burn, creek, crick, kill, lick, rill, river, syke, bayou, rivulet, streamage, wash, run or runnel.
Runnels is a surname, and may refer to:
A corrugation or TROUGH formed in the foreshore or in the bottom just OFFSHORE by WAVES or TIDAL CURRENTS.
Channel on a beach, usually running approximately shore-parallel and separated by beach ridges
In common usage a rivulet or brook. In mountaineering, a groove in snow created by a falling cornice. Crossing runnels is slow going. A series of runnels often ends an ascent.
(1) A rivulet; a brook. (2) A narrow channel or course, as for water.
A groove in an otherwise featureless area of rock, cause by water erosion (or, in old quarries, by quarrymen drilling and inserting explosives). [Andrew Meldrum]