From the Chambers Concise Scots Dictionary:

Sheuch, sheugh, sough etc. n1 a trench in the ground, esp for drainage, a ditch, an open drain 16thC- 2 a temporary trench or furrow for plants 19thC- 3 a furrow made by a plough 19th-e20thC 4 a street gutter la19thC-... [from northern early Middle English sogh, a swamp].