The river channel has been heavily modified over centuries. This has included the construction of dams to impound water for milling and metal working. The earliest mentions are of Shepherd's Wheel, possibly in 1566 and certainly in 1584, while Mayfield corn mill on Mayfield Brook is mentioned in 1641. Expansion took place in the 18th century, and by 1780 there were 20 mills, with no obvious locations left where others could be built. Weirs were built with no thought for the ecology of the river, and while most were constructed to feed water into a dam at the side of the channel, the Fullwood mill impounded the whole of the flow of Mayfield Brook, as did Forge mill on the Porter Brook.