The River Irk bisects the Alkrington Wood Nature Reserve and it is likely that the first human settlement in Middleton would have been at the point where Wince Brook joins it near the current Middleton Way. The Irk rises some 4 miles away in Royton in a field close to the Puckersley Inn and the ancient settlement of Hanging Chadder. The source is 630 feet above sea level, falling to 260 feet at Middleton. It feeds into the River Irwell near Victoria Station, Manchester.
Early maps show the River Irk meandering between Middleton and Blackley however it was re-engineered into a straight course during the early 20th century and weirs were added to maintain constant water supplies to the lodges. This, together with the continuing urban development of Middleton, means the River bursts its banks in times of heavy rain.
There are 5 mill lodges within the reserve at Rhodes, remnants of the Schwabes calico printing works and one lake which was formed after sand was quarried near the Blackley border. There are two ornamental lakes located near Alkrington Hall.