A feeder stream also known as Black Brook joins near Kittiwake Road - this short and weak water course commences at Eagle Tower. The jointed brook feeds Anglezarke Reservoir, and joins the River Yarrow in lowland Chorley at Yarrow Bridge.
A tributary, Black Brook, joins near Kittiwake Road, starting at Eagle Tower, feeding Anglezarke Reservoir and merging with the River Yarrow in Chorley's lowlands at Yarrow Bridge.