The river Worth, which gives the valley its name, is fed by streams that start their life high up on the Pennine Moors. Just downstream of this bridge the beck meets the Worth and flows all along the valley bottom to Keighley where is joins the much bigger River Aire. In the early days of the industrial revolution it was water, rather than coal that powered the mills and all across the Worth valley the remains of small mills and mill ponds are found alongside the numerous becks and streams. Water wheels were replaced by water turbines and later steam engines, which also needed copious amounts of water. All the way to Keighley, the River Worth is lined with dark chimneys and mill buildings, although most are now an empty shell or have been converted to other uses.