After Kentmere Tarn was drained to provide agricultural land in the 1840s, water supply to the mills further downstream became erratic, and the mill owners met to plan a reservoir to regulate the flow. They employed the water engineer John Frederick Bateman to advise, and the Act of Parliament obtained in 1845 authorised five reservoirs. Despite Bateman's preference for the reservoir at Skeggles Water, the millers opted to build that at Kentmere Head, which was completed in 1848, but cost a lot more than estimated. Millers paid for the water based on the drop in river level at their mill, with small mills exempt from charges. Soon after its completion, cheap coal became available, as railways arrived in the area, and the number of mills using water power steadily declined. This process was exacerbated by the Water Resources Act 1963, under which the Lancashire River Authority levied prohibitive charges for using water to generate power.