Reservoir opened in 1869 (Umpleby 2000, 126). Fed by the Broadstone Dike which is shown cutting through Parliamentary Enclosure on the 1851 1:10560 OS. This land was probably part of the Ingbirchworth parliamentary award of 1813 (date from English 1985, 78). This previous landscape also featured the mill race for Ingbirchworth Corn Mill (See HSY9). The mill race and dam and the area of enclosed land have been fully covered by the reservoir so legibility of the past landscape is invisible. The origin of the moorland landscape is uncertain though this area is likely to be moorland by the Roman period (see Bevan 2003 for discussion of environmental evidence in region).