Geology and Hydrology
The River Camel rises on Hendraburnick Down (UK Grid Reference SX135875) on the edge of Bodmin Moor, an area which forms part of the granite spine of Cornwall. The river's course is then through upper and middle Devonian rocks, predominantly slates such as Upper Delabole Slates, Trevose Slates and Polzeath Slates. These stretch right to the coast, although Pentire head is composed mainly of pillow lavas. The only active quarry in the River Camel catchment area is Delabole Quarry although there has been mining for lead and antimony on Pentire Head, as well as building stone at various locations. Further inland mines surrounding the Camel and its tributaries produced lead, copper and iron, while Mulberry Mine near Ruthernbridge also produced tin.
The source of the River Camel is at an altitide of 218 metres (715 ft) above sea level and has an average incline of 7m/km. The upper reaches of the Camel and its tributaries are mainly moorland giving way to woodland and farmland, predominantly livestock. This means that 64.8% of the catchment is grassland, with a further 14.8% arable land and 12.9% woodland. Of the remaining 7.4%, 4.5% is urban or built-up areas, 2.7% is mountain, heath and bog and the remainder is inland waters.
The catchment area of the River Camel covers a total of 413 km² on the western side of Bodmin Moor, and is mainly Devonian slates and granite, with some shales and sandstones. Water volumes are affected by the reservoir at Crowdy Marsh, by abstraction of water for public supply, and by effluent from the sewage system around Bodmin. Data collected by the National Water Archive shows that water flow in the River Camel for 2006 was considerably below average. This correlates with reduced rainfall, particularly between the months of June and September.
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