River Otter, Devon River Otter, Devon The River Otter rises in the Blackdown Hills just inside the county of Somerset, England near Otterford, then flows south for some 32 km through East Devon to the English Channel at the western end of Lyme Bay, part of the Jurassic Coast, a UNESCO World Heritage Site. The Permian and Triassic sandstone aquifer in the Otter Valley is one of Devon's largest groundwater sources, supplying drinking water to 200,000 people. The river's source is north of Otterford, where a stream feeds the Otterhead Lakes: and then through Churchstanton before entering Devon. The river flows through a
Geology of Dorset around the Dorset and Devon border, although these may have been transported here with the other river deposits. Chesil Bank a long barrier beach stretching from West Bay to Portland, was created 10,000 years ago, when sea levels rose at the end of the last ice age. The Variscan orogeny is the oldest event for which there is evidence in Dorset, forming a major series of thrust faults in Carboniferous and older rocks. These thrusts trend west–east, dip moderately towards the south and have controlled later basin development and subsequent phases of inversion. During the Permo-Triassic the area was affected