Introduction to the River Sid
Where does the River Sid originate and how long is it?
The River Sid originates 206 metres above sea level at Crowpits Covert, located just north of the Ottery St. Mary to Seaton road. It is considered the smallest river in Devon, measuring just over six miles (10.5 km) in length.
The River Sid's catchment area covers approximately 40 Km2 and is characterised by steep-sided valleys of Triassic mudstones and sandstones. The river has a relatively steep average gradient and is described as having a "very flashy" catchment, meaning its water level can rise and fall rapidly, often within a few hours, due to its rapid response to rainfall. This rapid change in water level can cause significant erosion of river banks.
Human intervention has significantly impacted the River Sid. Activities such as straightening the river, like the west bank at The Ham, have exacerbated erosion. Channels have been modified, straightened, embanked, or canalised in other areas. Additionally, a large weir built in The Byes in the 1970s has negatively affected aquatic life by restricting the upstream movement of fish like salmon and eels.
Catchment-wide issues contribute to pollution in the River Sid, meaning few waters are unpolluted. These issues include afforestation, soil management, overgrazing, the use of artificial fertilisers and pesticides, run-off from roads and urban areas, and sewage effluents. Nutrient enrichment is a widespread problem which can lead to a loss of key species. Run-off from fields during heavy rain also washes soil and nutrients into the river, causing it to run red.
Historically, the lower reaches of the river valley formed an inlet that became silted up by river alluvium and marine sediment behind a shingle ridge. The river outlet, which initially cut through this shingle ridge near Port Royal, shifted eastwards due to the ridge's growth, particularly after a storm in 1322. In the early 1700s, the outlet was re-routed to its current straight line.
Several areas along the River Sid are important for public access and nature observation. The Byes Riverside Park, between Sidford and the old Toll House, is a key green space with fields used as water meadows and areas managed for wildlife. Gilchrist Field, adjoining the river, is specifically managed to encourage wildlife and features a pond and newly planted hedging trees. Sidbury's Millennium Green also has the Sid flowing through parkland with riparian plants.