The River Soar () is a major tributary of the River Trent in the English East Midlands and is the principal river of Leicestershire. The source of the river is midway between Hinckley and Lutterworth. The river then flows north through Leicester, where it is joined by the Grand Union Canal. Continuing on through the Leicestershire Soar Valley, it passes Loughborough and Kegworth until it reaches the Trent at the county boundary. In the 18th century, the Soar was made navigable, initially between Loughborough and the Trent, and then through to Leicester. It was not until the early 19th century that it was linked by the Grand Union Canal to the wider network to the south and to London.
Name
The name of the Soar is included in a family of old river-names derived from a root *ser- "to flow", alongside (among others) Saravus (Soar, a tributary of the Moselle in Belgium), Sera (la Serre, la Cère and le Séran, three rivers in France), Serantia (Sierentz, Alsace), Serma (Schremm, Brandenburg), Sora (Cwm Sorgwm, Wales), Sorna (die Zorn, Alsace), Sara (Saire), Saar(e) (Brandenburg), Saros (Sar, Spain), Sarius (Serio, Lombardy), Sarià (Lithuania), Saravus (Saar, Germany), Sarnivos (Sernf, Glarus), etc.
According to a suggestion due to William Somner (1701) the Soar river may formerly have been called the Leir, from Brittonic *Ligera or *Ligora, cognate with the French Loire. This theory is based on the name of Leicester (as well as Loughborough and the village of Leire) being derived from the name of the river.
Course
The Soar rises near Wibtoft in Warwickshire, and flows north to join the Soar Brook near Sharnford, it then continues in a north-easterly direction, passing through Croft and between Narborough and Littlethorpe, until on the outskirts of Leicester it is joined by the Sence near Enderby. Before flowing through the centre of the city it meets the Grand Union Canal at Aylestone, where it is also joined by the River Biam. After passing over Freemens Weir, the river splits and recombines with the canal, creating an area of Leicester called Bede Island. The navigable arm that runs to the east has been canalised with parallel banks and is known as 'The Mile Straight'. Beyond Blackfriars, the river splits again to form Frog Island and Abbey Park; it recombines at Belgrave where it passes beside the National Space Centre.
Once out of the city the Soar passes Birstall and threads its way through the lakes of Watermead Country Park, until it reaches Wanlip. The river then meets the once navigable River Wreake, near Cossington Mill, with another tributary the Rothley Brook, joining the river just downstream. The Soar continues north-east to reach Mountsorrel then passes between Quorn and Barrow-on-Soar, at which point an arm of the canal extends into Loughborough, although the river passes to the East of the town at Cotes. Downstream of Stanford on Soar the river forms the county boundary between Nottinghamshire and Leicestershire. Between Stanford and Normanton on Soar, the canal rejoins the river, which then continues to Zouch, passing the 'Devils Elbow' to reach Kegworth. Downstream of Kegworth, it meets the Kingston Brook, near the village of the same name, passing Ratcliffe-on-Soar and its power station, before flowing into the Trent at Trent Lock.
Pollution
The River Soar is rich in wildlife with thriving bird, fish and plant populations being popular with wildlife enthusiasts. The river was once notorious for its unusual pink colour - a result of discharges from Leicester's prosperous textile industries. However the end to textile industries near the river in Leicester and clean-up work by the Environment Agency has now restored it to its natural state.
Industry now wanting to attempt to discharge any sewage waste into the river must now obtain an agreement from the Environment Agency. Several consents have been granted to companies to use the River Soar, however the quantity and quality of the sewage is strictly controlled to a preset amount that is agreed on with the Environment Agency.
The quality of any water is determined by what is able to contaminate the river upstream, the River Soar is constantly monitored by the Environment Agency which keeps check on the level of pollution. The pollution in the water running through the Soar in the city of Leicester is low and the water is generally of good quality; however there is a significant decrease in the quality just downstream of the city, where the Wanlip sewage treatment works enters the river.