| River Leven | |
| Image Alt: | A large expanse of water with trees on the banks |
| Source1 Location: | Kildale Moor, North Yorkshire |
| Source1 Coordinates: | 54.4639°N -1.0464°W |
| Mouth Coordinates: | 54.5086°N -1.3367°W |
| Subdivision Type1: | Country |
| Length: | 46.2km (28.7miles) |
| Source1 Elevation: | 279m (915feet) |
| Basin Size: | 196.3km2 |
| Mouth Elevation: | 16m (52feet) |
The River Leven (pronounced) in North Yorkshire, England is a tributary of the River Tees. It rises on Warren Moor, part of Kildale Moor, in the North York Moors and flows to the north of the moors to join the River Tees at Yarm.
The source of the river is on Warren Moor, part of Kildale Moor, just south of the village of Kildale. The river flows east until it reaches the Whitby to Middlesbrough railway line where it turns around to flow west to Kildale. It then flows south-south-west through woodland to its confluence with Dundale Beck where it turns north-west through Low Easby and Little Ayton, before turning west and then south-west at Great Ayton. It runs parallel to the A173 to Stokesley. The river becomes increasingly meandering as it continues south-west past Skutterskelfe to Hutton Rudby and Rudby, where it turns north-west and then west again over Slape Stones waterfall. At Crathorne it turns north and then north-east as far as Middleton-on-Leven before passing under the A19 in a north-west direction. The final couple of miles are north and north-west between Ingleby Barwick and Yarm, before the river joins the River Tees.[1]
| Monitoring station[2] | Station elevation | Low water level | High water level | Record high level | |
|---|---|---|---|---|---|
| Easby | 101.3m (332.3feet) | 0.11m (00.36feet) | 0.4m (01.3feet) | 1.25m (04.1feet) | |
| Great Ayton | 83m (272feet) | 0.03m (00.1feet) | 0.5m (01.6feet) | 1.64m (05.38feet) | |
| Stokesley | 67m (220feet) | 0.09m (00.3feet) | 0.8m (02.6feet) | 1.62m (05.31feet) | |
| Foxton Bridge | 56m (184feet) | 0.21m (00.69feet) | 1.5m (04.9feet) | 2.63m (08.63feet) |
In October 2022, a new flood defence project was opened on the river above Stokesley. When river levels are high, a new flood channel diverts the excess water around the town, meeting the Leven again further downstream. The Environment Agency funded the project at a cost of £3.7 million.[3]
The river drains from the Cleveland Hills across a mixed geology of mostly Permian and Jurassic age bedrock of low permeability. Most of the deposits on top of the bedrock are boulder clay. There is mixed agriculture, with some moorland and forestry near the source.[4]
Since a weir on the lower river was built during the Industrial Revolution, migratory and territorial fish and mammals had been missing from the river. In 2007, the Environment Agency built a fish bypass at the weir. In 2011, they announced the return of spawning salmon for the first time in 150 years.[5]
In 2020, it was confirmed that crayfish plague had infected the river after 40 dead white-clawed crayfish were found along a 700m (2,300feet) stretch of river.[6]
In Stokesley, the river is crossed by Taylorson's Bridge, a 17th-century packhorse bridge,[7] which was once the only crossing in the town.[8] The Domesday Book records a water mill on the banks of the river in the town.[9] In Hutton Rudby, a plaque on a bridge marks the site of a water mill that, amongst several uses, once made sailcloth.[10]