Location of the river mouth just outside Suffolk
|• elevation||104 m (341 ft)|
|2nd source||Bradfield Combust|
|• elevation||65 m (213 ft)|
|Mouth||Littleport, River Great Ouse|
|0 m (0 ft)|
|Length||57 km (35 mi)|
|• left||River Linnet|
The River Lark is a river in England that crosses the border between Suffolk and Cambridgeshire. It is a tributary of the River Great Ouse, and was extended when that river was re-routed as part of drainage improvements. It is thought to have been used for navigation since Roman times, and improvements to its navigability were made in 1638 and in the early 18th century, when locks and staunches were built. The upper terminus was on the northern edge of Bury St Edmunds, but a new dock was opened near the railway station after the Eastern Union Railway opened its line in 1846.
The navigation was officially abandoned in 1888, but despite this, commercial use of the river continued until 1928. Following an acquisition by the Great Ouse Catchment Board, locks at Barton Mills and Icklingham were rebuilt in the 1960s, but were isolated when the A11 road bridge was lowered soon afterward. It now has one operational lock at Isleham, and can be navigated to Jude's Ferry.
Water quality in the river was generally moderate in 2016, although there was a section where the quality was bad, the lowest rating given by the Environment Agency, who monitor English rivers. The river hosts a large population of signal crayfish, an invasive species which has increased as the eel population has diminished.
Rising at Bradfield Combust, to the south of Bury St Edmunds in Suffolk, it flows through Bury, Mildenhall and Prickwillow, and joins the Great Ouse south of Littleport in Cambridgeshire. It is about 31 miles (50 km) long, of which 10.1 miles (16.3 km) is navigable.
The upper river is an important focus for prehistoric activity, particularly relating to the Neolithic enclosure at Fornham All Saints. This comprises a large causewayed enclosure, several ring features, and a long cursus.
Just above Barton Mills, a side weir connects the river to the start of the Cut-off Channel, a 28-mile (45 km) drain running from there to Denver along the south-eastern edge of the Fens, which was constructed in the 1950s and 1960s. During times of flood it carries the headwaters of the River Lark, the River Wissey and the Little Ouse to Denver Sluice on the River Great Ouse.
Below Barton Mills, the mill stream at Mildenhall marks the start of a footpath which follows the north bank of the river, passing Mildenhall Cricket Club, to Isleham, after which there are footpaths and drove roads on both sides of the river to its junction with the Great Ouse. There is a weir at King's Staunch, after which comes Jude's Ferry, the current head of navigation, where boats at least 60 feet (18 m) in length can be turned. A magnificent hoard of late Roman silver was discovered at nearby Thistley Green in 1942, and the 34 pieces, which included bowls, spoons, dishes and goblets, were declared to be Treasure trove and are now in the British Museum.
The stretch from Jude's Ferry to Isleham includes several pill-boxes, which were constructed during World War II to defend against invasion. Above the start of the lock cut is a memorial to the famous Baptist preacher Charles Spurgeon, who was baptised in the river on 3 May 1850. The site, where a chain ferry once crossed the river, and another near the weir were used for public baptisms until 1970. Isleham itself has three pubs, all dating from the 17th century, some shops and a large marina. There was an outbreak of cholera here in the 1850s, when over 500 people were "living in hollows" as a result of poverty which affected many fenland villages. In medieval times, Isleham was an important port with three quays. Remains of a Roman villa and over 6,000 Bronze-Age artefacts, which are now in the Moyse's Hall Museum at Bury St Edmunds, indicate that it has been a centre of occupation since antiquity.
From Isleham to Prickwillow, the river flows for almost 4 miles (6.4 km) in an artificial cut, thought to have been constructed by the Romans, and joined the River Great Ouse at Prickwillow until 1830. The Great Ouse was then diverted, and its old course occupied by the Lark. There are a number of pumping stations on the banks of this section, including the Lark Engine, which has been the main outlet for the drainage of the southern part of Burnt Fen since 1842. Many of the surrounding ditches once flowed into the river by gravity, but the draining of the fens has resulted in the land surface dropping, and the water must now be raised by up to 16 feet (4.9 m) from the ditches to the river. At Mile End, two pumping stations sit one above the other, indicating the progressive sinking of the land. Prickwillow is home to the Museum of Fen Pumping Engines, itself once a working pumping station, and now holding several engines which were used in the draining of the Fens.
Prickwillow vicarage also demonstrates the shrinking of the land. Its ground floor rooms were originally the cellars, and the two steps leading to the front door have been replaced by nine. Below Prickwillow, the river is crossed by the Ely to Norwich railway line. The final 0.9 miles (1.4 km) of the river's course are quite straight, as the river flows through another artificial channel. At its junction with the Great Ouse, the channel is crossed by a road which was formerly the A10, which ran along the banks of the Great Ouse at this point on its route from Ely to Littleport, but this section has been bypassed by a new alignment of the road further to the west.
The river is managed and maintained by the Environment Agency, from whom boat owners must obtain a licence in order to use the waterway. The Agency have designated the section from Sicklesmere through Bury St Edmunds and Fornham St Martin to Isleham as a Flood Warning Area.
The Environment Agency assesses the water quality within the river systems in England. Each is given an overall ecological status, which may be one of five levels: high, good, moderate, poor and bad. There are several components that are used to determine this, including biological status, which looks at the quantity and varieties of invertebrates, angiosperms and fish. Chemical status, which compares the concentrations of various chemicals against known safe concentrations, is rated good or fail.
The water quality of the River Lark system was as follows in 2019.
|Section||Ecological Status||Chemical Status||Length||Catchment||Channel|
|Lark (US Hawstead)||Moderate||Fail||2.8 miles (4.5 km)||5.79 square miles (15.0 km2)|
|Lark (Hawstead to Abbey Gardens)||Bad||Fail||4.1 miles (6.6 km)||11.24 square miles (29.1 km2)||heavily modified|
|Lark (Abbey Gardens to Mildenhall)||Moderate||Fail||14.1 miles (22.7 km)||33.60 square miles (87.0 km2)||heavily modified|
|Lark downstream of Mill Street Bridge||Moderate||Fail||3.4 miles (5.5 km)||8.21 square miles (21.3 km2)||heavily modified|
|Ely Ouse (South Level)||Moderate||Fail||54.5 miles (87.7 km)||180.02 square miles (466.2 km2)||artificial|
Separate figures for the Lark downstream of Isleham are not available, and the final row covers the lower section of the Lark, parts of the River Great Ouse and a number of its other tributaries. The Hawstead to Abbey Gardens section deteriorated from poor quality in 2015 to bad in 2016. The Environment Agency have set a target for ensuring it is moderate by 2027. Like many rivers in the UK, the chemical status changed from good to fail in 2019, due to the presence of polybrominated diphenyl ethers (PBDE) and perfluorooctane sulphonate (PFOS), neither of which had previously been included in the assessment.
The river hosts a large population of the invasive species, the signal crayfish. A study published in 2011 identified the decline in eels, which predate the crayfish, as the major factor in their dramatic increase.
(Links to map resources)
|OS Grid Ref||Notes|
|Jn with River Great Ouse||TL572844|
|Museum of Fen Pumping Engines||TL597824|
|Judes Ferry Bridge||TL677748||Head of navigation|
|Barton Mills Lock||TL710742|
|Start of Cut-off Channel||TL731738|
|Chimney Mill Lock||TL821698|
|Fornham Dock||TL848664||original terminus|
|Northgate Dock||TL855652||1850s terminus|
|Source near Bradfield Combust||TL869563||spring|
There is a second, much shorter, River Lark also in Suffolk which flows into the River Deben at Martlesham.