The River Allen is a

river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of w ...

in the

county A county is a geographic region of a country used for administrative or other purposes Chambers Dictionary, L. Brookes (ed.), 2005, Chambers Harrap Publishers Ltd, Edinburgh in certain modern nations. The term is derived from the Old French ...

Dorset Dorset ( ; archaically: Dorsetshire , ) is a county in South West England on the English Channel coast. The ceremonial county comprises the unitary authority areas of Bournemouth, Christchurch and Poole and Dorset. Covering an area of , ...

South West England South West England, or the South West of England, is one of nine official regions of England. It consists of the counties of Bristol, Cornwall (including the Isles of Scilly), Dorset, Devon, Gloucestershire, Somerset and Wiltshire. Cities ...

. It flows for and has its confluence with the River Stour in

Wimborne Minster Wimborne Minster (often referred to as Wimborne, ) is a market town in Dorset in South West England, and the name of the Church of England church in that town. It lies at the confluence of the River Stour and the River Allen, north of Poo ...

. It has two main tributaries, the Gussage Stream and the Crichel Stream.

Route

The River Allen starts at Wyke Farm as a winterbourne and flows down to Monkton Up Wimborne and then tracks its way to the Watercress farm, follows down to Honeybrook Farm, to a mill and then to Canford Bridge in Wimborne Minster that is the mouth of the river. The river is known as a classic chalkstream which supports a good fishery for trout and used to support a good salmonid population. A large amount of the river banks are privately owned by two estates including the Shaftsebury Estate at the source.

Watermills

There have been a number of corn mills on the river, Loverley Mill at Crichel survives as a Grade II

listed building In the United Kingdom, a listed building or listed structure is one that has been placed on one of the four statutory lists maintained by Historic England in England, Historic Environment Scotland in Scotland, in Wales, and the Northern Irel ...

. Originally using two wheels, they were replaced in the early 20th century by a water turbine driving a pump to supply water to Crichel House. Other mills were Hinton Farm Mill, Stanbridge Mill and Didlington Mill.

Environment

Since 1946, the water from the Allen has been abstracted for domestic and industrial use. The amount of water taken was having a detrimental effect on the river flow whilst at the same time the salmonid population dropped significantly. Studies have been undertaken as a correlation between the two events and have resulted in the abstraction rate being reduced by 50%. Over the last twenty years there has been an increase in arable farming (wheat, barley, oats oilseed rape and peas) as well as some water cress farming discharge reaching the river. The Allen is involved in a major restoration project led by Dorset Wildlife Trust with funding from Wessex Water and Dorset Area of Outstanding Natural Beauty. The Allen had the strongest population of white clawed crayfish in Dorset and measures such as tree planting and slowing the flow of the river down were implemented to help the species. However, an outbreak of Crayfish Plague was discovered on the river in 2014 with at least 100 of the native species found dead in the river. The river also contains an abundance of macrophytes including the two most abundant taxa; common water-crowfoot (''

Ranunculus aquatilis ''Ranunculus aquatilis'', the common water-crowfoot or white water-crowfoot, is a plant species of the genus ''Ranunculus'', native throughout most of Europe and western North America, and also northwest Africa. This is an aquatic plant Aqua ...

'') and bur-reeds (''

Sparganium ''Sparganium'' (bur-reed) is a genus of flowering plants, described as a genus by Linnaeus in 1753. It is widespread in wet areas in temperate regions of both the Northern and Southern Hemispheres. The plants are perennial marsh plants that c ...

''). As well as an abundance of brown trout the river is also home to minnow, dace, grayling, salmon, perch, roach, pike, bullhead and brook lamprey and the critically endangered European eel.

Water quality

The Environment Agency measure water quality of 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

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

s, angiosperms and fish. Chemical status, which compares the concentrations of various chemicals against known safe concentrations, is rated good or fail. Water quality of the River Allen in 2016:

References

{{DEFAULTSORT:Allen, Dorset

Allen Allen, Allen's or Allens may refer to: Buildings * Allen Arena, an indoor arena at Lipscomb University in Nashville, Tennessee * Allen Center, a skyscraper complex in downtown Houston, Texas * Allen Fieldhouse, an indoor sports arena on the Unive ...

Wimborne Minster 1Allen