River Wensum SSSI
Encyclopedia
The River Wensum SSSI is a 'whole river' Site of Special Scientific Interest
located on the River Wensum
that flows through the English
county of Norfolk
. The river was designated a SSSI in 1993 and a Special Area of Conservation
SAC in 2000. It covers 44 miles (70.8 km) of the Upper Wensum from its source close to South Raynham downstream to Hellesdon Mill
an area of 971.9 acres (393.3 ha).
that rise from chalk
and was selected as being one of the best examples of a lowland chalk and oolite
river type III. There are four species of European
importance in the river; bullhead
, brook lamprey
, white-clawed crayfish and the desmoulin's whorl snail
. In addition the river holds 100 plant species including water crowfoot and water starwort
in 2002. It showed that the ecological condition of the river had declined. The principal reasons for this were water quality
and siltation
. Water quality has been addressed and was improving, but the physical character of the river needs to be restored. In 2008, a partnership known as the River Wensum Restoration Strategy (RWRS) was formed between; Environment Agency
; Water Management Alliance and Natural England to restore the physical functioning of the Wensum. The 2002 report found that fourteen redundant water mills along the Wensum as having the most significant factor affecting morphology
of the river channel, with 67% of the river backed up behind these structures. As a priority, the strategy recommended the lowering, removal or bypassing of these structures to allow more of the river to function naturally. Since 2008, the (RWRS) has made several improvements to the river. The holistic whole river approach with co-operation from land owners, fisheries managers and other organizations has seen ongoing projects ranging from restoring gravel glides to removing silt.
The Norfolk Anglers Conservation Association (NACA) carried out a successful river habitat restoration at their Sayers Meadow fishery at Lyng
in the early 1980s. After dredging and a major abstraction
pipeline had a detrimental effect on the Costessey
Point
fishery, the association has taken action to restore this well known water. The ongoing work will be used as a blueprint for future river conservation projects.
Site of Special Scientific Interest
A Site of Special Scientific Interest is a conservation designation denoting a protected area in the United Kingdom. SSSIs are the basic building block of site-based nature conservation legislation and most other legal nature/geological conservation designations in Great Britain are based upon...
located on the River Wensum
River Wensum
The River Wensum is a chalk fed river in Norfolk, England and a tributary of the River Yare despite being the larger of the two rivers. The complete river is a designated Site of Special Scientific Interest and Special Area of Conservation ....
that flows through the English
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
county of Norfolk
Norfolk
Norfolk is a low-lying county in the East of England. It has borders with Lincolnshire to the west, Cambridgeshire to the west and southwest and Suffolk to the south. Its northern and eastern boundaries are the North Sea coast and to the north-west the county is bordered by The Wash. The county...
. The river was designated a SSSI in 1993 and a Special Area of Conservation
Special Area of Conservation
A Special Area of Conservation is defined in the European Union's Habitats Directive , also known as the Directive on the Conservation of Natural Habitats and of Wild Fauna and Flora...
SAC in 2000. It covers 44 miles (70.8 km) of the Upper Wensum from its source close to South Raynham downstream to Hellesdon Mill
Hellesdon
Hellesdon is a thriving suburb of Norwich in the District of Broadland in Norfolk, England. It lies approximately 4 miles north-west of Norwich and has 11,177 inhabitants.- History :...
an area of 971.9 acres (393.3 ha).
Description
The Wensum's upper reaches are fed by springsSpring (hydrosphere)
A spring—also known as a rising or resurgence—is a component of the hydrosphere. Specifically, it is any natural situation where water flows to the surface of the earth from underground...
that rise from chalk
Chalk stream
Chalk streams have characteristics which set them apart from watercourses associated with other rock types.Aside from those with an interest in the geological and ecological disciplines, the term chalk stream is most widely used among a small group of fly fishermen ,...
and was selected as being one of the best examples of a lowland chalk and oolite
Oolite
Oolite is a sedimentary rock formed from ooids, spherical grains composed of concentric layers. The name derives from the Hellenic word òoion for egg. Strictly, oolites consist of ooids of diameter 0.25–2 mm; rocks composed of ooids larger than 2 mm are called pisolites...
river type III. There are four species of European
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
importance in the river; bullhead
European bullhead
The bullhead is a freshwater fish that is widely distributed in Europe, mainly in rivers. It is a member of the Cottidae family, a type of sculpin...
, brook lamprey
Brook lamprey
The European brook lamprey is a small European lamprey species that exclusively inhabits freshwater...
, white-clawed crayfish and the desmoulin's whorl snail
Desmoulin's whorl snail
Desmoulin's whorl snail, scientific name Vertigo moulinsiana, is a species of minute air-breathing land snail, a terrestrial pulmonate gastropod mollusc or micromollusc in the family Vertiginidae, the vertigo snails....
. In addition the river holds 100 plant species including water crowfoot and water starwort
Callitriche
Callitriche is a genus of largely aquatic plants known as water-starworts. Previously, it was the only genus in the family Callitrichaceae. However, according to the APG II system this family is now included in the Plantaginaceae...
Conservation
After many years of decline a survey was commissioned by Natural EnglandNatural England
Natural England is the non-departmental public body of the UK government responsible for ensuring that England's natural environment, including its land, flora and fauna, freshwater and marine environments, geology and soils, are protected and improved...
in 2002. It showed that the ecological condition of the river had declined. The principal reasons for this were water quality
Water quality
Water quality is the physical, chemical and biological characteristics of water. It is a measure of the condition of water relative to the requirements of one or more biotic species and or to any human need or purpose. It is most frequently used by reference to a set of standards against which...
and siltation
Siltation
Siltation is the pollution of water by fine particulate terrestrial clastic material, with a particle size dominated by silt or clay. It refers both to the increased concentration of suspended sediments, and to the increased accumulation of fine sediments on bottoms where they are undesirable...
. Water quality has been addressed and was improving, but the physical character of the river needs to be restored. In 2008, a partnership known as the River Wensum Restoration Strategy (RWRS) was formed between; Environment Agency
Environment Agency
The Environment Agency is a British non-departmental public body of the Department for Environment, Food and Rural Affairs and an Assembly Government Sponsored Body of the Welsh Assembly Government that serves England and Wales.-Purpose:...
; Water Management Alliance and Natural England to restore the physical functioning of the Wensum. The 2002 report found that fourteen redundant water mills along the Wensum as having the most significant factor affecting morphology
River morphology
The terms river morphology and its synonym fluvial geomorphology are used to describe the shapes of river channels and how they change over time...
of the river channel, with 67% of the river backed up behind these structures. As a priority, the strategy recommended the lowering, removal or bypassing of these structures to allow more of the river to function naturally. Since 2008, the (RWRS) has made several improvements to the river. The holistic whole river approach with co-operation from land owners, fisheries managers and other organizations has seen ongoing projects ranging from restoring gravel glides to removing silt.
The Norfolk Anglers Conservation Association (NACA) carried out a successful river habitat restoration at their Sayers Meadow fishery at Lyng
Lyng, Norfolk
Lyng is a village and civil parish in the English county of Norfolk. It is situated on the River Wensum, some north-east of the town of East Dereham and north-west of the city of Norwich....
in the early 1980s. After dredging and a major abstraction
Abstraction
Abstraction is a process by which higher concepts are derived from the usage and classification of literal concepts, first principles, or other methods....
pipeline had a detrimental effect on the Costessey
Costessey
Costessey is a civil parish situated west of Norwich in Norfolk, England. The parish comprises two settlements: the long-established village of Costessey , and New Costessey , which developed during the first half of the 20th century and has become a suburb of Norwich...
Point
fishery, the association has taken action to restore this well known water. The ongoing work will be used as a blueprint for future river conservation projects.