Luxhay Reservoir is an artificial reservoir

Reservoir

A reservoir , artificial lake or dam is used to store water.Reservoirs may be created in river valleys by the construction of a dam or may be built by excavation in the ground or by conventional construction techniques such as brickwork or cast concrete.The term reservoir may also be used to...

 near Angersleigh, Somerset

Somerset

The ceremonial and non-metropolitan county of Somerset in South West England borders Bristol and Gloucestershire to the north, Wiltshire to the east, Dorset to the south-east, and Devon to the south-west. It is partly bounded to the north and west by the Bristol Channel and the estuary of the...

, England. It is now owned by Wessex Water

Wessex Water

Wessex Water Services Limited, known as Wessex Water, is a water supply and sewerage utility company serving an area of the south west of England, covering 10,000 square kilometres including Dorset, Somerset, Bristol, most of Wiltshire and parts of Gloucestershire and Hampshire...

.

It was built in 1905 by the town corporation to provide drinking water for Taunton

Taunton

Taunton is the county town of Somerset, England. The town, including its suburbs, had an estimated population of 61,400 in 2001. It is the largest town in the shire county of Somerset....

.

The reservoir is fed by other local water sources including Otterhead Lakes

Otterhead Lakes

Otterhead Lakes are a pair of reservoirs in the Blackdown Hills Area of Outstanding Natural Beauty south of Otterford in Somerset, England. They are fed by the River Otter and managed by the Otterhead Estate Trust Company Limited, working with the Somerset Wildlife Trust on behalf of Wessex Water...

 and Blagdon reservoir.

From 1969 leakage was detected in the retaining dam

Dam

A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...

. This got worse in 1990s remedial works, including a diaphragm wall were undertaken.

In 2006 the lake was found to have an intense bloom of Microcystin

Microcystin

Microcystins are cyclic nonribosomal peptides produced by cyanobacteria . They are cyanotoxins and can be very toxic for plants and animals including humans. Their hepatotoxicity may cause serious damage to the liver. Microcystins can strongly inhibit protein phosphatases type 1 and 2A , and are...

s which was associated high concentrations of cyanotoxin

Cyanotoxin

Cyanotoxins are toxins produced by bacteria called cyanobacteria . Cyanobacteria are found almost everywhere, but particularly in lakes and in the ocean where, under certain conditions, they reproduce exponentially to form blooms. Blooming cyanobacteria can produce cyanotoxins in such...

s probably associated with eutrophication

Eutrophication

Eutrophication or more precisely hypertrophication, is the movement of a body of water′s trophic status in the direction of increasing plant biomass, by the addition of artificial or natural substances, such as nitrates and phosphates, through fertilizers or sewage, to an aquatic system...

of nutrient enriched sediments.