Catchment area 18.3km2, length 6.2km. Not designated artificial or heavily modified.

 

Waterbody description

The Cerney Wick Brook runs along the parish boundary of Ashton Keynes and South Cerney, entering the parish of Ashton Keynes at the northerly extent and then running in a south-easterly direction, reaching the River Thames to the northwest of Cricklade. It is a very small channel, only 0.3-0.5m wide, and often has very little water (5-30cm deep). It has consistently failed to reach good ecological status due to poor fish numbers and high levels of phosphates. The failures are considered due to point source pollution from South Cerney Waste Water Treatment works and physical modification of the channel.

 

Land use and designations

A river habitat survey in May 2015 (1) found the brook runs mainly through open countryside owned by a wide variety of landowners from farmers to leisure businesses and with one section bordering an industrial unit. Surrounding land is used for agricultural small holdings, semi-improved grassland and arable farmland. Ex-mineral extraction land now is used for nature reserves, sailing and fishing lakes. In places where livestock access the brook there is some damage to the bank and sedimentation of the watercourse. The Thames & Severn Way canal runs through the land and over the river. Overshading is a significant issue where the brook flows behind hedgerows and dense scrub and reduced sunlight is inhibiting marginal and aquatic plant growth. There is limited public access and it has a reputation for smelling due to the high input from South Cerney Waste Waste Treatment Works.

 

Flora from preliminary assessment May 2015 (1):

The banks were dominated by stinging nettles and shaded by hawthorn scrub, elder and willow trees. In less shaded areas there was marginal vegetation including Branched Bur-reed, Lesser water-parsnip, Water mint. There was little aquatic vegetation present but there was filamentous algae growing on the bed.

Fauna from preliminary assessment May 2015 (1):

Invertebrates included Common Blue damselflies and Beautiful damoiselle. Large Signal crayfish were present. The brook is known to have some small fish species such as Minnow and Bullhead. There was no indication of Water Vole, but signs of Otter were noted on and around the brook. Hedgerows and woodland bird species were noted including Song Thrush, a Red Listed species.

 

Main conclusions from the WILD parish reports (1)

Overall Cerney Wick Brook through South Cerney parish is of significant ecological value, mainly as a migration corridor with its associated scrub habitat rather than the brook itself. It would need significant investment in both water quality and habitat improvements to bring it up to good ecological status.

 

Catchment issues

There is no real risk of flooding to Ashton Keynes as the village itself over a kilometre away from the brook, however, there is a high risk of flooding throughout South Cerney Parish.

Phosphate pollution from point and diffuse sources (Wastewater treatment works and land management)

Signal crayfish are established in this water body.

  1. WILD Project, River Thames Management Plan, Ashton Keynes Parish (March 2016), South Cerney Parish (June 2015)

 

Water Framework Directive

WFD 2016 Cycle 2 failing due to fish and phosphates (poor status)

 

http://environment.data.gov.uk/catchment-planning/WaterBody/GB106039023800

 

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