Sheeps Green Bathing Waters

Overview

Bathing water designation

Bathing waters are designated at locations where an interest group or owner of a potential bathing water has applied to Defra and been successful in getting the water designated as a bathing water. That location will be tested by us during the bathing water season and given a classification. Designation does not necessarily mean that the site meets water quality standards or is safe to swim in.

Bathing water season

The Bathing Water Regulations 2013 set out the bathing water season, which runs from 15 May to 30 September inclusive each year. We are responsible for sampling for two types of bacteria at designated bathing waters during the season. Sampling must start just before the season and include some weekend and bank holiday samples, when the largest number of bathers are often present.

When and how we sample

The legislation dictates that we must set a sampling program before the beginning of the season and stick to it as much as possible, taking each water sample at 30cm depth after wading into one metre of water.  This sample must then be analysed within 4 hours of being taken, or within 24 hours if refrigerated (our vans are refrigerated).

The results are then available 2-5 days later as the bacteria have to be plated up and grown before being counted. There is a set protocol for the sampling, including sterile bottles and aseptic techniques.

What we sample for

We analyse samples by set protocol for Escherichia Coli (E.C) and Intestinal Enterococci (I.E), two bacteria found in the gut of many animals such as humans, birds, dogs, and seals. These are used as faecal indicator organisms for other pathogens such as viruses.

Classification of bathing water

The bathing water bacterial counts taken over the last 4 years (excluding 2020 as the number of samples taken were impacted by Covid) are put through a complicated calculation using log10 means and standard deviations, which is set out in the legislation.  The resulting figure is then compared with the table below to give the classification.

NB. If a beach is ‘poor’ for 5 years then it is de-designated.

Origin of the bacteria

I.E. and E.C. are often from the faeces of a human or other animal including birds, dogs, seals, cows and pigs. They can be washed in from various sources:

• roofs (bird faeces)
• pavements or roads through surface water systems during rainfall
• misconnections from homes or businesses into the surface water
• issues with overflowing sewers or consented overflows
• agricultural runoff
• washed in at high tide after being deposited on beaches by animals defaecating
• deposited directly into the sea by birds or seals

Rivers often run through both urban and agricultural areas, which can potentially affect water quality. There may also be combined sewer overflows, emergency overflows (from sewage pumping stations) and surface water outfalls within the river catchment that can adversely impact the water quality.

Where to find out more about bathing water quality

The Swimfo site Bathing water quality (data.gov.uk) contains lots of useful information about bathing water quality – you can see all the data through the years with maps and details of investigations. If there is a known relevant ongoing pollution incident this will also be flagged on this site.

Pollution Risk Forecasting

There are some bathing waters in England where we know water quality can be affected by factors such as rain, tide, or wind that we can measure and use to make a daily forecast of quality.

At these sites, we make active water quality forecasts called Pollution Risk Forecasts (PRF) if factors that have previously been associated with reduced quality re-occur. This warns the public of a risk of reduced water quality to give an informed choice of where and when to bathe. It is not warning of an actual pollution incident occurring.

It is important to recognise these forecasts are not absolute and that these are just a means to flag higher risk days than the annual classification average. 

We make PRFs each day at 08:30 and post on Swimfo shortly afterwards. These are our best estimate of the risk, specific to each bathing water for that day.

In summary, we expect people to make their own decisions on what is an acceptable risk to them and will provide PRFs to help them make this decision. Additional information can be found at Swim healthy - GOV.UK (www.gov.uk)

Sheeps Green bathing water area

The River Cam flows through the city of Cambridge, it is popular for punting, canoeing and rowing. There is significant growth around the Cambridge conurbation. Elsewhere the catchment is mainly rural. 

Sheep's Green is located on the west bank of the River Cam in Cambridge. It is within the Sheep's Green and Coe Fen Local Nature Reserve.

Map shows location of bathing water site on River Cam.

Sheep’s Green was a new designation for the 2024 bathing water season. Designation does not guarantee a certain standard of water for swimming and the location has not been managed for bathing before.

Summary of Actions completed in 2024 Season.

Agriculture

Our agricultural team compliance officers inspected seven farms upstream. The initial focus was on Grantchester Meadows, out to Haslingfield and Hauxton. All grazing land has full perimeter stock-proof fencing and drinking is from troughs or pasture pumps.

We have further inspections planned, including patrols of the catchment as part of a ‘National Day of Action’ which is aimed at detecting spreading of slurry and digestates during the closed period.

Sewage

Haslingfield Water Recycling Centre is approximately 5km upstream of Sheep’s Green bathing water. As this is a newly designated site, disinfection (such as UV) is not present at the works. Officers visited Haslingfield WRC on 12 August 2024. No non-compliances of the current permit were noted.

Officers undertook a visit to Foxton WRC on 6 June 2024 to take bacteria samples upstream and downstream of the outlet. There was an increase in bacteria observed downstream (which is to be expected as there is no disinfection at this site).

Compliance visits to Anglian Water assets will continue in the upstream catchment. We will work with Anglian Water on investigations and improvements within the catchment.

Following analysis using portable monitoring equipment, we completed a walkover of the River Rhee. Observations, field measurements and photographs were taken at six established sample points and at the current location of the sonde (automatic monitoring device) downstream of Haslingfield Water Recycling Centre (WRC).

We took variable measurements, including ammonia and temperature upstream and downstream of the smaller discharges within the catchment. These particular field measurements did not include bacteria.

Other

We met with Cambridge City Council in May 2024 to discuss the bathing water season signage, and responsibilities of each organisation.

Land & Water officers undertook bacterial sampling training sessions at Sheep’s Green. These inlcuded out of hours Site Controllers  to raise awareness of the new bathing water site in relation to incident response.

We completed a catchment walkover with members of Cam Valley Forum; concerns of the local group were discussed alongside actions we would be taking e.g. compliance visits, farm visits.

Land & Water officers undertook initial field tests in May 2024, at 6 locations, to establish a baseline understanding of the catchment.

We deployed an automatic monitoring device (Sonde) at the end of June 2024, approximately 500m downstream of Haslingfield WRC.

Internal Environment Agency funding for Microbial Source Tracking (MST) analysis was secured for some samples. MST can provide supporting information when identifying sources of faecal pollution. The analysis will show which known genetic markers have been picked up in the sample e.g. ruminant. human, bird, dog.

Bathing water samples in the ’24 season have been filtered and stored for further MST/DNA analysis in the future, should funding become available. Samples taken during the ’25 season will also be filtered and stored.

We completed a drone survey of the upstream catchment in November 2024. This survey will help inform and focus further action.

We will continue engagement with local stakeholders and citizen science groups to identify opportunities for collaborative working.