Bathing Water Designation

Following an application by Cam Valley Forum in October 2023, the River Cam at Sheeps Green was granted Designated Bathing Water Status just before the start of the 2024 bathing water season: 15 May-30 September

Sheeps Green is now listed on the Swiminfo website here, where you can see the results of the Environment Agencies water quality tests. These are taken roughly every week from 15 May-30 September

The graph below shows the water quality test results in the first year of bathing water designation. As expected this resulted in an official designation of “Poor” in November 2024.

The red line shows the threshold, and if test results are above this, the classification for the season is likely to be “Poor” (though the actual way of calculating the classification for the season is quite complicated) This webpage explains how the Environment Agency interprets the results, but at simple level, an E.Coli reading of above 1000 is “considered elevated” and if continued would be likely to indicate a possible overall “poor” rating for the season.

What happens next?

Now that the River Cam at Sheep’s Green has become “Designated Bathing Water” the Environment Agency will monitor the water quality every week during the bathing season each year, to decide its official classification.

The City Council will put up an official signboard at Sheep’s Green informing people about the Bathing Water Quality, based on the test results from the previous year(s). This will include a QR code to the Sheep’s Green page of the swiminfo website so that swimmers can judge if they wish to swim.   

We knew from our monitoring work over the last few years that the level of faecal indicator bacteria in the River Cam means that this initial classification would almost certainly be “Poor”, with “Bathing not advised” (although of course it’s still permitted)

Importantly, when there is Designated Bathing Water with a “Poor” water quality classification, this then acts as a statutory “Driver” requiring the water company to investigate the source of pollution and remedy it. The Environment Agency also launches an investigation.

Anglian Water have confirmed to us that if the River Cam becomes “Designated Bathing Water” and has “Poor” water quality, they will start by doing a “Source Apportionment” study to understand and uncover the causes of the problem. This will include looking at both their various assets (pipes, pumping stations and sewage works) and other 3^rd party sources.

As Cam Valley Forum we will be very interested in the results of the Environment Agency’s investigations and the Source Apportionment study. We are also doing our own investigations and analysis to contribute to this official study. You can read a summary of these here

We all expect that a big source of the problem will be the ageing and overloaded sewage infrastructure at Haslingfield. This includes the Haslingfield Sewage Treatment works, and the sewage pumping stations in the villages of Haslingfield, Harston and Grantchester, which frequently overflow in wet weather.

Subject to the findings of the Source Apportionment study and approval of Anglian Water’s Business Plan by Ofwat they’re expecting to spend around £5M on improvements at Haslingfield, with work completed by 2027. The details of what needs to be done, will of course depend on what the source apportionment study discovers, but the overall aim is to improve the water quality in the River Cam at Sheep’s Green from Poor to Good

Without the statutory “Driver” of Bathing Water Designation, the improvements would have been likely to take much longer…. probably decades.

It’s going to take a while, but now we have got Bathing Water Designation, a cleaner Cam is on the way.

Further Resources