A council has said South West Water has used a gagging clause in the freedom of information regulations to prevent them from receiving data about sewage discharge which lies within the public’s interest.

Calstock Parish Council says there were over 1,000 sewage spills into the Tamar in the Parish which lasted for a total of 12,951 hours from South West Water’s 13 combined sewage overflows. These are designed to allow spillage into the river at times of heavy rainfall to prevent sewage backing up into homes and on the streets.

The Council wanted to check whether all those hours of spillage were really happening only during excessive rainfall. Cllr Andrew Brown said: ‘‘The Environment Agency had no problem about giving us the rainfall figures for 2021. We know exactly how much rain there was every 15 minutes during the year.’’

The Council then asked for the same detail from South West Water on when exactly all the 1,117 spill events occurred. This would enable them to match the rainfall data with the spill events to see whether they were all really happening when there was heavy rain.

South West Water refused on the grounds that OFWAT, the water industry regulators, are investigating the use of overflows and that there is a risk of ‘undue influence’ if they release the information.  They told the Council that this risk outweighed the public interest in having this information.

However, the rainfall data for Gunnislake obtained from Environment Agency showed that in 2021 there were only 43 days when there was significant rainfall for a total of just over 30 hours.  SWW spillage data for Gunnislake alone records 100 events resulting in 1690 hours of sewage discharge into the Tamar.  This is a huge discrepancy.

Cllr Alastair Tinto said: ‘‘There is a massive public interest in having this information. We have just carried out a survey of Calstock car park to see why it floods so badly – one of the most concerning findings was that raw sewage was seen in a storm manhole cover, the chamber of which discharged directly into the river! Every user of this car park is entitled to know how much and how often sewage is going into the river and perhaps also into the carpark.’’

The Parish Council has applied to DEFRA to get a Designated Bathing Water Status for the Tamar in Calstock.  Councillor Richard Newton Chance, who is heading up this application said: ‘‘Our surveys for this application showed just how many people use the river for  swimming, sailing and canoeing. They deserve to know how safe their water is.”

Cllr Wakem, Chair of the Parish Council, explained: ‘‘This refusal to co-operate is very disappointing. What are they trying to hide? We will continue to pursue this request for information and to clean up our River for the sake of all the people who use it.  We have a busy waterfront used by children and adults.

‘‘We have a rowing and gig club we also have a number of moorings and a pontoon which is used by many visitors to our village.  Sewage is toxic – to people, to wildlife, and to the environment. We don’t want it in our river, or any river.”

A spokesperson for SWW, said: “We know reducing storm overflow usage is an important issue for customers, as is the health of our rivers and seas – and it is one of our key priorities too. We have been working hard to reduce the impact of storm overflows, and in this year’s bathing season, we reduced spills by 50% on last year, with the duration of those spills down by 75%. However, we recognise there is more to do. Our largest environmental investment programme in 15 years is now well underway, delivering benefits for customers and the environment, and in April we launched WaterFit to go further and faster. Storm overflows are a legacy of our combined sewage system from the 19th century, but through WaterFit we will dramatically reduce our use of storm overflows and reduce our impact on rivers by one-third by 2025.’’

SWW says that during periods of heavy rain, storm overflows perform a necessary and very important job by acting as legal safety valves to prevent sewers from becoming overloaded and to avoid sewage backing up and flooding into homes, roads, and businesses.

The combined system takes in both domestic wastewater as well as rain and surface water. Overflows are designed to relieve pressure on the combined system when there is excess amounts of rainwater.

But there are a number of factors that make up the compliance of storm overflows – not just rainfall. Rainfall records don’t allude to the compliance – and therefore the legality – of the spills, as often assumed.

SWW continued to say that they are investing over £330 million in its wastewater network, which includes upgrades and improvements to hundreds of overflows across the region.

They will also carry out running pilot schemes in the Rivers Dart and Tavy measuring the whole river’s health, which will also help identify what may be required to work with others to achieve designated bathing water status.