Raw sewage spilled into Bristol’s waterways 2,806 times throughout 2022 - the equivalent of almost 8 a day. In total, sewage seeped into the city’s water network for a total duration of 5,383 hours.
Conversation experts, the Rivers Trust has compiled data from 190 of the 215 storm overflows across Bristol which shows how many spills occurred and the combined time sewage was discharged. Storm overflows operate automatically during or after intense rainfall to protect properties from flooding and are licensed by the Environment Agency. Once overwhelmed, sewage can seep out of the system into the waterway.
The Avonmouth Sewage Treatment Works (STW) overflow spilled for the longest duration of time - accounting for almost a fifth of the total hours. This sewage hotspot spilled 86 times throughout 2022 for 1080 hours. The sewage was discharged into the Severn Estuary which suffered the two longest overflow spills.
A table of the 10 worst affected areas for storm overflows is below:
|Location of storm overflow||Total spills||Total duration (hours)||Discharged into (waterway)|
|Avonmouth STW||86||1080||Severn Estuary|
|Portbury Wharf STW||99||749||Severn Estuary|
|Muller Road Cso||105||447||Horfield Brook|
|The Portway Cso||39||254||River Avon|
|Filton Avenue||90||204||Horfield Brook|
|Lower Hanham Road||41||174||River Avon|
|Plimsoll Statue||38||142||River Avon|
|Ellesmere Road||39||139||Brislington Brook|
|Portway Combined Sewer Overflow||77||126||River Avon|
|West Town Road Pumping Station||56||103||River Avon|
The Rivers Trust map shows that storm overflow discharges in Bristol reduced from 2021 to 2022. In 2021, a total of 3,492 spills were accounted for with a duration totalling 7,144 hours. This data was extracted from fewer storm overflows with 171 of the city’s 215 being monitored.
A spokesperson for Wessex Water, which is responsible for the region, told BristolWorld: “Storm overflow discharges in the Wessex Water region significantly reduced in 2022, and this is down to dry weather as well as our £3 million a month investment in improvement schemes.
“In Bristol, we’re increasing the sewage treatment capacity at our largest water recycling centre in Avonmouth so we can deal with more rainwater. But clearly, there’s more to do and we’re committed to continuing to reduce the frequency of discharges, starting with those that operate most frequently or have any environmental impact.
“We’re also planning to go even further and, if approved by our regulators, will invest more than £9 million per month from 2025.”
To view the Rivers Trust interactive map, click here