Evidence of illegal sewage dumping revealed by 'Dry Spills'

Evidence of illegal sewage dumping revealed

 in SAS 2022 Water Quality Report

24 November 2022

We found water companies have committed 146 ‘dry spills’ in the last year. For the first time, we’ve used rainfall data to investigate potentially illegal ‘dry spills’. Sewage outflows are only permitted in ‘unusually heavy rainfall’, but our analysis shows water companies have been dumping untreated sewage into our waterways even when there hasn’t been any rain. We would love to hear from water companies on why they’re releasing highly concentrated swathes of raw sewage into our parched waterways during one of the hottest summers on record?

The SAS Water Quality Report 2022 reveals 146 ‘dry spills’ in the last year, using rainfall data to show potentially illegal spills from CSO overflows.

SAS looked only at the most popular surf and swim spots, so not at Barry and Penarth

 

“Dry spills” are evident also for Lower Penarth’s Brockhill Rise CSO which spilled 114 times in 2020 and 67 times last year, averaging near 3 hours a time.  Other CSOs in Penarth discharge many fewer times, most 10-20 times nearer to storm frequencies.  In Barry, The Knap long outfall and Barry Dock storm CSO are worse (Welsh Water data).

 

Brockhill Rise CSO, goes from the pumping and storage plant on the
Railway Path (left) to the discharge point just below the low tide mark

 

NRW’s licence for the Brockhill Rise CSO specifies discharges are permitted solely of “storm sewage”.  Welsh Water built a huge underground storage tank on the railway path in the noughties. The CSO was modernised and discharges just below the low tide mark.  Welsh Water have to store peak flow there until there’s capacity to pump it through to Cog Moors works for treatment.  Instead, they appear to discharge it frequently to sea, evidently during many non-storm times.  

Extract of discharge consent from Brockhill Rise CSO
The discharge pipe is high capacity 1050mm

Welsh Water should report the licence breach to NRW but don’t.  And NRW make no check of the clearly over-frequent use of the CSO.  Welsh Water save on the treatment costs at Cog Moors and on the pumping cost to get the sewage there and pump the treated effluent to the Lavernock Point long outfall.

FOE briefed the regional MS on the 23 Dec.2020 flooding 

Barry&Vale FoE met with Heledd Fychan MS for the Cardiff region early November, briefing her on flooding due to sewer overload relating to the 23 Dec’2020 rainstorm, and unlawful discharges of untreated sewage. Flooding in Dinas Powys happened when the surface water sewers were unable to discharge into the river at high flows and the ‘attenuation’ tanks at Llandough hospital discharged quickly to the Eastbrook which itself overflowed and fed the Cadoxton river. The VoG Section 19 statutory report ducked these issues while the Section 19 report for Penarth is still delayed.  

 

Heledd agreed to take up the issues, alongside her findings on flooding in the Rhondda.  The last Senedd report in March disregarded sewage impacts on sea recreation, as does the Welsh Government. Heledd agreed this needs to change - the special Senedd committee on the floods could take up the evidence on NRW failing to regulate sewage spills during both floods and dry spells.