Overdevelopment into an outdated sewer system leads to polluted rivers and increases flood risk
Back in 2021, AberdareOnline put out a news story on how clean are our rivers and the lack of capacity within the Cynon Valley sewer system. Sewer outfalls are never out of the news now as more and more people are made aware of the pollution caused by these outdated systems not only in our local rivers but small watercourses also suffer from sewer outfall pollution.
AberdareOnline contacted Dŵr Cymru Welsh Water and requested under Environmental Information Regulations 2004 what size and type of sewer system we have running through the Cynon Valley. The reply is quite interesting and relates to a mishmash of a main sewer system with bits added as and when there are many different types of pipes that make up this what can only be called a hodgepodge made out of asbestos cement Cast Iron Ductile Iron Concrete Plastic.
The Cynon Valley sewer system dates back to 1880
Part of the Cynon Valley sewer system dates back to 1880 and until 2022, is it clear that so many add-ons to this outdated system are the reason for so many sewer outfalls into our rivers and watercourses? Is there another problem with the system’s larger diameter pipework discharging into smaller diameter pipework, any drainage engineer would inform you that just would not happen, on paper it just doesn’t seem correct.
Dŵr Cymru Welsh Water have no problem in allowing large developments to proceed even with an outdated system, do Natural Resources Wales know with every new development sewer outfall pollution will increase? But that’s ok because Dŵr Cymru Welsh Water have a licence allowing them to pollute our rivers care of Natural Resources Wales is run by the Welsh Government one would say they all work in harmony, nothing Untoward here they have got government approval to pollute.
The development proceeds unhindered, a question to Dŵr Cymru Welsh Water referencing the Aberdare Hospital development.
The question
What new infrastructure are you putting in place to compensate for the additional sewage waste generated from the 300 new properties on the Aberdare Hospital site?
Dŵr Cymru Welsh Water answer
The public sewerage network was assessed as part of the statutory pre-application planning consultation as directed by the applicant, and the RCT Council planning consultation process. It was determined that no reinforcement works were required to accommodate the foul flows from this site. The SAB (SuDS Approving Body) application confirms that surface water will be dealt with by way of a SuDS (Sustainable Drainage System) feature.
Basically, WW are saying all the foul sewage will go into an existing combined sewer that already has sewer outfalls
Below is a response from Dŵr Cymru Welsh Water
- What diameter of the main sewer pipelines from Hirwaun to Penywaun and what year was this section of pipeline installed and how many sewage outfalls on this section of the sewer?
The length of the sewer pipe between Hirwaun and Penywaun is a 600mm AC (Asbestos Cement) Combined sewer laid in 1960.
There are no Outfalls along this length.
- What diameter of the main sewer pipelines from Penywaun to Trecynon and what year was this section of pipeline installed and how many sewage outfalls on this section of the sewer?
The length of the sewer pipe between Penywaun and Trecynon is mostly 525mm AC (Asbestos Cement) Combined sewer was laid between 1969 and 1972. There are small sections of 525mm CONC (Concrete) and a small section of 600 and 675 mm AC.
There is one Outfall along this length from CSO 32468.
- What diameter of the main sewer pipelines from Trecynon to Aberdare and what year was this section of pipeline installed and how many sewage outfalls on this section of the sewer?
The length of sewer pipe between Trecynon and Aberdare is a mixture from 450 to 850mm AC (Asbestos Cement) and CONC (Concrete) Combined sewers and 1000 to 1800mm CONC Combined sewers with the majority laid between 1973 and 1984.
There are 2 Outfalls directly along this length from CSOs 32458, 33182.
- What diameter of the main sewer pipelines from Aberdare to Cwmbach and what year was this section of pipeline installed and how many sewage outfalls on this section of the sewer?
The length of the sewer pipe between Trecynon and Aberdare is a mixture of 825 to 1500mm CONC (Concrete) Combined sewers laid in 1984.
There is 1 Outfall directly along this length from CSO 33183.
- What diameter of the main sewer pipelines from Cwmbach to Mountain Ash and what year was this section of pipeline installed and how many sewage outfalls on this section of the sewer?
The length of sewer pipe between Cwmbach and Mountain Ash is a mixture of 750 to 825mm CI (Cast Iron) and CONC (Concrete) Combined sewers laid between 1880, 1935, 1972 and 2013.
There are no Outfalls directly along this length.
- What diameter of the main sewer pipelines from Mountain Ash to Abercynon and what year was this section of pipeline installed and how many sewage outfalls on this section of the sewer?
The length of sewer pipe between Mountain Ash and Abercynon is a mixture of 450 to 950mm CI (Cast Iron), DI (Ductile Iron), PVC (Polyvinylchloride) and STEEL Combined sewers laid between 1890, 1935, 1950, 1972 and 2021.
There are 3 Outfalls directly along this length from CSOs 71275, 32407.
- What diameter of the main sewer pipeline from Abercynon to Cilfynydd treatment works and what year was this section of pipeline installed and how many sewage outfalls on this section of the sewer?
Abercynon feeds into Cynon Treatment Works, not Cilfynydd. The length of the sewer pipe between Abercynon and Cynon STW is 1200mm CONC (Concrete) Combined sewers were laid between, 1969, 1972.
There are No Outfalls directly along this length.
- What amount of treated sewage water was discharged back into the River Taff for the months of June July August 2022 from the Cilfynydd treatment works?
Please find attached a spreadsheet containing the Total Daily Volume (TDV) data catering from June – August 2022.
- What diameter of the main sewer pipeline from Cilfynydd treatment works to Pontypridd what year was this section of pipeline installed and how many sewage outfalls on this section of the sewer?
There is no direct pipeline from Cilfynydd SWK to Pontypridd. However, we have traced from the nearest one. The length of sewer pipe between Cilfynydd STW and Pontypridd is a mixture of 375mm CONC (Concrete), 525 to 750mm CI (Cast Iron) Combined sewers laid between, 1900, 2002, 2013.
There are No Outfalls directly along this length.
