Professor R Malby
Ilkley Clean River Campaign 30 Nelson Road
Ilkley
LS29 8HN
Dear Professor Malby
Our ref: 2019/AM/4308
Date: 19 August 2019
Ilkley Clean River Campaign - Ashlands Sewage Treatment Works
Thank you for your letter dated 30 July 2019 to our Chief Executive, Sir James Bevan. James was pleased to meet Professor Malby recently and has read your letter and asked me to respond on his behalf. He will also receive a copy of this response.
In your letter you asked for a plan to be provided to Ilkley residents by the end of September 2019 for work to commence in 2020. I can confirm that the options and timescales described in the letter from Martin Christmas on 7 June 2019 comprise our plan to address concerns related to storm sewage and settled storm sewage discharges at Ilkley WwTW.
The next stage of which is the commissioning of Event Duration Monitoring (EDM) at the works. You referenced information provided by the Times reporter in this regard and I can confirm that they were partly correct in their assertions. The instruments required for EDM were installed in January at Ilkley WwTW and currently measure storm tank levels, meaning we can confirm when a discharge has occurred.
However at the moment the instrumentation does not indicate when the discharge stops and therefore cannot be used to assess the discharges against the Storm Overflow Assessment Framework (SOAF). Yorkshire Water Services (YWS) are aware and in the process of rectifying this issue. We will update you once they confirm that EDM commissioning is complete.
You also asked in your letter for ‘a consent limit compliant with the UWWTD’. In the letter from Martin Christmas on 7 June 2019 we outlined the process through which a change of consent limit would be considered and implemented if appropriate. Our position in this regard has not changed since that time.
You raised concerns regarding the maintenance programme for the sewerage system in Ilkley following reports of surcharging manholes alongside the river. As you have highlighted, discharges of raw sewage from manholes does constitute an unpermitted discharge and is therefore both unacceptable and illegal.
Water companies should take appropriate proactive measures to prevent discharges of this nature. When receiving and investigating reports of pollution relating to the sewerage network, such as surcharging manholes, we commonly request details of maintenance to allow consideration of whether adequate measures were taken to prevent an incident and therefore inform our regulatory response.
Lateral, 8 City Walk, Leeds, LS11 9AT Customer services line: 03708 506 506 Email: enquiries@environment-agency.gov.uk www.environment-agency.gov.uk
Following the report of surcharging manholes to the rear of Rivadale View on the footpath adjacent to the River Wharfe on 21 July 2019, Yorkshire Water Services (YWS) have been investigating the cause of the discharge. There is a Combined Sewer Overflow (CSO) located just upstream of the manholes in question and they confirmed that this section of sewerage had previously been identified by their CSO trend monitoring system as a potential risk in May 2019. This risk instigated CCTV surveys and proactive de-silting which was completed in July 2019.
Unfortunately, as demonstrated by the surcharging on 21 July 2019, this has not removed the risk. CCTV carried out since has found small amounts of silt still present in patches downstream of the CSO and it is thought that the manhole where discharges occur may be lower than the weir of the CSO, preventing it operating effectively. YWS are now investigating what work needs to be carried out to prevent further surcharges and has arranged further de-silting. We will be monitoring this situation closely to ensure that YWS take all appropriate measures to prevent reoccurrence. Please continue to report all issues such as this to our 24hr incident hotline on 0800 80 70 60.
Finally you requested an interim plan for securing water quality and enabling Bathing Water Status in the Wharfe in Ilkley. We do not consider an interim plan to be necessary at this time. This is because, as described previously, the current evidence does not suggest that Ilkley WwTW is preventing the River Wharfe from achieving its Water Framework Directive targets. Additional sampling to consider this in more detail is underway.
Phytobenthos has not been included in this additional sampling because it is used as an indicator of high nutrient loading. As part of the additional sampling we are already measuring the nutrients associated with sewage discharges directly and therefore the additional cost is not justified when we are specifically considering outputs from the WwTW.
The River Wharfe in Ilkley is not currently designated as a bathing water and the Environment Agency is not responsible for enabling such a designation to take place. In the event of a designation we would develop a bathing water profile and put plans in place to monitor and protect the bathing water. We are not able to do this before such a designation and in this regard we await the outcome of your designation application.
I hope this is helpful. Please let me know if I can be of anymore assistance. Yours sincerely
Oliver Harmar
Yorkshire Area Director
Lateral, 8 City Walk, Leeds, LS11 9AT Customer services line: 03708 506 506 Email: enquiries@environment-agency.gov.uk www.environment-agency.gov.uk