The Water Quality Working Group (WQWG) reconvened back in 2023, with a new impetus to tackle the failings of the Culm. According to Environment Agency assessments, updated in 2022, the Culm’s water quality has continued to decline. As the image above shows, the number of sub-catchments rated Bad increased from 1 to 2 between 2019 and 2022. Two sub-catchments improved from Poor to Moderate but 2 declined from Moderate to Poor. And it should be noted that “Moderate” still means a failure to meet the standards we expect in our rivers.

The WQWG’s initial focus has been on South West Water (SWW) and understanding what their investment plans are for the Culm. We submitted an Environmental Information Request (EIR) asking for SWW to clarify what those plans are (their published plans being hard to interpret) and to share data on the performance of storm water overflows. We had a useful meeting with staff from the Asset Management team and some of our questions were answered, but we await a full response. What is clear is that the River Culm has a disproportionate number (in relation to its length) of SWW asset investigations and issues. However, in the next investment period (2025-30) only one major investment is planned, to Plymtree Sewage Treatment Works, alongside a new investigation into issues on the Spratford Stream, which could lead to investment there in 2030-35.

There is the hope that in the meantime that SWW will invest in improving the performance of the storm-water overflows (CSOs) in the catchment. The government has set a target of less than 10 spills per year per CSO by 2050 but this has been criticised for being far too long to wait. Richard Horrocks, one of the WQWG members, analysed the most recent spill data from 2022 for CSOs and found that there was an average of 43 spills per year across all of the CSOs on the Culm, with some being activated as much as 86 times a year. Total spill hours were 7200. 2022 was in an exceptionally dry year and we are looking forward to analysing the data against rainfall records. CSOs are designed to spill in periods of extreme rainfall, so it’s important to look at why they spill when it hasn’t been raining recently. We have been told that this can happen where water is getting into the sewage system from springs underground and we are requesting more data on this possibility from SWW.

The WQWG is also interested in all the other potential sources of pollution affecting the river, the primary ones being farming, other industrial activity, private septic tanks and road run-off. In a further development, SWW is working with us to identify the full range of these issues, building on the work we’ve already done on Connecting the Culm.