In late April 2024, the University contacted the Environment Agency to report concerns about the Riseholme Lake immediately after discovering discolouration of the water. The Environment Agency advised that they would begin to monitor the lake via satellite. We have also continued to monitor and record any changes in the lake.
As part of our Environmental and Energy Management System processes, the University contracted an independent specialist consultant, Adler & Allan, to conduct water quality testing shortly after. Both in-situ and laboratory testing analysis against the Water Framework Directive classification values were undertaken. The sampling was completed on 21 May 2024 and the report was received on 21 June 2024.
In summary, analysis found that water quality in the lake is predominately ‘good’ or ‘high’, reporting that even with the discoloured water, the water quality is not reduced to a concerning level. At two of the seven monitoring points sampled (which included both upstream and downstream samples), large amounts of filamentous, non-toxic, green algae (mainly Cladophora and Spirogyra) were identified. Above trace amounts of Blue-green algae was observed at two monitoring points, at only one location onsite and one location upstream.
As part of the vegetation analysis conducted, the presence of New Zealand Pygmy Weed was identified at one monitoring point, which is an invasive species. A management plan will be developed and implemented, to reduce the risk of spread of this invasive species.
We have not surveyed any negative impact on wildlife on or around the lake during this period.
The consultants suggested that discolouration of the lake could be due to poor circulation of the water through the lake, or the presence of a compound not included in this analysis.
Signage asking people not to enter the lake remains in place at the lake as a precaution, whilst we continue to monitor the lake and plan next steps.
If you have any specific questions or concerns, please contact the Sustainability team at environment@lincoln.ac.uk
June 2024