While Winvic was working on the East Midlands Gateway warehouse development site, a drain blocker failed during heavy rainfall, causing the contamination of nearby Hemington Brook.
At Nottingham Magistrates’ Court this week Winvic Construction Limited admitted causing pollution and was fined £160,000 plus costs of £25,577.79.
The court was told that Winvic was contractor at the site when Hemington Brook became highly turbid and discoloured with clay solids. A biological survey revealed that the discharge of contaminated run-off from the site had caused ‘gross and chronic’ pollution, adversely affecting invertebrates.
A member of the public alerted the Environment Agency when the brook started “running red with silt pollution” on or before 27th September 2019.
The source was traced to an outfall near the development site, which was the responsibility of the company.
Staff told officers from the Environment Agency that a drain blocker had failed. This had allowed the contaminated contents of two ponds to drain and discharge into the brook via a flood attenuation basin.
Officers from the Environment Agency attended the site again on 30th September 2019 and found that the discharge had not been stopped.
Analysis was carried out revealing that the level of suspended solids in Hemington Brook had measured between 1200 and 1400 mg/l downstream. By comparison, historical sampling data from 2019/20 indicated an average level of 50 mg/l suspended solids with a maximum of 240 mg/l.
High levels of suspended solids in water inhibit plant photosynthesis and lower oxygen levels. They can clog fish gills and smother fish spawning areas.
The court accepted that the offence was due in part to unprecedented rainfall in the local area.
A Winvic spokesperson said: "We acknowledge and regret the discharge of surface water containing Mercia Mudstone held in the East Midlands Gateway (EMG) site’s ponds into Hemington Brook in August 2019. Whilst industry defined and agreed best practice mitigation measures were in place at the site, a number of factors combined to leave Winvic, in the words of the court, 'between a rock and a hard place'.
“Due to the acknowledged heaviest period of rainfall in the area since records began, significant volumes of water built up in the approved siltation ponds on the site. This unforeseen event unfortunately attracted large numbers of migrating birds which presented a very real and potentially fatal risk of a bird-strike at the adjacent East Midlands Airport, conflicting with the requirement from the Environment Agency (EA) to hold and clean water prior to discharge. The decision was therefore taken to discharge water from the ponds in order to avoid the possibility of a more catastrophic event occurring – hence the 'rock and a hard place' comment above. However, we accept that in doing so water containing suspended solids of Mercia Mudstone was discharged into Hemington Brook.
“The Mercia Mudstone naturally occurs not only on the EMG site but in the wider catchment area. Both the EA and the court accepted that the environmental harm caused by the water discharge was 'minor and localised… incurring low costs through clean-up, site restoration or animal rehabilitation'.
"The construction work undertaken by Winvic on the EMG site was fully in accordance with a development consent order granted by the secretary of state and, more specifically, fully complied with the recommendations within the construction management framework plan and Construction Industry Research & Information Association (CIRIA) guidance. The company, however, also implemented additional measures to treat the water and manage the site run off. All flood prevention measures were endorsed by the EA before the project commenced. The additional measures employed by Winvic were reviewed by the EA and noted as being unprecedented in respect of water management. Furthermore, we are pleased that the measures have improved the pre-existing local situation, significantly reducing the risk of potential flooding at Hemington.
“Nonetheless, we have welcomed working with the EA throughout the process to ensure lessons could be learned and applied across the business. Winvic is committed to ‘doing it right’ and strives for continuous improvement in all areas. We continue to liaise with the EA on numerous projects to achieve successful outcomes.”
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