Over the weekend, residents and swimmers in Norwich discovered hundreds of dead fish washed up in the River Wensum, prompting distress from the local community. The incident affected multiple species and prompted concerns from those familiar with the river's normally healthy state.

The Environment Agency attributed the deaths to combined environmental factors: sustained high temperatures reduced dissolved oxygen in the water whilst heavy rainfall on Thursday likely introduced surface drainage contaminants. The Wensum, a 44-mile chalk river spanning Norfolk and designated as a Site of Special Scientific Interest, supports over 100 plant species and is considered one of England's most significant chalk river ecosystems. Officials stated they would continue monitoring and coordinate with partner organisations to address the situation.