Hundreds of fish in a city centre river are believed to have died as a result of the recent heatwave and contamination from drainage water. Residents and wild swimmers were horrified to find them washed up on Saturday, appearing to gasp for air, in the River Wensum through Norwich. Local river campaigner Sarah Eglington said the scenes were "absolutely heartbreaking". The Environment Agency said it believed the incident was the result of the recent heatwave - ultimately depleting the river's oxygen - and because heavy rainfall on Thursday had likely flushed in contamination from surface water drainage systems. A spokesperson explained that high temperatures created the conditions that "significantly" reduced dissolved oxygen levels in the water.