I tell you, the UK has a strange way of terming rivers. What I would have called streams are called as rivers. Anyway.
What a sad state of affairs, needs to be further cleaned up, Im afraid. Did you know this river was dammed in the WW2 times to provide a water reservoir in case of fires? Its on the flight path to RAF Northolt, the oldest military airfield in the UK. The Germans tried to bomb it regularly and several bombs went awol. Nice.