Concerns are being voiced over depleted water levels in the River Arun in Horsham.
Photographs taken last week show the dried up river bed - strewn with debris - at the end of Denne Road.
Louise Oakley, who took the photos, said: “Normally, the water is a couple of feet deep.”
She said she was concerned about the effect on fish in the area, as well as rubbish in the river.
A spokesman for the Environment Agency said: “We were not informed at the time of this incident, but our subsequent checks have revealed the low water levels seen on a tributary of the River Arun were not the result of Environment Agency activity.
“We strongly urge people noticing extreme low water levels or fish in distress to call our free 24-hour National Incident Hotline on 0800 807060.”