Four crews from Shropshire Fire and Rescue Service, including a fire engine and the water rescue team, were scrambled and searched an area by the Welsh Bridge.
The 999 calls were made just after 11.30pm on Friday and police and the firefighters spent an hour searching before police confirmed that no-one was in the water.
Earlier in the evening a fire crew from Shrewsbury went to the Battlefield Enterprise Park in the north east of the town to deal with a fire in the open.
The fire, involving wood, was extinguished using a knapsack sprayer.
The emergency call was made at 7.25pm and the firefighters had the blaze under control within half an hour.