A woman had to be rescued after she got into difficulty when having a swim at 4am in Brayford Pool in Lincoln.
The incident happened on May 27, near to Brayford Quays on Brayford Wharf North.
Police said the 20-year-old woman was swimming in the Brayford but got into difficulty.
Officers attended to help the woman, who was taken to hospital as a precaution, but was not seriously injured.
Lincolnshire Police also thanked three members of the public who assisted their rescue.
John Beaumont, a security guard at Brayford Quays Student Accommodation, helped officers pull the woman from the water to safety.
Meanwhile, Mark Jackson and Emma Thompson gave the woman clothing to help warm her up and looked after her belongings.
A statement from Lincolnshire Police said: “Thank you to all of you.
“It was with help from you that Lincolnshire Police officers were able to quickly and effectively respond and provide assistance, ensuring the woman concerned was subsequently safe and well.”