The River Steeping burst its banks at Wainfleet All Saints in Lincolnshire on Wednesday after two months' worth of rain fell in two days.
A state of emergency was declared on Thursday with more than 70 properties in the town being flooded and residents evacuated.
Crews are due to resume work on the breach later.
An RAF Chinook helicopter was used to help the operation carrying ballast and sandbags to the site - an operation which carried on into the night.
Karl Foxall, watch manager with Lincolnshire Fire and Rescue Service, said: "That's going to commence again at 09:00 this morning.
"The water levels currently haven't changed but we have brought in four high-volume pumps and they're currently at Gibraltar Point."
Assistant Chief Constable Shaun West of Lincolnshire Police added the rescue effort was showing some early signs of success.
"We are hopeful we will be able to stem the flow and block the breach," he said.
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The weather is due to improve in the coming hours but Mr West said the water could take some considerable time to subside.
He said the priority was to keep people safe.
Fire crews are continuing to evacuate some of the worst affected residents.
A rest centre for Wainfleet residents has also been set up in nearby Skegness.
Up to 35 homes in the town have been left without power after a substation on Matt Pit Lane flooded.
Western Power are on site and are working to restore the supply.
The utility company is also checking the homes of affected residents.
A number of flood warnings for Lincolnshire also remain in place.
Jean Hart, who has lived in the town for 40 years, said it was the worst flooding she had ever seen.
"To see our house underwater is absolutely horrendous," she said.
"The whole of my house is completely devastated.
Emergency services also rescued her tortoise Mr T from her home, and she had earlier been reunited with her cat Aurora.