Just how much rain fell in the Brainerd area during the June 19 storm is finally coming into focus.
And some effects may still be felt.
Jeff Hulsether, Brainerd city engineer, told the city council, portions of East River Road were closed between Washington and Front streets last Friday.
“We sort of had a scary situation there,” Hulsether said.
Crews patched a pot hole by a sanitary sewer manhole only to find a day later it had settled significantly.
“So we had a sink hole developing by a sanitary manhole about 20 feet away from the railroad grade,” Hulsether said. The soil was so loosely compacted in the area of the sink hole they were able to push a rod down 26 feet. A second boring made between the hole and railroad grade was better. They excavated the site to verify the problem and filled the area with water
There was so much water with that storm and so much pressure water pushed out of joints of pipe and saturated soils and volume of water going through sucked in material creating the sink hole.
Hulsether said the automated weather station at the Brainerd Lakes Regional Airport indicated more than 7 inches of rain fell June 19, with 3 inches falling in a 20-minute period from 10:30 p.m. to 11 p.m.
“These numbers are pretty much off the chart,” Hulsether stated in his report, adding having 5 inches fall in a 12-hour period is a 140-year storm while 7 inches in a 24-hour period represents a 200-year storm. Five inches of rain falling on the eight square miles of land representing the city of Brainerd equates to about 700 million gallons of water, Jeff Hulsether reported.
The wastewater treatment plant received almost 5.9 million gallons from the storm, compared to a daily average of about 2.8 million. Flows were back down to 3.2 million last Friday, Hulsether said, adding that indicates some basements in the city are starting to dry out.
The storm caused minor flooding in the city and created washouts on North 10th Street, but Hulsether said damage was limited. College Drive, he said, had challenges with Anderson Brothers putting on a full crew the night of the storm to construct and maintain berms, direct runoff and maintain erosion control. One berm failed next to the Legacy Apartment building and four basement units had wet floors. Significant damage was reported to the drainage ditch north of Buffalo Hills Lane. A portion of Southeast 19th Street was underwater the day after the storm. East River Road was closed between Kiwanis Park and Jenny Street because of flooding and as of Monday morning was still under about 2 feet of water.
Still, the city’s investment in the last 15-20 years in the storm sewer capacity paid off with this storm, Hulsether said.
“Without these improvements, there surely would have been substantial damage to private property,” Hulsether reported.