Independent review finds East Lansing's sewer system is not prepared for heavy rainfall
Increased rainfall fueled by climate change is posing a threat to East Lansing’s sewer system, according to findings from an independent review.
The review was first presented at last week’s East Lansing City Council meeting. It studied the flooding that affected the city in the summer of 2021. The review was conducted by engineering firm Tetra Tech.
Dan Christian, the senior water resource engineer at the company, told council members that the city is only prepared to withstand 10-year storm events. That's a storm that has a one in 10 chance of happening each year. Last summer’s rainfall was categorized as a 140-year storm event.
“The storm event that we saw on August 12 2021, was just more severe, higher intensity and larger total rainfall than what the city's design standard is for the capacity for the conveyance system," he said.
The review includes interviews with five East Lansing residents who suffered damage inside their homes because of the flooding. According to the interviews, these residents had several inches of water in their basements from the overflow of rain.
"Observations indicated that the bypass pumping system and sewer collection system was running full during and immediately following the rain event. This suggests that there were no significant restrictions preventing water from entering the collection system," Christian said.
In other words, the system was functioning the way it was supposed to, but couldn't keep up with the heavy rainfall.
East Lansing’s acting Director of Public Works Nicole McPherson agreed with Christian's assessments.
“Storms are getting more intense. It appears that we're getting a few more of them and you know, we're going to try and do what we can but there's just not a quick solution to resetting the infrastructure throughout the city," she added.
To sustain the amount of rain the area saw in August of 2021, the pipes need to be increased in diameter. McPherson says doing those updates right now is just not feasible.
"It would be a full reset of the entire sewer system to be able to account for that type of an event," she said.
McPherson says the sewer system will undergo a $10 million dollar update in the coming months. It's expected to prevent some flooding in the east side of the city. The city is also planning for another study on how to update its infrastructure to increase rainwater capacity.