GOSHEN — Knee-deep water in Alan Hamlet’s basement in South Bend last year was a sign that some would attribute to climate change.
The neighboring St. Joseph River flooded in February 2018 when heavy rains were accompanied by melting snow; water tables in the ground were saturated. There was nowhere for rainwater to go, so it found basements like Hamlet’s.
“We can never say with great certainty that any particular extreme event is caused by climate change, per se,” Hamlet, a climate researcher in affiliation with the University of Notre Dame, said at a recent seminar.
“What we can do, though, is point to those events as examples of what future conditions say,” Hamlet continued. “This is not just a single event. It is a systematic change that is happening over time.”
The 2018 flooding was deemed a once-in-a-2,500-year event.
In the year-and-a-half through February 2018, South Bend experienced a 500-year flood and a 1,000-year rain event, when 8.49 inches fell in a 24-hour period beginning Aug. 15, 2016.
Predictions indicate that the St. Joseph River at nearby Niles, Michigan, will see a 45% increase in 100-year floods by 2080.
Hamlet’s flooded basement and the swollen river were shown in photographs to about 175 people attending the fourth annual Climate Leadership Summit.
The gathering, hosted by Earth Charter Indiana, was conducted at Goshen College, a Mennonite-based liberal arts school of 845 undergraduates that made a commitment in 2013 to purchase 100% of its electricity from renewable energy sources such as wind and solar. The move is expected to reduce the college’s carbon footprint by 45%.
Many speakers focused on the effects of a predicted increase in Indiana of more rain, particularly in the springs.
City planners attending the conference were advised by engineer Siavash Beik to take measures to reduce the possibility of flood damage in their communities.
Beik, with Christopher B. Burke Engineering, said communities should relocate valuable properties and assets in safer areas, urge development of critical facilities such as hospitals in areas less prone to flooding and adopt standards where development will not have an adverse effect on drainage.
Over the past century, Indiana has become warmer by 1.2 degrees Fahrenheit, according to Jeffrey Dukes, director of the Purdue Climate Change Research Center. Rainfall has increased by 5.5 inches a year, causing more floods, Dukes said.
Nutrients from agricultural products run off into streams and lakes. Algal blooms form, trapping cooler water closer to the lake bottoms. Dead algae sinks to the bottom and is eaten by bacteria, depleting the water’s oxygen. In turn, that creates bottom waters of hypoxia, or low oxygen levels.
“Hypoxia zones are basically dead zones where fish can’t live,” Dukes said.