It’s a problem throughout Indiana and the U.S. – human waste and runoff from cities is flowing into local rivers after heavy rainfalls, including the Wabash River.
In West Lafayette after large storms, an alert is sent out to citizens who have signed up for the service notifying them of a Combined Sewer Overflow (CSO) event. In other words, it is notifying them that the rainwater that is mixed with sewage from the city has surpassed the capacity of the city’s facilities and as a result has been dumped into the Wabash River.
In June, the City had five overflow events out of 14 days of rain. The largest overflow event drained about 150,000 gallons of combined storm and waste water into the Wabash.
Ron Turco, a professor in agronomy at Purdue and director of the Indiana Water Resources Research Center, emphasized that the problem happens all over the U.S. and tends to accumulate farther downstream of the river.
“What happens is that everything associated with human existence in the urban area: gasoline, oils, antifreeze, fertilizers that are not applied correctly, grease from restaurants, animal waste are all sitting on the land surface. So when it rains, it runs off and enters the storm drain,” Turco explained.
For that reason, there is signage near the points where the City drains this combined overflow warning citizens not to swim in the area after a rain storm. These signs can be seen by the riverbank at Quincy and Dehart Streets.
Turco said the overflow events are not a concern for human safety the majority of the time, but after swimming or coming in contact with any inland freshwater, wash your hands.
“It’s an old saying that dilution is the answer to pollution. Well, there is truth to that,” Turco said. “When you put materials into a volume of water as big as the Wabash, you tend to dilute the material down quite a bit to take an amount of time to get to a troublesome range.”
According to Utility Director David Henderson, the City has taken steps to reduce the amount of waste released into the river.
“In our first version of the long-term control plan, we did about $50 million worth of work and in our second update to this long-term control plan, we have another about $25 million dollars worth of work in the years ahead,” he said.
The City is expected to meet the level of combined sewer overflow control sought by the State by 2027.