July was quite a rainy month for us here in the Bloomington/Normal area! According to data from the Central Regional Airport and the National Weather Service, we received more than 6 inches of precipitation in July 2025, which is significantly more than the rainfall recorded in July 2024 and July 2023. This wetter-than-usual trend wasn’t just local, though; most areas across Illinois saw 1 to 4 inches above average rainfall last month. But how does all this rain impact our environment?
A quick and heavy burst of precipitation can lead to inadequate time for the soil to absorb the water, which can result in flash flooding. If there are prolonged amounts of rain, the ground becomes too saturated and cannot absorb any more rainwater. This excess runoff water must go somewhere—and often, it leads to erosion.
Erosion is a natural process that wears away and transports rocks, soil, and other materials. Over time, or even during a single heavy rain event, erosion can reshape our landscapes in significant ways. It occurs when soil particles are dislodged, carried away, and deposited elsewhere. While erosion can be caused by wind, water erosion is especially relevant during rainy months. There are several types of water erosion, including the following:
- Splash erosion—when rainfall initially impacts the soil, it dislodges soil particles, creating a crater or indentation
- Sheet Erosion—runoff water that spreads across the soil like a sheet, and removes soil in a uniform thin layer
- Rill erosion—water runs through little streamlets within a small channel, and the flow exceeds the soil’s resistance to detachment, cutting into the soil
- Gully erosion—a concentrated flow erosion that creates larger channels that can run deep or shallow
- Stream Bank erosion—wears away the banks of a stream or river when water picks up momentum
Heavy rainfall and increased precipitation can intensify these erosion processes, leading to loss of topsoil, increased nutrient pollution/nutrient runoff, and land degradation.
As we experience heavy rains, be on the lookout to observe what types of erosion occur on our land and identify ways you can take action to care for your land and the environment. Check out https://extension.illinois.edu/rainfall-management to find solutions for too much or too little rainfall. Let’s see what the rest of this month brings!