Climate change could have a real impact on the Chicago River. In fact, climate change research shows that by the end of the 21st century scientists are projecting noticeable temperatures increases in Chicago, including extreme heat days, which are those days that exceed 97°F.  Illinois could see more than 25 such days annually.

Increasingly variable precipitation is also expected. Meaning, while annual average precipitation may not change much, the state may grow drier overall because rainfall cannot compensate for the drying effects of a warmer climate.

Conversely, rainstorms will be harder and more intense, which will directly impact our system. Therefore,  for the Chicago River system, climate change means:

• More erosion and fluctuation of river levels, which can kill off native species and allow non-natives to flourish;
• Extreme runoff, which would result in more germs in the water;
• We could see less aquatic habitat because reduced summer water levels;  and
• An increase in flooding, CSOs, and stormwater pollution because of more heavy rain, which is already impacting our system.

Learn more about the impacts of climate change on the Chicago River system from temperature changes to increased flooding. Open this power point, and click through to read!

What Does Temperature Mean for Fish?

Native fish species have evolved to thrive in our local environments, or ecosystems. According to fish sampling conducted by the Illinois Department of Natural Resources and the MWRD, the Chicago River contains a diverse collection of almost 70 species of fish. Unnaturally high water temperatures have a tremendous negative impact on the fish. In addition, such warm water can create environments that are readily utilized by invasive species, such as the Asian carp, that are able to thrive in degraded ecosystems. The proposed water quality standards include provisions that protect native fish.