I-355 Des Plaines Valley Bridge vs. Wetlands

Al Pawloski posted
Hines Emerald Dragonfly!

The 1.3 mile I-355 Des Plaines River Valley Bridge crosses a pristine wetland that is home to 3 endangered species---Hine's Emerald Dragonfly, Blanding's Turtle, and Spotted Turtle. (Update: a different source lists the species as the Indiana Bat, the Hine's Emerald Dragonfly, and the Blanding's Turtle.) Of note for the Hine's Emerald Dragonfly is that the wetland lays on dolostone bedrock. In fact the bedrock is at the surface in Lemont where the I&M Canal had to be dug through it and in Lockport where there were surface quarries. Determining how to construct the bridge with a sufficiently small impact on the wetland and the endangered species delayed construction of the south extension from I-55 to I-80 by a decade.

(Update: EJ&E had to modify their locomotives to help protect the turtles.)

"The entire alignment was shifted to the west to avoid and minimize impacts to a nature preserve." (ConcreteProducts) The tollway authority built three additional dragonfly habitats in forest preserves in DuPage (Waterfall Glen), Cook, and Will (Wikipedia). The design was changed to raise the roadway 10-15 feet because the original height was at the average flying height of the dragonfly. (Walsh video, time mark 6:00) Only 34 piers are used to minimize the footprint. The permanent disturbance of the wetlands is 3.87 acres.

The wetlands extends from the Des Plaines River to the north bluff of the valley, and...

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...to the east all the way to Lemont Road.  The white tower in the distance is the top of the Hindu Temple of Greater Chicago.

It also extends quite a ways to the west. And there seems to be some prairie land that is being restored.

Below I zoomed in on some of the flowers. I spent quite a bit of time trying to frame the shot so that both purple flowers would show. The purple on the right is easy to see. The purple on the left looked better in "real life." It is not in this clump, but the prairie also had quite a bit of Queen's Anne Lace. It still needs some more time and/or work, because it also had quite a bit of ragweed.

An overview of the construction bridge that is now a trail/maintenance bridge, the I-355 bridge, the river, and part of the wetlands.

Another game of "Wheres Waldo." Can you spot the little yellow butterfly that caught my attention as I was leaving?

The butterfly is about a fourth from the left and a little below center. I lucked out because it had taken off and I caught it flying against a solid background.