Elgin O’Hare Western Access – I-390

Map of Elgin OhareIn 2013, the Elgin O’Hare West Access Project (EOWA) was announced to connect the Elgin-O’Hare Expressway (IL-390) to O’Hare Airport and connect I-90 and I-294 via the new I-490 tollway.

As preparation for the construction project, we assessed stream sites in the corridor. We surveyed for aquatic macroinvertebrates, mussels, and fish at Higgins Creek, Salt Creek-Thorndale Ave., Salt Creek-Salt Creek Forest Preserve, and Spring Brook.


Aquatic Macroinvertebrates

  • Sensitive groups of macroinvertebrates (EPT) were absent or extremely depressed at some sites and replaced with more tolerant taxa (e.g., worms, isopods).
  • Overall, 3 families of Ephemeroptera, no Plecoptera, and 4 families of  Trichoptera were found
  • Flatworms (Platyhelminthes), amphipods, oligochaete worms (Clitellata), and chironomids were collected at all sites
  • Hydropsychid caddisflies (Hydropsychidae: Cheumatopsyche spp.), blackflies (Simuliidae: Simulium spp.), isopods (Asellidae: Caecidotea spp.) and snails (Gastropoda) were found at 3 out of 4 sites


White heelsplitter – Lasmigona complanata
  • Native freshwater mussels were rarely encountered across the study sites.
  • The 2 species found (P. grandis and L. complanata) are typically considered tolerant to poor water quality and use a suite of host fish for successful metamorphosis, allowing them to persist in degraded stream
  • Historically, 10 species were found in that area




Bluegill – Lepomis macrochirus
  • 16 species of fish total
  • Fish communities consisted of primarily common tolerant species.
  • One species, Smallmouth Bass, is moderately intolerant
  • Three most abundant species were Bluegill (Lepomis macrochirus), Blackstripe Topminnow (Fundulus notatus), and Bluntnose Minnow (Pimephales notatus)




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Sivicek, V.A., S.A. Johnson, J.L. Jarvis, and M.J. Dreslik. 2019. Noxious and selected invasive plant populations along Illinois toll highway rights-of-way. Illinois Natural History Survey Technical Reports 2019 (28):1–87.

Bilger, E.E., A.J. Stites, J.L. Sherwood, S.A. Douglass, and M.J. Dreslik. 2017. Aquatic community surveys of the Elgin-O’Hare western access project area. Illinois Natural History Survey Technical Report. 2017(9):1–20.

Mui, Jennifer M., Michael J. Dreslik, and Charles A. Warwick. 2021. Illinois Natural History Survey Urban Biotic Assessment Program 2015-2020. INHS Technical Report 2021 (02).

For more information on construction visit the Illinois Tollway website.