Cook County's soil moisture whiplash, and a compliance flag on the river

August 6, 2026

Cook County's soil moisture has been on a wild ride this growing season. In mid-May the county showed no dryness at all. Within two weeks it had flipped to abnormally dry conditions countywide, and by early June nearly 70 percent of the county sat in moderate drought. Then, just as fast, conditions cleared completely by mid-July. Now, in the first days of August, mild dryness is creeping back in.

That's a full dry-drought-clear-dry cycle in about twelve weeks, a lot of hydrological whiplash for one summer. Shallow-rooted plants, lawns, turf, and many street trees draw water from the top foot or so of soil, so they feel every one of these swings almost immediately, going stressed and green again in quick succession. Deep-taprooted prairie natives don't have that problem the same way. Compass plant, covered here in July after its bloom appeared at sites across the city, sends a root down as far as 15 feet, well below where these surface fluctuations reach. That difference in root architecture is a big part of why prairie natives tend to hold steady through a summer like this one while turf grass and ornamental plantings show the strain.

Water stress on the landscape isn't only a matter of rainfall and root depth, though. Along the river, River City Facilities is currently listed by EPA as being in significant non-compliance with its discharge permit. A query for the specific pollutants, exceedance levels, and dates behind that listing turned up no further detail, so it's not yet clear what the violation involves or whether it has affected water quality in the river. Still, it's a reminder that the water moving through this system is shaped by more than the season's weather swings \u2014 permitted dischargers are part of that picture too, even when the specifics of a given compliance issue aren't yet public. Even as the prairie's deep roots ride out the surface swings undisturbed, what reaches the river also depends on oversight of facilities like this one.

Data from U.S. Drought Monitor (NIDIS / drought.gov) and EPA ECHO

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