Chicago Lake Plain

A Tule Bluet, a state-threatened damselfly, was observed on 2026-08-24 in Chicago. Damselflies are indicator taxa requiring well-oxygenated freshwater habitats, and their presence in the ecosystem suggests adequate conditions in occupied sites.

An Eastern Massasauga rattlesnake was observed in Cook County on 2026-09-06. This Threatened species, found in wetlands and open prairie habitats, indicates persistent habitat quality in the region and demonstrates its presence within the ecosystem's range.

Red maple, bur oak, and northern red oak displayed colored leaves and falling leaves on September 21. The past 30 days averaged 2.9 degrees Fahrenheit above the normal high temperature, with a peak of 96 degrees on September 2. Fall color timing aligns with the normal start of the season in this region.

Fifty chimney swifts were reported at Horner Park on September 21. In the Midwest, chimney swifts depart in early October after gathering in large numbers to roost and feed before the long migration to South America. This is peak staging season when flocks congregate at traditional chimneys.

A Hooded Warbler was confirmed at Montrose Point Bird Sanctuary on September 22, part of the southbound movement of this eastern breeder to Central American wintering grounds. This neotropical migrant's presence here on the Great Lakes represents its expected fall passage through the region.

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.

At the height of summer swimming season, nearly every public beach along the lakefront carries an official federal designation as an impaired water body — not a seasonal advisory posted on a sign, but a standing regulatory determination that these waters consistently fail to meet their intended use. The cause is pathogens: bacteria flushed into the lake when combined sewer overflows release during and after heavy rain, pushing untreated or undertreated wastewater through outfalls that discharge directly to the nearshore. This is not an emerging crisis or a newly discovered hazard. It is a chronic, documented failure of urban water infrastructure playing out in plain sight on one of the most celebrated freshwater shorelines in the world. The bitter irony of this moment is inseparable from this city's engineering history. In 1900, Chicago reversed the flow of its river — one of the most audacious hydraulic interventions in American urban history — specifically to stop sending sewage-contaminated water into Lake Michigan. Over the following century, the city built the Tunnel and Reservoir Plan, known as the Deep Tunnel, an underground network of caverns and conduits reaching depths of 300 feet, designed to capture combined sewer overflows before they could reach the lake. That system represents one of the largest and most expensive public works projects ever undertaken in the United States, and yet the problem it was built to solve persists at the public beaches every summer. The engineering was visionary; the operational reality has not kept pace. The regulatory picture makes the gap between ambition and outcome concrete. The Calumet City and Skokie combined sewer systems are both currently in significant non-compliance with their discharge permits, meaning the controls meant to prevent these overflow releases are not holding under real-world conditions — particularly the intensifying rain events that have become more frequent across the Chicago Lake Plain. Combined sewer systems were built when the city was young and storm runoff and sanitary sewage shared a single pipe — a design logic that made a certain kind of sense before the region was paved. Today, even a modest rain event can overwhelm that legacy infrastructure and trigger a release. The lagoons embedded in the city's great West and South Side parks tell the same story with equal persistence. Humboldt Park, Garfield Park, Columbus, Douglas, Marquette, McKinley, Washington, Sherman — nearly every lagoon in that network is officially listed as impaired, and most are still waiting for an active cleanup plan. These lagoons were designed in the late nineteenth and early twentieth centuries as civic amenities, places where working-class Chicagoans without access to private green space could experience something of the natural world. Their impairment is not merely an ecological failure; it is a failure of a specific promise about who the city's natural resources are for. What to watch going forward is whether significant non-compliance determinations translate into enforceable timelines and capital investment, or whether they remain paper designations while the overflow season cycles through another year. Intensifying precipitation across the Great Lakes region means the hydraulic stress on these aging combined systems is more likely to increase than decrease. The lake itself remains extraordinary — deep, cold, ecologically complex — and the nearshore recovers quickly when inputs stop. The question is whether the inputs will stop, and when.

Compass plant is blooming at 46 sites citywide since May — lakefront to Southwest Side. Its 15-foot taproot takes a decade to establish; when it flowers, the soil has earned it. Settlers once navigated the Illinois prairie by its north-south leaves.

Blue Dashers and Eastern Pondhawks are patrolling the lagoons on the West Side this week — both tolerant species adapted to marginal water quality. This preference for resilience over choosiness makes ecological sense: all three of the major lagoons here are officially designated as impaired waterways, and none have cleanup plans in place. Streamflow has dropped to just over 12 cubic feet per second, roughly a third of the long-term average of 41 feet per second. Warm, still water holds the least dissolved oxygen of the year, creating conditions that only generalist dragonflies can exploit reliably. The visible presence of these species is less a sign of health than of their extraordinary tolerance for stress.

Monarchs and Red Milkweed Beetles have converged on the lakefront milkweed patches this June — a quiet milestone marking the transformation of this urban edge into essential breeding habitat. Three monarch sightings and four beetle records in recent weeks document what appears to be active reproduction on common milkweed — a coupling that persisted through the Midwest's agricultural intensification but has grown increasingly rare. Over the past three decades, the application of herbicides to corn and soybean crops has stripped milkweed from hundreds of thousands of acres across the region, collapsing the landscape resources that monarchs and their specialist associates once took for granted. The migration corridor now depends on fragmented urban and semi-wild refuges like this one. What was once common is now significant.