River Report

Mackinaw River river

2 streamgauges 23% of normal Last updated 2026-05-30
Aggregate flow
657cfs
% of normal
23%
Daily volume
1,303AF
Seasonal avg
2,876cfs

Total streamflow across the Mackinaw River was last observed at 657 cfs, and is expected to yield approximately 1,303 acre-ft of water today; about 23% of normal. River levels are low and may signify a drought. Average streamflow for this time of year is 2,876 cfs, with recent peaks last observed on 2019-05-04 when daily discharge volume was observed at 26,190 cfs.

Maximum discharge along the river is currently at the Mackinaw River Near Green Valley reporting a streamflow rate of 370 cfs. This is also the highest stage along the Mackinaw River, with a gauge stage of 14.2 ft at this location. This river is monitored from 2 different streamgauging stations along the Mackinaw River, the highest being situated at an altitude of 611 ft, the Mackinaw River Near Congerville.

Max discharge

Mackinaw River Near Green Valley

370cfs
Highest stage

Mackinaw River Near Green Valley

14.2ft
Highest-elevation gauge

Mackinaw River Near Congerville

611ft
Aggregate trend

River streamflow levels

Daily aggregate streamflow across every monitored gauge along the Mackinaw River. Use the range buttons to zoom in on a specific period.

Total streamflow

Sum of all monitored streamgauges · daily

Per-gauge breakdown

Every streamgauge along the Mackinaw River

All 2 USGS gauges Snoflo tracks for this river, with current flow, stage, recent change, percent of normal, and the gauge's all-time min / max. Click any header to sort. Cells are heatmapped relative to the column min/max -- darker blue = higher.

Streamgauge Streamflow (cfs) Gauge stage (ft) 24h Δ (%) % Normal Min (cfs) Max (cfs) Elevation (ft)
Mackinaw River Near Congerville IL
USGS 05567500
287 1.84 -7.9 53% 0 23,700 611
Mackinaw River Near Green Valley IL
USGS 05568000
370 14.20 -10.3 39% 11 18,800 501
Annual peaks

Maximum streamflow discharge by year

The single highest aggregate discharge recorded each year. Spotting the multi-year trend reveals droughts vs. wet cycles long before the headline daily flow does.

Annual peak discharge

From the river's full record · one point per water year

Profile

Streamflow elevation profile

Each bubble is one gauge along the river, plotted by current streamflow (x-axis) vs elevation (y-axis), sized by gauge stage. Reading top-to-bottom traces the river from headwaters down to its mouth -- you can see flow accumulate as elevation drops.

Elevation vs streamflow

One point per monitored gauge · bubble size = gauge stage

About this river

Mackinaw River

The Mackinaw River flows through central Illinois, spanning 130 miles from its headwaters in McLean County to its confluence with the Illinois River in Tazewell County. The river's name comes from the Native American word "Makinauk," meaning turtle. The Mackinaw River has a drainage area of 1,800 square miles and is fed by several tributaries. The river has two major reservoirs, including the Evergreen Lake and Lake Bloomington, which serve as sources of drinking water for nearby communities. The river is also used for recreational activities such as fishing, canoeing, and camping. It is a popular spot for fly fishing and is home to several species of fish, including smallmouth bass and channel catfish. The river also supports agricultural activities, including crop irrigation and livestock watering.

Track the Mackinaw River in the Snoflo app

Set per-gauge push alerts (e.g. "alert me when flow at the Russian R Nr Healdsburg crosses 5,000 cfs"), and Snoflo's iOS app pushes the moment USGS reports the crossing.

FAQ

About the Mackinaw River

Where does the data for the Mackinaw River come from?

Streamflow and gauge stage data are sourced from the U.S. Geological Survey (USGS) National Water Information System. The aggregate flow shown at the top of the page is computed by Snoflo as the sum of all monitored gauges along the river.

How is "percent of normal" calculated?

Today's aggregate streamflow is compared to the historical average aggregate streamflow on this calendar day across the river's full record. 100% means right on average; values above 100% indicate above-normal flow (wet year); values below indicate below-normal (dry year or drought).

Why are some gauges showing very different flows?

Gauges along a river measure flow at different points: headwater gauges read what's coming off the snowpack or mountain runoff; downstream gauges integrate everything upstream, including tributary inputs. Wide spreads usually mean a tributary is contributing significantly between gauges.

What's the elevation profile chart showing?

Each bubble is one gauge along the river, plotted by streamflow (x-axis) and elevation (y-axis), sized by gauge stage. Reading top-down traces the river from headwaters to mouth -- you can see flow build as elevation drops.

Can I get alerts when a specific gauge crosses a threshold?

Yes -- alerts are managed in the Snoflo iOS app on a per-gauge basis. Open any individual streamgauge from the table above and favorite it to set a discharge threshold.