Explore · Fox River
St. Charles Pool Historical River Analysis
Up to fifteen completed years of seasonal observations, current-year context, and the historical baselines used by the St. Charles Pool water model.
About the St. Charles Pool
The St. Charles Pool is the roughly seven-and-a-half-mile reach of the Fox River between the South Elgin Dam and the St. Charles Dam. Through this section, the river changes character several times: from the developed riverfront of South Elgin, through forest preserves, islands and relatively natural shoreline, then into the increasingly developed river corridor of northern St. Charles.
The pool is used heavily for recreation. Fishing, paddling, recreational boating, cycling, walking and wildlife viewing all share the corridor. The Fox River Trail follows the river through much of the reach, while the Fabulous Fox! Water Trail provides a connected paddling route and designated access sites. The water trail was added to the National Water Trails System in 2023.
Long-Term River Context
Historical measurements show the river's normal seasonal movement, the range of conditions observed in individual years, and how the current year compares with the model's fifteen-year reference period.
These charts use the same monitoring network and seasonal baselines as the water model. They are a long-term analytical reference, not a live conditions dashboard.
Historical Reference
Seasonal Patterns by Monitoring Station
These charts compare available annual observations with the model's seasonal median and P25–P75 reference band.
Fox River at Johnsburg
Gage Height · 15-Year Reference Window
Gage height is the water-surface elevation at the station and helps confirm whether the river is unusually high or low.
Fox River near McHenry
Water Temperature · 15-Year Reference Window
Water temperature affects metabolism, dissolved oxygen, fish location and seasonal behavior.
Gage Height · 15-Year Reference Window
Gage height is the water-surface elevation at the station and helps confirm whether the river is unusually high or low.
Specific Conductance · 15-Year Reference Window
Specific conductance reflects dissolved ions in the water and can change with runoff, groundwater influence and seasonal chemistry.
Dissolved Oxygen · 15-Year Reference Window
Dissolved oxygen indicates how much oxygen is available in the water for fish and other aquatic life.
pH · 15-Year Reference Window
pH describes how acidic or alkaline the water is and provides additional water-quality context.
Chlorophyll Fluorescence · 15-Year Reference Window
Chlorophyll fluorescence is a proxy for algal abundance and can help characterize biological productivity.
Phycocyanin Fluorescence · 15-Year Reference Window
Phycocyanin fluorescence is a proxy for cyanobacteria and provides additional biological water-quality context.
Turbidity · 15-Year Reference Window
Turbidity indicates suspended material in the water and serves as a useful visibility and runoff proxy.
Fox River Tailwater near McHenry
Gage Height · 15-Year Reference Window
Gage height is the water-surface elevation at the station and helps confirm whether the river is unusually high or low.
Fox River at Algonquin
Gage Height · 15-Year Reference Window
Gage height is the water-surface elevation at the station and helps confirm whether the river is unusually high or low.
Fox River Tailwater at Algonquin
Water Temperature · 15-Year Reference Window
Water temperature affects metabolism, dissolved oxygen, fish location and seasonal behavior.
Discharge · 15-Year Reference Window
Discharge is the volume of water moving past the gauge and is the primary measure of river flow.
Gage Height · 15-Year Reference Window
Gage height is the water-surface elevation at the station and helps confirm whether the river is unusually high or low.
Specific Conductance · 15-Year Reference Window
Specific conductance reflects dissolved ions in the water and can change with runoff, groundwater influence and seasonal chemistry.
Dissolved Oxygen · 15-Year Reference Window
Dissolved oxygen indicates how much oxygen is available in the water for fish and other aquatic life.
pH · 15-Year Reference Window
pH describes how acidic or alkaline the water is and provides additional water-quality context.
Tyler Creek at Elgin
Precipitation · 15-Year Reference Window
Local precipitation helps explain runoff pulses entering the pool through nearby tributaries.
Discharge · 15-Year Reference Window
Discharge is the volume of water moving past the gauge and is the primary measure of river flow.
Gage Height · 15-Year Reference Window
Gage height is the water-surface elevation at the station and helps confirm whether the river is unusually high or low.
Poplar Creek at Elgin
Discharge · 15-Year Reference Window
Discharge is the volume of water moving past the gauge and is the primary measure of river flow.
Gage Height · 15-Year Reference Window
Gage height is the water-surface elevation at the station and helps confirm whether the river is unusually high or low.
Fox River at South Elgin
Discharge · 15-Year Reference Window
Discharge is the volume of water moving past the gauge and is the primary measure of river flow.
Gage Height · 15-Year Reference Window
Gage height is the water-surface elevation at the station and helps confirm whether the river is unusually high or low.
Fox River at South Elgin Tailwater
Gage Height · 15-Year Reference Window
Gage height is the water-surface elevation at the station and helps confirm whether the river is unusually high or low.
Ferson Creek near St. Charles
Precipitation · 15-Year Reference Window
Local precipitation helps explain runoff pulses entering the pool through nearby tributaries.
Discharge · 15-Year Reference Window
Discharge is the volume of water moving past the gauge and is the primary measure of river flow.
Gage Height · 15-Year Reference Window
Gage height is the water-surface elevation at the station and helps confirm whether the river is unusually high or low.
Mill Creek near Batavia
Precipitation · 15-Year Reference Window
Local precipitation helps explain runoff pulses entering the pool through nearby tributaries.
Discharge · 15-Year Reference Window
Discharge is the volume of water moving past the gauge and is the primary measure of river flow.
Gage Height · 15-Year Reference Window
Gage height is the water-surface elevation at the station and helps confirm whether the river is unusually high or low.
Fox River at Montgomery
Discharge · 15-Year Reference Window
Discharge is the volume of water moving past the gauge and is the primary measure of river flow.
Gage Height · 15-Year Reference Window
Gage height is the water-surface elevation at the station and helps confirm whether the river is unusually high or low.
Blackberry Creek near Montgomery
Precipitation · 15-Year Reference Window
Local precipitation helps explain runoff pulses entering the pool through nearby tributaries.
Discharge · 15-Year Reference Window
Discharge is the volume of water moving past the gauge and is the primary measure of river flow.
Gage Height · 15-Year Reference Window
Gage height is the water-surface elevation at the station and helps confirm whether the river is unusually high or low.
National Accelerator Laboratory near West Chicago
DuPage County Airport near St. Charles
Elgin Water Treatment Facility at Elgin
About These Measurements
Values shown are locally archived USGS observations. USGS observations may be provisional and subsequently revised. Temperature is stored in its original Celsius value and converted to Fahrenheit for display.
Historical charts use up to the fifteen completed years immediately before the current year, with the current year highlighted separately. Continuous measurements are reduced to daily averages and precipitation to daily totals. The P25–P75 band and seasonal median come from the locally generated baseline table used by the water model.
This page is a generated snapshot. The date shown above identifies how far the current-year overlay extends. Rebuilding the seasonal baselines also regenerates this snapshot.