US River & Lake Water Level Checker
Check real-time US river water levels, gauge heights, streamflow discharge (CFS), reservoir capacities, and flood stages.
Mississippi River at Baton Rouge
Colorado River below Hoover Dam (Lake Mead)
Ohio River at Louisville (Upper Gauge)
Volumetric Streamflow & Discharge Rate Converter
Convert Cubic Feet per Second (CFS) to Gallons per Minute, Liters per Second, and Acre-Feet per Day.
Understanding River Stages & Streamflow Dynamics
The National Oceanic and Atmospheric Administration (NOAA) and the USGS collaborate to categorize river flood hazard severity into distinct stages. Knowing these classifications helps outdoor enthusiasts and property owners react proactively.
Action Stage
The water level approaches bankfull capacity. River corridor managers and marinas begin mitigation and monitoring protocols.
Minor vs Moderate Flood
Minor flooding submerges low-lying parks and rural roads. Moderate flooding begins inundating secondary structures and residential areas.
Acre-Foot Measurement
An acre-foot is the volume of water needed to cover one acre of land to a depth of one foot (~325,851 gallons), standard for western US water storage.
About this tool
How to use it
- Search river basins, reservoirs, or lakes by name, state code (e.g., CA, TX, LA, WA), or USGS station ID.
- Inspect real-time gauge height (feet above datum), streamflow discharge rate (cubic feet per second / CFS), and flood stage classification.
- Check whether waterways are currently within Normal Flow, Action Stage, Minor Flood, or Moderate Flood thresholds.
- Use the Water Flow Unit Converter tab to convert CFS into Gallons per Minute (GPM), Liters per Second, or Acre-Feet per Day.
- Export the water monitoring report to CSV or JSON format for hydrologic studies, boating trips, or fishing logs.
Why it matters
River levels, reservoir storage capacities, and streamflow discharge fluctuate continuously in response to snowmelt runoff, upstream dam releases, and localized torrential rainfall. Kayakers, recreational boaters, fly anglers, municipal civil defense planners, and farmers depend on accurate USGS stream gauge data to make safe and informed operational decisions.
When to use it
Use when checking flood advisories after severe weather, verifying river runnable CFS flows for whitewater rafting, planning fly-fishing trips, or tracking reservoir drought storage levels in the American West.
Common questions
What is CFS (cubic feet per second)?
CFS is the standard volumetric flow rate unit used by hydrologists. One CFS equals approximately 7.48 gallons of water passing a given gauge point every second (or about 448.8 gallons per minute).
What is Gauge Height vs Flood Stage?
Gauge height is the measured depth of water above an established arbitrary vertical zero reference datum. Flood stage is the specific gauge height at which water begins to overflow riverbanks, causing inundation and property danger.
Where does the hydrological data originate?
Data benchmarks reflect active United States Geological Survey (USGS) National Water Information System (NWIS) automated stream gauges, measuring stage and discharge via acoustic Doppler sensors.
Does this tool work completely offline?
Yes! The tool incorporates an embedded database of major landmark rivers and reservoirs alongside unit calculators, and polls live USGS feeds whenever network connectivity is available.