Every number on this site traces to a public monitoring instrument, and every page names its sources. This is the whole pipeline: no secret sauce, no invented catches.
The U.S. Geological Survey operates thousands of monitoring stations on American rivers and reservoirs. We read flow (cubic feet per second), gauge height and reservoir storage from the official National Water Dashboard instantaneous-values service, typically updated every 15 minutes. Each water page shows its station name and number.
Coastal reports pull tide predictions (highs, lows and timing) from NOAA CO-OPS, the same harmonic-prediction service mariners use. The station is named on every saltwater page, with times localized to the water.
Forecasts come from the Open-Meteo model for each water's exact coordinates: barometric pressure by the hour, wind speed and direction, cloud cover, precipitation and temperature, in the water's own timezone.
Sunrise, sunset, moon phase, moonrise and the solunar majors and minors are calculated astronomically from the water's coordinates and date: no lookup tables, no third-party feed. The method is documented in our solunar theory guide.
Before dawn in each water's timezone we pull the current gauge reading, the last 30 days of flow or storage history, the hourly weather forecast and the tide table where it applies. The 30-day history is what lets a page say a river is dropping into shape or a reservoir is still swollen: today's number only means something against its own recent past.
The activity score starts at a neutral 3 of 5 and moves only when conditions justify it: falling pressure without a washout raises it; rising pressure under bluebird skies lowers it; a workable chop in the prime temperature band helps; gusts over 22 mph or extreme heat and cold cost points. The same rules apply to every water, every day, which is why our scores are comparable and why some days simply read "Slow. Work for them."
Each water carries a species profile: which fish live there and how each behaves across temperature bands. The engine crosses the day's estimated water temperature with each species' comfort curve to rate activity and pick tactics: what to throw, where in the water column, and which solunar windows to build the day around. The biology behind it is in our water temperature guide.
Data tells you about today; it does not know the lake. Every water page carries an editorial guide we write and maintain: how the fishery is structured, what each season looks like, proven areas and access points, and the regulations context with a pointer to the state agency. When the live data and the seasonal pattern disagree, the report says so.
Every page accepts catch reports and observations from anglers. Each submission is reviewed by a person before it publishes: no bots, no invented reviews, no borrowed photos. Where reports contradict the model, they win, and the page's Water Log keeps an honest daily record generated from each day's actual readings.
Reports regenerate every morning in each water's local timezone and pages re-check their data through the day. The date you see on a report is the date it describes: never a reheated page wearing today's date.
Found a wrong number, a misnamed ramp or a dated claim? Use the report form on the water's page ("Share your catch" also takes corrections) and flag it. Fixes ship the same week, and the angler-report review queue is read daily. Further reading on how to use all of this: how to read a fishing report and how to fish with USGS gauge data.
Directly from the U.S. Geological Survey's instantaneous-values service: 488 of our waters are tied to a specific USGS gauge that reports flow, level or storage, usually every 15 minutes. Coastal pages use NOAA CO-OPS stations for tide predictions. Every water page names its station, so you can verify any number against the official source.
The daily conditions block is generated by our own scoring engine from the morning's live readings: it is arithmetic on real data, not a language model improvising. The editorial guide on each page (structure, seasons, tactics, access) is maintained by us and reviewed against the live data. We never publish invented catch reports or fake testimonials.
Every report regenerates each morning in the water's own timezone, and pages re-check their data throughout the day: a report you open at noon reflects the morning's readings, and tide or flow changes appear as the instruments report them.
Not every water has a thermometer in it. Where a value is modeled rather than measured, such as seasonal water temperature on an ungauged lake, the page says "estimated" right next to the number. We would rather show you a labeled estimate than a fake precision.