Method
Every number on this site comes from one source’s own report history, correlated against the rain that fell on its exact coordinates. This is how that works, and where it stops working.
Method
How the read is built
01
Field reports
Dated observations from people who were actually standing there, each scored from bone dry to raging. A source with a long report history is one we can say something about; a source with three reports is not.
02
Precipitation
Daily rainfall back to 2007 for that source's exact coordinates, then antecedent totals over the 30, 60, 90, 180, 270 and 365 days before every single report.
03
Correlation
How tightly flow tracks rain in each of those windows, with the seasonal cycle statistically removed. The strongest window is that source's memory — how far back its water remembers the weather.
The more reliable a water source is, the less precipitation predicts it.
Scoring
Every report becomes one number
Trail reports are prose — “good flow at the box,” “bone dry, tanks held.” The engine needs a number, so every observation is mapped onto one scale.
- 0.0
- Dry
- No water at all — not even pools
- 0.2
- Pools or dripping
- Water present but not flowing; stagnant pools, a drip, a full spring box with no outflow
- 0.4
- Trickle
- Light but filterable — you can fill a bottle, slowly
- 0.6
- Moderate
- Steady flow, roughly a quart per minute
- 0.8
- Strong
- Roughly a gallon per minute
- 1.0
- Raging
- Gallon-plus, loud, no question about it
Score the water you could actually use. If the seep itself has stopped but the rock tanks below it are holding, that is water — score the tanks.
Honesty
What this cannot tell you
It is a base rate, not a measurement
Nobody is watching the spring. This is what the historical record says about conditions like today's — genuinely useful for planning, and no substitute for the report of someone who walked past yesterday.
No reports, no read
The whole method rests on a source's own report history. For an unreported spring, the most we can honestly offer is how this year's rain compares to normal at that spot — which is not the same as saying there is water in it.
Summer storms are the weak spot
The precipitation model averages over roughly a 9–11 km grid, so it smooths out isolated monsoon cells — least reliable in exactly the season when a desert water call matters most. For a summer go/no-go, cross-check radar.
Thin data stays thin
Under 10 reports this site issues no read at all: the engine will still produce a number and that number is noise. Between 10 and 25 you get a read labelled weak — suggestive, not solid. We would rather show an honest shrug than a confident number built on four observations.
Carry your water. This is a planning aid built from historical correlation, not a promise that anything is wet. Never carry less because of what you read here.
Status
What is here, and what is coming
The forecasting engine is built, open source, and has been used before real trips. This site is the front door for it, and it is being assembled now.
The honest constraint: the model is free, but the reports are the hard part. Every dated observation someone contributes sharpens the source it belongs to and the ones around it, because nearby sources lend each other statistical strength. If you keep trip notes on water, you already have the valuable thing.
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