Hydrohistorian
CRO-SIEV TH-2
Monitored well · 152978 · Division 1 · Water District 1
Source DWR administrative record · verify at DWR well record ↗
Unclassified
No aquifer or designated-basin assignment — administrative world unknown, kept out of recharge math.
Water-level record
No water-level measurements are cached for this well. It is in the well inventory — permit, construction and aquifer below — but nobody has logged a level we hold.
Geophysical log
DWR holds a geophysical log for this well, run 2018-12-20 (resistivity, spontaneous_potential). DWR's log page.
Formation picks (DWR)
| Aquifer | Top ft | Base ft | Net sand ft |
|---|---|---|---|
| LARAMIE-FOX HILLS | 230 | 745 |
Net sand is DWR's own reading of the log (its gLogThickness), not the gross interval.
Net sand per aquifer, from the gamma curve
Computed here from DWR's own digital log (LAS): linear gamma index, clean/shale lines at p10/p90 of the gamma over the interval, sand where Vsh < 0.4, beds under 1.0 ft merged. DWR’s own pick is beside it, never averaged with it.
| Aquifer | Interval ft | Net sand ft | Net / gross | DWR net sand ft | Difference ft |
|---|---|---|---|---|---|
| LARAMIE-FOX HILLS | 230–745 | 10 | 0.02 |
A gamma cutoff is a convention, not a measurement. Against DWR’s own picks on 50 wells this one correlates at r 0.86 with a median error near 30% and no bias (how it was scored).
Curves digitized from the scan
Hydrohistorian traced the scanned log automatically. 1 curve passed the confidence gate; 8 did not and are listed with the reason. Screening data: the scan stays the record.
| Curve | Interval ft | Coverage | Verdict | Curves like this one scored | |
|---|---|---|---|---|---|
| 16" Normal Resistivity (Ohm-m) | 10–817 | 94% | pass | r 0.86 median, error 4.8% of scale, 23% below r 0.8 (n 13) | LAS |
| Natural Gamma (CPS) | 10–817 | 98% | not used: scale OCR confidence 0.79 | ||
| Single-Point Resistance (ohm) | 10–817 | 94% | not used: scale OCR confidence 0.57 | ||
| Spontaneous Potential (mV) | 10–817 | 89% | not used: SP: the printed scale is a span with an unknown offset, and the benchmark could not verify the shape (median r 0.28 after offset removal) | ||
| Far Density | 0–812 | 8% | not used: coverage 8%; ambiguous rows 17%; scale OCR confidence 0.57; curve name not recognized: 'Far Density' | ||
| Natural Gamma (cps) | 0–812 | 28% | not used: coverage 28%; scale OCR confidence 0.55 | ||
| Natural Gamma (CPS) | 0–812 | 6% | not used: coverage 6%; scale OCR confidence 0.66 | ||
| Near Neutron Rate (CPS) | 0–812 | 4% | not used: coverage 5%; ambiguous rows 38%; curve name not recognized: 'Near Neutron Rate' | ||
| Neutron Porosity | 0–812 | 8% | not used: coverage 9%; ambiguous rows 7%; scale OCR confidence 0.77; curve class not verified by the benchmark: Neutron Porosity traced as thick |
"Curves like this one" is the benchmark row for this curve's class: curves of the same name traced the same way, scored against DWR's own digital log of the same run. r is correlation (the print's own smoothing allowed for); error is mean absolute error as a share of the track's printed range; "below r 0.8" is the share of passing curves in the class that still disagreed with DWR's log, which this curve's own numbers cannot rule out.
The LAS files and every verdict are in the statewide groundwater release
(/data, table gw_digitized); the MCP server's gw_digitized_curves and
gw_net_sand work from them. How well the tracer does was
measured against DWR's own digital logs.
The well itself
| Total depth | 800.0 ft |
|---|---|
| Ground elevation | 4955.0 ft |
| Location | 40.70000, -104.28000 |
What this page is not
Monitoring records are irregular: measurements cluster where somebody chose to look, so a trend describes this well's record, not the aquifer as a whole. Levels are DWR's published measurements, unedited. A trend here is not a prediction, and it is not a determination about anyone's water right.