Hydrohistorian
CENTENNIAL W&S PA-7S
Monitored well · 150511 · Division 1 · Water District 8
Its well permit here · Well permit at DWR ↗
Source DWR administrative record · verify at DWR well record ↗ Source DWR administrative record · verify at DWR permit 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 2013-07-29 (gamma, resistivity, spontaneous_potential). DWR's log page.
Formation picks (DWR)
| Aquifer | Top ft | Base ft | Net sand ft |
|---|---|---|---|
| DENVER | 344 | 1115 | 215 |
| ARAPAHOE | 1150 | 1714 | 440 |
| LOWER DAWSON | 255 |
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 gamma digitized from the scan (gate pass, coverage 91%): 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 |
|---|---|---|---|---|---|
| DENVER | 344–1115 | 370 | 0.48 | 215 | +155 |
| ARAPAHOE | 1150–1714 | 177 | 0.31 | 440 | -263 |
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). This well’s gamma was digitized from a scan: two conventions stacked, so read the beds, not the total.
Curves digitized from the scan
Hydrohistorian traced the scanned log automatically. 1 curve passed the confidence gate; 9 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 | |
|---|---|---|---|---|---|
| Caliper (in) | 100–7817 | 18% | not used: dashed curve on a Phoenix/Pioneer print: not traceable (benchmark median r 0.38 for the shallow resistivity, 0.00 before the dash/dot split); coverage 18%; ambiguous rows 40% | ||
| Conductivity (mmho/m) | 100–7817 | 88% | not used: solid curve on a Phoenix/Pioneer print: only the gamma is verified (its resistivity scales are log/backup scales the parser does not read, benchmark r < 0.5); ambiguous rows 8%; curve class not verified by the benchmark: Conductivity traced as solid | ||
| Gamma Ray (GAPI) | 100–7817 | 91% | pass | r 0.99 median, error 0.6% of scale, 7% below r 0.8 (n 411) | LAS |
| Spontaneous Potential (mV) | 100–7817 | 8% | not used: dashed curve on a Phoenix/Pioneer print: not traceable (benchmark median r 0.38 for the shallow resistivity, 0.00 before the dash/dot split); coverage 9%; ambiguous rows 87%; 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) | ||
| Bulk Density (g/cc) | 100–2382 | 91% | not used: solid curve on a Phoenix/Pioneer print: only the gamma is verified (its resistivity scales are log/backup scales the parser does not read, benchmark r < 0.5); ambiguous rows 51%; curve class not verified by the benchmark: Bulk Density traced as solid | ||
| Corr (g/cc) | 100–2382 | 88% | not used: solid curve on a Phoenix/Pioneer print: only the gamma is verified (its resistivity scales are log/backup scales the parser does not read, benchmark r < 0.5); ambiguous rows 19%; curve name not recognized: 'Corr' | ||
| Density Caliper (in) | 100–2382 | 93% | not used: solid curve on a Phoenix/Pioneer print: only the gamma is verified (its resistivity scales are log/backup scales the parser does not read, benchmark r < 0.5); ambiguous rows 33%; curve name not recognized: 'Density Caliper' | ||
| Density Porosity (pu) | 100–2382 | 37% | not used: dashed curve on a Phoenix/Pioneer print: not traceable (benchmark median r 0.38 for the shallow resistivity, 0.00 before the dash/dot split); coverage 37%; ambiguous rows 65%; scale OCR confidence 0.55 | ||
| Gamma Ray (GAPI) | 100–2382 | 21% | not used: dashed curve on a Phoenix/Pioneer print: not traceable (benchmark median r 0.38 for the shallow resistivity, 0.00 before the dash/dot split); coverage 21%; ambiguous rows 77% | ||
| Gamma Ray (GAPI) | 100–2382 | 19% | not used: dashed curve on a Phoenix/Pioneer print: not traceable (benchmark median r 0.38 for the shallow resistivity, 0.00 before the dash/dot split); coverage 19%; ambiguous rows 88% |
"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 | 1750.0 ft |
|---|---|
| Perforated interval | 1300.0–1710.0 ft |
| Ground elevation | 5980.0 ft |
| Permit | 77202 |
| Location | 39.52000, -104.93000 |
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.