Hydrohistorian
Full diagnostic snapshot pending — this district's weekly-style report (system status, active calls, hydrographs, anomaly flags) is produced by the nightly rotation and appears here after its first run. The tabs above are live now.
Evolution of the network
Gage flow trend & changepoints
What counts as a trend here
Computed 2026-08-20 09:12 from 9 gage(s) with cached period-of-record data. Mann-Kendall (trend) and Pettitt (changepoint) both require at least 8 years spanning at least 10 years of record. A gage below that reports no signal — which is not the same as “no change.”
Of the 9 gages with enough record, 2 are trending down and 0 up, and 1 carries a detected shift. The clearest is WEST DIVIDE CREEK NEAR RAVEN, CO, -12.8 points of its long-term median per decade over 71 years (p=0.0328). The other 7 show no clear signal either way.
| Gage | Trend | Change / decade points of median | Significance | Years | Changepoint |
|---|---|---|---|---|---|
|
▸
WEST DIVIDE CREEK NEAR RAVEN, CO WSDRAVCO |
↓ decreasing | -12.8 | p=0.033 | 71 | ~2011 |
|
▸
COLORADO RIVER BELOW GLENWOOD SPRINGS, CO. COLGLECO |
↓ decreasing | -3.6 | p=0.038 | 60 | — |
7 other gage(s) show no significant trend or changepoint (not shown).
How the measurement network itself changed
This basin was not always measured the way it is today — the API-era record is dense and recent, the early record sparse. 7 gage(s) and 99 structure(s) report in 2026, but structure reporting only reached half its modern level around ~1985. Every historical claim below is checked against this: long-term shifts that co-move with the growth of the network carry an explicit measurement-evolution caution, and abandonment screens whose idleness begins before the modern reporting era are flagged †.
| Decade | Gages with data (median yr) | Structures reporting (median yr) |
|---|---|---|
| 1900s | 0 | 1 |
| 1930s | 1 | 0 |
| 1940s | 1 | 0 |
| 1950s | 1 | 0 |
| 1960s | 1 | 0 |
| 1970s | 3 | 39 |
| 1980s | 3 | 161 |
| 1990s | 3 | 306 |
| 2000s | 6 | 168 |
| 2010s | 7 | 107 |
| 2020s | 7 | 96 |
Mass-balance (network closure) trend
Structure divrec-history backfill coverage as of the last check: 11% of 662 schematic-relevant structures. 0 year(s) clear the 30% coverage gate so far -- the trend activates automatically once qualifying years span a full decade. No action needed; the nightly backfill keeps extending the record.
Reach gain/loss shifts (1967–2026)
Mass-balance kinks computed for every summer month back to 1967 (205 reach-snapshots) — which reaches gain or lose water, and how that has shifted across decades. Each shift is cross-checked against the observation record above: as more diversions became metered, "unaccounted" water shrinks mechanically, which can masquerade as a hydrologic shift.
No reach shows a statistically significant long-term gain/loss shift.
Groundwater now has its own tab: 44 monitored well(s), water-table trends, stream corridors, and the advisory depletion screen.
Reservoirs now has its own tab: 82 reservoir(s), end-of-year storage back to 1976, click-to-chart histories.
Cross-gage pattern fingerprint
Over the 16-year window with full coverage (2011–2026), the dominant shared pattern across 3 gage(s) explains 65% of year-to-year variance (almost certainly a basin-wide climate/snowpack driver).
All gages in this window move with the shared pattern -- no localized outlier.
Structures most implicated by reconciliation (as of 2026-07-06)
Which structures' data absorbed the most correction when the current mass-balance snapshot was reconciled -- see the Historical tab for the full picture on any date.
- RIVERBEND EFFLUENT POND (return): -1815.7 cfs (100% of that reach's correction)
Data provenance & quality
Where these numbers come from and how far they can be trusted. Grade D (2/6 points) — the components below are the finding; the letter alone is not. Sources: DWR HydroBase snapshot HydroBase_CO_20260707 (imported 2026-08-19) for history, plus the CDSS REST API for current conditions.
| Check | State | What was measured |
|---|---|---|
| gage freshness | stale | newest gage reading is 45 day(s) old (target 7) |
| diversion record | stale | newest diversion record is 1754 day(s) old (DWR publishes ~1 year in arrears) |
| structure coverage | sparse | 11% of schematic structures have data |
Independent check: PASS — 100.0000% agreement across 91,146 stored values re-checked against DWR's authoritative record (HydroBase_CO_20260707), over 20 structures. 0 disagreement(s) beyond a 0.01 cfs tolerance. Checked 2026-08-19; a rotating sample covers the whole basin across successive runs, and the structures this report cites are checked every time.
Federal cross-check: PASS — 99.51% day-level agreement with USGS's own published records for the same gages, across 3 co-listed station(s) and 50,537 overlapping days (within max(2%, 0.5 cfs) daily). Pre-1950 records at some gages carry known between-agency day-stamp and transcription differences — scored at each year's best ±1-day alignment; residual disagreement is real historical divergence, flagged for review.
9 gage(s) / 84,648 daily values (1939-06-01–2026-07-06); 502 structure(s) with diversion records; 1378 with decreed rights. Methodology has not yet had independent expert review — treat every figure as an advisory screen, not an administrative or legal conclusion.
174 water-level measurements across 44 monitored well(s) — 24 alluvial, 5 bedrock — plus 28 administered well(s) reporting metered pumping.
What is being counted
Observation wells and pumping wells are different populations and are never conflated: water levels come from monitored observation wells, and metered pumping comes from administered wells reporting through diversion records. Click any well to chart its own record.
Well map
3D aquifer x-ray
Every aquifer unit as its own head surface, animated through time.
How the surfaces are built, and what they are not
Alluvial water table on top, Denver Basin members (Dawson, Denver, Arapahoe, Laramie–Fox Hills) stacked beneath where measured, interpolated from measured water levels. Units are never mixed; a surface exists only inside its own unit's well coverage, with no extrapolation; thin epochs are suppressed and say why. Vertical scale is exaggerated for readability and z is head elevation in feet. These are measured heads, not a calibrated groundwater model.
Water-table trends
Of 4 well(s) with enough record for a trend test: 1 declining, 0 rising.
| Fastest-declining wells | Setting | ft / decade | Span | p |
|---|---|---|---|---|
| ▸ WS-35 | bedrock | -12.61 | 46 yr | 0.015 |
Wells labeled by administrative world before anything else is said about them: tributary alluvium participates in the priority system; designated-basin and Denver Basin bedrock aquifers are governed differently and are excluded from stream-connection reasoning. Read bedrock declines differently too: deep bedrock aquifers recharge negligibly on human timescales, so a falling bedrock level is storage mining — effectively permanent — not a drought response that a wet year undoes. All screens advisory.
82 reservoir(s) with 975 storage measurement(s), 1976–2011. Basin storage as of 2010-12-02 (the record's own end — reservoir records publish ~annually): 333 AF across 2 reservoir(s).
Why storage matters to the flow network
Storage change is real water the mass balance must credit — a losing reach beside a filling reservoir isn't losing water, it's banking it.
Reservoir map — how full is each vessel?
What “full” is measured against
Bubble size is proportional to a reservoir's record-high storage. Fill is its last recorded storage as a share of its surveyed capacity (USACE National Inventory of Dams) where a confident NID match exists — the tooltip names the matched dam — and as a share of its own record high otherwise. A wrong capacity would be worse than an honest record high, so only confident joins upgrade.
A dashed teal ring marks reservoirs reporting live DWR telemetry: their fill reflects yesterday's storage, is drawn as a dotted tail on charts, and is treated as provisional until the next verified HydroBase snapshot supersedes it.
Basin storage, end of each water year
End-of-water-year totals; per-year reservoir counts shown because reporting coverage varies -- a total is only comparable to years with similar counts.
Largest reservoirs on record
Click a reservoir to chart its full storage history.
| Reservoir | Last recorded storage (AF) | As of |
|---|---|---|
| ▸ BARTON PORTER RESERVOIR (4503603) | 310 | 2009-10-31 |
| ▸ ANDERSON POND NO 1 (4503524) | 292 | 2005-10-31 |
| ▸ BUD NO 2 DITCH (4500531) | 220 | 2005-10-31 |
| ▸ CENTENIAL LAKE (4503642) | 192 | 2004-10-31 |
| ▸ BATTLEMENT MESA POND (4505409) | 75 | 2004-10-31 |
| ▸ GARDNER-WERHONIG RESERVOIR NO. 1 (4503712) | 52 | 1990-09-05 |
| ▸ BATTLEMENT NO 3 RES (4503574) | 47 | 1990-09-05 |
| ▸ ALSBURY RESERVOIR (4503695) | 42 | 2009-08-02 |
Decreed rights on this network run from 1880-04-01 to 2024-07-09. 25 abandonment screens and 216 compliance flags are listed below as leads for review — a screen is not an abandonment and a flag is not a violation.
Rights on file: 1757 across 1378 structure(s); 78 structure(s) carry 0 court-case references. Advisory reading aids on public DWR data — not administrative or legal conclusions.
Abandonment radar (25 screens)
Absolute rights with 10+ years of no recorded diversions. Screens only — storage, alternate points, and plan operations can explain nonuse lawfully. And diversion REPORTING itself only reached its modern level ~1985 — idleness that begins before then may be unreported use, not nonuse (flagged † below).
- EAKEN DITCH NO 2 (4500579) (1916-04-01, 0.4 cfs decreed): last active 1980 — 31 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1985) -- early absence of record is weak evidence of nonuse
- VINAL HAYWARD PIPELINE (4500805) (1940-07-15, 2.5 cfs decreed): last active 1980 — 31 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1985) -- early absence of record is weak evidence of nonuse
- HAYWARD AND WYATT PL (4500623) (1950-02-02, 12.7 cfs decreed): last active 1982 — 29 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1985) -- early absence of record is weak evidence of nonuse
- FAIRVIEW MESA DITCH (4500597) (1955-08-01, 10.0 cfs decreed): last active 1983 — 28 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1985) -- early absence of record is weak evidence of nonuse
- NORMANS SPRINGS NO 1 (4500938) (1921-12-31, 0.0 cfs decreed): last active 1984 — 27 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1985) -- early absence of record is weak evidence of nonuse
- EMS WELL (4505034) (1966-06-30, 0.1 cfs decreed): last active 1985 — 26 years idle
- MCPHERSON WATER WELL (4500683) (1962-05-15, 1.0 cfs decreed): last active 1986 — 25 years idle
- PEISAR SPRING DITCH (4500718) (1940-05-01, 0.5 cfs decreed): last active 1986 — 25 years idle
- UPTON SPRING A (4500872) (1980-03-31, 0.0 cfs decreed): last active 1986 — 25 years idle
- UPTON SPRING B (4500873) (1980-03-31, 0.0 cfs decreed): last active 1986 — 25 years idle
Compliance screens (216 advisory flags)
Screened 424 of 1378 structures with rights (451 have diversion history on file). A flag is a lead for expert review — augmentation plans, exchanges, and free-river conditions can make over-decree diversions lawful and are deliberately not modeled.
- MULTA-TRINA DITCH (4500704): Observed p99 daily rate 56.8 cfs (max 75.6) exceeds total decreed absolute 49.8 cfs across 30156 recorded day(s). Structure holds an Augmentation-use decree -- diversions above the direct-flow decree can be lawful under plan operations; interpret with care.
- RISING SUN DITCH (4500743): Observed p99 daily rate 46.3 cfs (max 80.0) exceeds total decreed absolute 20.9 cfs across 21416 recorded day(s). Structure holds an Augmentation-use decree -- diversions above the direct-flow decree can be lawful under plan operations; interpret with care.
- J T PEARCE DITCH (4500643): Observed p99 daily rate 38.3 cfs (max 41.2) exceeds total decreed absolute 5.0 cfs across 826 recorded day(s).
- LARKIN DITCH (4500861): Observed p99 daily rate 38.2 cfs (max 64.9) exceeds total decreed absolute 37.3 cfs across 30274 recorded day(s). Structure holds an Augmentation-use decree -- diversions above the direct-flow decree can be lawful under plan operations; interpret with care.
- TAUGHENBAUGH DITCH (4500793): Observed p99 daily rate 37.3 cfs (max 52.2) exceeds total decreed absolute 32.6 cfs across 13241 recorded day(s).
- W A SKELTON DITCH (4500806): Observed p99 daily rate 36.4 cfs (max 37.2) exceeds total decreed absolute 10.0 cfs across 2668 recorded day(s).
- HIGHLINE ALKALI DITCH (4500627): Observed p99 daily rate 31.0 cfs (max 31.0) exceeds total decreed absolute 17.2 cfs across 3526 recorded day(s).
- WEST DIVIDE CREEK DITCH (4500818): Observed p99 daily rate 18.1 cfs (max 22.6) exceeds total decreed absolute 10.9 cfs across 10834 recorded day(s). Structure holds an Augmentation-use decree -- diversions above the direct-flow decree can be lawful under plan operations; interpret with care.
- COTTONWOOD GULCH DITCH (4500558): Observed p99 daily rate 17.0 cfs (max 19.5) exceeds total decreed absolute 6.5 cfs across 7956 recorded day(s).
- CLEAR CREEK DITCH (4500550): Observed p99 daily rate 15.1 cfs (max 16.9) exceeds total decreed absolute 7.7 cfs across 9881 recorded day(s).
Seniority (top structures by decreed rate)
| Structure | Senior priority date | Rights | Decreed abs (cfs) | Decreed abs (AF) | Conditional? |
|---|---|---|---|---|---|
| DIVIDE CREEK HIGHLINE D (4500576) | 1900-05-05 | 3 | 155.0 | 0 | yes |
| BLUESTONE VALLEY DITCH (4500969) | 1895-01-01 | 4 | 106.0 | 0 | — |
| GOLDMAN DITCH PUMP & PL (4500845) | 1880-04-01 | 6 | 103.5 | 0 | — |
| PORTER DITCH (4500725) | 1885-10-15 | 7 | 62.5 | 0 | — |
| TALLMADGE AND GIBSON D (4500790) | 1885-08-14 | 11 | 56.0 | 0 | — |
| LAST CHANCE DITCH (4500668) | 1887-03-23 | 5 | 54.8 | 0 | yes |
| MULTA-TRINA DITCH (4500704) | 1906-09-01 | 2 | 49.8 | 0 | — |
| LARKIN DITCH (4500861) | 1888-04-01 | 4 | 37.3 | 0 | — |
| TAUGHENBAUGH DITCH (4500793) | 1885-07-28 | 5 | 32.6 | 0 | — |
| MURRAY AND YULE DITCH (4500705) | 1881-06-10 | 7 | 31.1 | 0 | — |
| EAST DIVIDE CREEK DITCH (4500584) | 1882-08-09 | 6 | 25.2 | 0 | — |
| BEAVER CR GRASS MESA D (4500519) | 1892-05-16 | 3 | 24.6 | 0 | — |
| MINEOTA DITCH (4500693) | 1882-05-25 | 9 | 23.5 | 0 | — |
| MOSQUITO DITCH (4500699) | 1914-06-09 | 3 | 23.5 | 0 | — |
| BATTLEMENT DITCH (4500514) | 1884-06-12 | 7 | 20.9 | 0 | — |
No inventory or legal-document changes detected since the daily watch began.
If a call were placed at a given seniority, which structures in this basin would be out of priority, and how much of their decreed rate would be curtailed? Computed from this basin's cached decrees.
What this does and doesn't model. Seniority arithmetic only: every right junior to the call is treated as curtailed. It does not model reach applicability — structures downstream of the calling point are not administered by it — and it applies no futile-call judgment. Read it as “who is junior to this date, and by how much,” not as a prediction of what the Division Engineer would actually order.
Pick a calling right
Real decrees from this basin, ordered by administration number — that is, by actual seniority. The years will look out of order, and that is correct: an administration number encodes the adjudication date as well as the appropriation date, so a right appropriated in 1970 can be administered ahead of one from 1950. A senior call curtails almost everything; a junior one curtails almost nothing.
Or enter an administration number directly
DWR administration numbers encode appropriation and adjudication dates; lower is more senior.