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 09:37 from 16 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 16 gages with enough record, 3 are trending down and 0 up, and 5 carry a detected shift. The clearest is DOLORES TUNNEL OUTLET NEAR DOLORES, -11.9 points of its long-term median per decade over 41 years (p<0.0001). The other 11 show no clear signal either way.
| Gage | Trend | Change / decade points of median | Significance | Years | Changepoint |
|---|---|---|---|---|---|
|
▸
LONE PINE CANAL BELOW GREAT CUT DIKE NEAR DOLORES MVIDIVCO |
no clear trend | +84.7 | p=0.277 | 32 | ~2002 |
|
▸
MCELMO CREEK ABOVE TRAIL CANYON NEAR CORTEZ, CO MCELMZCO |
↓ decreasing | -41.4 | p=0.000 | 33 | ~2011 |
|
▸
MUD CREEK AT STATE HIGHWAY 32, NEAR CORTEZ, CO. MUDHIGCO |
↓ decreasing | -23.0 | p=0.000 | 37 | ~1998 |
|
▸
DOLORES TUNNEL OUTLET NEAR DOLORES DOLTUNCO |
↓ decreasing | -11.9 | p=0.000 | 41 | ~2011 |
|
▸
MCELMO CREEK NEAR COLORADO-UTAH STATE LINE MCELMSCO |
no clear trend | -5.0 | p=0.096 | 75 | ~2000 |
11 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. 10 gage(s) and 182 structure(s) report in 2026, but structure reporting only reached half its modern level around ~1980. 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) |
|---|---|---|
| 1920s | 1 | 0 |
| 1940s | 1 | 0 |
| 1950s | 1 | 1 |
| 1960s | 1 | 52 |
| 1970s | 3 | 126 |
| 1980s | 6 | 169 |
| 1990s | 6 | 186 |
| 2000s | 8 | 233 |
| 2010s | 10 | 200 |
| 2020s | 10 | 184 |
Mass-balance (network closure) trend
Structure divrec-history backfill coverage as of the last check: 58% of 136 schematic-relevant structures. Kink count trend: increasing (p=0.000), kink magnitude trend: increasing (p=0.000) across 46 qualifying year(s).
Reach gain/loss shifts (1985–2026)
Mass-balance kinks computed for every summer month back to 1985 (148 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.
- ROCKY FORD CANAL #2 ABOVE TOTTEN RESERVOIR NEAR CORTEZ: reach shifted from -243 cfs to -89 cfs summer mean (more gaining, p=0.007, 24 yr) [alluvial valley: real alluvial aquifer -- a decades-long shift toward losing is the classic signature of alluvial pumping and urbanization] [measurement-evolution caution: this shift co-moves with the growth of the gage/metering network (rho=-0.63) -- part of it may be unaccounted water becoming accounted, not hydrologic change]
Groundwater now has its own tab: 22 monitored well(s), water-table trends, stream corridors, and the advisory depletion screen.
Reservoirs now has its own tab: 15 reservoir(s), end-of-year storage back to 1975, click-to-chart histories.
Cross-gage pattern fingerprint
Not enough gages with a long enough common-coverage window yet to fingerprint shared patterns.
Data provenance & quality
Where these numbers come from and how far they can be trusted. Grade B (4/6 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 | expected-lag | newest diversion record is 293 day(s) old (DWR publishes ~1 year in arrears) |
| structure coverage | partial | 58% of schematic structures have data |
Independent check: PASS — 100.0000% agreement across 184,831 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 — 99.85% day-level agreement with USGS's own published records for the same gages, across 8 co-listed station(s) and 75,162 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.
16 gage(s) / 141,431 daily values (1926-10-01–2026-07-06); 357 structure(s) with diversion records; 638 with decreed rights. Methodology has not yet had independent expert review — treat every figure as an advisory screen, not an administrative or legal conclusion.
96 water-level measurements across 22 monitored well(s) — 7 alluvial, 0 bedrock — plus 1 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 0 well(s) with enough record for a trend test: 0 declining, 0 rising.
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.
15 reservoir(s) with 8,715 storage measurement(s), 1975–2026. Basin storage as of 2025-10-31 (the record's own end — reservoir records publish ~annually): 3,647 AF across 3 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 |
|---|---|---|
| ▸ TOTTEN RESERVOIR (3203601) | 2,135 | 2025-10-31 |
| ▸ A M PUETT RES OUTLET (3200704) | 978 | 2009-10-16 |
| ▸ A M PUETT RESERVOIR (3203603) | 770 | 2025-10-31 |
| ▸ NARRAGUINNEP RESERVOIR (3203602) | 742 | 2025-10-31 |
| ▸ MARINE LIFE RESORT RESERVOIR (3203794) | 35 | 2017-10-31 |
| ▸ WILKERSON POND NO 1 (3203604) | 11 | 2011-10-31 |
| ▸ BUTTS RESERVOIR (3203605) | 9 | 2011-10-31 |
| ▸ LIVELY RESERVOIR (3203597) | 5 | 2011-10-31 |
Decreed rights on this network run from 1868-03-02 to 2022-08-05. 25 abandonment screens and 145 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: 687 across 638 structure(s); 20 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 ~1980 — idleness that begins before then may be unreported use, not nonuse (flagged † below).
- DAWSON DITCH (MCELMO) (3200537) (1943-04-25, 1.1 cfs decreed): last active 1974 — 51 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1980) -- early absence of record is weak evidence of nonuse
- MURRAY PUMP AND PIPELINE (3200633) (1961-06-30, 0.1 cfs decreed): last active 1974 — 51 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1980) -- early absence of record is weak evidence of nonuse
- PALMER PUMP AND DITCHES (3200639) (1920-12-31, 1.0 cfs decreed): last active 1976 — 49 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1980) -- early absence of record is weak evidence of nonuse
- STRATTON DITCH (3200676) (1937-06-10, 0.2 cfs decreed): last active 1979 — 46 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1980) -- early absence of record is weak evidence of nonuse
- OLD STAGE STATION DIVR (3200637) (1966-12-31, 0.6 cfs decreed): last active 1981 — 44 years idle
- HARMON DITCH ALT PT #1 (3200776) (1950-08-19, 0.2 cfs decreed): last active 1983 — 42 years idle
- MURPHY DIVERSION NO 1 (3200751) (1978-06-01, 0.5 cfs decreed): last active 1984 — 41 years idle
- FETTERMAN HYDRAM (3200756) (1980-04-15, 0.1 cfs decreed): last active 1985 — 40 years idle
- HARMON DITCH SPRUELL #2 (3200578) (1950-08-19, 0.1 cfs decreed): last active 1986 — 39 years idle
- CULLEN DITCH (3200535) (1900-12-31, 2.5 cfs decreed): last active 1989 — 36 years idle
Compliance screens (145 advisory flags)
Screened 222 of 638 structures with rights (262 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.
- HAMBELTON DITCH (3200574): Observed p99 daily rate 16.2 cfs (max 19.0) exceeds total decreed absolute 12.5 cfs across 36288 recorded day(s).
- COTTONWOOD DITCH NO 2 (3200529): Observed p99 daily rate 15.0 cfs (max 17.0) exceeds total decreed absolute 10.0 cfs across 33971 recorded day(s).
- BLACK DIKE DITCH (3200509): Observed p99 daily rate 13.9 cfs (max 16.9) exceeds total decreed absolute 13.1 cfs across 32347 recorded day(s).
- COTTONWOOD DITCH NO 1 (3200528): Observed p99 daily rate 13.5 cfs (max 16.0) exceeds total decreed absolute 10.0 cfs across 26852 recorded day(s).
- ROBERT B DUNHAM DITCH (3200651): Observed p99 daily rate 12.6 cfs (max 12.6) exceeds total decreed absolute 3.0 cfs across 2972 recorded day(s).
- EATON DITCH (3200558): Observed p99 daily rate 8.4 cfs (max 11.2) exceeds total decreed absolute 6.0 cfs across 19763 recorded day(s).
- MURRAY-ZWICKER-TOZER D (3200634): Observed p99 daily rate 8.4 cfs (max 10.3) exceeds total decreed absolute 6.0 cfs across 37422 recorded day(s).
- OLD KANIGA DITCH (3200636): Observed p99 daily rate 8.0 cfs (max 8.0) exceeds total decreed absolute 2.0 cfs across 4142 recorded day(s).
- SCHALLES DITCH (3200662): Observed p99 daily rate 7.0 cfs (max 8.5) exceeds total decreed absolute 4.0 cfs across 20069 recorded day(s).
- BORD DITCH (3200512): Observed p99 daily rate 6.0 cfs (max 7.0) exceeds total decreed absolute 4.0 cfs across 18027 recorded day(s).
Seniority (top structures by decreed rate)
| Structure | Senior priority date | Rights | Decreed abs (cfs) | Decreed abs (AF) | Conditional? |
|---|---|---|---|---|---|
| ROCK CREEK DITCH (3200652) | 1888-03-20 | 3 | 39.3 | 0 | — |
| WILSON DITCH (3200690) | 1888-06-01 | 8 | 28.5 | 0 | yes |
| BLACK DIKE DITCH (3200509) | 1889-04-15 | 1 | 13.1 | 0 | — |
| HAMBELTON DITCH (3200574) | 1891-04-20 | 2 | 12.5 | 0 | yes |
| COTTONWOOD DITCH NO 1 (3200528) | 1891-01-25 | 1 | 10.0 | 0 | — |
| COTTONWOOD DITCH NO 2 (3200529) | 1890-05-21 | 1 | 10.0 | 0 | — |
| MTN UTE SAN JUAN DIVR (3200938) | 1868-03-02 | 1 | 10.0 | 0 | — |
| BRUMLEY DRAW IRR DITCH (3200514) | 1889-04-20 | 2 | 7.3 | 0 | — |
| EATON DITCH (3200558) | 1908-03-10 | 3 | 6.0 | 0 | — |
| MURRAY-ZWICKER-TOZER D (3200634) | 1892-06-15 | 2 | 6.0 | 0 | yes |
| ISMAY DITCH (3200590) | 1955-01-01 | 1 | 5.0 | 0 | — |
| SHUMWAY PERKINS PMPG STA (3200665) | 1972-01-18 | 1 | 5.0 | 0 | — |
| N E CARPENTER SEEPAGE D (3200635) | 1970-07-31 | 2 | 4.8 | 0 | — |
| BORD DITCH (3200512) | 1910-04-20 | 2 | 4.0 | 0 | — |
| POWELL AND CODY DITCH (3200644) | 1907-02-14 | 3 | 4.0 | 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.