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 09:04 from 1 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.”
None of the 1 gage with enough record shows a significant trend or a detected shift — which is itself the finding.
No gage shows a statistically significant trend or changepoint yet.
1 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. 0 gage(s) and 51 structure(s) report in 2025, but structure reporting only reached half its modern level around ~2008. 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) |
|---|---|---|
| 1970s | 0 | 22 |
| 1980s | 1 | 28 |
| 1990s | 0 | 26 |
| 2000s | 0 | 24 |
| 2010s | 0 | 52 |
| 2020s | 0 | 52 |
Mass-balance (network closure) trend
Structure divrec-history backfill coverage as of the last check: 39% of 28 schematic-relevant structures. 7 year(s) clear the 30% coverage gate so far (2015–2021) -- 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 (–)
Mass-balance kinks computed for every summer month back to (0 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.
Reservoirs now has its own tab: 10 reservoir(s), end-of-year storage back to 1996, 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 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 14021 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 | sparse | 39% of schematic structures have data |
Independent check: PASS — 100.0000% agreement across 123,747 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 — 100.00% day-level agreement with USGS's own published records for the same gages, across 1 co-listed station(s) and 1,827 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.
1 gage(s) / 1,918 daily values (1983-04-01–1988-03-31); 79 structure(s) with diversion records; 221 with decreed rights. Methodology has not yet had independent expert review — treat every figure as an advisory screen, not an administrative or legal conclusion.
10 reservoir(s) with 843 storage measurement(s), 1996–2026.
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 |
|---|---|---|
| ▸ GREEN SHAFT RES (7303602) | 0 | 2025-10-24 |
| ▸ SPRING CREEK RES (7303607) | 0 | 2025-10-24 |
| ▸ THOMPSON RES #1 (7303608) | 0 | 2012-10-15 |
| ▸ THOMPSON RES #2 (7303609) | 0 | 2012-10-15 |
| ▸ THOMPSON RES #3 (7303610) | 0 | 2012-10-15 |
| ▸ CARNS NO 1 RESERVOIR (7303611) | 0 | 2014-09-02 |
| ▸ DUVALL RES. NO. 1 (7303612) | 0 | 2025-10-24 |
| ▸ FRUITA RES #3 (7303621) | 0 | 2025-10-28 |
Decreed rights on this network run from 1883-05-10 to 2020-12-07. 7 abandonment screens and 29 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: 275 across 221 structure(s); 2 structure(s) carry 0 court-case references. Advisory reading aids on public DWR data — not administrative or legal conclusions.
Abandonment radar (7 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 ~2008 — idleness that begins before then may be unreported use, not nonuse (flagged † below).
- COOK IRRIGATING DITCH (7300532) (1886-11-26, 4.0 cfs decreed): last active 1996 — 29 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~2008) -- early absence of record is weak evidence of nonuse
- RAY FILES DITCH (7300514) (1916-06-15, 0.8 cfs decreed): last active 1997 — 28 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~2008) -- early absence of record is weak evidence of nonuse
- MCGINLEY DITCH (7300511) (1913-08-07, 4.7 cfs decreed): last active 2011 — 14 years idle
- GREEN SHAFT RES (7303602) (1911-11-15, 0.0 cfs decreed): last active 2011 — 14 years idle
- HALAVITY WELL (7305004) (1913-12-31, 0.0 cfs decreed): last active 2012 — 13 years idle
- LOCKHART SPRING (7300565) (1910-05-01, 0.2 cfs decreed): last active 2014 — 11 years idle
- ROBBINS DITCH (7300516) (1886-04-01, 5.9 cfs decreed): last active 2015 — 10 years idle
Compliance screens (29 advisory flags)
Screened 53 of 221 structures with rights (68 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.
- CHIQUITO DOLORES NO 2 (7300505): Observed p99 daily rate 10.6 cfs (max 13.5) exceeds total decreed absolute 6.0 cfs across 15522 recorded day(s).
- ROBBINS DITCH (7300516): Observed p99 daily rate 9.4 cfs (max 11.8) exceeds total decreed absolute 5.9 cfs across 6006 recorded day(s).
- NELLIE S DITCH (7300513): Observed p99 daily rate 9.0 cfs (max 15.8) exceeds total decreed absolute 5.6 cfs across 10901 recorded day(s).
- SELBY IRRIGATING DITCH (7300538): Observed p99 daily rate 6.1 cfs (max 7.4) exceeds total decreed absolute 5.1 cfs across 12003 recorded day(s).
- THOMPSON FEEDER DITCH (7300518): Observed p99 daily rate 6.0 cfs (max 6.0) exceeds total decreed absolute 3.0 cfs across 1327 recorded day(s).
- COOK IRRIGATING DITCH (7300532): Observed p99 daily rate 5.6 cfs (max 6.5) exceeds total decreed absolute 4.0 cfs across 3868 recorded day(s).
- REED DITCH (7300515): Observed p99 daily rate 5.3 cfs (max 5.4) exceeds total decreed absolute 4.1 cfs across 4168 recorded day(s).
- HAFEY SOUTH SIDE DITCH (7300508): Observed p99 daily rate 5.1 cfs (max 5.6) exceeds total decreed absolute 1.1 cfs across 2266 recorded day(s).
- COOK IRRIGATING DITCH ALTERNATE POINT (7300641): Observed p99 daily rate 3.8 cfs (max 4.0) exceeds total decreed absolute 2.2 cfs across 1980 recorded day(s).
- SKINNER DITCH (7300634): Observed p99 daily rate 3.8 cfs (max 4.5) exceeds total decreed absolute 2.5 cfs across 1402 recorded day(s).
Seniority (top structures by decreed rate)
| Structure | Senior priority date | Rights | Decreed abs (cfs) | Decreed abs (AF) | Conditional? |
|---|---|---|---|---|---|
| CHIQUITO DOLORES DITCH (7300504) | 1885-12-31 | 4 | 17.7 | 0 | — |
| MOORLAND DITCH (7300537) | 1886-11-26 | 9 | 13.0 | 0 | — |
| BRIER DITCH (7300531) | 1903-04-15 | 4 | 9.9 | 0 | yes |
| UPPER SAXBURY DITCH (7300519) | 1885-04-01 | 7 | 7.7 | 0 | — |
| KELL DITCH NO 1 (7300541) | 1913-06-01 | 1 | 6.0 | 0 | — |
| CHIQUITO DOLORES NO 2 (7300505) | 1886-04-01 | 3 | 6.0 | 0 | — |
| ROBBINS DITCH (7300516) | 1886-04-01 | 2 | 5.9 | 0 | — |
| NELLIE S DITCH (7300513) | 1910-12-10 | 1 | 5.6 | 0 | — |
| SELBY IRRIGATING DITCH (7300538) | 1883-05-10 | 4 | 5.1 | 0 | — |
| H H RUSSEL D (7300533) | 1910-06-23 | 6 | 4.9 | 0 | — |
| MCGINLEY DITCH (7300511) | 1913-08-07 | 1 | 4.7 | 0 | — |
| HILL DITCH (7300534) | 1929-06-01 | 2 | 4.7 | 0 | — |
| REED DITCH (7300515) | 1892-04-01 | 3 | 4.1 | 0 | — |
| COOK IRRIGATING DITCH (7300532) | 1886-11-26 | 1 | 4.0 | 0 | — |
| BROUSE DITCH (7300502) | 1911-08-10 | 1 | 3.4 | 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.