Hydrohistorian
Evolution of the network
Gage flow trend & changepoints
What counts as a trend here
Computed 2026-08-20 08:28 from 3 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 3 gages 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.
3 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. 3 gage(s) and 2 structure(s) report in 2026, but structure reporting only reached half its modern level around ~1996. 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) |
|---|---|---|
| 1930s | 2 | 0 |
| 1940s | 2 | 0 |
| 1950s | 2 | 0 |
| 1960s | 2 | 0 |
| 1970s | 2 | 0 |
| 1980s | 2 | 0 |
| 1990s | 3 | 0 |
| 2000s | 3 | 0 |
| 2010s | 3 | 2 |
| 2020s | 3 | 2 |
Mass-balance (network closure) trend
Structure divrec-history backfill coverage as of the last check: 0% of 4 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 (–)
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.
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 C (3/6 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 | current | newest gage reading is 3 day(s) old |
| diversion record | stale | newest diversion record is 764 day(s) old (DWR publishes ~1 year in arrears) |
| structure coverage | sparse | 0% of schematic structures have data |
Independent check: PASS — 100.0000% agreement across 8,589 stored values re-checked against DWR's authoritative record (HydroBase_CO_20260707), over 3 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.
3 gage(s) / 82,188 daily values (1933-05-01–2026-08-17); 3 structure(s) with diversion records; 16 with decreed rights. Methodology has not yet had independent expert review — treat every figure as an advisory screen, not an administrative or legal conclusion.
Decreed rights on this network run from 1879-06-01 to 2014-01-28. Of the 16 structures with a yield estimate, the median one’s senior right was in priority 13% of a median irrigation season and 0% in a dry one.
Rights on file: 16 across 16 structure(s); 0 structure(s) carry 0 court-case references. Advisory reading aids on public DWR data — not administrative or legal conclusions.
Right yield — how often could these rights actually divert?
Share of irrigation-season days each structure's rights were not called out, derived from the 22-year district-scoped call record (senior right = floor, junior right = ceiling constraint). Call-record-derived; DWR's own analysis governs where available.
| Structure | Senior priority | Senior right: median / dry yr | Junior right: median / dry yr |
|---|---|---|---|
| DRY CREEK DITCH (7600506) | 1909-06-11 | 12.8% / 0.0% | 12.8% / 0.0% |
| JOHN GOETZ DITCH 2 (7600504) | 1909-06-09 | 12.8% / 0.0% | 12.8% / 0.0% |
| SAND CREEK DITCH (7600500) | 1896-06-18 | 20.1% / 0.0% | 20.1% / 0.0% |
| JOHN GOETZ DITCH 1 (7600503) | 1879-06-01 | 14.8% / 0.0% | 14.8% / 0.0% |
| SHELL CREEK DITCH (7600505) | 1909-06-10 | 12.8% / 0.0% | 12.8% / 0.0% |
| SPRING CREEK DITCH 2 (7600508) | 1900-05-02 | 17.8% / 0.0% | 17.8% / 0.0% |
| SEEPAGE DITCH 2 (7600501) | 1900-05-01 | 17.8% / 0.0% | 17.8% / 0.0% |
| SPRING CREEK DITCH 1 (7600502) | 1900-04-15 | 17.8% / 0.0% | 17.8% / 0.0% |
| SHELL CREEK MINMUM FLOW (7600507) | 2014-01-28 | 5.6% / 0.0% | 5.6% / 0.0% |
| BULL MTN SPRING (7601500) | 1954-06-30 | 5.6% / 0.0% | 5.6% / 0.0% |
| ORECCHIO ET AL SPRING (7601501) | 1983-09-30 | 5.6% / 0.0% | 5.6% / 0.0% |
| O'QUINN SPRING W 150111 (7605000) | 1987-10-01 | 5.6% / 0.0% | 5.6% / 0.0% |
Seniority (top structures by decreed rate)
| Structure | Senior priority date | Rights | Decreed abs (cfs) | Decreed abs (AF) | Conditional? |
|---|---|---|---|---|---|
| JOHN GOETZ DITCH 2 (7600504) | 1909-06-09 | 1 | 10.0 | 0 | — |
| DRY CREEK DITCH (7600506) | 1909-06-11 | 1 | 10.0 | 0 | — |
| SAND CREEK DITCH (7600500) | 1896-06-18 | 1 | 8.3 | 0 | — |
| JOHN GOETZ DITCH 1 (7600503) | 1879-06-01 | 1 | 7.8 | 0 | — |
| SHELL CREEK DITCH (7600505) | 1909-06-10 | 1 | 7.0 | 0 | — |
| SPRING CREEK DITCH 2 (7600508) | 1900-05-02 | 1 | 6.6 | 0 | — |
| SEEPAGE DITCH 2 (7600501) | 1900-05-01 | 1 | 5.8 | 0 | — |
| SPRING CREEK DITCH 1 (7600502) | 1900-04-15 | 1 | 2.7 | 0 | — |
| SHELL CREEK MINMUM FLOW (7600507) | 2014-01-28 | 1 | 1.1 | 0 | — |
| BULL MTN SPRING (7601500) | 1954-06-30 | 1 | 0.0 | 0 | — |
| ORECCHIO ET AL SPRING (7601501) | 1983-09-30 | 1 | 0.0 | 0 | — |
| O'QUINN SPRING W 150111 (7605000) | 1987-10-01 | 1 | 0.0 | 0 | — |
| OWL SPRING #1 STOCKWATER DVLPMNT (7601502) | 1950-12-31 | 1 | 0.0 | 0 | — |
| WILSON SUPPLY DITCH (7600600) | 1896-06-18 | 1 | 0.0 | 0 | — |
| BULL RUN RESERVOIR (7600800) | 2009-02-28 | 1 | 0.0 | 0 | yes |
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.
| Gage ⇅ | Station ⇅ | Avg cfs Aug 10–Aug 16 ⇅ |
% Hist Median ⇅ | Rank ⇅ | Δ1wk ⇅ | Δ4wk ⇅ | Yrs ⇅ | Status ⇅ |
|---|---|---|---|---|---|---|---|---|
| DEADDPCO | DEADMAN DITCH NEAR DEADMAN PARK | 0.0 | 0% | 0 | +0 | +0 | 0.0 | NO_DATA |
| WSDEARCO | WILSON SUPPLY DITCH NEAR EATON RESERVOIR @ 10 FT PARSHALL FLUME | 0.0 | 0% | 0 | +0 | +0 | 0.0 | NO_DATA |
| SANCRKCO | SAND CREEK AT THE COLORADO-WYOMING STATELINE | 0.0 | 1% | 0 | -0 | -0 | 21.1 | SHORT_RECORD |
Call details in gantt above
3 alert(s) · 2 warning(s) · 4 info. Each gage contributes at most one flag per category (its single most-severe match), so this list shouldn't multiply-count the same underlying condition.