Clear Creek

Evolution of the network

Computed 2026-08-26 12:43 from 120 gage(s) with cached period-of-record data. Statistical tests (Mann-Kendall trend, Pettitt changepoint) require at least 8 years spanning at least 10 years of record -- gages below that report no signal, not "no change."

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.

Independent check: PASS — 100.0000% agreement across 580,149 stored values re-checked against DWR's authoritative record (HydroBase_CO_20260707), over 25 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: WARN — 93.27% day-level agreement with USGS's own published records for the same gages, across 20 co-listed station(s) and 155,784 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.

120 gage(s) / 546,515 daily values (1899-04-01–2026-08-09); 266 structure(s) with diversion records; 1815 with decreed rights. Methodology has not yet had independent expert review — treat every figure as an advisory screen, not an administrative or legal conclusion.

Read this first: the measurement network itself evolved

This basin was not always measured the way it is today — the API-era record is dense and recent, the early record sparse. 102 gage(s) and 139 structure(s) report in 2026, but structure reporting only reached half its modern level around ~1981. 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 †.

Gage flow trend & changepoints

Every located gage with a period of record — dot size scales with the strength of its flow trend (|Sen slope| in %/decade, the same statistic as the table below), color with direction. An amber ring marks a detected Pettitt changepoint. Click a gage to chart its trend and shift.

106 other gage(s) show no significant trend or changepoint (not shown).

Mass-balance (network closure) trend

Structure divrec-history backfill coverage as of the last check: 45% of 226 schematic-relevant structures. 10 year(s) clear the 30% coverage gate so far (2016–2025) -- 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 (1950–2026)

Mass-balance kinks computed for every summer month back to 1950 (1011 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.

• CLEAR CREEK NEAR GOLDEN, CO.: reach shifted from +78 cfs to +157 cfs summer mean (more gaining, p=0.030, 30 yr) [mountain crystalline canyon: minimal groundwater storage -- large or shifting unaccounted losses here are more consistent with data/measurement issues or unmodeled plumbing than with aquifer exchange]
• CLEAR CREEK AT GOLDEN, CO: reach shifted from +92 cfs to +32 cfs summer mean (more losing, p=0.009, 52 yr) [sedimentary plains/foothills: moderate groundwater connectivity -- gain/loss shifts can be real aquifer response; corroborate with nearby well records]

Groundwater now has its own tab: 510 monitored well(s), water-table trends, stream corridors, and the advisory depletion screen.

Reservoirs now has its own tab: 151 reservoir(s), end-of-year storage back to 1920, click-to-chart histories.

Cross-gage pattern fingerprint

Over the 52-year window with full coverage (1975–2026), the dominant shared pattern across 3 gage(s) explains 87% 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 2026-08-09)

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.

• CLEAR LAKE RES (diversion): +12.0 cfs (100% of that reach's correction)
• SEA OF TRANQUILLITY RES (diversion): -10.0 cfs (50% of that reach's correction)
• DORY LAKE INLET DITCH (diversion): -10.0 cfs (50% of that reach's correction)
• GOLDEN CITY WATER WORKS RESERVOIR (diversion): -0.9 cfs (4% of that reach's correction)
• AGRICULTURAL DITCH (diversion): -0.9 cfs (4% of that reach's correction)
• COORS INDUSTRIAL DITCH (diversion): -0.9 cfs (4% of that reach's correction)
• COORS COOLING WATER RT BELOW INLET (return): -0.9 cfs (4% of that reach's correction)
• FARMERS HIGHLINE CANAL (diversion): -0.9 cfs (4% of that reach's correction)
• FARMERS HIGHLINE RT TO CLEAR CR (return): -0.9 cfs (4% of that reach's correction)
• COORS HOT W 2 COOLING WTR RT (diversion): -0.9 cfs (4% of that reach's correction)

The basin's aquifer story, from 4,042 water-level measurements across 510 monitored well(s) (276 alluvial, 96 bedrock, rest unclassified) — plus 6 administered well(s) reporting metered pumping through diversion records. Observation wells and pumping wells are different populations and are never conflated. Click a well to chart its record.

Well map

Every monitored well with a location — hover for identity, click to chart its water-level record below. ● alluvial   ● bedrock / confined (Denver Basin, High Plains, etc. — one-way, no human-timescale recharge)   ● unclassified — marker size scales with the strength of the well's water-level trend (|Sen slope| in ft/decade — the same Mann-Kendall/Sen statistic as the trends table below); the smallest, faintest dots have too little record to test.

3D aquifer x-ray

Every aquifer unit as its own 3D head surface — alluvial water table on top, Denver Basin members (Dawson, Denver, Arapahoe, Laramie–Fox Hills) stacked beneath where measured — interpolated from measured water levels and animated through time. Units are never mixed; surfaces exist only inside each unit's well coverage (no extrapolation); thin epochs are suppressed with their reason shown. Vertical scale exaggerated for readability; z is head elevation in feet. Advisory — measured heads, not a calibrated model.

Water-table trends

Of 6 well(s) with enough record for a trend test: 1 declining, 3 rising.

Stream corridors — the surface connection

For each reach whose gain/loss has shifted (Trends tab), the wells within 2 miles of its anchoring gage, their pooled water-table history over the same era, and an advisory Glover screen of lagged stream depletion from nearby metered pumping. v1 proximity = distance to the reach's anchoring gage; segment-based reach join is a flagged upgrade.

CLEAR CREEK NEAR GOLDEN, CO.: 4 alluvial well(s) nearby. Glover screen: 3.1 cfs of nearby metered alluvial pumping → est. lagged depletion 1.9–2.9 cfs (uncalibrated T/S ranges; flagged for SPDSS calibration, AWAS cross-check, and expert review — DWR's AWAS is the authority).

CLEAR CREEK AT GOLDEN, CO: 4 alluvial well(s) nearby. Glover screen: 3.1 cfs of nearby metered alluvial pumping → est. lagged depletion 2.5–3.0 cfs (uncalibrated T/S ranges; flagged for SPDSS calibration, AWAS cross-check, and expert review — DWR's AWAS is the authority).

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.

151 reservoir(s) with 33,869 storage measurement(s), 1920–2025. Basin storage as of 2024-10-31 (the record's own end — reservoir records publish ~annually): 30,687 AF across 39 reservoir(s). 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?

Each reservoir drawn as a vessel: bubble size ∝ its record-high storage, fill level = 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 of its own record high otherwise (a wrong capacity would be worse than an honest record high, so only confident joins upgrade). Hover for numbers, click to chart its history below the map. A dashed teal ring marks reservoirs reporting live DWR telemetry — their fill reflects yesterday's storage, drawn as a dotted tail on charts and treated as provisional until the next verified HydroBase snapshot supersedes it. ● <25% ● 25–60% ● 60–90% ● >90%

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.

Decrees, seniority, and administrative calls connected to this basin's flow network. Advisory reading aids on public DWR data — not administrative or legal conclusions. Rights on file: 3627 across 1815 structure(s); 153 structure(s) carry 955 court-case references.

Why diversions stopped — call-based explanations

Sustained diversion stops matched to senior administrative calls. Self-check: 84% of the 19 explanations coverable by DWR's own out-of-priority analysis agree with it (6 outside its scope).

• COLO AGRICULTURAL D (0700549)☆ stopped 2025-10-04 (27+ days) — call at CLEAR CR PLATTE RIVER D curtailing 100% of its decreed rate [heuristic-partial, district-confirmed]
• CROKE CANAL (0700553)☆ stopped 2025-08-07 (11+ days) — call at CLEAR CR PLATTE RIVER D curtailing 100% of its decreed rate [heuristic-partial, district-confirmed]
• CHURCH DITCH (0700540)☆ stopped 2025-08-06 (86+ days) — call at CLEAR CR PLATTE RIVER D curtailing 100% of its decreed rate [heuristic-partial, district-confirmed]
• GREEN LAKE DITCH (0700582)☆ stopped 2025-08-03 (89+ days) — call at CLEAR CR PLATTE RIVER D curtailing 100% of its decreed rate [heuristic-strong, district-confirmed]
• MANHART DITCH (0700614)☆ stopped 2025-06-23 (8+ days) — call at BLUNN RES curtailing 93% of its decreed rate [heuristic-partial, district-confirmed]
• CROKE CANAL (0700553)☆ stopped 2025-06-14 (10+ days) — call at BLUNN RES curtailing 100% of its decreed rate [heuristic-partial, district-confirmed]
• CROKE CANAL (0700553)☆ stopped 2025-04-07 (29+ days) — call at WANNAMAKER DITCH curtailing 100% of its decreed rate [heuristic-partial, district-confirmed]
• AGRICULTURAL DITCH (0700502)☆ stopped 2024-11-01 (155+ days) — call at TUCKER RES curtailing 98% of its decreed rate [heuristic-partial, district-confirmed]
• FARMERS HIGHLINE CANAL (0700569)☆ stopped 2024-11-01 (150+ days) — call at TUCKER RES curtailing 99% of its decreed rate [heuristic-partial, district-confirmed]
• FISHER DITCH (0700570)☆ stopped 2024-11-01 (171+ days) — call at TUCKER RES curtailing 60% of its decreed rate [heuristic-partial, district-confirmed]
• CLEAR CR PLATTE RIVER D (0700547)☆ stopped 2024-10-31 (151+ days) — call at TUCKER RES curtailing 63% of its decreed rate [heuristic-partial, district-confirmed]
• CHURCH DITCH (0700540)☆ stopped 2024-10-04 (220+ days) — call at B H EATON DITCH curtailing 100% of its decreed rate [heuristic-partial]

DWR out-of-priority analysis (scoped structures)

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.

Abandonment radar (23 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 ~1981 — idleness that begins before then may be unreported use, not nonuse (flagged † below).

• GOLDEN CITY WATER WORKS PIPELINE (0700575)☆ (1860-02-25, 21.2 cfs decreed): last active 1952 — 73 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1981) -- early absence of record is weak evidence of nonuse
• 0700666☆ (1893-08-23, 5.0 cfs decreed): last active 1974 — 51 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1981) -- early absence of record is weak evidence of nonuse
• 0700581☆ (1863-05-21, 0.1 cfs decreed): last active 1980 — 45 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1981) -- early absence of record is weak evidence of nonuse
• 0703398☆ (1974-04-01, 0.0 cfs decreed): last active 1981 — 44 years idle
• 0704396☆ (1871-12-31, 0.0 cfs decreed): last active 1987 — 38 years idle
• SMALL STORAGE TANKS (0704079)☆ (1988-07-01, 0.0 cfs decreed): last active 1991 — 34 years idle
• RHODES SOUTH DITCH (0700650)☆ (1865-07-05, 2.8 cfs decreed): last active 1992 — 33 years idle
• LOWER LOVELAND SNOWMAKING & DOMESTIC DIVERSION (0700874)☆ (1988-12-30, 11.0 cfs decreed): last active 1992 — 33 years idle
• LOVELAND BASIN RES (0703391)☆ (1984-08-21, 0.0 cfs decreed): last active 1992 — 33 years idle
• LOVELAND VALLEY RES (0703392)☆ (1984-08-21, 0.0 cfs decreed): last active 1992 — 33 years idle

Compliance screens (30 advisory flags)

Screened 83 of 1815 structures with rights (134 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.

• GOLDEN CITY WATER WORKS PIPELINE (0700575)☆: Observed p99 daily rate 110.0 cfs (max 110.0) exceeds total decreed absolute 21.2 cfs across 1029 recorded day(s).
• 0700666☆: Observed p99 daily rate 49.0 cfs (max 68.0) exceeds total decreed absolute 5.0 cfs across 2950 recorded day(s).
• BLUNN RES (0703308)☆: Observed p99 daily rate 32.1 cfs (max 416.6) exceeds total decreed absolute 15.1 cfs across 51491 recorded day(s).
• CROKE CANAL RALSTON CREEK DIVERSION (0700728)☆: Observed p99 daily rate 19.0 cfs (max 19.1) exceeds total decreed absolute 0.1 cfs across 192 recorded day(s).
• KERSHAW DITCH (0700597)☆: Observed p99 daily rate 13.0 cfs (max 16.0) exceeds total decreed absolute 11.4 cfs across 34138 recorded day(s).
• GOLDEN CITY DITCH (0700542)☆: Observed p99 daily rate 11.2 cfs (max 49.6) exceeds total decreed absolute 11.1 cfs across 63001 recorded day(s).
• MANHART DITCH (0700614)☆: Observed p99 daily rate 11.0 cfs (max 17.2) exceeds total decreed absolute 9.8 cfs across 32584 recorded day(s).
• CORT GRAVES HUGHES DITCH (0700551)☆: Observed p99 daily rate 7.0 cfs (max 7.0) exceeds total decreed absolute 0.6 cfs across 18023 recorded day(s).
• APEX GULCH FEEDER D (0700717)☆: Observed p99 daily rate 6.1 cfs (max 6.8) exceeds total decreed absolute 2.0 cfs across 6113 recorded day(s).
• OUELETTE DITCH (0700632)☆: Observed p99 daily rate 6.0 cfs (max 11.0) exceeds total decreed absolute 1.1 cfs across 18892 recorded day(s).

Seniority (top structures by decreed rate)

Recent inventory & legal-document changes

• 2026-08-26 — call set: LOWER PLATTE BEAVER D (39357)
• 2026-08-26 — call set: OGILVY DITCH (39359)
• 2026-08-26 — call released: 39331
• 2026-08-26 — call released: 39335
• 2026-08-26 — call released: 39333
• 2026-08-26 — call set: SOUTH FLAT DITCH (39348)
• 2026-08-26 — call set: HARRIMAN DITCH (39347)
• 2026-08-26 — call released: 39287

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.

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.