Computed 2026-08-20 09:34 from 34 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 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	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	sparse	15% of schematic structures have data

Independent check: PASS — 100.0000% agreement across 403,299 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 — 98.37% day-level agreement with USGS's own published records for the same gages, across 23 co-listed station(s) and 251,954 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.

34 gage(s) / 396,872 daily values (1897-10-01–2026-07-06); 656 structure(s) with diversion records; 2277 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. 23 gage(s) and 319 structure(s) report in 2026, but structure reporting only reached half its modern level around ~1968. 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)
1890s	1	0
1900s	1	0
1910s	1	0
1920s	3	0
1930s	4	138
1940s	8	110
1950s	6	122
1960s	8	114
1970s	9	231
1980s	5	241
1990s	11	277
2000s	18	286
2010s	22	331
2020s	24	314

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.

Gage	Trend	Change / decade	Significance	Years	Changepoint
▸ ELBERT CREEK ABOVE CASCADE RESERVOIR☆ ELACASCO	↓ decreasing	-1285.0%	p=0.006	24	~2014
▸ FLORIDA FARMERS CANAL☆ FARMERCO	↓ decreasing	-272.6%	p=0.002	27	~2010
▸ CASCADE CANAL ABOVE CASCADE RESERVOIR☆ CASCANCO	↓ decreasing	-168.1%	p=0.000	34	~2008
▸ CASCADE CR BLW CASCADE CR DIVERSION NR ROCKWOOD CO☆ CASBCACO	↓ decreasing	-166.2%	p=0.029	15	—
▸ FLORIDA CANAL☆ FLOCANCO	↓ decreasing	-94.2%	p=0.012	19	—
▸ ANIMAS RIVER AT SILVERTON, CO.☆ ANISILCO	↓ decreasing	-38.8%	p=0.000	34	~2017
▸ ELBERT CREEK BELOW CASCADE RESERVOIR☆ ELBCASCO	↑ increasing	+37.0%	p=0.030	27	~2011
▸ MINERAL CREEK AT SILVERTON, CO☆ MINASICO	↓ decreasing	-35.5%	p=0.001	34	~2017
▸ FLORIDA RIVER NEAR DURANGO, CO.☆ FLODURCO	↓ decreasing	-29.4%	p=0.000	43	~1942
▸ ANIMAS RIVER BELOW SILVERTON, CO☆ ANIBSICO	↓ decreasing	-25.2%	p=0.002	35	~2017
▸ FLORIDA RIVER BELOW FLORIDA FARMERS CANAL NEAR DURANGO☆ FLOFARCO	↓ decreasing	-19.3%	p=0.031	43	—
▸ FLORIDA RIVER BELOW LEMON RESERVOIR☆ FLOBLECO	↓ decreasing	-13.7%	p=0.001	55	~2008
▸ FLORIDA RIVER AT BONDAD, CO.☆ FLOBONCO	↓ decreasing	-13.5%	p=0.021	48	—
▸ CEMENT CREEK AT SILVERTON, CO☆ CEMSILCO	↓ decreasing	-11.6%	p=0.010	34	~2019
▸ HERMOSA CREEK NEAR HERMOSA, CO.☆ HERHERCO	↓ decreasing	-7.7%	p=0.012	56	~1949
▸ FLORIDA RIVER ABOVE LEMON RESERVOIR NEAR DURANGO☆ FLOALECO	↓ decreasing	-6.8%	p=0.042	55	—
▸ ANIMAS RIVER NEAR CEDAR HILL, NM☆ ANICEDNM	no clear trend	-2.1%	p=0.177	93	~2008

17 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: 15% of 476 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 (1950–2026)

Mass-balance kinks computed for every summer month back to 1950 (1271 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.

• FLORIDA RIVER BELOW FLORIDA FARMERS CANAL NEAR DURANGO: reach shifted from -154 cfs to -8 cfs summer mean (more gaining, p=0.000, 39 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=0.5) -- part of it may be unaccounted water becoming accounted, not hydrologic change]
• FLORIDA RIVER AT BONDAD, CO.: reach shifted from +129 cfs to -58 cfs summer mean (more losing, p=0.000, 48 yr) [sedimentary plains/foothills: moderate groundwater connectivity -- gain/loss shifts can be real aquifer response; corroborate with nearby well records] [measurement-evolution caution: this shift co-moves with the growth of the gage/metering network (rho=-0.6) -- part of it may be unaccounted water becoming accounted, not hydrologic change]

Groundwater now has its own tab: 145 monitored well(s), water-table trends, stream corridors, and the advisory depletion screen.

Reservoirs now has its own tab: 75 reservoir(s), end-of-year storage back to 1929, click-to-chart histories.

Cross-gage pattern fingerprint

Over the 91-year window with full coverage (1936–2026), the dominant shared pattern across 3 gage(s) explains 91% 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.

• EDGEMONT WASTEWATER EFFLUENT (return): -13.7 cfs (100% of that reach's correction)

The basin's aquifer story, from 226 water-level measurements across 145 monitored well(s) (84 alluvial, 0 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.

Load 3D x-ray

Water-table trends

Of 0 well(s) with enough record for a trend test: 0 declining, 0 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.

FLORIDA RIVER BELOW FLORIDA FARMERS CANAL NEAR DURANGO: 4 alluvial well(s) nearby

FLORIDA RIVER AT BONDAD, CO.: 9 alluvial well(s) nearby

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.

75 reservoir(s) with 25,201 storage measurement(s), 1929–2026. Basin storage as of 2025-10-31 (the record's own end — reservoir records publish ~annually): 145,284 AF across 31 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.

Reservoir	Last recorded storage (AF)	As of
▸ RIDGES BASIN RESERVOIR (3003623) ☆	121,244	2025-10-31
▸ CASCADE RESERVOIR (3003536) ☆	20,592	2024-10-31
▸ LEMON RESERVOIR (3003581) ☆	14,164	2010-10-31
▸ JOHNSON RESERVOIR (3003707) ☆	823	2025-10-29
▸ KEELER RESERVOIR (3003547) ☆	488	2025-10-28
▸ HAVILAND LAKE RESERVOIR (3003540) ☆	459	2025-10-31
▸ DURANGO RESERVOIR NO 1 (3003571) ☆	450	1978-10-31
▸ ICE LAKE RESERVOIR (3003546) ☆	416	2025-10-28

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: 2854 across 2277 structure(s); 152 structure(s) carry 0 court-case references.

Abandonment radar (4 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 ~1968 — idleness that begins before then may be unreported use, not nonuse (flagged † below).

• FLORIDA CANAL AND RES (3003576)☆ (1911-05-29, 0.0 cfs decreed): last active 1955 — 19 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1968) -- early absence of record is weak evidence of nonuse
• WATER WITCH DITCH (3000672)☆ (1882-05-05, 0.2 cfs decreed): last active 1958 — 16 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1968) -- early absence of record is weak evidence of nonuse
• MCCLUER MURRAY ANNALA EX (3001531)☆ (1878-04-15, 0.5 cfs decreed): last active 1960 — 14 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1968) -- early absence of record is weak evidence of nonuse
• JAMES DITCH (3000578)☆ (1908-04-04, 0.5 cfs decreed): last active 1962 — 12 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1968) -- early absence of record is weak evidence of nonuse

Compliance screens (271 advisory flags)

Screened 439 of 2277 structures with rights (507 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.

• ANIMAS CONSOLIDATED D (3000506)☆: Observed p99 daily rate 88.7 cfs (max 104.0) exceeds total decreed absolute 85.9 cfs across 73040 recorded day(s).
• REID DITCH (3000617)☆: Observed p99 daily rate 77.9 cfs (max 116.5) exceeds total decreed absolute 64.4 cfs across 75517 recorded day(s).
• ANIMAS DITCH (3001023)☆: Observed p99 daily rate 61.0 cfs (max 74.0) exceeds total decreed absolute 56.2 cfs across 48557 recorded day(s).
• J P LAMB DITCH (3000581)☆: Observed p99 daily rate 35.0 cfs (max 40.0) exceeds total decreed absolute 7.0 cfs across 30629 recorded day(s).
• EAST FORK HERMOSA CREEK (3001929)☆: Observed p99 daily rate 24.6 cfs (max 79.6) exceeds total decreed absolute 3.0 cfs across 3133 recorded day(s).
• GREGG PIPELINE (3001115)☆: Observed p99 daily rate 24.0 cfs (max 24.0) exceeds total decreed absolute 0.8 cfs across 484 recorded day(s).
• TWIN ROCK DITCH (3004665)☆: Observed p99 daily rate 21.5 cfs (max 27.2) exceeds total decreed absolute 2.2 cfs across 40259 recorded day(s).
• HERMOSA COMPANY DITCH (3000568)☆: Observed p99 daily rate 19.0 cfs (max 27.6) exceeds total decreed absolute 12.5 cfs across 42894 recorded day(s).
• NORTON PUMP AND PL (3000606)☆: Observed p99 daily rate 18.0 cfs (max 18.0) exceeds total decreed absolute 0.2 cfs across 668 recorded day(s).
• PIONEER DITCH (3001019)☆: Observed p99 daily rate 17.0 cfs (max 38.0) exceeds total decreed absolute 14.9 cfs across 47277 recorded day(s). Structure holds an Augmentation-use decree -- diversions above the direct-flow decree can be lawful under plan operations; interpret with care.

Seniority (top structures by decreed rate)

Structure	Senior priority date	Rights	Decreed abs (cfs)	Decreed abs (AF)	Conditional?
DURANGO BOATING PARK STRUCTURE 5 (3001691)☆	2006-02-23	1	1400.0	0	—
DURANGO BOATING PARK STRUCTURE 9 (3001692)☆	2006-02-23	1	1400.0	0	—
DURANGO BOATING PARK STRUCTURE 11 (3001693)☆	2006-02-23	1	1400.0	0	—
DURANGO BOATING PARK STRUCTURE 12 (3001694)☆	2006-02-23	1	1400.0	0	—
CASCADE CANAL (3000523)☆	1902-10-02	2	400.0	0	—
ANIMAS DIVERSION CANAL (3000509)☆	1938-09-02	2	287.0	0	yes
POWER CANAL NO 1 (3000612)☆	1902-10-02	1	250.0	0	—
FLORIDA FARMERS DITCH (3001011)☆	1883-12-05	8	185.0	0	—
LITTLE CASCADE CR CANAL (3000588)☆	1902-10-02	1	120.0	0	—
FLORIDA CANAL (3001013)☆	1888-09-29	4	111.0	0	—
ANIMAS CONSOLIDATED D (3000506)☆	1875-01-01	8	85.9	0	—
REID DITCH (3000617)☆	1876-01-01	12	64.4	0	—
ANIMAS DITCH (3001023)☆	1868-03-02	5	56.2	0	—
HERMOSA CR(LOWER REACH) (3001928)☆	1984-07-13	1	37.0	0	—
EAST MESA DITCH (3001094)☆	1904-07-19	2	26.0	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.

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

Administration number
Simulate

DWR administration numbers encode appropriation and adjudication dates; lower is more senior.