Computed 2026-08-20 09:41 from 11 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.

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	42% of schematic structures have data

Independent check: PASS — 100.0000% agreement across 143,293 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 6 co-listed station(s) and 78,459 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.

11 gage(s) / 152,235 daily values (1912-10-01–2026-07-06); 113 structure(s) with diversion records; 187 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. 6 gage(s) and 68 structure(s) report in 2026, but structure reporting only reached half its modern level around ~1969. 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)
1910s	1	0
1920s	1	0
1930s	4	0
1940s	3	0
1950s	3	0
1960s	3	28
1970s	4	61
1980s	4	66
1990s	6	74
2000s	6	78
2010s	6	71
2020s	7	60

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
▸ LITTLE NAVAJO RIVER AT CHROMO, CO.☆ LITTRACO	↓ decreasing	-76.2%	p=0.041	18	—
▸ LITTLE NAVAJO RIV BEL L OSO DIV DAM, NR CHROMO, CO☆ LITNACCO	no clear trend	+22.4%	p=0.086	26	~1981
▸ NAVAJO RIVER AT EDITH, CO.☆ NAVEDICO	↓ decreasing	-5.9%	p=0.009	71	~1945
▸ NAVAJO RIVER BELOW OSO DIVERSION DAM NEAR CHROMO☆ NAVOSOCO	↓ decreasing	-4.6%	p=0.010	56	~1999

7 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: 42% of 158 schematic-relevant structures. Kink count trend: no_trend (p=0.308), kink magnitude trend: no_trend (p=0.225) across 42 qualifying year(s).

Reach gain/loss shifts (1950–2026)

Mass-balance kinks computed for every summer month back to 1950 (789 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.

• NAVAJO RIVER AT EDITH, CO.: reach shifted from +33 cfs to +7 cfs summer mean (more losing, p=0.038, 45 yr) [alluvial valley: real alluvial aquifer -- a decades-long shift toward losing is the classic signature of alluvial pumping and urbanization]

Groundwater now has its own tab: 4 monitored well(s), water-table trends, stream corridors, and the advisory depletion screen.

Reservoirs now has its own tab: 17 reservoir(s), end-of-year storage back to 1969, click-to-chart histories.

Cross-gage pattern fingerprint

Over the 30-year window with full coverage (1997–2026), the dominant shared pattern across 3 gage(s) explains 84% 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.

The basin's aquifer story, from 9 water-level measurements across 4 monitored well(s) (2 alluvial, 0 bedrock, rest unclassified) — plus 4 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.

NAVAJO RIVER AT EDITH, CO.: 1 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.

17 reservoir(s) with 1,166 storage measurement(s), 1969–2025. Basin storage as of 2025-09-01 (the record's own end — reservoir records publish ~annually): 30 AF across 2 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
▸ GOMEZ RESERVOIR (7703699) ☆	38	2011-10-26
▸ SPENCE RESERVOIR (7703512) ☆	20	2025-09-01
▸ GARDNER LAKE RESERVOIR (7703505) ☆	15	2011-10-24
▸ THREE LAKES RES NO 3 (7703515) ☆	10	1984-10-24
▸ SAPPINGTON RESERVOIR (7703696) ☆	10	2025-09-01
▸ KRUGER RESERVOIR NO 2 (7703510) ☆	9	1975-10-01
▸ THREE LAKES RES NO 2 (7703514) ☆	8	1975-10-01
▸ MUDDY CREEK RESERVOIR (7703511) ☆	8	1975-10-01

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: 241 across 187 structure(s); 80 structure(s) carry 0 court-case references.

Abandonment radar (13 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 ~1969 — idleness that begins before then may be unreported use, not nonuse (flagged † below).

• BOND HOUSE DITCH (7700508)☆ (1896-05-31, 0.8 cfs decreed): last active 1970 — 55 years idle
• HAVENS PIPELINE (7700541)☆ (1946-06-01, 0.0 cfs decreed): last active 1974 — 51 years idle
• OSTERHOUDT PUMPING STATIONS (7700566)☆ (1945-06-15, 0.2 cfs decreed): last active 1974 — 51 years idle
• MUDDY CREEK RESERVOIR (7703511)☆ (1956-07-01, 0.0 cfs decreed): last active 1974 — 51 years idle
• I R CROWLEY ART WELL NO3 (7705001)☆ (1944-08-01, 0.5 cfs decreed): last active 1976 — 49 years idle
• BEAVER CREEK RESERVOIR (7703690)☆ (1949-07-01, 0.0 cfs decreed): last active 1981 — 44 years idle
• OLEN W CROWLEY ART WELL (7705004)☆ (1951-10-08, 1.0 cfs decreed): last active 1981 — 44 years idle
• I R CROWLEY ART WELL SYS (7705000)☆ (1932-08-01, 0.5 cfs decreed): last active 1985 — 40 years idle
• SPENCE RESERVOIR (7703512)☆ (1963-07-06, 0.0 cfs decreed): last active 1987 — 38 years idle
• NO 4 GRAHAM-A C FITZHUGH (7700565)☆ (1914-05-01, 4.0 cfs decreed): last active 1989 — 36 years idle

Compliance screens (59 advisory flags)

Screened 78 of 187 structures with rights (88 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.

• ENTERPRISE DITCH (7700531)☆: Observed p99 daily rate 34.1 cfs (max 38.1) exceeds total decreed absolute 24.0 cfs across 18607 recorded day(s).
• SOUTH SIDE DITCH (7700579)☆: Observed p99 daily rate 24.0 cfs (max 29.5) exceeds total decreed absolute 21.1 cfs across 15418 recorded day(s). Structure holds an Augmentation-use decree -- diversions above the direct-flow decree can be lawful under plan operations; interpret with care.
• NAVAJO MEADOW DITCH (7700562)☆: Observed p99 daily rate 21.6 cfs (max 23.4) exceeds total decreed absolute 6.0 cfs across 8412 recorded day(s).
• NAVAJO RIVER DITCH (7700564)☆: Observed p99 daily rate 19.9 cfs (max 23.4) exceeds total decreed absolute 7.5 cfs across 9399 recorded day(s).
• LITTLE MUDDY CREEK DITCH (7700554)☆: Observed p99 daily rate 18.2 cfs (max 21.6) exceeds total decreed absolute 15.0 cfs across 7376 recorded day(s).
• ELMER DITCH NO 1 (7700529)☆: Observed p99 daily rate 16.4 cfs (max 18.8) exceeds total decreed absolute 15.0 cfs across 21486 recorded day(s).
• BOND HOUSE DITCH (7700508)☆: Observed p99 daily rate 16.0 cfs (max 16.0) exceeds total decreed absolute 0.8 cfs across 294 recorded day(s).
• THREE LAKES INLET DITCH (7700583)☆: Observed p99 daily rate 15.6 cfs (max 23.8) exceeds total decreed absolute 15.0 cfs across 19862 recorded day(s).
• EAST FORK DITCH (7700527)☆: Observed p99 daily rate 15.2 cfs (max 21.6) exceeds total decreed absolute 15.0 cfs across 13598 recorded day(s).
• UPPER CAMP DITCH (7700587)☆: Observed p99 daily rate 15.2 cfs (max 19.0) exceeds total decreed absolute 15.0 cfs across 15560 recorded day(s).

Seniority (top structures by decreed rate)

Structure	Senior priority date	Rights	Decreed abs (cfs)	Decreed abs (AF)	Conditional?
NAVAJO RIVER MIN FLOW (7702005)☆	1974-12-04	1	55.0	0	—
NEW BOND HOUSE D(NAVAJO) (7700597)☆	1966-10-05	1	35.0	0	yes
EAKLOR DITCH (7700524)☆	1889-05-27	3	34.3	0	—
ENTERPRISE DITCH (7700531)☆	1891-05-01	6	24.0	0	yes
SOUTH SIDE DITCH (7700579)☆	1915-06-15	2	21.1	0	—
MIDLAND DITCH (7700559)☆	1884-06-30	5	19.2	0	—
EAST FORK DITCH (7700527)☆	1966-10-05	1	15.0	0	—
ELMER DITCH NO 1 (7700529)☆	1882-12-31	8	15.0	0	—
LITTLE MUDDY CREEK DITCH (7700554)☆	1966-10-05	1	15.0	0	—
THREE LAKES INLET DITCH (7700583)☆	1966-10-05	1	15.0	0	—
UPPER CAMP DITCH (7700587)☆	1966-10-05	1	15.0	0	—
FITZHUGH DITCH (7700536)☆	1888-06-21	6	13.0	0	—
WEST RANCH CREEK DITCH (7700592)☆	1916-06-23	2	11.0	0	—
HEADACHE CREEK DITCH (7700542)☆	1966-10-05	1	10.0	0	yes
SPRING GULCH DITCH (7700581)☆	1914-12-31	1	10.0	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.