Lower Colorado River

Evolution of the network

This year, in context

In the weeks around 2026-07-06 (the newest reading on file), flows at the 13 ranked gages are running at a median 50% of their own long-term norm for this window — 11 below a typical year, 2 at or above. Driest relative to its record: OWENS CREEK DITCH NEAR RENO MOUNTAIN, CO, ranking 1st lowest of 25 years.

How this comparison is made

Each gage's mean flow over the 3 days either side of 2026-07-06, compared with the same window in every year of its own record — so a gage is only ever measured against itself, and gages with no record in the window are counted out rather than guessed.

Gage flow trend & changepoints

What counts as a trend here

Computed 2026-08-30 20:56 from 53 gage(s) with cached period-of-record data. The series is each gage's annual mean flow in cfs (years with ≥300 days of record). Mann-Kendall (trend, with the Hamed–Rao correction for serial correlation — persistence can otherwise fake significance) 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.” The %-per-decade figure is the same Sen slope divided by the gage's median annual flow, for comparing across streams of very different size; it is omitted for near-ephemeral channels where the median is too small to divide by honestly.

Of the 53 gages with enough record, 11 are trending down and 1 up, and 5 carry a detected shift. The clearest is Plateau Creek near Collbran, its annual mean flow changing -18.17 cfs per decade (-27.2% of its median annual flow) over 58 years (p<0.0001). The other 41 show no clear signal either way.

Gage	Trend	Change / decade cfs · % of median annual flow	Significance	Years	Changepoint
▸ ⚠️ Plateau Creek near Collbran☆ PLACOLCO	↓ decreasing	-18.17 cfs -27.2%	p<0.001	58	~1958
▸ Reed Wash near Mack☆ REEMACCO	↓ decreasing	-5.38 cfs -12.2%	p<0.001	24	~1987
▸ Bull Creek above South Side Canal near Molina☆ BULLCRCO	↓ decreasing	-2.32 cfs -39.0%	p=0.002	15	~2017
▸ Government Highline Canal near Cameo☆ GHICANCO	↓ decreasing	-80.61 cfs -7.3%	p=0.004	24	—
▸ Grand Valley Canal near Palisade☆ GRDVALCO	↑ increasing	+39.75 cfs +9.1%	p=0.017	21	~2007
▸ Mesa Creek near Mesa☆ MESAMECO	↓ decreasing	-2.85 cfs -25.8%	p=0.021	19	—
▸ Southside Canal at Mesa☆ SOCAMECO	↓ decreasing	-1.13 cfs -20.9%	p=0.022	16	—
▸ Big Creek at Upper Station near Collbran☆ BIGUPPCO	↓ decreasing	-1.70 cfs -6.7%	p=0.023	15	—
▸ Orchard Mesa Irrigation District above Palisade☆ ORCHIDCO	↓ decreasing	-94.60 cfs -13.3%	p=0.023	21	~2016
▸ Cottonwood Creek at Upper Sta, near Molina☆ COTAUPCO	↓ decreasing	-8.13 cfs -55.9%	p=0.029	11	—
▸ Plateau Creek near Cameo☆ PLACAMCO	↓ decreasing	-7.24 cfs -4.8%	p=0.044	86	—
▸ Buzzard Creek near Collbran☆ BUZCOLCO	↓ decreasing	-3.93 cfs -8.5%	p=0.046	58	—

⚠️ 1 gage flagged: their records may have quietly shifted against their neighbours, so treat their trends with caution.

How drift is detected

Every gage's annual flows are compared against each neighbour's as a double-mass curve (Searcy & Hardison, USGS WSP 1541-B); a Pettitt step test looks for a break in the ratio. A gage is flagged only when the breaks AGREE across its references, and a break against an already-suspect gage is never counted against a healthy one. A double-mass break means the ratio between two gages changed, not that either gage is faulty: a new diversion, a reservoir, or an import changes that ratio exactly as a rating shift does. Screening aid for expert review, never a measurement verdict.

41 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. 14 gage(s) and 320 structure(s) report in 2026, but structure reporting only reached half its modern level around ~1994. 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)
1900s	1	0
1910s	2	0
1920s	3	0
1930s	4	0
1940s	8	0
1950s	11	0
1960s	8	0
1970s	16	163
1980s	8	206
1990s	7	361
2000s	12	528
2010s	11	421
2020s	13	307

Mass-balance (network closure) trend

Structure divrec-history backfill coverage as of the last check: 18% of 2636 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 (1503 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.

• REED WASH NEAR MACK, CO.: reach shifted from -2542 cfs to -4818 cfs summer mean (more losing, p=0.009, 15 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=-0.55) -- part of it may be unaccounted water becoming accounted, not hydrologic change]
• COLORADO RIVER NEAR COLORADO-UTAH STATE LINE: reach shifted from +9751 cfs to +5009 cfs summer mean (more losing, p=0.000, 76 yr) [sedimentary plains/foothills: moderate groundwater connectivity -- gain/loss shifts can be real aquifer response; corroborate with nearby well records]
• BIG SALT WASH AT FRUITA, CO.: reach shifted from -1490 cfs to -1490 cfs summer mean (more losing, p=0.016, 9 yr) [alluvial valley: real alluvial aquifer -- a decades-long shift toward losing is the classic signature of alluvial pumping and urbanization]
• GRAND VALLEY CANAL NEAR PALISADE, CO: reach shifted from -874 cfs to -109 cfs summer mean (more gaining, p=0.001, 41 yr) [alluvial valley: real alluvial aquifer -- a decades-long shift toward losing is the classic signature of alluvial pumping and urbanization]
• ORCHARD MESA IRRIGATION DISTRICT ABOVE PALISADE: reach shifted from -766 cfs to -734 cfs summer mean (more gaining, p=0.037, 27 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]

Groundwater now has its own tab: 31 monitored well(s), water-table trends, stream corridors, and the advisory depletion screen.

Reservoirs now has its own tab: 203 reservoir(s), end-of-year storage back to 1975, click-to-chart histories.

Cross-gage pattern fingerprint

Over the 41-year window with full coverage (1986–2026), the dominant shared pattern across 3 gage(s) explains 95% 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.

• PALISADE IRR DIST CANAL (diversion): -40.8 cfs (9% of that reach's correction)
• MESA CO IRR DIST CANAL (diversion): -40.8 cfs (9% of that reach's correction)
• PALISADE BYPASS PIPELINE (diversion): -40.8 cfs (9% of that reach's correction)
• GRAND JCT COLO R PL AP 4 (diversion): -40.8 cfs (9% of that reach's correction)
• GRAND VALLEY CANAL (diversion): -40.8 cfs (9% of that reach's correction)
• ORCHARD MESA CHECK (diversion): -40.8 cfs (9% of that reach's correction)
• RICE PIPELINE (diversion): -40.8 cfs (9% of that reach's correction)
• OBERGFELL DIVERSION (diversion): -40.8 cfs (9% of that reach's correction)
• UTE PUMPING STATION (diversion): -40.8 cfs (9% of that reach's correction)
• TALBOTT PIPELINE (diversion): -40.8 cfs (9% of that reach's correction)

203 reservoir(s) with 46,798 storage measurement(s), 1975–2025. Basin storage as of 2024-10-31 (the record's own end — reservoir records publish ~annually): 7,207 AF across 38 reservoir(s).

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.

A dashed red ring marks a dam under an active storage restriction from DWR's Dam Safety branch — the State Engineer has limited how much it may legally store, so a low fill can be an order, not a drought. Hazard class and inspection condition come from the same record, joined only where the dam carries this reservoir's WDID or a confident NID match — a wrong dam's restriction would be worse than none shown.

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 row to chart its full storage history, or open its dossier for rights, documents and dam-safety facts.

Reservoir	Last recorded storage (AF)	As of	Full	Dam (DWR Dam Safety)
▸ JERRY CREEK RESERVOIR TOTALIZER (7204128) ☆	6,936	2008-10-31	—	—	dossier →
▸ JERRY CREEK RES NO 2 (7203962) ☆	6,527	2022-10-01	—	—	dossier →
▸ VEGA RESERVOIR (7203844) ☆	4,336	2020-10-31	—	—	dossier →
▸ HIGHLINE RESERVOIR (7203957) ☆	3,272	2015-10-12	—	—	dossier →
▸ COTTONWOOD LAKES RES 1 (7203923) ☆	1,321	2024-10-28	—	—	dossier →
▸ JERRY CREEK RES NO 1 (7203961) ☆	1,086	2022-10-01	—	—	dossier →
▸ PALISADE CABIN RESERVOIR (7203854) ☆	985	2023-10-02	—	—	dossier →
▸ BIG CREEK RESERVOIR NO 3 (7203905) ☆	941	2024-10-28	—	—	dossier →

Snow-water equivalent, WY2026

No snow on the ground — normal for the date; the snow year begins in October. The chart shows the full water year just ending.

SNOTEL site	Elev (ft)	SWE (in)	Median (in)	% of median	Typical peak
Mesa Lakes	10160	0.1	0.0	—	April 15 (19.0 in)

NRCS SNOTEL, daily. Sites are assigned to the district whose boundary contains them — the snow that feeds this district can also sit in a neighboring headwater district.

Two ways a snow year goes wrong (1987–2026)

A bad snow year here comes in two flavors (both called snow droughtA winter that shorts the snowpack. It happens two ways: a dry one, where the snow never comes, and a warm one, where near-normal snow falls but melts off weeks early -- and the river feels them differently.), and the river feels them differently. In 11 of the last 40 winters the snow never came — the pack peaked below 80% of its median. In 1 more, the snow came but left early — a near-normal peak melted out two weeks or more ahead of its usual date, sending the water down before the season needed it. This year was one of the dry ones: the pack peaked at 35% of median.

The snow never came: 1988, 1990, 2002, 2007, 2012, 2015, 2018, 2020, 2021, 2025, 2026. The snow left early: 2000.

Computed by this site from 1 SNOTEL site’ full daily records (NRCS AWDB, back to 1987). Each year is measured against each site’s own multi-decade median — not the 1991–2020 normal the chart above uses — so the 1980s grade against a fair baseline. Peak and melt-out need 85% of the season’s days on the record; thin years are dropped, not guessed. Derived from snow measurements alone — it cannot tell dry-from-warm causes apart, only what the snowpack did.

Runoff outlook — Colorado R nr Cameo

NRCS's final issue (2026-06-01) calls it even odds that at least 255 kAF arrives over 06-01 to 07-31 — 19% of a normal season; almost certainly at least 140, probably not more than 450. Our own record at this gage shows 180 kAF actually delivered (partial record: 36 of 61 days). New forecasts begin in January. How to read these numbers →

90% chance of at least	70% chance of at least	50% chance of at least	30% chance of at least	10% chance of at least	Normal	Observed
140	200	255	340	450	1360	180

How good are these forecasts here? (1965–2025)

Grading every April issue against what the river then delivered, measured at this gage’s own record — 60 seasons: the median miss of the 50% forecast is 32%, with a high bias of 32%, and the observed volume landed inside the stated 10–90% band 50% of the time (a calibrated forecast would say 80%).

Computed by this site: NRCS's archived April issues (their period as issued each year) against the observed volume in DWR’s published record; years with under 90% daily coverage are dropped, not summed. A grade of the forecast, never of the forecasters — these are hard rivers. How this point ranks among every graded Colorado forecast point →

What April snow has meant for this river (1987–2025)

Across 39 measured years, the season’s water has closely followed the April snowpack: a year opening April with 80% of median snow has typically gone on to deliver about 67% of a normal season (a snow-to-runoff elasticityHow strongly one number moves with another. A snow-to-runoff elasticity of 1.5 means a 10% shortfall in April snowpack has typically become a 15% shortfall in the season's water. of 1.1). In warm, early-melt years the river delivered a median of 76% of a normal season, against 97% in typical years — the timing of the melt matters, not just its size.

Computed by this site: the district’s April 1 SWE (% of each SNOTEL site’s own-record median) against the observed April–July volume at this gage (% of its median season) — a fixed window every year, unlike the forecast grades above, which use each issue’s own period. The slope is fit so single wild years can’t steer it (Theil–Sen, log space); years missing 10% of their days are dropped.

Right now

This is the 3rd-driest week 27 in 93 years of record at COLORADO RIVER NEAR CAMEO, CO. (as of 2026-06-29; this week’s flow sits at the 3rd percentile for the date). On this week’s US Drought Monitor, Garfield County is 34% in D4 exceptional drought (2026-09-01). The law agrees: the most senior active call leaves 100% of this district’s decreed flow rights junior to the calling right this week.

Every year since 1933, week by week

Each thin row is a year at COLORADO RIVER NEAR CAMEO, CO.; each cell is one week’s flow ranked against the same calendar week of every other year — warm means dry for the date, blue wet, so seasonality cancels and droughts appear as warm bands. Gaps are missing record, never a dry river. Click a year to reconstruct it on the Historical tab.

The Drought Monitor’s view since 2000

Mean share of area in each class across Garfield, Mesa counties — the counties this district’s gages sit in, which overlap the district imperfectly. The Drought Monitor weighs soils, vegetation and local reports; it is CONTEXT beside the river’s own record above, not the water-rights picture.

The law’s own drought gauge

When water runs short, administration answers: calls reach further back in time, and more decreed rights go junior to the calling right. This is that response, weekly since 1987 — the share of this district’s decreed flow rights junior to the most senior active call. Watch it spike in the named droughts below, and linger after the river recovers.

Computed from DWR’s call record (916 calls touching this district) against the district’s rights index. Scoping is deliberately coarse — a call’s own district, or districts named in its comments — and this is administration’s RESPONSE, not a per-structure verdict (each dossier’s curtailment card does that, with stream miles). A deepening call can also reflect growing demand, not only shrinking supply.

This basin’s droughts, by its own record

Drought	Span	Weeks	Trough percentile	Recovery
unnamed dry spell	2025-06-23 → 2026-07-06	54	9th (2026-07-06)	not yet
the 2020-22 drought	2020-08-17 → 2022-10-31	115	9th (2021-03-29)	31 weeks
the 2018 drought	2018-06-11 → 2019-07-01	55	15th (2018-11-26)	2 weeks
the 2012-13 drought	2012-08-13 → 2013-11-25	67	6th (2013-04-22)	5 weeks
the 2002 drought	2004-04-19 → 2005-01-10	38	21st (2004-07-12)	33 weeks
the 2002 drought	2002-03-11 → 2003-11-10	87	3rd (2002-10-21)	94 weeks
unnamed dry spell	1989-10-23 → 1991-08-19	95	16th (1990-05-28)	15 weeks
the 1981 drought	1981-04-06 → 1982-03-29	51	11th (1981-08-03)	20 weeks
the 1977 drought	1977-06-20 → 1978-06-19	52	8th (1977-11-07)	6 weeks
unnamed dry spell	1966-09-12 → 1967-05-22	36	16th (1966-11-07)	74 weeks
the 1963-64 drought	1963-07-15 → 1964-11-02	68	4th (1964-05-11)	36 weeks
unnamed dry spell	1961-07-10 → 1961-11-27	20	18th (1961-08-28)	1 week
unnamed dry spell	1960-10-24 → 1961-03-13	20	25th (1960-12-12)	38 weeks
unnamed dry spell	1958-11-17 → 1959-04-13	21	20th (1958-12-29)	44 weeks

Detected mechanically: the 26-week smoothed percentile below the 30th for at least 20 weeks; recovered on regaining the 50th. The knobs are stated because the episode list depends on them — a different reasonable choice merges or splits episodes at the edges. Names are attached where an episode overlaps a drought Colorado already talks about.

When this basin claimed its water

Every bar is a year’s new appropriations (1,857 rights across 94 years of shared record), colored by that year’s wetness from the barcode above. Here the correlation is +0.1 — essentially no wet-dry pattern; here, law and settlement set the pace, not the weather. Across the state both behaviors exist: ephemeral southwest basins file after wet demonstrations, transbasin-source basins under drought — and the biggest statewide filing waves sat in the 1950s drought and after 2002, not in the wet 1980s–90s.

Appropriation dates are the CLAIMED initiation of a right, not the courthouse filing date; the record is survivor-biased (abandoned claims are absent, so failed dry-era scrambles are undercounted); and the big 1960s and 2000s spikes sit on legal events — the pre-1969-Act adjudication era and 2000s legislation — not on weather. A correlation here is a description, never a cause.

New to how a dry winter becomes a call on the river? Anatomy of a drought walks the chain in four minutes — snow to rivers to reservoirs to calls to the water table.

Decreed rights on this network run from 1880-12-31 to 2025-04-12. Of the 20 structures with a yield estimate, the median one’s senior right was in priority 33% of a median irrigation season and 0% in a dry one. 25 abandonment screens and 504 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: 2841 across 2166 structure(s); 218 structure(s) carry 0 court-case references. Advisory reading aids on public DWR data — not administrative or legal conclusions.

Is the river getting harder to divert from?

Over 1988–2025, administration on this district has been tightening: 3 of 3 measures (days under call, calls set, seniority of the controlling call) are moving toward more administration, none the other way.

The three measures, year by year

One row per whole calendar year inside the call record's coverage (38 years); partly-covered years are omitted rather than reported as quiet. Trend is Mann-Kendall with the same significance gate as every other trend on this site. Counted from DWR's published call record, which begins in the early 2000s: earlier years are absent, not quiet. A rise in the number of calls set can also reflect how finely an administrator records one episode, which is why days under call -- insensitive to that -- is the component to read first. Advisory summary of the public record, not an administrative finding.

Year	Days under call	Calls set	Controlling priority (median)
2014	365	184	1884-04-07
2015	365	256	1885-07-28
2016	366	237	1884-04-26
2017	365	330	1884-05-01
2018	365	290	1884-03-02
2019	365	165	1886-08-09
2020	366	221	1883-03-30
2021	365	218	1883-03-15
2022	365	201	1885-06-01
2023	365	120	1885-07-28
2024	366	164	1886-08-09
2025	365	232	1885-06-16

Why diversions stopped — call-based explanations

Sustained diversion stops matched to senior administrative calls.

• BARNES DITCH (7200526) DWR↗☆ stopped 2024-09-27 (12+ days) — call at GRAND VALLEY CANAL curtailing 100% of its decreed rate [heuristic-strong]
• BACON IRRIGATION DITCH (7200521) DWR↗☆ stopped 2024-08-27 (29+ days) — call at SHOSHONE POWER PLANT curtailing 100% of its decreed rate [heuristic-strong]
• BULL BASIN HIGHLINE D (7200557) DWR↗☆ stopped 2024-08-13 (21+ days) — call at HIGHLINE DITCH (BUZZARD) curtailing 100% of its decreed rate [heuristic-strong]
• BONHAM BRANCH PIPELINE (7200542) DWR↗☆ stopped 2024-08-06 (7+ days) — call at CAMP BIRD DITCH curtailing 100% of its decreed rate [heuristic-strong]
• ATKINSON DITCH (7200515) DWR↗☆ stopped 2024-08-05 (20+ days) — call at CAMP BIRD DITCH curtailing 100% of its decreed rate [heuristic-strong]
• ARKANSAS DITCH (7200514) DWR↗☆ stopped 2024-08-02 (7+ days) — call at CAMP BIRD DITCH curtailing 100% of its decreed rate [heuristic-strong]
• BARNES DITCH (7200526) DWR↗☆ stopped 2024-08-02 (7+ days) — call at CAMP BIRD DITCH curtailing 100% of its decreed rate [heuristic-strong]
• BIESER NO 1 DITCH (7200535) DWR↗☆ stopped 2024-08-02 (11+ days) — call at CAMP BIRD DITCH curtailing 100% of its decreed rate [heuristic-strong]
• BOWER DITCH (7200545) DWR↗☆ stopped 2024-08-02 (7+ days) — call at CAMP BIRD DITCH curtailing 100% of its decreed rate [heuristic-strong]
• BULL BASIN HIGHLINE D (7200557) DWR↗☆ stopped 2024-07-16 (7+ days) — call at EAST DIVIDE CREEK DITCH curtailing 100% of its decreed rate [heuristic-strong]
• BARNES DITCH (7200526) DWR↗☆ stopped 2024-06-18 (7+ days) — call at BAKER DITCH curtailing 100% of its decreed rate [heuristic-strong]
• BARKER AND WEBER DITCH (7200525) DWR↗☆ stopped 2024-06-11 (59+ days) — call at BAKER DITCH curtailing 100% of its decreed rate [heuristic-strong]

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
GRAND VALLEY PROJECT (7200646) DWR↗☆	1889-10-01	33.2% / 0.0%	33.2% / 0.0%
GRAND VALLEY CANAL (7200645) DWR↗☆	1882-08-22	33.2% / 0.0%	9.8% / 0.0%
MIN FLOW COLORADO RIVER USFW (7202003) DWR↗☆	1992-03-05	5.6% / 0.0%	5.6% / 0.0%
MESA CO IRR DIST CANAL (7200783) DWR↗☆	1903-07-06	33.2% / 0.0%	33.2% / 0.0%
PALISADE IRR DIST CANAL (7200817) DWR↗☆	1889-10-01	33.2% / 0.0%	33.2% / 0.0%
LEON PARK FEEDER CANAL (7200746) DWR↗☆	1952-08-19	9.8% / 0.0%	9.8% / 0.0%
SOUTHSIDE CANAL (7200879) DWR↗☆	1952-08-19	9.8% / 0.0%	9.8% / 0.0%
PARK CREEK DITCH (VEGA) (7200820) DWR↗☆	1963-08-16	9.8% / 0.0%	9.8% / 0.0%
LEON TUNNEL CANAL (7204715) DWR↗☆	1900-06-12	33.2% / 0.0%	33.2% / 0.0%
BONHAM BRANCH PIPELINE (7200542) DWR↗☆	1952-08-19	9.8% / 0.0%	9.8% / 0.0%
NEW ERIE CANAL (7200616) DWR↗☆	1906-06-01	33.2% / 0.0%	9.8% / 0.0%
MORMON MESA DITCH (7200799) DWR↗☆	1888-01-12	100.0% / 0.0%	5.6% / 0.0%

Abandonment radar (25 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 ~1994 — idleness that begins before then may be unreported use, not nonuse (flagged † below).

• WEIMER DITCH (7200931) DWR↗☆ (1915-05-25, 1.7 cfs decreed): last active 1970 — 44 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1994) -- early absence of record is weak evidence of nonuse
• PISEL DITCH (7200832) DWR↗☆ (1905-02-07, 0.7 cfs decreed): last active 1977 — 37 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1994) -- early absence of record is weak evidence of nonuse
• LITTLE TRICKLE DITCH (7201298) DWR↗☆ (1974-07-31, 0.1 cfs decreed): last active 1985 — 29 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1994) -- early absence of record is weak evidence of nonuse
• SCHORN COLLECTION D NO 2 (7201413) DWR↗☆ (1935-06-01, 1.0 cfs decreed): last active 1985 — 29 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1994) -- early absence of record is weak evidence of nonuse
• BARKER PUMP AND PIPELINE (7200997) DWR↗☆ (1941-04-01, 1.6 cfs decreed): last active 1986 — 28 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1994) -- early absence of record is weak evidence of nonuse
• CLEGHORN DRAIN DITCH NO2 (7201422) DWR↗☆ (1972-02-01, 1.5 cfs decreed): last active 1987 — 27 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1994) -- early absence of record is weak evidence of nonuse
• OAK CREEK RES NO 1 (7204080) DWR↗☆ (1946-05-01, 0.0 cfs decreed): last active 1987 — 27 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1994) -- early absence of record is weak evidence of nonuse
• HALL DITCH (BEAVER CR) (7200657) DWR↗☆ (1914-05-01, 1.8 cfs decreed): last active 1988 — 26 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1994) -- early absence of record is weak evidence of nonuse
• HENDERSON WELL (7205040) DWR↗☆ (1971-03-04, 0.0 cfs decreed): last active 1988 — 26 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1994) -- early absence of record is weak evidence of nonuse
• NICHOLS AND KNAPP WELL (7205050) DWR↗☆ (1962-12-31, 0.0 cfs decreed): last active 1988 — 26 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1994) -- early absence of record is weak evidence of nonuse

Compliance screens (504 advisory flags)

Screened 775 of 2166 structures with rights (989 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.

• ROADSIDE MINE DEWAT SYS1 (7205407) DWR↗☆: Observed p99 daily rate 137.3 cfs (max 137.8) exceeds total decreed absolute 0.6 cfs across 367 recorded day(s).
• PARK CREEK DITCH (PARK) (7200819) DWR↗☆: Observed p99 daily rate 56.0 cfs (max 102.0) exceeds total decreed absolute 6.5 cfs across 18283 recorded day(s).
• UTE PIPELINE HGT NO 1 (7201487) DWR↗☆: Observed p99 daily rate 48.2 cfs (max 3473.1) exceeds total decreed absolute 30.0 cfs across 30181 recorded day(s).
• HARTMAN DIVERSION-WEBB (7201753) DWR↗☆: Observed p99 daily rate 38.0 cfs (max 38.0) exceeds total decreed absolute 0.2 cfs across 304 recorded day(s).
• OWENS CREEK DITCH (7204721) DWR↗☆: Observed p99 daily rate 24.2 cfs (max 33.1) exceeds total decreed absolute 18.9 cfs across 6799 recorded day(s).
• ANDERSON FEEDER DITCH (7200506) DWR↗☆: Observed p99 daily rate 22.7 cfs (max 22.7) exceeds total decreed absolute 22.7 cfs across 1802 recorded day(s).
• PALMER DITCH (7200818) DWR↗☆: Observed p99 daily rate 20.8 cfs (max 31.7) exceeds total decreed absolute 20.2 cfs across 29152 recorded day(s).
• BULL ELK DITCH (7200559) DWR↗☆: Observed p99 daily rate 19.5 cfs (max 19.5) exceeds total decreed absolute 19.1 cfs across 4420 recorded day(s).
• BULL CREEK DITCH (7200558) DWR↗☆: Observed p99 daily rate 17.9 cfs (max 23.3) exceeds total decreed absolute 16.4 cfs across 38749 recorded day(s).
• R M G DITCH (7200852) DWR↗☆: Observed p99 daily rate 16.4 cfs (max 16.6) exceeds total decreed absolute 15.8 cfs across 5748 recorded day(s).

Seniority (top structures by decreed rate)

Structure	Senior priority date	Rights	Decreed abs (cfs)	Decreed abs (AF)	Conditional?
GRAND VALLEY PROJECT (7200646) DWR↗☆	1889-10-01	7	2313.7	0	—
GRAND VALLEY CANAL (7200645) DWR↗☆	1882-08-22	5	940.3	0	—
MIN FLOW COLORADO RIVER USFW (7202003) DWR↗☆	1992-03-05	2	881.0	0	—
MESA CO IRR DIST CANAL (7200783) DWR↗☆	1903-07-06	1	667.0	0	—
PALISADE IRR DIST CANAL (7200817) DWR↗☆	1889-10-01	1	573.0	0	—
LEON PARK FEEDER CANAL (7200746) DWR↗☆	1952-08-19	2	450.0	0	—
SOUTHSIDE CANAL (7200879) DWR↗☆	1952-08-19	1	240.0	0	—
PARK CREEK DITCH (VEGA) (7200820) DWR↗☆	1963-08-16	1	100.0	0	—
LEON TUNNEL CANAL (7204715) DWR↗☆	1900-06-12	1	54.0	0	—
BONHAM BRANCH PIPELINE (7200542) DWR↗☆	1952-08-19	1	45.0	0	—
NEW ERIE CANAL (7200616) DWR↗☆	1906-06-01	7	36.4	0	—
MORMON MESA DITCH (7200799) DWR↗☆	1888-01-12	8	34.0	0	—
SILVER GAUGE DITCH (7200870) DWR↗☆	1888-08-10	5	32.6	0	—
KIGGINS SALISBURY DITCH (7200730) DWR↗☆	1900-08-12	3	31.3	0	—
EAST FORK FEEDER CANAL (7200609) DWR↗☆	1952-08-19	1	30.0	0	—

No inventory or legal-document changes detected since the daily watch began.

Water-court filings this month (division-wide)

1 application in the 2026-08 resume for this basin's division — new rights, changes, augmentation plans — from the water clerk's statutory monthly notice (C.R.S. 37-92-302), the earliest public signal of a new claim. Filings are division-wide, not district-filtered: check the county column. Full resume PDF at the Judicial Branch →

Anyone affected may file a statement of opposition until 2026-10-31 (56 days left). C.R.S. 37-92-302(3): due by the last day of the second month following the filing month — computed, not legal advice; confirm with the water clerk.

All 1 filings, with excerpts

Case	What it asks	County	Excerpt
26CW3012	change of water right	RIO BLANCO	26CW3012 Rio Blanco County. Application For Change of Water Right and Approval of Augmentation Plan. Applicant: Three Crown Ranch, LLC, Balcomb & Green, P.C., P.O. Drawer 790, Glenwood Springs, CO 81602, (970) 945-6546; balcombgreen.com. First Claim for Change…

Active substitute water supply plans in this district

Temporary State Engineer approvals to divert out of priority (37-92-308 / 37-90-137). A structure operating under one behaves differently under a call than its decreed rights alone suggest — the priority tables above don't know about these; this list does. Source: DWR’s active-SWSP register, refreshed nightly.

Plan	Type	Status	Expires	Structure	Documents
SNOWCAP COAL CO - ROADSIDE PORTALS MINE	37-92-308(5) PLANS LESS THAN 5 YEARS	Approved	2027-07-30	—	plan file
SNOWCAP COAL CO - ROADSIDE PORTALS MINE	37-92-308(4) PLAN PENDING COURT APPLICATION	Approved	2027-07-31	—	plan file

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.