East River Basin

Division 4 · Water District 59

Auto-mapped

East River Basin on the ground — the ditches, wells, reservoirs and gages of Water District 59 · clicktap anything for its record

Snowpack — no snow on the ground at 3 SNOTEL sites — normal for the date; the snow year begins in October and typically peaks around April 8. Runoff outlook — Taylor Park Reservoir Inflow : even odds of at least 15 kAF over 06-01 to 07-31 — 31% of a normal season, per NRCS, issued 2026-06-01 — the season’s final; new forecasts begin in January. Runoff outlook — Slate R nr Crested Butte: even odds of at least 12 kAF over 06-01 to 07-31 — 28% of a normal season, per NRCS, issued 2026-06-01 — the season’s final; new forecasts begin in January. Runoff outlook — East R at Almont: even odds of at least 19 kAF over 06-01 to 07-31 — 21% of a normal season, per NRCS, issued 2026-06-01 — the season’s final; new forecasts begin in January. Runoff outlook — Gunnison R near Gunnison : even odds of at least 35 kAF over 06-01 to 07-31 — 20% of a normal season, per NRCS, issued 2026-06-01 — the season’s final; new forecasts begin in January. Full snow & runoff picture — charts, forecast history and how the forecasts have verified →

Sites, exceedance bands and sources

SNOTEL site	Elev (ft)	SWE (in)	% of median	Typical peak
Butte	10190	0.0	—	April 8 (13.7 in)
Park Cone	9600	0.1	—	April 9 (10.4 in)
Upper Taylor	10710	0.0	—	April 3 (13.6 in)

Taylor Park Reservoir Inflow — 06-01 to 07-31 volume, thousand acre-feet (chance the volume is AT LEAST this):

90%	70%	50%	30%	10%	Normal
8	12	15	20	27	48

Slate R nr Crested Butte — 06-01 to 07-31 volume, thousand acre-feet (chance the volume is AT LEAST this):

90%	70%	50%	30%	10%	Normal
9	11	12	16	21	43

East R at Almont — 06-01 to 07-31 volume, thousand acre-feet (chance the volume is AT LEAST this):

90%	70%	50%	30%	10%	Normal
16	18	19	26	35	91

Gunnison R near Gunnison — 06-01 to 07-31 volume, thousand acre-feet (chance the volume is AT LEAST this):

90%	70%	50%	30%	10%	Normal
24	30	35	51	75	176

Snow-water equivalent and medians (1991–2020) from NRCS SNOTEL; seasonal volume forecasts from the NRCS National Water and Climate Center. Sites and forecast points are assigned to the district whose boundary contains them — snowpack that feeds this district can also sit in a neighboring headwater district. Toggle the Snow chip on the map above to see the sites.

Topology cross-check: 14 parent disagreements, 3 sizable streams not on this network (vs DWR's route framework — under review)

This flow network was built mechanically; DWR's Source Water Route Framework disagrees with it in the places below. Each row is a question a human reviewer has not yet answered — not an error verdict. Checked 31 streams, 17 agree. Know this water? Tell us →

Stream	This site routes it to	DWR routes it to
Coal Creek	the mainstem	Slate River
Willow Creek	the mainstem	Gunnison River
Beaver Creek	the mainstem	Gunnison River
Antelope Creek	the mainstem	Gunnison River
Mill Creek	the mainstem	Curecanti Creek
Coal Creek	the mainstem	Soap Creek
Burnt Mill Creek	the mainstem	Willow Creek
Taylor River	the mainstem	Gunnison River

Sizable streams DWR maps here that this network does not carry:

Squirrel Creek (5 mi) · Wilson Creek (5 mi) · Middle Creek (5 mi)

Full diagnostic snapshot pending — this district's weekly-style report (system status, active calls, hydrographs, anomaly flags) is produced by the nightly rotation and appears here after its first run. The tabs above are live now.

Reconstruct conditions as of

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 26% of their own long-term norm for this window — 13 below a typical year, 0 at or above. Driest relative to its record: OHIO CREEK NEAR BALDWIN, CO., ranking 1st lowest of 34 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 20:02 from 20 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 20 gages with enough record, 5 are trending down and 0 up, and 3 carry a detected shift. The clearest is Taylor River at Almont, its annual mean flow changing -9.20 cfs per decade (-2.9% of its median annual flow) over 115 years (p=0.0007). The other 15 show no clear signal either way.

Gage	Trend	Change / decade cfs · % of median annual flow	Significance	Years	Changepoint
▸ Taylor River at Almont TAYALMCO	↓ decreasing	-9.20 cfs -2.9%	p<0.001	115	~1930
▸ Gunnison River near Gunnison GUNGUNCO	↓ decreasing	-22.23 cfs -3.2%	p=0.003	98	~1952
▸ Taylor Park Reservoir at Taylor Park TAYRESCO	↓ decreasing	-332.05 cfs -135.4%	p=0.011	12	—
▸ East River at Almont EASALMCO	↓ decreasing	-7.77 cfs -2.4%	p=0.021	102	—
▸ Slate River near Crested Butte SLATBUCO	↓ decreasing	-4.98 cfs -3.7%	p=0.028	22	~1997

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

2 of those show a significant trend once extended backwards from a retired neighbour's record: Slate R Ab Baxter Gl @Hwy 135 near Crested Butte (103 yr, decreasing, suspect); East River below Cement Creek near Crested Butte (84 yr, decreasing, suspect). Those are reconstructions, not measurements — each gage's page shows both.

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 238 structure(s) report in 2026, but structure reporting only reached half its modern level around ~1975. 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	4	0
1920s	2	0
1930s	3	0
1940s	7	0
1950s	6	0
1960s	6	0
1970s	4	74
1980s	5	144
1990s	9	170
2000s	8	212
2010s	9	229
2020s	14	236

Mass-balance (network closure) trend

Structure divrec-history backfill coverage as of the last check: 10% of 1482 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 (412 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.

Groundwater now has its own tab: 51 monitored well(s), water-table trends, stream corridors, and the advisory depletion screen.

Reservoirs now has its own tab: 9 reservoir(s), end-of-year storage back to 1975, click-to-chart histories.

Cross-gage pattern fingerprint

Not enough gages with a long enough common-coverage window yet to fingerprint shared patterns.

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.

HINKLE IRG DITCH (diversion): -3.6 cfs (1% of that reach's correction)
HINKLE HAMILTON DITCH (diversion): -3.6 cfs (1% of that reach's correction)
J H HINKLE DITCH (diversion): -3.6 cfs (1% of that reach's correction)
WASTE WATER NO2 DITCH (diversion): -3.6 cfs (1% of that reach's correction)
HAMILTON DITCH (diversion): -3.6 cfs (1% of that reach's correction)
LEHMAN HARRIS DITCH (diversion): -3.6 cfs (1% of that reach's correction)
COLLEN MOORE SPRING (return): -3.6 cfs (1% of that reach's correction)
MESA DITCH (diversion): -3.6 cfs (1% of that reach's correction)
TEACHOUT DITCH (diversion): -3.6 cfs (1% of that reach's correction)
STOCK POND (711) (diversion): -3.6 cfs (1% of that reach's correction)

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 55 day(s) old (target 7)
diversion record	expected-lag	newest diversion record is 304 day(s) old (DWR publishes ~1 year in arrears)
structure coverage	sparse	10% of schematic structures have data

Independent check: PASS — 100.0000% agreement across 158,017 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 — 99.21% day-level agreement with USGS's own published records for the same gages, across 18 co-listed station(s) and 241,967 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.

20 gage(s) / 248,686 daily values (1910-07-27–2026-07-06); 297 structure(s) with diversion records; 2360 with decreed rights. Methodology has not yet had independent expert review — treat every figure as an advisory screen, not an administrative or legal conclusion.

134 water-level measurements across 51 monitored well(s) — 43 alluvial, 0 bedrock — plus 0 administered well(s) reporting metered pumping.

What is being counted

Observation wells and pumping wells are different populations and are never conflated: water levels come from monitored observation wells, and metered pumping comes from administered wells reporting through diversion records. Click any well to chart its own record.

Well map

3D aquifer x-ray

Every aquifer unit as its own head surface, animated through time.

How the surfaces are built, and what they are not

Alluvial water table on top, Denver Basin members (Dawson, Denver, Arapahoe, Laramie–Fox Hills) stacked beneath where measured, interpolated from measured water levels. Units are never mixed; a surface exists only inside its own unit's well coverage, with no extrapolation; thin epochs are suppressed and say why. Vertical scale is exaggerated for readability and z is head elevation in feet. These are measured heads, not a calibrated groundwater model.

Water-table trends

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

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.

9 reservoir(s) with 4,352 storage measurement(s), 1975–2026. Basin storage as of 2025-10-31 (the record's own end — reservoir records publish ~annually): 460,436 AF across 3 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)
▸ BLUE MESA RESERVOIR (6203532)	395,776	2025-10-31	—	—	dossier →
▸ TAYLOR PARK RESERVOIR (5903666)	64,457	2025-10-31	—	—	dossier →
▸ SPRING CREEK RESERVOIR (5903665)	1,270	2011-10-20	—	—	dossier →
▸ MERIDIAN LAKE RESERVOIR (5903663)	343	2012-10-31	—	—	dossier →
▸ LAKE GRANT RESERVOIR (5903684)	203	2025-10-31	—	—	dossier →
▸ MERIDIAN LAKE PARK RESERVOIR NO. 1 (5903689)	192	2011-10-31	—	—	dossier →
▸ RAINBOW LAKE RESERVOIR (5903664)	5	2002-07-26	—	—	dossier →
▸ HEADLEE RESERVOIR (5903772)	3	2001-09-06	—	—	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)	% of median	Typical peak
Butte	10190	0.0	—	April 8 (13.7 in)
Park Cone	9600	0.1	—	April 9 (10.4 in)
Upper Taylor	10710	0.0	—	April 3 (13.6 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 (1981–2026)

A bad snow year here comes in two flavors (both called snow drought), and the river feels them differently. In 9 of the last 46 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 57% of median.

The snow never came: 1981, 1988, 1990, 2002, 2007, 2012, 2015, 2018, 2026. The snow left early: 1992.

Computed by this site from 3 SNOTEL sites’ full daily records (NRCS AWDB, back to 1981). 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 — Taylor Park Reservoir Inflow

NRCS's final issue (2026-06-01) calls it even odds that at least 15 kAF arrives over 06-01 to 07-31 — 31% of a normal season; almost certainly at least 8, probably not more than 27. 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
8	12	15	20	27	48

Runoff outlook — Slate R nr Crested Butte

NRCS's final issue (2026-06-01) calls it even odds that at least 12 kAF arrives over 06-01 to 07-31 — 28% of a normal season; almost certainly at least 9, probably not more than 21. 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
9	11	12	16	21	43

How good are these forecasts here? (2001–2006)

Grading every April issue against what the river then delivered, measured at this gage’s own record — 6 seasons: the median miss of the 50% forecast is 12%, with a high bias of 12%, and the observed volume landed inside the stated 10–90% band 83% 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 (1994–2006)

Across 13 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 74% of a normal season (a snow-to-runoff elasticity of 1.0).

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.

Runoff outlook — East R at Almont

NRCS's final issue (2026-06-01) calls it even odds that at least 19 kAF arrives over 06-01 to 07-31 — 21% of a normal season; almost certainly at least 16, probably not more than 35. Our own record at this gage shows 19 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
16	18	19	26	35	91	19

How good are these forecasts here? (1982–2025)

Grading every April issue against what the river then delivered, measured at this gage’s own record — 43 seasons: the median miss of the 50% forecast is 14%, with a low bias of 0%, and the observed volume landed inside the stated 10–90% band 69% of the time (a calibrated forecast would say 80%).

What April snow has meant for this river (1981–2025)

Across 45 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 64% of a normal season (a snow-to-runoff elasticity of 1.2). In warm, early-melt years the river delivered a median of 66% of a normal season, against 105% in typical years — the timing of the melt matters, not just its size.

Runoff outlook — Gunnison R near Gunnison

NRCS's final issue (2026-06-01) calls it even odds that at least 35 kAF arrives over 06-01 to 07-31 — 20% of a normal season; almost certainly at least 24, probably not more than 75. Our own record at this gage shows 34 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
24	30	35	51	75	176	34

How good are these forecasts here? (1995–2025)

Grading every April issue against what the river then delivered, measured at this gage’s own record — 30 seasons: the median miss of the 50% forecast is 21%, with a high bias of 13%, and the observed volume landed inside the stated 10–90% band 77% of the time (a calibrated forecast would say 80%).

What April snow has meant for this river (1981–2025)

Across 45 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 61% of a normal season (a snow-to-runoff elasticity of 1.4). In warm, early-melt years the river delivered a median of 67% of a normal season, against 103% in typical years — the timing of the melt matters, not just its size.

Decreed rights on this network run from 1874-05-01 to 2025-04-20. Of the 20 structures with a yield estimate, the median one’s senior right was in priority 7% of a median irrigation season and 0% in a dry one. 25 abandonment screens and 178 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: 2950 across 2360 structure(s); 266 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 2003–2025, administration on this district has been tightening: 1 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 (23 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	0	0	—
2015	277	127	1885-08-11
2016	366	108	1890-11-17
2017	319	94	1888-01-23
2018	291	160	1882-06-01
2019	319	93	1888-01-25
2020	246	141	1881-12-17
2021	275	103	1883-05-05
2022	365	93	1884-11-01
2023	277	59	1898-10-15
2024	275	56	1883-06-01
2025	365	100	1884-11-01

Why diversions stopped — call-based explanations

Sustained diversion stops matched to senior administrative calls.

CUNNINGHAM DITCH (5900542) DWR↗ stopped 2025-09-14 (47+ days) — call at WEST DITCH curtailing 100% of its decreed rate [heuristic-strong]
EAST RIVER NO 2 DITCH (5900550) DWR↗ stopped 2025-08-18 (38+ days) — call at MCMINN DITCH curtailing 100% of its decreed rate [heuristic-strong]
CASTLE CREEK NO 2 DITCH (5900533) DWR↗ stopped 2025-08-12 (66+ days) — call at MOODY DITCH curtailing 100% of its decreed rate [heuristic-strong]
CARBON DITCH (5900529) DWR↗ stopped 2025-08-11 (65+ days) — call at MOODY DITCH curtailing 100% of its decreed rate [heuristic-strong]
EAST RIVER NO 1 DITCH (5900549) DWR↗ stopped 2025-08-11 (45+ days) — call at MOODY DITCH curtailing 100% of its decreed rate [heuristic-strong]
CARRON DITCH (5900531) DWR↗ stopped 2025-08-03 (67+ days) — call at CRAWFORD CLIPPER DITCH curtailing 100% of its decreed rate [heuristic-strong]
CHANNEL DITCH (5900538) DWR↗ stopped 2025-08-03 (67+ days) — call at CRAWFORD CLIPPER DITCH curtailing 100% of its decreed rate [heuristic-strong]
DEAN IRRIGATING DITCH (5900544) DWR↗ stopped 2025-08-03 (67+ days) — call at CRAWFORD CLIPPER DITCH curtailing 100% of its decreed rate [heuristic-strong]
DOOLEY ANTELOPE IRG D (5900547) DWR↗ stopped 2025-08-03 (89+ days) — call at CRAWFORD CLIPPER DITCH curtailing 100% of its decreed rate [heuristic-strong]
BOURNE DITCH (5900524) DWR↗ stopped 2025-07-15 (92+ days) — call at CRAWFORD CLIPPER DITCH curtailing 76% of its decreed rate [heuristic-partial]
BUCKEY DITCH (5900527) DWR↗ stopped 2025-07-15 (87+ days) — call at CRAWFORD CLIPPER DITCH curtailing 90% of its decreed rate [heuristic-partial]
CASTLETON DITCH (5900535) DWR↗ stopped 2025-07-15 (92+ days) — call at CRAWFORD CLIPPER DITCH curtailing 51% of its decreed rate [heuristic-partial]

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
GUNNISON RIVER WHITEWATER COURSE (5901327) DWR↗	1998-10-20	0.0% / 0.0%	0.0% / 0.0%
TAYLOR RIVER AND TRIBS (5901273) DWR↗	1910-06-01	0.0% / 0.0%	0.0% / 0.0%
TAYLOR RIVER (5901741) DWR↗	1987-10-02	0.0% / 0.0%	0.0% / 0.0%
GUNNISON & OHIO CREEK CANAL (5900569) DWR↗	1902-11-10	8.4% / 0.0%	0.0% / 0.0%
ROARING JUDY SPG & SEEP (5901084) DWR↗	1947-06-01	0.0% / 0.0%	0.0% / 0.0%
EAST RIVER NO 1 DITCH (5900549) DWR↗	1882-07-31	53.3% / 0.0%	0.0% / 0.0%
GUNNISON R OHIO CR IRG D (5900570) DWR↗	1889-03-15	10.7% / 0.0%	0.0% / 0.0%
TAYLOR RIVER (5901592) DWR↗	1987-10-02	0.0% / 0.0%	0.0% / 0.0%
COPPER CREEK LABORATORY (5900831) DWR↗	1921-07-05	0.0% / 0.0%	0.0% / 0.0%
GUNNISON TOWN DITCH (5900572) DWR↗	1880-06-01	83.9% / 10.7%	0.0% / 0.0%
ESTESS DITCH (5901765) DWR↗	1993-01-05	0.0% / 0.0%	0.0% / 0.0%
KELMEL OWENS NO 1 DITCH (5900607) DWR↗	1879-06-01	94.8% / 30.8%	0.0% / 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 ~1975 — idleness that begins before then may be unreported use, not nonuse (flagged † below).

CASTLE PK FDR DITCH (5900534) DWR↗ (1906-07-03, 7.0 cfs decreed): last active 1975 — 50 years idle
GRAY-TANNER ANTELOPE CR (5900567) DWR↗ (1881-05-10, 14.7 cfs decreed): last active 1976 — 49 years idle
TWIN BRIDGES ASSN DITCH (5900696) DWR↗ (1953-11-13, 1.0 cfs decreed): last active 1976 — 49 years idle
ANNIE IRG DITCH (5900511) DWR↗ (1894-06-11, 1.0 cfs decreed): last active 1977 — 48 years idle
LACY D SPR HDGT 1 (5900612) DWR↗ (1906-09-08, 4.2 cfs decreed): last active 1977 — 48 years idle
BOTTENFIELD DITCH (5900523) DWR↗ (1900-08-09, 12.0 cfs decreed): last active 1978 — 47 years idle
CUNNINGHAM LAKE RES (5903660) DWR↗ (1914-05-15, 5.8 cfs decreed): last active 1978 — 47 years idle
GOOSEBERRY DITCH (5900565) DWR↗ (1911-08-10, 1.1 cfs decreed): last active 1979 — 46 years idle
IMOBERSTEG WILLOW CR D (5900598) DWR↗ (1882-06-15, 15.6 cfs decreed): last active 1979 — 46 years idle
MEADS NO 2 DITCH (5900636) DWR↗ (1899-08-23, 1.2 cfs decreed): last active 1979 — 46 years idle

Compliance screens (178 advisory flags)

Screened 274 of 2360 structures with rights (285 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.

GUNNISON RIVER WHITEWATER COURSE (5901327) DWR↗: Observed p99 daily rate 4150.0 cfs (max 16620.0) exceeds total decreed absolute 1200.0 cfs across 4654 recorded day(s).
CAMPBELL DITCH W BRANCH (5900793) DWR↗: Observed p99 daily rate 530.0 cfs (max 530.0) exceeds total decreed absolute 3.0 cfs across 3178 recorded day(s).
CUNNINGHAM LAKE RES (5903660) DWR↗: Observed p99 daily rate 318.0 cfs (max 318.0) exceeds total decreed absolute 5.8 cfs across 92 recorded day(s).
EAST RIVER NO 1 DITCH (5900549) DWR↗: Observed p99 daily rate 174.1 cfs (max 195.0) exceeds total decreed absolute 137.1 cfs across 13451 recorded day(s).
SUMMERVILLE DITCH NO 2 (5900726) DWR↗: Observed p99 daily rate 103.0 cfs (max 103.0) exceeds total decreed absolute 1.5 cfs across 6906 recorded day(s).
EAST RIVER NO 2 DITCH (5900550) DWR↗: Observed p99 daily rate 75.0 cfs (max 80.3) exceeds total decreed absolute 49.4 cfs across 15612 recorded day(s).
LAFAYETTE DITCH (5900613) DWR↗: Observed p99 daily rate 73.0 cfs (max 78.4) exceeds total decreed absolute 41.3 cfs across 15308 recorded day(s).
HARRIS BOHM POTATO DITCH (5900578) DWR↗: Observed p99 daily rate 58.0 cfs (max 68.1) exceeds total decreed absolute 53.0 cfs across 13712 recorded day(s).
SLIDE DITCH (5900672) DWR↗: Observed p99 daily rate 51.2 cfs (max 55.5) exceeds total decreed absolute 24.5 cfs across 14836 recorded day(s).
VERZUH YOUNG BIFANO D (5900700) DWR↗: Observed p99 daily rate 49.9 cfs (max 53.9) exceeds total decreed absolute 25.1 cfs across 15310 recorded day(s).

Seniority (top structures by decreed rate)

Structure	Senior priority date	Rights	Decreed abs (cfs)	Conditional?
GUNNISON RIVER WHITEWATER COURSE (5901327) DWR↗	1998-10-20	1	1200.0	—
TAYLOR RIVER AND TRIBS (5901273) DWR↗	1910-06-01	1	445.0	—
TAYLOR RIVER (5901741) DWR↗	1987-10-02	1	200.0	—
GUNNISON & OHIO CREEK CANAL (5900569) DWR↗	1902-11-10	4	169.6	—
ROARING JUDY SPG & SEEP (5901084) DWR↗	1947-06-01	1	139.5	—
EAST RIVER NO 1 DITCH (5900549) DWR↗	1882-07-31	17	137.1	yes
GUNNISON R OHIO CR IRG D (5900570) DWR↗	1889-03-15	8	101.7	—
TAYLOR RIVER (5901592) DWR↗	1987-10-02	1	100.0	—
COPPER CREEK LABORATORY (5900831) DWR↗	1921-07-05	1	90.0	—
GUNNISON TOWN DITCH (5900572) DWR↗	1880-06-01	4	75.0	yes
ESTESS DITCH (5901765) DWR↗	1993-01-05	1	75.0	—
KELMEL OWENS NO 1 DITCH (5900607) DWR↗	1879-06-01	9	74.2	—
SPRING CR IRG DITCH (5900679) DWR↗	1891-06-01	3	73.2	—
LONE PINE DITCH (5900617) DWR↗	1877-08-15	9	72.1	—
ACME DITCH (5900501) DWR↗	1897-06-22	3	70.0	—

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

Water-court filings this month (division-wide)

7 applications in the 2026-07 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 2026-09-30 (30 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 7 filings, with excerpts

Case	What it asks	County	Excerpt
`2026CW3030`	reasonable diligence, make absolute	DELTA	Case No. 2026CW3030 (Ref No. 19CW3044, 12CW89) DELTA COUNTY 1. Applicant: Daniel J. Thomas, 14976 Deer Run Rd. Delta, CO 81416-9171; (970) 209-1656 c/o Camp & Skarka, LLC, 415 Palmer St., Delta, CO 81416. APPLICATION TO MAKE ABSOLUTE IN PART, AND FOR FINDING O…
`25CW3085`	new storage right	DELTA	Case No. 25CW3085. DELTA COUNTY. GUNNISON RIVER OR ITS TRIBUTARIES. Columbine Family Ranch LLC, c/o Corona Water Law, 218 E. Valley Road #104 PMB 166, Carbondale, CO 91623, (970) 948 -6523, cc@craigcoronalaw.com. APPLICATION FOR WATER STORAGE RIGHTS. Reservoir…
`26CW18`	make absolute	—	Case No. 26CW18 (Ref No. 20CW2) Applicant Stewart Sto rms 708 Agape Circle Rockwall TX, 75087 Application to make Absolute. Storms Pump - Section15 T15S R84W Easting 346460 Northing 4290042. Source: Spring Creek . Date of Appropriation: December 1, 1953. Amoun…
`26CW3031`	plan for augmentation, new underground right	DELTA	Case No. 26CW3031, DELTA COUNTY, NORTH FORK OF THE GUNNISON AND GUNNISON RIVERS. Application for Conditional Underground Water Right, Approval of Plan for Augmentation and Conditional Exchange Project Right. Anastasia Suderman and Bryce Frazee, c/o Ryan Jarvis…
`26CW3033`	—	—	Case No. 26CW 3033 (Ref No. CA 2710; 20CW3017) Name, Address, and Telephone Number of Applicant. JBARM, Inc. (JBARM), c/o Andrew Bowles, 200 W. Nationwide Boulevard, Columbus, Ohio 43215; (614) 436 -2418. Please direct communications related to this applicatio…
`26CW3034`	—	DELTA	Case No. 26CW3034 (Ref 91CW0007) Delta County - Gunnison River; Town of Cedaredge; c/o John R. Pierce, DUFFORD WALDECK, 744 Horizon Court, Suite 300, Grand Junction, CO 81506, (970) 248-5865; APPLICATION FOR DETERMINATION OF WATER RIGHT (SURFACE); Name, addres…
`26CW3035` 2801276 2801277	reasonable diligence	GUNNISON	Case No. 26CW3035 (Ref No. 19CW3011) GUNNISON COUNTY. Fossil Creek Mines LLC, c/o Joseph Harrington, 8400 E. Prentice Avenue, Suite 1500, Greenwood Village, 80111. Please address all correspondence to: Peter D. Nichols, Esq., Katherine Carter, Esq., Berg Hill …

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

Administration number

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

East River Basin

Schematic

Historical

Evolution of the network

Trends

This year, in context

Gage flow trend & changepoints

How the measurement network itself changed

Mass-balance (network closure) trend

Reach gain/loss shifts (1950–2026)

Cross-gage pattern fingerprint

Structures most implicated by reconciliation (as of 2026-07-06)

Data provenance & quality

Groundwater

Well map

3D aquifer x-ray

Water-table trends

Reservoirs

Reservoir map — how full is each vessel?

Basin storage, end of each water year

Largest reservoirs on record

Snow and runoff

Snow-water equivalent, WY2026

Two ways a snow year goes wrong (1981–2026)

Runoff outlook — Taylor Park Reservoir Inflow

Runoff outlook — Slate R nr Crested Butte

How good are these forecasts here? (2001–2006)

What April snow has meant for this river (1994–2006)

Runoff outlook — East R at Almont

How good are these forecasts here? (1982–2025)

What April snow has meant for this river (1981–2025)

Runoff outlook — Gunnison R near Gunnison

How good are these forecasts here? (1995–2025)

What April snow has meant for this river (1981–2025)

Legal

Is the river getting harder to divert from?

Why diversions stopped — call-based explanations

Right yield — how often could these rights actually divert?

Abandonment radar (25 screens)

Compliance screens (178 advisory flags)

Seniority (top structures by decreed rate)

Water-court filings this month (division-wide)

Call cascade

Pick a calling right