La Plata River Basin

Division 7 · Water District 33

Auto-mapped

La Plata River Basin on the ground — the ditches, wells, reservoirs and gages of Water District 33 · clicktap anything for its record

Snowpack — no snow on the ground at 1 SNOTEL site — normal for the date; the snow year begins in October and typically peaks around April 17. Runoff outlook — La Plata R at Hesperus: even odds of at least 2 kAF over 06-01 to 07-31 — 27% 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)	Median (in)	% of median	Typical peak
Columbus Basin	10780	0.0	0.0	—	April 17 (25.8 in)

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

90%	70%	50%	30%	10%	Normal
1	1	2	2	4	6

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: 2 parent disagreements, 2 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 7 streams, 5 agree. Know this water? Tell us →

Stream	This site routes it to	DWR routes it to
Cinder Gulch	the mainstem	nan
McDermott Arroyo	the mainstem	nan

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

San Juan Arroyo (11 mi) · Deadwood Creek (4 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 20 ranked gages are running at a median 9% of their own long-term norm for this window — 18 below a typical year, 2 at or above. Driest relative to its record: CHERRY CREEK AT THE MOUTH NEAR RED MESA, ranking 1st lowest of 39 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 21:19 from 25 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 25 gages with enough record, 8 are trending down and 0 up, and 7 carry a detected shift. The clearest is Long Hollow at the Mouth near Red Mesa, its annual mean flow changing -2.06 cfs per decade (-43.5% of its median annual flow) over 32 years (p<0.0001). The other 16 show no clear signal either way.

What drought has cost here

Since 1994, federal crop insurance has paid $689,401 in drought-caused claims across La Plata county — 18.3% of all insured crop losses there. The worst year was 2002 ($75,597).

USDA crop-insurance indemnities where the recorded cause of loss is drought, summed over the counties this district's gages sit in. Counties overlap water districts imperfectly, and insured-crop claims are a floor on drought damage, not a total. Source: USDA RMA cause-of-loss files.

Gage	Trend	Change / decade cfs · % of median annual flow	Significance	Years	Changepoint
▸ Long Hollow at the Mouth near Red Mesa LONREDCO	↓ decreasing	-2.06 cfs -43.5%	p<0.001	32	~2001
▸ Hay Gulch above Red Mesa Reservoir HAYREDCO	↓ decreasing	-0.48 cfs -27.1%	p<0.001	34	~1999
▸ La Plata River at the Colorado-New Mexico Stateline LAPMEXCO	↓ decreasing	-1.67 cfs -7.6%	p=0.001	105	~1999
▸ Enterprise Ditch at the Colorado-New Mexico Stateline ENTDITCO	↓ decreasing	-0.26 cfs -22.8%	p=0.002	34	~2017
▸ La Plata River at Hesperus LAPHESCO	↓ decreasing	-1.65 cfs -4.4%	p=0.003	108	~1997
▸ Pine Ridge Ditch near Hesperus PINDITCO	↓ decreasing	-0.28 cfs -32.7%	p=0.011	32	—
▸ Cherry Creek at the Mouth near Red Mesa CHEREDCO	↓ decreasing	-1.65 cfs -31.6%	p=0.017	37	—
▸ Pioneer Ditch at the Colorado-New Mexico Stateline PIODITCO	↓ decreasing	-0.14 cfs -15.1%	p=0.023	33	~2000
▸ La Plata River near Farmington, Nm. LAPFARNM	no clear trend	-0.80 cfs -7.0%	p=0.102	82	~2000

⚠️ 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.

16 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. 23 gage(s) and 47 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)
1910s	1	0
1920s	2	0
1930s	3	0
1940s	4	0
1950s	3	30
1960s	3	31
1970s	3	76
1980s	4	53
1990s	10	48
2000s	11	48
2010s	23	48
2020s	23	47

Mass-balance (network closure) trend

Structure divrec-history backfill coverage as of the last check: 16% of 463 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 (971 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.

LA PLATA RIVER AT HESPERUS, CO: reach shifted from +57 cfs to +0 cfs summer mean (more losing, p=0.000, 41 yr) [alluvial valley: real alluvial aquifer -- a decades-long shift toward losing is the classic signature of alluvial pumping and urbanization]
LONG HOLLOW AT THE MOUTH NEAR RED MESA: reach shifted from +0 cfs to -28 cfs summer mean (more losing, p=0.024, 22 yr) [alluvial valley: real alluvial aquifer -- a decades-long shift toward losing is the classic signature of alluvial pumping and urbanization]
LA PLATA RIVER AT THE COLORADO-NEW MEXICO STATELINE: reach shifted from -19 cfs to +36 cfs summer mean (more gaining, p=0.002, 75 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: 49 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 1950, click-to-chart histories.

Cross-gage pattern fingerprint

Over the 38-year window with full coverage (1989–2026), 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.

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	16% of schematic structures have data

Independent check: PASS — 100.0000% agreement across 295,064 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 — 99.77% day-level agreement with USGS's own published records for the same gages, across 5 co-listed station(s) and 120,076 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.

25 gage(s) / 284,494 daily values (1917-10-01–2026-07-06); 102 structure(s) with diversion records; 364 with decreed rights. Methodology has not yet had independent expert review — treat every figure as an advisory screen, not an administrative or legal conclusion.

94 water-level measurements across 49 monitored well(s) — 30 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.

Stream corridors — the surface connection

Where a reach's gain or loss has shifted, the wells within two miles of its anchoring gage and what their water table did over the same era.

How the corridor is assembled

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.

LA PLATA RIVER AT HESPERUS, CO: 4 alluvial well(s) nearby

LA PLATA RIVER AT THE COLORADO-NEW MEXICO STATELINE: 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.

9 reservoir(s) with 600 storage measurement(s), 1950–2011. Basin storage as of 2010-10-31 (the record's own end — reservoir records publish ~annually): 358 AF across 2 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)
▸ RED MESA WARD RESERVOIR (3303522)	272	2010-10-31	—	—	dossier →
▸ TAYLOR RESERVOIR (3303523)	86	2010-10-31	—	—	dossier →
▸ LAPP NORTH RES SYSTEM (3303525)	0	1980-10-31	—	—	dossier →
▸ JOHN F REIT DITCH (3300558)	0	1950-09-01	—	—	dossier →
▸ FELLERS RESERVOIR (3303524)	0	1980-10-31	—	—	dossier →
▸ LAPP HOME RES SYSTEM (3303526)	0	1980-10-31	—	—	dossier →
▸ LAPP-DAVIS RES SYSTEM (3303527)	0	1980-10-31	—	—	dossier →
▸ LAPP RANCH S STK RES SYS (3303528)	0	1980-10-31	—	—	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
Columbus Basin	10780	0.0	0.0	—	April 17 (25.8 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 (1995–2026)

A bad snow year here comes in two flavors (both called snow drought), and the river feels them differently. In 7 of the last 32 winters the snow never came — the pack peaked below 80% of its median. In 2 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 48% of median.

The snow never came: 2002, 2013, 2015, 2018, 2021, 2025, 2026. The snow left early: 1996, 2022.

Computed by this site from 1 SNOTEL site’ full daily records (NRCS AWDB, back to 1995). 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 — La Plata R at Hesperus

NRCS's final issue (2026-06-01) calls it even odds that at least 2 kAF arrives over 06-01 to 07-31 — 27% of a normal season; almost certainly at least 1, probably not more than 4. Our own record at this gage shows 1 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
1	1	2	2	4	6	1

How good are these forecasts here? (1950–2025)

Grading every April issue against what the river then delivered, measured at this gage’s own record — 75 seasons: the median miss of the 50% forecast is 19%, with a high bias of 4%, and the observed volume landed inside the stated 10–90% band 81% 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 (1995–2025)

Across 31 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 54% of a normal season (a snow-to-runoff elasticity of 1.6). In warm, early-melt years the river delivered a median of 57% of a normal season, against 92% 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.

Decreed rights on this network run from 1868-03-02 to 2020-05-31. Of the 20 structures with a yield estimate, the median one’s senior right was in priority 23% of a median irrigation season and 1% in a dry one. 25 abandonment screens and 30 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: 447 across 364 structure(s); 83 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	319	117	1883-05-15
2015	316	90	1899-05-13
2016	273	94	1888-02-08
2017	297	98	1904-01-02
2018	285	164	1878-05-15
2019	186	53	1880-06-01
2020	240	171	1986-11-23
2021	246	143	1876-11-01
2022	261	161	1888-03-20
2023	198	82	1880-06-01
2024	231	114	1876-10-10
2025	281	169	1888-03-20

Why diversions stopped — call-based explanations

Sustained diversion stops matched to senior administrative calls.

LA PLATA IRG DITCH (3300501) DWR↗ stopped 2025-08-13 (11+ days) — call at HENRY BOLEN DITCH curtailing 100% of its decreed rate [heuristic-strong]
WHITE-ROUX AND OWENS D (3300539) DWR↗ stopped 2025-08-12 (43+ days) — call at HENRY BOLEN DITCH curtailing 100% of its decreed rate [heuristic-strong]
H H DITCH (3300536) DWR↗ stopped 2025-07-19 (82+ days) — call at CONLEY DITCH curtailing 100% of its decreed rate [heuristic-strong]
WARREN-VOSBURGH DITCH (3300550) DWR↗ stopped 2025-07-14 (91+ days) — call at CONLEY DITCH curtailing 100% of its decreed rate [heuristic-strong]
BIG STICK DITCH (3300554) DWR↗ stopped 2025-07-07 (94+ days) — call at HENRY BOLEN DITCH curtailing 100% of its decreed rate [heuristic-strong]
HAY GULCH DITCH (3300504) DWR↗ stopped 2025-06-27 (15+ days) — call at HENRY BOLEN DITCH curtailing 100% of its decreed rate [heuristic-strong]
LA PLATA IRG DITCH (3300501) DWR↗ stopped 2025-06-26 (17+ days) — call at HENRY BOLEN DITCH curtailing 100% of its decreed rate [heuristic-strong]
KELLER DITCH (3300515) DWR↗ stopped 2025-06-25 (18+ days) — call at LA PLATA RIVER BASIN curtailing 100% of its decreed rate [heuristic-strong]
NEW SPONSEL DITCH (3300506) DWR↗ stopped 2025-06-22 (9+ days) — call at LA PLATA RIVER BASIN curtailing 100% of its decreed rate [heuristic-strong]
ENTERPRISE ENLARGEMENT D (3300540) DWR↗ stopped 2025-06-22 (7+ days) — call at LA PLATA RIVER BASIN curtailing 100% of its decreed rate [heuristic-strong]
LA PLATA R & CHERRY CR D (3300508) DWR↗ stopped 2025-06-20 (112+ days) — call at HENRY BOLEN DITCH curtailing 100% of its decreed rate [heuristic-strong]
MCCALEB DITCH (3300502) DWR↗ stopped 2025-06-19 (126+ days) — call at HENRY BOLEN 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
RED MESA WARD RES SUPPLY (3300563) DWR↗	1905-04-30	4.4% / 0.0%	4.4% / 0.0%
H H DITCH (3300536) DWR↗	1899-05-13	23.3% / 0.5%	2.3% / 0.0%
TREANOR DITCH (3300549) DWR↗	1904-05-01	7.7% / 0.0%	2.3% / 0.0%
LA PLATA R & CHERRY CR D (3300508) DWR↗	1890-06-02	28.3% / 11.7%	23.3% / 1.4%
BIG STICK DITCH (3300554) DWR↗	1890-06-02	28.3% / 11.7%	2.3% / 0.0%
SLADE DITCH (3300542) DWR↗	1901-03-25	19.8% / 0.0%	2.3% / 0.0%
JOSEPH FREED DITCH (3300547) DWR↗	1904-01-02	11.7% / 0.0%	2.3% / 0.0%
PINE RIDGE DITCH (3300533) DWR↗	1899-02-18	23.3% / 1.4%	2.3% / 0.0%
HAY GULCH DITCH (3300504) DWR↗	1888-02-08	41.4% / 15.4%	1.8% / 0.0%
TOWNSITE DITCH (3300551) DWR↗	1906-05-03	6.3% / 0.0%	2.3% / 0.0%
WARREN-VOSBURGH DITCH (3300550) DWR↗	1898-05-17	23.3% / 1.4%	2.3% / 0.0%
SOONER VALLEY DITCH (3300535) DWR↗	1899-05-07	23.3% / 1.4%	2.3% / 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 ~1968 — idleness that begins before then may be unreported use, not nonuse (flagged † below).

WELBORN-SENA DITCH (3300573) DWR↗ (1915-05-27, 0.5 cfs decreed): last active 1968 — 57 years idle
WILLOW CREEK DITCH (3300521) DWR↗ (1882-08-15, 0.5 cfs decreed): last active 1970 — 55 years idle
HUBBS DITCH NO 2 (3300580) DWR↗ (1923-06-01, 2.0 cfs decreed): last active 1970 — 55 years idle
HUBBS NO 3 DITCH (3300581) DWR↗ (1923-07-01, 1.0 cfs decreed): last active 1970 — 55 years idle
MCGUIRE DITCH (3300524) DWR↗ (1887-07-01, 1.0 cfs decreed): last active 1980 — 45 years idle
WALKER DITCH (3300584) DWR↗ (1932-12-31, 1.0 cfs decreed): last active 1980 — 45 years idle
GREER DITCH (3300626) DWR↗ (1910-12-31, 0.8 cfs decreed): last active 1980 — 45 years idle
NARANJO DITCH (3300537) DWR↗ (1899-06-10, 1.3 cfs decreed): last active 1982 — 43 years idle
ENO SEEPAGE DITCH (3300570) DWR↗ (1912-06-17, 2.0 cfs decreed): last active 1984 — 41 years idle
ISGAR IRRIGATION SYSTEM (3300616) DWR↗ (1925-12-31, 3.0 cfs decreed): last active 1985 — 40 years idle

Compliance screens (30 advisory flags)

Screened 64 of 364 structures with rights (71 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.

TOWNSITE DITCH (3300551) DWR↗: Observed p99 daily rate 20.0 cfs (max 30.3) exceeds total decreed absolute 15.5 cfs across 19866 recorded day(s).
CAVINESS DITCH (3300505) DWR↗: Observed p99 daily rate 9.1 cfs (max 16.6) exceeds total decreed absolute 4.0 cfs across 7987 recorded day(s).
SPONSEL AND MYERS DITCH (3300514) DWR↗: Observed p99 daily rate 9.0 cfs (max 13.0) exceeds total decreed absolute 2.0 cfs across 7669 recorded day(s).
GH DITCH (3300669) DWR↗: Observed p99 daily rate 7.0 cfs (max 7.0) exceeds total decreed absolute 0.5 cfs across 2048 recorded day(s).
AMMONS DITCH (3300518) DWR↗: Observed p99 daily rate 6.7 cfs (max 108.0) exceeds total decreed absolute 6.0 cfs across 26144 recorded day(s).
ENTERPRISE ENLARGEMENT D (3300540) DWR↗: Observed p99 daily rate 5.4 cfs (max 11.0) exceeds total decreed absolute 2.6 cfs across 43455 recorded day(s).
NEW SPONSEL DITCH (3300506) DWR↗: Observed p99 daily rate 4.9 cfs (max 8.0) exceeds total decreed absolute 2.5 cfs across 9920 recorded day(s).
UPPER DAVIS DITCH (3300541) DWR↗: Observed p99 daily rate 4.5 cfs (max 4.5) exceeds total decreed absolute 1.0 cfs across 3606 recorded day(s).
WHITE-ROUX AND OWENS D (3300539) DWR↗: Observed p99 daily rate 3.5 cfs (max 12.0) exceeds total decreed absolute 1.0 cfs across 11421 recorded day(s).
MORGAN AND STAMBAUGH D (3300546) DWR↗: Observed p99 daily rate 3.5 cfs (max 4.2) exceeds total decreed absolute 2.5 cfs across 9079 recorded day(s).

Seniority (top structures by decreed rate)

Structure	Senior priority date	Rights	Decreed abs (cfs)	Conditional?
RED MESA WARD RES SUPPLY (3300563) DWR↗	1905-04-30	1	120.0	—
H H DITCH (3300536) DWR↗	1899-05-13	7	85.0	yes
TREANOR DITCH (3300549) DWR↗	1904-05-01	4	67.0	yes
LA PLATA R & CHERRY CR D (3300508) DWR↗	1890-06-02	4	41.2	—
BIG STICK DITCH (3300554) DWR↗	1890-06-02	4	40.0	—
SLADE DITCH (3300542) DWR↗	1901-03-25	3	36.9	yes
JOSEPH FREED DITCH (3300547) DWR↗	1904-01-02	6	30.9	yes
PINE RIDGE DITCH (3300533) DWR↗	1899-02-18	3	28.0	yes
HAY GULCH DITCH (3300504) DWR↗	1888-02-08	6	19.9	yes
TOWNSITE DITCH (3300551) DWR↗	1906-05-03	2	15.5	yes
WARREN-VOSBURGH DITCH (3300550) DWR↗	1898-05-17	6	13.2	yes
SOONER VALLEY DITCH (3300535) DWR↗	1899-05-07	4	12.0	—
REVIVAL DITCH (3300548) DWR↗	1895-07-06	5	10.9	yes
LA PLATA RIVER MIN FLOW (3301905) DWR↗	1984-07-13	1	9.0	—
LA PLATA IRG DITCH (3300501) DWR↗	1880-06-01	5	8.0	—

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

Water-court filings this month (division-wide)

4 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 4 filings, with excerpts

Case	What it asks	County	Excerpt
`2026CW3007` 3001335	change of water right	LA PLATA	2026CW3007 La Plata County, AMENDED APPLICATION FOR CHANGE OF WATER RIGHT AND NEW WATER RIGHTS. 1. Name and address of Applicants : Gilleland Enterprises, LLC and C&J Gravel Products, Inc. (“Applicants”)c/o John Gilleland 27661 Highway 160 Durango, CO 81301 jo…
`2026CW3016`	reasonable diligence	LA PLATA	2026CW3016 La Plata County, Application for Finding of Reasonable Diligence in the Florida River Watershed; Prior case no. 18CW3047: Applicant: The Bingel-Davis Gratitude Trust, u/a dated April 17, 2025, c/o Kimberly C. Perdue, Southwest Water and Property Law…
`2026CW3017`	—	LA PLATA	2026CW3017 La Plata County, (20CW3008, 13CW3027, 05CW90)…
`2026CW4`	—	ARCHULETA	2026CW4 Archuleta County, Jess E. Ketchum, 320 Stevens Lake Road, Pagosa Springs, CO 81147: Watson Reservoir (Reservoir Pump); Located in the SW 1/4 SE 1/4 of Section 5, T35N, R2W, NMPM, the axis intersects the East abutment at a point approximately 875 ft. No…

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.