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Animas River Basin

Division 7 · Water District 30 · As of 2026-10-06 05:16 MDT · 2 weeks ago

Who may take water from the Animas River Basin, who is calling for it today, and how it is running, compiled from Colorado Division of Water Resources records. Click anything on the map for its record.

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Animas River Basin on the ground — the ditches, wells, reservoirs and gages of Water District 30 · clicktap anything for its record

Browse this district’s ditches, gages, reservoirs, wells and springs as a list.

92% of normal flow, week of 2026-09-21
1 call the record places on it, 2 unsettled

The Animas River is near normal for late September -- 92% of normal flow, its 10th-wettest such week in 116 years of record. 1 call stands against it right now; the most senior right calling dates to 1936. DWR's statements do not settle whether 2 more calls reach it.

Snow and runoff

Source Independent agency measurement · fetched 2026-10-21 · verify at NRCS report generator ↗ Source Our computation, scored against a reference · NRCS forecast, graded here against the gage record

Snow-water equivalent, WY2027

SNOTEL siteElev (ft)SWE (in)Median (in)% of medianTypical peak
Cascade #28990 0.10.0 — March 6 (10.4 in)
Mineral Creek10030 0.10.0 — April 9 (15.6 in)
Molas Lake10610 0.10.0 — April 11 (22.0 in)
Red Mountain Pass11060 1.40.4 — April 25 (25.0 in)
Spud Mountain10660 0.00.0 — April 4 (25.6 in)
Stump Lakes11230 0.80.2 — April 22 (18.8 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 (1979–2026)

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 8 of the last 48 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.

The snow never came: 1981, 1990, 2002, 2003, 2015, 2018, 2025, 2026. The snow left early: 2012, 2022.

Computed by this site from 6 SNOTEL sites’ full daily records (NRCS AWDB, back to 1979). 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 — Animas R at Durango

NRCS's final issue (2026-06-01) calls it even odds that at least 52 kAF arrives over 06-01 to 07-31 — 29% of a normal season; almost certainly at least 20, probably not more than 93. Our own record at this gage shows 50 kAF actually delivered. New forecasts begin in January. How to read these numbers →

The record-adjusted April benchmark

NRCS’s April issue (2026-04-01) called even odds at 115 kAF over 04-01 to 07-31. Re-anchoring that number on this river’s own history — how its April issues have verified, the winter’s baseflow, and the district’s April 1 snowpack — moves it to 130 kAF. The river delivered 128 kAF.

Computed by this site — not an NRCS number, and shown only because it earned it: replayed over 70 past seasons here (1962–2025), never seeing the year it predicts, the adjustment cut the typical April miss from 16% to 12%. At points where it does not beat NRCS, no adjusted number appears. Coefficients are frozen each August; the model never changes mid-season. Method and honest limits →

90% chance of at least70% chance of at least50% chance of at least30% chance of at least10% chance of at leastNormalObserved
2036527093 177 50

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 16%, with a high bias of 4%, and the observed volume landed inside the stated 10–90% band 84% 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 (1979–2026)

Across 48 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 71% 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 59% of a normal season, against 109% 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.

Runoff outlook — Lemon Reservoir Inflow

NRCS's final issue (2026-06-01) calls it even odds that at least 5 kAF arrives over 06-01 to 07-31 — 25% of a normal season; almost certainly at least 2, probably not more than 12. New forecasts begin in January. How to read these numbers →

The record-adjusted April benchmark

NRCS’s April issue (2026-04-01) called even odds at 13 kAF over 04-01 to 07-31. Re-anchoring that number on this river’s own history — how its April issues have verified, the winter’s baseflow, and the district’s April 1 snowpack — moves it to 16 kAF. The river delivered 16 kAF.

Computed by this site — not an NRCS number, and shown only because it earned it: replayed over 38 past seasons here (1988–2026), never seeing the year it predicts, the adjustment cut the typical April miss from 16% to 15%. At points where it does not beat NRCS, no adjusted number appears. Coefficients are frozen each August; the model never changes mid-season. Method and honest limits →

90% chance of at least70% chance of at least50% chance of at least30% chance of at least10% chance of at leastNormal
245812 21

How good are these forecasts here? (1987–2026)

Grading every April issue against what the river then delivered, measured against NRCS’s naturalized volumes (this point forecasts the river as it would run without upstream storage and diversions — which no gage measures) — 39 seasons: the median miss of the 50% forecast is 16%, with a high bias of 2%, and the observed volume landed inside the stated 10–90% band 88% 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 NRCS’s own naturalized monthly volumes; years missing any month 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 (1979–2026)

Across 48 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 83% 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 1.0). In warm, early-melt years the river delivered a median of 71% of a normal season, against 121% 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.

Drought

Source Our computation, no independent reference · computed here from the screened DWR record Source Independent agency measurement · fetched 2026-10-13 · verify at U.S. Drought Monitor ↗

Right now

This is the 107th-driest week 39 in 116 years of record at ANIMAS RIVER AT DURANGO, CO (as of 2026-09-21; this week’s flow sits at the 92nd percentileRank against the record: a river at its 5th percentile is lower than it was in 95 of the past 100 years on this same date. for the date). On this week’s US Drought Monitor, Clear Creek County is 19% in D3 extreme drought (2026-10-13). The law agrees: the most senior active call leaves 82% of this district’s decreed flow rights junior to the calling right this week.

Every year since 1897, week by week

Each thin row is a year at ANIMAS RIVER AT DURANGO, 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.

This year against its analogs

Over the 39 weeks recorded so far, 2026’s weekly trace most resembles 2002 (mean gap 18.5 percentile points; next closest 1940 (19.3), 2012 (19.5)). The analog’s remainder is drawn as context — its ending is what happened to it, not a forecast for this year.

The Drought Monitor’s view since 2000

Mean share of area in each class across Clear Creek, La Plata, San Juan 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 2002 — 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 (211 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

DroughtSpanWeeks Trough percentileFlows recovered Water table back
unnamed dry spell 2025-05-05 → 2025-12-29 34 18th (2025-09-01) 8 weeks —
unnamed dry spell 2023-11-27 → 2024-10-28 48 5th (2024-04-08) 69 weeks —
the 2020-22 drought 2020-01-27 → 2022-10-24 143 1st (2021-03-22) 40 weeks —
the 2018 drought 2017-12-25 → 2019-06-10 76 4th (2018-07-02) 2 weeks —
the 2012-13 drought 2012-09-10 → 2013-11-18 62 5th (2012-11-26) 1 week —
unnamed dry spell 2009-10-26 → 2010-07-19 38 11th (2010-01-25) 52 weeks —
the 2002 drought 2001-11-26 → 2003-11-17 103 3rd (2002-09-02) 33 weeks —
unnamed dry spell 1989-10-23 → 1990-11-05 54 5th (1990-04-30) 0 weeks —
the 1981 drought 1981-03-16 → 1981-11-09 34 20th (1981-07-06) 0 weeks not yet (9 of 10 wells still below)
the 1977 drought 1978-11-27 → 1979-04-16 20 25th (1978-12-25) 1 week 1 yr (9 wells)
the 1977 drought 1977-02-14 → 1978-06-12 69 5th (1977-07-11) 4 weeks 2 yr (10 wells)
unnamed dry spell 1974-06-24 → 1975-07-07 54 18th (1974-10-07) 1 week —
unnamed dry spell 1967-11-20 → 1968-05-27 27 26th (1968-02-12) 6 weeks —
unnamed dry spell 1966-11-07 → 1967-04-17 23 25th (1966-11-28) 64 weeks —

Detected mechanically: the 26-week smoothed percentile below the 30th for at least 20 weeks; recovered on regaining the 50th. The water-table clock compares each monitoring well against its own pre-drought median (the 3 years before onset) and dates the year the median well got back — the aquifer remembers longest, and “still below” is a finding, not a gap. 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.

What drought has cost here

Since 1994, federal crop insurance has paid $689,401 in drought-caused claims across Clear Creek, La Plata, San Juan counties — 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.

When this basin claimed its water

Every bar is a year’s new appropriations (2,256 rights across 119 years of shared record), colored by that year’s wetness from the barcode above. Here the correlation is +0.02 — 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.

Snowpack — 6 SNOTEL sites report here. Runoff outlook — Animas R at Durango: even odds of at least 52 kAF over 06-01 to 07-31 — 29% of a normal season, per NRCS, issued 2026-06-01 — the season’s final; new forecasts begin in January. Runoff outlook — Lemon Reservoir Inflow: even odds of at least 5 kAF over 06-01 to 07-31 — 25% 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 siteElev (ft)SWE (in)Median (in)% of medianTypical peak
Cascade #28990 0.10.0 — March 6 (10.4 in)
Mineral Creek10030 0.10.0 — April 9 (15.6 in)
Molas Lake10610 0.10.0 — April 11 (22.0 in)
Red Mountain Pass11060 1.40.4 — April 25 (25.0 in)
Spud Mountain10660 0.00.0 — April 4 (25.6 in)
Stump Lakes11230 0.80.2 — April 22 (18.8 in)

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

90%70%50%30%10%Normal
2036527093 177

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

90%70%50%30%10%Normal
245812 21

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: 11 parent disagreements, 9 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 26 streams, 15 agree. Know this water? Tell us →

StreamThis site routes it toDWR routes it to
Salt Creek the mainstem Hermosa Creek
Lightner Creek the mainstem Animas River
Junction Creek the mainstem Animas River
Big Spring Creek the mainstem Hermosa Creek
Elbert Creek the mainstem Animas River
Spring Creek the mainstem Animas River
Spring Gulch the mainstem Animas River
Wilson Gulch the mainstem Animas River

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

Dry Creek (6 mi) · Red Creek (5 mi) · Miller Creek (5 mi) · Long Hollow (4 mi) · True Creek (4 mi) · Phillips Canyon (4 mi) · Brice Canyon (3 mi) · Shearer Creek (3 mi)

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