Tribs. North of Colorado River

Source Our computation, no independent reference · computed here from the screened DWR record Source Our computation, no independent reference · no independent reference; see /methods

This year, in context

In the weeks around 2026-10-01 (the newest reading on file), flows at the 2 ranked gages are running at a median 52% of their own long-term norm for this window — 2 below a typical year, 0 at or above. Driest relative to its record: COLORADO RIVER NEAR KREMMLING, CO, ranking 2nd lowest of 79 years.

Gage flow trend & changepoints

Of the 8 gages with enough record, 2 are trending down and 0 up, and 2 carry a detected shift. The clearest is Colorado River at Glenwood Springs, its annual mean flow changing -201.33 cfs per decade (-7.6% of its median annual flow) over 66 years (p=0.0003). The other 6 show no clear signal either way.

Drought history, cost, and the four-century context moved to the Drought tab.

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

1 of those show a significant trend once extended backwards from a retired neighbour's record: Colorado River near Dotsero (125 yr, decreasing). 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. 2 gage(s) and 134 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 †.

Mass-balance (network closure) trend

Structure divrec-history backfill coverage as of the last check: 28% of 362 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 (–)

Mass-balance kinks computed for every summer month back to (0 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: 14 monitored well(s), water-table trends, stream corridors, and the advisory depletion screen.

Reservoirs now has its own tab: 91 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.

Source DWR administrative record · verify at DWR groundwater wells ↗ Source DWR administrative record · verify at DWR well permits ↗

52 water-level measurements across 14 monitored well(s) — 10 alluvial, 0 bedrock — plus 9 administered well(s) reporting metered pumping.

Well map

3D aquifer x-ray

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

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.

Source DWR administrative record · verify at DWR structure records ↗

91 reservoir(s) with 4,253 storage measurement(s), 1975–2025. Basin storage as of 2024-10-17 (the record's own end — reservoir records publish ~annually): 1,044 AF across 11 reservoir(s).

Reservoir map — how full is each vessel?

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.

Source Independent agency measurement · fetched 2026-10-27 · verify at NRCS report generator ↗ Source Our computation, scored against a reference · NRCS forecast, graded here against the gage record

Snow-water equivalent, WY2027

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 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 3 of the last 45 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, 2012, 2026. The snow left early: 2002, 2025.

Computed by this site from 2 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 — Colorado R nr Kremmling

NRCS's final issue (2026-06-01) calls it even odds that at least 115 kAF arrives over 06-01 to 07-31 — 23% of a normal season; almost certainly at least 60, probably not more than 215. Our own record at this gage shows 98 kAF actually delivered. New forecasts begin in January. How to read these numbers →

We test a record-based adjustment of the April benchmark at every graded point. Here it did not beat NRCS over None replayed seasons (—% typical miss unadjusted vs —% adjusted), so none is shown — NRCS’s own forecast, unadjusted, is the best April benchmark available for this river. Why we test →

How good are these forecasts here? (2018–2026)

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) — 9 seasons: the median miss of the 50% forecast is 16%, with a high bias of 16%, and the observed volume landed inside the stated 10–90% band 100% 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 (1981–2026)

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 69% 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 1.2). In warm, early-melt years the river delivered a median of 80% of a normal season, against 100% 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 — Colorado R nr Dotsero

NRCS's final issue (2026-06-01) calls it even odds that at least 165 kAF arrives over 06-01 to 07-31 — 21% of a normal season; almost certainly at least 90, probably not more than 295. Our own record at this gage shows 148 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 490 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 266 kAF. The river delivered 273 kAF.

Computed by this site — not an NRCS number, and shown only because it earned it: replayed over 61 past seasons here (1970–2025), never seeing the year it predicts, the adjustment cut the typical April miss from 45% to 24%. 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 →

How good are these forecasts here? (1969–2026)

Grading every April issue against what the river then delivered, measured at this gage’s own record — 57 seasons: the median miss of the 50% forecast is 46%, with a high bias of 46%, and the observed volume landed inside the stated 10–90% band 30% 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 (1981–2026)

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 49% 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 1.6). In warm, early-melt years the river delivered a median of 52% of a normal season, against 98% 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.

Source Our computation, no independent reference · computed here from the screened DWR record Source Independent agency measurement · fetched 2026-10-20 · verify at U.S. Drought Monitor ↗

Right now

This is the 1st-driest week 40 in 86 years of record at COLORADO RIVER NEAR DOTSERO, CO (as of 2026-09-28; this week’s flow sits at the 1st 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, Eagle County is 91% in D4 exceptional drought (2026-10-20). The law agrees: the most senior active call leaves 98% of this district’s decreed flow rights junior to the calling right this week.

Every year since 1940, week by week

Each thin row is a year at COLORADO RIVER NEAR DOTSERO, 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 40 weeks recorded so far, 2026’s weekly trace most resembles 2002 (mean gap 8.1 percentile points; next closest 2004 (13.8), 1981 (18.8)). 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 Eagle, Garfield, Grand, Routt 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 (312 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

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 1998, federal crop insurance has paid $185,072 in drought-caused claims across Eagle, Garfield, Grand, Routt counties — 1.7% of all insured crop losses there. The worst year was 2013 ($98,049).

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 (1,047 rights across 87 years of shared record), colored by that year’s wetness from the barcode above. Here the correlation is +0.17 — 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.

Who serves it, who protects it

Two registers the site fetches on their own schedules, read for this district. Neither is a DWR record; each links its own page and its agency.

Public water systems here

Source Register of another agency · fetched 2026-10-06 · verify at EPA SDWIS ↗

3 systems touch this district (3 community systems reporting 10,484 people served, a figure that counts a wholesaler's customers twice); none carries an open health-based violation on EPA's record.

Instream-flow rights held by the state

Source Register of another agency · fetched 2026-10-25 · verify at CWCB instream flow program ↗

34 reaches over 250.3 miles and 2 natural lake levels, held by the Colorado Water Conservation Board so that water stays in the stream. Every reach, with its schedule and case →

• Colorado River, 20.8 mi: 525 (9/16 - 5/14), 650 (5/15 - 7/31), 800 (8/1 - 9/15) cfs (appropriated 2011, 11CW0160) · dossier
• Deep Creek, 20.8 mi: 0.18 (04/01 - 04/30), 1.01 (05/01 - 05/31), 1.62 (06/01 - 06/30), 1.54 (07/01 - 07/31), 1.3 (08/01 - 08/31), 1.01 (09/01 - 09/30), 0.42 (10/01 - 10/31) cfs
• Deep Creek, 20.8 mi: 8 (10/1 - 4/30), 14 (5/1 - 9/30) cfs (appropriated 1980, 80CW0312) · dossier
• Sweetwater Creek, 19.8 mi: 18 (1/1 - 12/31) cfs (appropriated 1980, 80CW0313) · dossier
• Egeria Creek, 17.0 mi: 4 (1/1 - 12/31) cfs (appropriated 1979, 79CW0363) · dossier
• Rock Creek, 15.0 mi: 10 (1/1 - 12/31) cfs (appropriated 1977, 77W3624) · dossier

and 30 more on the district's instream-flow page.

What the water is like -- USGS sensors right now, where it has been sampled, the impaired-waters list, and how the tap water here stands with EPA -- is on the Water quality tab.

Designated groundwater basins are on their own page.

Source Adjudicated record · verify at DWR water-right transactions ↗ Source Adjudicated record · verify at DWR net amounts ↗

Decreed rights on this network run from 1870-12-31 to 2023-01-24. Of the 20 structures with a yield estimate, the median one’s senior right was in priority 32% of a median irrigation season and 0% in a dry one. 4 abandonment screens and 299 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: 1596 across 1231 structure(s); 99 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 callA senior water right demanding its water, which requires everyone junior on that stream to stop diverting until it is satisfied., calls set, seniorityColorado shares water by date: the earlier the right, the stronger its claim when the river runs short. "First in time, first in right." of the controlling call) are moving toward more administration, none the other way.

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.

Abandonment radar (4 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).

• PARK DITCH (5300751) DWR↗☆ (1911-08-01, 0.4 cfs decreed): last active 1976 — 11 years idle
• HADLEY NO 2 RESERVOIR (5303969) DWR↗☆ (1931-06-01, 0.0 cfs decreed): last active 1976 — 11 years idle
• REID NO 3 RESERVOIR (5303992) DWR↗☆ (1903-09-12, 0.0 cfs decreed): last active 1976 — 11 years idle
• ROBERTA RESERVOIR (5303993) DWR↗☆ (1904-06-14, 0.0 cfs decreed): last active 1976 — 11 years idle

Compliance screens (299 advisory flags)

Screened 503 of 1231 structures with rights (548 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.

• SHOSHONE POWER PLANT (5300584) DWR↗☆: Observed p99 daily rate 1415.0 cfs (max 13272.0) exceeds total decreed absolute 1408.0 cfs across 35124 recorded day(s).
• WILSON AND DOLL DITCH (5300883) DWR↗☆: Observed p99 daily rate 60.0 cfs (max 61.0) exceeds total decreed absolute 11.7 cfs across 15647 recorded day(s).
• CABIN CREEK DITCH (5300521) DWR↗☆: Observed p99 daily rate 30.0 cfs (max 30.0) exceeds total decreed absolute 2.5 cfs across 8237 recorded day(s).
• H M S RELOCATED DITCH (5300767) DWR↗☆: Observed p99 daily rate 23.0 cfs (max 24.0) exceeds total decreed absolute 20.3 cfs across 11952 recorded day(s).
• GRAND RIVER L AND C CO D (5300591) DWR↗☆: Observed p99 daily rate 21.0 cfs (max 45.6) exceeds total decreed absolute 18.4 cfs across 10072 recorded day(s).
• OAK GROVE DITCH (5300745) DWR↗☆: Observed p99 daily rate 18.0 cfs (max 20.0) exceeds total decreed absolute 10.2 cfs across 8908 recorded day(s).
• LUARK DITCH (5300683) DWR↗☆: Observed p99 daily rate 17.0 cfs (max 17.0) exceeds total decreed absolute 10.7 cfs across 9844 recorded day(s).
• STEWART IRRIGATING DITCH (5300810) DWR↗☆: Observed p99 daily rate 16.9 cfs (max 16.9) exceeds total decreed absolute 11.1 cfs across 8229 recorded day(s).
• GLENWOOD L WTR CO SYS/NO NAME (5300585) DWR↗☆: Observed p99 daily rate 16.1 cfs (max 1189.0) exceeds total decreed absolute 12.0 cfs across 38602 recorded day(s).
• KREMMLING SHEEP CREEK DITCH HGT 1 (5300670) DWR↗☆: Observed p99 daily rate 16.0 cfs (max 22.4) exceeds total decreed absolute 6.5 cfs across 8918 recorded day(s).

Seniority (top structures by decreed rate)

Recent inventory & legal-document changes

• 2026-10-25 — call released: 39726
• 2026-10-17 — call set: COOLEY L E NO 2 DITCH (39749)
• 2026-10-17 — call released: 39194
• 2026-10-17 — call released: 38756
• 2026-10-16 — call set: SHOSHONE POWER PLANT (39739)
• 2026-10-16 — call released: 38795
• 2026-10-16 — call released: 39690
• 2026-10-16 — call released: 39253

Water-court filings this month (division-wide)

10 applications in the 2026-09 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 2026-11-30 (33 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.

The water itself, in this district

Four registers, each on its own schedule: what USGS sensors read right now, where samples have been taken, which stretches the state lists as impaired, and how the tap water of the systems here stands with EPA. None is a DWR record; each links its own page.

Right now

Source Provisional telemetry · fetched 2026-10-28 · verify at USGS current conditions ↗

2 USGS sensors report temperature, conductance, dissolved oxygen or turbidity from inside this district; provisional readings, never merged into the verified record.

Where water has been sampled

Source Register of another agency · fetched 2026-10-08 · verify at Water Quality Portal ↗

The portal lists 1,156 sampling stations in this district's watershed (Colorado Headwaters 14010001), of which 123 reported a sample in the last 5 years on the state and tribal side (USGS activity is in the station count, not in that figure). Most active: USGS Colorado Water Science Center (58), Colorado Dept. of Public Health & Environment-WQCD (53), Colorado River Watch (10). Most-sampled groups: Physical, Inorganics, Major, Non-metals, Nutrient, Inorganics, Minor, Metals. Every station as a file ↗

Results themselves are not fetched here; USGS samples added after March 2024 may not be in the portal's legacy profiles yet.

Drinking water

Source Register of another agency · fetched 2026-10-07 · verify at EPA SDWIS ↗

3 community systems touch this district. None carries an open health-based violation on EPA's record. EPA sampled 2 of them for PFAS in 2023–25; none had PFOA or PFOS at or above the 2024 limit.

EPA's record carries violations and lead/copper percentiles; nitrate and disinfection by-product results are not in it. UCMR 5 samples are monitoring, not compliance, and the 2024 PFOA/PFOS limits equal its reporting limit, so any detection of those two is at or above them.

Impaired waters

Source Register of another agency · verify at EPA ATTAINS ↗

The state's 303(d) impaired-waters list has not been joined to this basin's own watershed boundary yet, so nothing is shown rather than a guess; the basins with a join carry the full list here. Why the join is geometry, not a name match.