Arkansas: Salida to Portland

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 2026-09-27 (the newest reading on file), flows at the 13 ranked gages are running at a median 67% of their own long-term norm for this window — 9 below a typical year, 4 at or above. Driest relative to its record: HAYDEN RANCH LOWER AUG STATION, ranking 1st lowest of 7 years.

Gage flow trend & changepoints

Of the 22 gages with enough record, 0 are trending down and 1 up, and 1 carries a detected shift. The clearest is Fourmile Creek near Canon City, its annual mean flow changing +4.37 cfs per decade (+21.7% of its median annual flow) over 30 years (p=0.0204). The other 21 show no clear signal either way.

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

21 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. 15 gage(s) and 278 structure(s) report in 2026, but structure reporting only reached half its modern level around ~1970. 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: 4% of 5005 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 (1052 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.

• BEAVER CREEK NEAR PORTLAND, CO.: reach shifted from -812 cfs to -1599 cfs summer mean (more losing, p=0.012, 18 yr) [sedimentary plains/foothills: moderate groundwater connectivity -- gain/loss shifts can be real aquifer response; corroborate with nearby well records] [2 alluvial wells within 2 mi of the gage; pooled water table +1.9 ft (1973–1994, no_trend)]
• BADGER CREEK, LOWER STATION, NEAR HOWARD, CO.: reach shifted from +9 cfs to +8 cfs summer mean (more losing, p=0.034, 18 yr) [sedimentary plains/foothills: moderate groundwater connectivity -- gain/loss shifts can be real aquifer response; corroborate with nearby well records] [2 alluvial wells within 2 mi of the gage; pooled water table -3.2 ft (1980–1990, no_trend)]

Groundwater now has its own tab: 187 monitored well(s), water-table trends, stream corridors, and the advisory depletion screen.

Reservoirs now has its own tab: 28 reservoir(s), end-of-year storage back to 1950, click-to-chart histories.

Cross-gage pattern fingerprint

Over the 52-year window with full coverage (1975–2026), the dominant shared pattern across 3 gage(s) explains 98% of year-to-year variance (almost certainly a basin-wide climate/snowpack driver).

All gages in this window move with the shared pattern -- no localized outlier.

Structures most implicated by reconciliation (as of 2026-09-27)

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.

• 1213544 (diversion): -12.8 cfs (9% of that reach's correction)
• CANON CITY WATER WORKS (diversion): -12.8 cfs (9% of that reach's correction)
• BACK WASH STILLING POND (diversion): -12.8 cfs (9% of that reach's correction)
• SETTLING POND A (diversion): -12.8 cfs (9% of that reach's correction)
• BACK WASH RECOVERY POND (diversion): -12.8 cfs (9% of that reach's correction)
• CANON CITY & OIL CREEK (diversion): -12.8 cfs (9% of that reach's correction)
• CANON CITY MILL DITCH (diversion): -12.8 cfs (9% of that reach's correction)
• GRAVESTOCK DITCH (diversion): -12.8 cfs (9% of that reach's correction)
• OLD CANON CITY WW INTAKE (diversion): -12.8 cfs (9% of that reach's correction)
• FRUITLAND DITCH (diversion): -12.8 cfs (9% of that reach's correction)

Source Independent agency measurement · fetched 2026-10-16 · verify at NRCS report generator ↗ Source Our computation, scored against a reference · NRCS forecast, graded here against the gage record

Snow-water equivalent, WY2027

A trace of snow at 1 of 1 sites (0.2 in of water at most); the median for the date is zero, so there is no percent to show yet. The snow year begins in October. The new water year began October 1; the chart fills in a day at a time as NRCS publishes each reading.

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 (2008–2026)

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 6 of the last 19 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.

The snow never came: 2011, 2018, 2022, 2023, 2025, 2026. The snow left early: 2020.

Computed by this site from 1 SNOTEL site’ full daily records (NRCS AWDB, back to 2008). 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.

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 10th-driest week 39 in 137 years of record at ARKANSAS RIVER AT CANON CITY (as of 2026-09-21; this week’s flow sits at the 7th 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, Fremont County is 87% in D3 extreme drought (2026-10-13). The law agrees: the most senior active call leaves 100% of this district’s decreed flow rights junior to the calling right this week.

Every year since 1888, week by week

Each thin row is a year at ARKANSAS RIVER AT CANON CITY; 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 7.4 percentile points; next closest 1931 (11.4), 1902 (11.7)). 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 Fremont, Pueblo, Teller 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 2005 — 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 (1018 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 1991, federal crop insurance has paid $3,076,450 in drought-caused claims across Fremont, Pueblo, Teller counties — 6.4% of all insured crop losses there. The worst year was 2012 ($356,114).

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 (1,826 rights across 138 years of shared record), colored by that year’s wetness from the barcode above. Here the correlation is -0.09 — 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 ↗

18 systems touch this district (18 community systems reporting 56,543 people served, a figure that counts a wholesaler's customers twice); none carries an open health-based violation on EPA's record.

and 10 more; the full directory filters by district.

Instream-flow rights held by the state

Source Register of another agency · fetched 2026-10-11 · verify at CWCB instream flow program ↗

35 reaches over 215.6 miles and 6 natural lake levels, held by the Colorado Water Conservation Board so that water stays in the stream. Every reach, with its schedule and case →

• Badger Creek, 16.0 mi: 2.5 (4/1 - 8/31), 2 (9/1 - 10/31) cfs (appropriated 2007, 07CW0117) · dossier
• Currant Creek, 15.8 mi: 2 (4/1 - 10/31), 1.4 (11/1 - 3/31) cfs (appropriated 2004, 04CW0080) · dossier
• Badger Creek, 14.4 mi: 3 (1/1 - 12/31) cfs (appropriated 1974, 74W4205) · dossier
• South Hardscrabble Creek, 12.0 mi: 1.5 (1/1 - 12/31) cfs (appropriated 1976, 76W4434) · dossier
• Eightmile Creek, 10.9 mi: 1.1 (7/15 - 10/14), 1.1 (4/1 - 5/14), 0.65 (10/15 - 3/31), 2.5 (5/15 - 7/14) cfs (appropriated 1998, 98CW0157) · dossier
• Thirtyone Mile Creek, 10.1 mi: 1 (4/15 - 5/14), 0.5 (5/15 - 10/31), 0.35 (11/1 - 4/14) cfs (appropriated 2004, 04CW0087) · dossier

and 35 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 1860-05-01 to 2023-12-28. Of the 20 structures with a yield estimate, the median one’s senior right was in priority 62% of a median irrigation season and 10% in a dry one. 25 abandonment screens and 163 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: 2502 across 1967 structure(s); 337 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: 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.

Why diversions stopped — call-based explanations

Sustained diversion stops matched to senior administrative calls.

• O'BRIEN DITCH (4 MILE) (1200528) DWR↗☆ stopped 2025-10-08 (22+ days) — call at CANON HEIGHTS DITCH curtailing 100% of its decreed rate [heuristic-strong]
• PLEASANT VALLEY DITCH (1200500) DWR↗☆ stopped 2025-09-30 (31+ days) — call at MARTIN DITCH curtailing 100% of its decreed rate [heuristic-strong]
• ROSEMONT RES PIPELINE (1200538) DWR↗☆ stopped 2025-08-26 (7+ days) — call at CHILILI DITCH curtailing 100% of its decreed rate [heuristic-partial]
• TITSWORTH DITCH (1200531) DWR↗☆ stopped 2025-08-15 (8+ days) — call at HARDSCRABBLE DITCH curtailing 100% of its decreed rate [heuristic-strong]
• WAFFORD DITCH (1200532) DWR↗☆ stopped 2025-07-10 (5+ days) — call at LEWELLING-MCCORMICK curtailing 100% of its decreed rate [heuristic-strong]
• O'BRIEN DITCH (4 MILE) (1200528) DWR↗☆ stopped 2025-07-06 (59+ days) — call at LEWELLING-MCCORMICK curtailing 100% of its decreed rate [heuristic-strong]
• ADAMS DITCH (4 MILE CRK) (1200527) DWR↗☆ stopped 2025-07-02 (63+ days) — call at TITSWORTH DITCH curtailing 100% of its decreed rate [heuristic-strong]
• WATSON DITCH NO 1 (1200520) DWR↗☆ stopped 2025-06-23 (71+ days) — call at HOEHNE DITCH curtailing 100% of its decreed rate [heuristic-strong]
• MARCOTT DITCH (1200522) DWR↗☆ stopped 2025-06-22 (71+ days) — call at HOEHNE DITCH curtailing 100% of its decreed rate [heuristic-strong]
• HOLE IN THE GROUND DITCH (1200526) DWR↗☆ stopped 2025-06-22 (72+ days) — call at HOEHNE DITCH curtailing 100% of its decreed rate [heuristic-strong]
• A L SMITH DITCH (1200556) DWR↗☆ stopped 2025-06-22 (60+ days) — call at HOEHNE DITCH curtailing 100% of its decreed rate [heuristic-strong]
• GARDEN PARK DITCH (1200529) DWR↗☆ stopped 2025-06-17 (79+ days) — call at PULASKI 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.

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 ~1970 — idleness that begins before then may be unreported use, not nonuse (flagged † below).

• 1200674 DWR↗☆ (1908-06-15, 1.5 cfs decreed): last active 1916 — 109 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1970) -- early absence of record is weak evidence of nonuse
• FIRST LEON DITCH (1200524) DWR↗☆ (1874-06-14, 1.2 cfs decreed): last active 1927 — 98 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1970) -- early absence of record is weak evidence of nonuse
• PAUL WALTON DITCH (1200837) DWR↗☆ (1911-04-01, 2.7 cfs decreed): last active 1939 — 86 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1970) -- early absence of record is weak evidence of nonuse
• HILLTOP DITCH (1201045) DWR↗☆ (1937-10-31, 4.1 cfs decreed): last active 1943 — 82 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1970) -- early absence of record is weak evidence of nonuse
• STATE DITCH NO 1 (1200559) DWR↗☆ (1930-06-01, 2.0 cfs decreed): last active 1958 — 67 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1970) -- early absence of record is weak evidence of nonuse
• KENNEDY DITCH NO 1 (1200775) DWR↗☆ (1912-04-13, 4.0 cfs decreed): last active 1970 — 55 years idle
• PHELPS DITCH (1200507) DWR↗☆ (1882-05-31, 2.0 cfs decreed): last active 1972 — 53 years idle
• FIBERBOARD PROD WELL 1 (1205000) DWR↗☆ (1870-05-31, 0.3 cfs decreed): last active 1972 — 53 years idle
• UETLEY DITCH (1200629) DWR↗☆ (1871-10-01, 0.5 cfs decreed): last active 1973 — 52 years idle
• GRAVESTOCK DITCH (1200668) DWR↗☆ (1874-04-01, 1.0 cfs decreed): last active 1973 — 52 years idle

Compliance screens (163 advisory flags)

Screened 269 of 1967 structures with rights (313 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.

• KITTRIDGE DITCH NO 1 (1200521) DWR↗☆: Observed p99 daily rate 763.0 cfs (max 763.0) exceeds total decreed absolute 4.3 cfs across 12702 recorded day(s).
• ST JOHNS TUNNEL (1200539) DWR↗☆: Observed p99 daily rate 257.1 cfs (max 411.5) exceeds total decreed absolute 6.4 cfs across 30981 recorded day(s).
• CANON CITY HYDRAULIC (1200505) DWR↗☆: Observed p99 daily rate 79.4 cfs (max 548.0) exceeds total decreed absolute 77.0 cfs across 66241 recorded day(s).
• COLO LIGHT & POWER P/L (1200506) DWR↗☆: Observed p99 daily rate 64.0 cfs (max 168.0) exceeds total decreed absolute 54.4 cfs across 60365 recorded day(s).
• BURROUGHS DITCH (1200651) DWR↗☆: Observed p99 daily rate 51.0 cfs (max 75.0) exceeds total decreed absolute 1.0 cfs across 18002 recorded day(s).
• UNION DITCH (1200835) DWR↗☆: Observed p99 daily rate 48.0 cfs (max 78.0) exceeds total decreed absolute 46.8 cfs across 68902 recorded day(s).
• CANON CITY & OIL CREEK (1200509) DWR↗☆: Observed p99 daily rate 31.3 cfs (max 807.1) exceeds total decreed absolute 24.7 cfs across 77633 recorded day(s).
• DAVIS DITCH (1200656) DWR↗☆: Observed p99 daily rate 22.0 cfs (max 22.0) exceeds total decreed absolute 2.2 cfs across 15978 recorded day(s).
• CANON CITY WATER WORKS (1200503) DWR↗☆: Observed p99 daily rate 21.5 cfs (max 39.2) exceeds total decreed absolute 4.7 cfs across 69395 recorded day(s).
• FREMONT COUNTY DITCH (1200510) DWR↗☆: Observed p99 daily rate 20.1 cfs (max 62.5) exceeds total decreed absolute 17.0 cfs across 57735 recorded day(s).

Seniority (top structures by decreed rate)

Recent inventory & legal-document changes

• 2026-10-10 — call set: FORT LYON CANAL (39703)
• 2026-10-10 — call set: JOHN MARTIN RESERVOIR (39705)
• 2026-10-10 — call released: 39701
• 2026-10-10 — call released: 39694
• 2026-10-09 — call set: FORT LYON CANAL (39701)
• 2026-10-09 — call released: 39660
• 2026-10-09 — call released: 39675
• 2026-10-09 — call released: 39659

Water-court filings this month (division-wide)

6 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 (45 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.

Active substitute water supply plans in this district

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

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 2026-10-17 · 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 8,420 sampling stations in this district's watersheds (Upper Arkansas 11020002, 50% of the district; Arkansas Headwaters 11020001, 49% of the district), of which 241 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: Colorado Dept. of Public Health & Environment-WQCD (123), Colorado River Watch (53), USGS Colorado Water Science Center (47). Most-sampled groups: Physical, Inorganics, Major, Metals, Nutrient, Inorganics, Major, Non-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 ↗

18 community systems touch this district. None carries an open health-based violation on EPA's record; 1 is listed by EPA as serious violator. EPA sampled 3 of them for PFAS in 2023–25; none had PFOA or PFOS at or above the 2024 limit.

and 8 more; the full directory filters by district.

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.