Hydrohistorian
Arkansas: Headwaters to Salida
Who may take water from the Arkansas: Headwaters to Salida, 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.
Arkansas: Headwaters to Salida on the ground — the ditches, wells, reservoirs and gages of Water District 11 · clicktap anything for its record
The well-permit cells in view, as a table
Each row is one ~1-mile cell (0.02°) with the permits the file spots inside it, split into water-supply permits and monitoring holes (DWR’s two monitoring categories: drilled to look at the water, not to pump it). These are permits, not wells: a permit is a piece of paper, and the file does not say which were drilled. Spotting is the file’s own, about a mile at best, which is why the cells are no finer.
| Lat | Lon | Water-supply permits | Monitoring holes |
|---|
Browse this district’s ditches, gages, reservoirs, wells and springs as a list.
The Arkansas River is critically low for late September -- 3% of normal flow, its 3rd-driest such week in 117 years of record. 5 calls stand against it right now; the most senior right calling dates to 1872. DWR's statements do not settle whether 15 more calls reach it. This year's runoff outlook, issued 2026-06-01, called for 35% of normal.
Schematic
Historical
Evolution of the network
Trends
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 33 ranked gages are running at a median 86% of their own long-term norm for this window — 20 below a typical year, 13 at or above. Driest relative to its record: CHARLES H. BOUSTEAD TUNNEL, ranking 1st lowest of 55 years.
How this comparison is made
Each gage's mean flow over the 3 days either side of 2026-09-27, 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 2026-10-11 19:54 from 62 gage(s) with cached period-of-record data. The series is each gage's annual mean flow in cfsCubic feet per second, a rate of flow. One cfs running for a day is about 2 acre-feet. (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 62 gages with enough record, 1 is trending down and 1 up, and 3 carry a detected shift. The clearest is Homestake-Otero Pumps near Granite, its annual mean flow changing +42.00 cfs per decade (+94.8% of its median annual flow) over 8 years (p=0.0094). The other 55 show no clear signal either way. 3 transbasin gages meter imported or exported water — marked ⇆ below and kept out of these counts, because that flow is an operator's decision, not the basin's hydrology (all transbasin diversions).
Drought history, cost, and the four-century context moved to the Drought tab.
| Gage | Trend | Change / decade cfs · % of median annual flow | Significance | Years | Changepoint |
|---|---|---|---|---|---|
|
▸
⇆
Busk-Ivanhoe Tunnel BUSTUNCO |
↓ decreasing | -0.90 cfs -13.5% | p<0.001 | 61 | ~1986 |
|
▸
Homestake-Otero Pumps near Granite HOMOTECO |
↑ increasing | +42.00 cfs +94.8% | p=0.009 | 8 | — |
|
▸
⚠️
⇆
Charles H. Boustead Tunnel BOUTUNCO |
↑ increasing | +6.14 cfs +8.2% | p=0.026 | 54 | — |
|
▸
⚠️
Lake Fork Creek below Sugar Loaf Dam near Leadville LFCBSLCO |
↓ decreasing | -8.60 cfs -58.1% | p=0.035 | 56 | ~1986 |
|
▸
⇆
Columbine Ditch near Fremont Pass COLDITCO |
no clear trend | +0.08 cfs +3.5% | p=0.102 | 75 | ~1964 |
|
▸
Arkansas River at Granite ARKGRNCO |
no clear trend | +4.97 cfs +1.4% | p=0.203 | 114 | ~1945 |
|
▸
⚠️
Larkspur Ditch at Marshall Pass LARDITCO |
no clear trend | +0.02 cfs | p=0.562 | 57 | ~2005 |
⚠️ 3 gages 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.
55 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: East Fork Arkansas River at US Highway 24, near Leadville (79 yr, increasing, suspect). Those are reconstructions, not measurements — each gage's page shows both.
How the measurement network itself changed
This basin was not always measured the way it is today — the API-era record is dense and recent, the early record sparse. 42 gage(s) and 153 structure(s) report in 2026, but structure reporting only reached half its modern level around ~1973. 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) |
|---|---|---|
| 1900s | 1 | 0 |
| 1910s | 8 | 0 |
| 1920s | 4 | 0 |
| 1930s | 4 | 0 |
| 1940s | 4 | 0 |
| 1950s | 14 | 1 |
| 1960s | 17 | 0 |
| 1970s | 25 | 110 |
| 1980s | 22 | 110 |
| 1990s | 26 | 170 |
| 2000s | 28 | 188 |
| 2010s | 36 | 212 |
| 2020s | 40 | 140 |
Mass-balance (network closure) trend
Structure divrec-history backfill coverage as of the last check: 3% of 4628 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 (4327 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.
- ARKANSAS RIVER AT BUENA VISTA, CO.: reach shifted from +959 cfs to +792 cfs summer mean (more losing, p=0.027, 23 yr) [mountain crystalline canyon: minimal groundwater storage -- large or shifting unaccounted losses here are more consistent with data/measurement issues or unmodeled plumbing than with aquifer exchange] [11 alluvial wells within 2 mi of the gage; pooled water table +1.3 ft (1971–2003, no_trend)]
- ARKANSAS RIVER AT GRANITE, CO.: reach shifted from +700 cfs to +266 cfs summer mean (more losing, p=0.000, 77 yr) [mountain crystalline canyon: minimal groundwater storage -- large or shifting unaccounted losses here are more consistent with data/measurement issues or unmodeled plumbing than with aquifer exchange] [measurement-evolution caution: this shift co-moves with the growth of the gage/metering network (rho=-0.47) -- part of it may be unaccounted water becoming accounted, not hydrologic change] [2 alluvial wells within 2 mi of the gage; pooled water table -0.4 ft (1972–1994, no_trend)]
- SOUTH ARKANSAS RIVER NEAR SALIDA, CO.: reach shifted from -47 cfs to -15 cfs summer mean (more gaining, p=0.010, 18 yr) [alluvial valley: real alluvial aquifer -- a decades-long shift toward losing is the classic signature of alluvial pumping and urbanization] [measurement-evolution caution: this shift co-moves with the growth of the gage/metering network (rho=0.62) -- part of it may be unaccounted water becoming accounted, not hydrologic change] [9 alluvial wells within 2 mi of the gage; pooled water table +1.3 ft (1990–2009, no_trend)]
- ARKANSAS RIVER AT SALIDA, CO.: reach shifted from +1277 cfs to -54 cfs summer mean (more losing, p=0.002, 77 yr) [alluvial valley: real alluvial aquifer -- a decades-long shift toward losing is the classic signature of alluvial pumping and urbanization] [measurement-evolution caution: this shift co-moves with the growth of the gage/metering network (rho=-0.63) -- part of it may be unaccounted water becoming accounted, not hydrologic change] [19 alluvial wells within 2 mi of the gage; pooled water table +4.2 ft (1971–2025, decreasing)]
- CLEAR CREEK ABOVE CLEAR CREEK RESERVOIR, CO.: reach shifted from -686 cfs to -426 cfs summer mean (more gaining, p=0.001, 75 yr) [mountain crystalline canyon: minimal groundwater storage -- large or shifting unaccounted losses here are more consistent with data/measurement issues or unmodeled plumbing than with aquifer exchange] [2 alluvial wells within 2 mi of the gage; pooled water table -0.4 ft (1972–1994, no_trend)]
- LAKE FORK CREEK BELOW SUGAR LOAF DAM NEAR LEADVILLE: reach shifted from +34 cfs to -116 cfs summer mean (more losing, p=0.000, 52 yr) [alluvial valley: real alluvial aquifer -- a decades-long shift toward losing is the classic signature of alluvial pumping and urbanization] [measurement-evolution caution: this shift co-moves with the growth of the gage/metering network (rho=-0.63) -- part of it may be unaccounted water becoming accounted, not hydrologic change]
Groundwater now has its own tab: 221 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 1949, click-to-chart histories.
Cross-gage pattern fingerprint
Over the 92-year window with full coverage (1935–2026), the dominant shared pattern across 3 gage(s) explains 61% of year-to-year variance (almost certainly a basin-wide climate/snowpack driver).
TWITUNCO doesn't move with that shared pattern -- a real, localized signal (a new diversion, land-use change, or a gage-specific data problem) worth a closer look, not necessarily noise.
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.
- 1113962 (diversion): +3.4 cfs (6% of that reach's correction)
- 1113469 (diversion): +3.4 cfs (6% of that reach's correction)
- SALIDA RIVERSIDE PARK IRRG SYSTEM (diversion): +3.4 cfs (6% of that reach's correction)
- SALIDA MARVIN PARK IRRG SYSTEM (diversion): +3.4 cfs (6% of that reach's correction)
- WILLARD SPRING PIPELINE (return): +3.4 cfs (6% of that reach's correction)
- D&RGW SALIDA STATION (diversion): +3.4 cfs (6% of that reach's correction)
- 1113343 (diversion): +3.4 cfs (6% of that reach's correction)
- 1113345 (diversion): +3.4 cfs (6% of that reach's correction)
- 1114036 (diversion): +3.4 cfs (6% of that reach's correction)
- 1113474 (diversion): +3.4 cfs (6% of that reach's correction)
Data provenance & quality
Where these numbers come from and how far they can be trusted. Grade C (3/6 points) — the components below are the finding; the letter alone is not. Sources: DWR HydroBase snapshot HydroBase_CO_20260928 (imported 2026-10-04) for history, plus the CDSS REST API for current conditions.
| Check | State | What was measured |
|---|---|---|
| gage freshness | stale | newest gage reading is 14 day(s) old (target 7) |
| diversion record | expected-lag | newest diversion record is 346 day(s) old (DWR publishes ~1 year in arrears) |
| structure coverage | sparse | 3% of schematic structures have data |
Independent check: PASS — 100.0000% agreement across 133,957 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 — 99.82% day-level agreement with USGS's own published records for the same gages, across 29 co-listed station(s) and 281,373 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.
62 gage(s) / 712,374 daily values (1909-10-01–2026-09-27); 423 structure(s) with diversion records; 1491 with decreed rights. Methodology has not yet had independent expert review — treat every figure as an advisory screen, not an administrative or legal conclusion.
Groundwater
Source DWR administrative record · verify at DWR groundwater wells ↗ Source DWR administrative record · verify at DWR well permits ↗
3,234 water-level measurements across 221 monitored well(s) — 142 alluvial, 0 bedrock — plus 3 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 23 well(s) with enough record for a trend test: 9 declining, 1 rising.
| Fastest-declining wells | Setting | ft / decade | Span | p |
|---|---|---|---|---|
| ▸ SC01108018AAA | unknown | -12.48 | 18 yr | 0.0 |
| ▸ NA05000814DCB | alluvial | -4.89 | 24 yr | 0.0001 |
| ▸ SC01507834CCD | alluvial | -2.32 | 36 yr | 0.0 |
| ▸ SC01407830DAA | unknown | -2.24 | 54 yr | 0.0 |
| ▸ NA05100833AAD | alluvial | -2.06 | 44 yr | 0.0 |
| ▸ NA05000835AAD | alluvial | -1.89 | 54 yr | 0.0001 |
| ▸ NA05000733DAB | alluvial | -1.87 | 45 yr | 0.0007 |
| ▸ SC00908032ACD | alluvial | -0.47 | 44 yr | 0.0055 |
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.
ARKANSAS RIVER AT BUENA VISTA, CO.: 11 alluvial well(s) nearby; pooled water table +1.3 ft (1971–2003, no_trend, p=0.4573)
ARKANSAS RIVER AT GRANITE, CO.: 2 alluvial well(s) nearby; pooled water table -0.4 ft (1972–1994, no_trend, p=0.8267)
SOUTH ARKANSAS RIVER NEAR SALIDA, CO.: 9 alluvial well(s) nearby; pooled water table +1.3 ft (1990–2009, no_trend, p=0.8711). Glover screen: 0.3 cfs of nearby metered alluvial pumping → est. lagged depletion 0.2–0.3 cfs (uncalibrated T/S ranges; flagged for SPDSS calibration, AWAS cross-check, and expert review — DWR's AWAS is the authority).
ARKANSAS RIVER AT SALIDA, CO.: 19 alluvial well(s) nearby; pooled water table +4.2 ft (1971–2025, decreasing, p=0.0001). Glover screen: 0.3 cfs of nearby metered alluvial pumping → est. lagged depletion 0.3–0.3 cfs (uncalibrated T/S ranges; flagged for SPDSS calibration, AWAS cross-check, and expert review — DWR's AWAS is the authority).
CLEAR CREEK ABOVE CLEAR CREEK RESERVOIR, CO.: 2 alluvial well(s) nearby; pooled water table -0.4 ft (1972–1994, no_trend, p=0.8267)
LAKE FORK CREEK BELOW SUGAR LOAF DAM NEAR LEADVILLE: 1 alluvial well(s) nearby
LAKE CREEK BELOW TWIN LAKES RESERVOIR: 1 alluvial well(s) nearby
CHALK CREEK AT NATHROP: 5 alluvial well(s) nearby; pooled water table -1.3 ft (1972–2025, decreasing, p=0.0269)
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.
59% are constructed wells; 9% tie to a decreed structure. A permit is permission to drill, not a water right; most here are exempt household wells. More in three things called “well”, or turn on the Well permits chip on the map above to see where they sit.
Permits issued here, by year
10,145 located water-supply permits with an issue date, 1908 to 2026; half of them had been issued by 1999, and the busiest year was 2002 with 365. The district’s 837 monitoring holes are counted apart: they are drilled to look, not to pump. A permit is not a well, and the year is the date the paper was issued, not a drilling date. The 13,158 above counts every permit on file here; 2,176 of them have no usable location or no issue date and are not in this chart.
water-supply permits issued that year monitoring holes, when shown 1 issued before 1950 is in the table, not the bars
The counts by year, as a table
| Year | Issued | Monitoring holes | Water-supply | Issued through that year |
|---|---|---|---|---|
| 1908 | 1 | 0 | 1 | 1 |
| 1953 | 7 | 0 | 7 | 8 |
| 1954 | 22 | 0 | 22 | 30 |
| 1955 | 16 | 0 | 16 | 46 |
| 1956 | 27 | 0 | 27 | 73 |
| 1957 | 26 | 0 | 26 | 99 |
| 1958 | 7 | 0 | 7 | 106 |
| 1959 | 18 | 0 | 18 | 124 |
| 1960 | 26 | 0 | 26 | 150 |
| 1961 | 6 | 0 | 6 | 156 |
| 1962 | 6 | 0 | 6 | 162 |
| 1963 | 21 | 0 | 21 | 183 |
| 1964 | 17 | 0 | 17 | 200 |
| 1965 | 21 | 0 | 21 | 221 |
| 1966 | 20 | 0 | 20 | 241 |
| 1967 | 12 | 0 | 12 | 253 |
| 1968 | 14 | 0 | 14 | 267 |
| 1969 | 17 | 0 | 17 | 284 |
| 1970 | 23 | 0 | 23 | 307 |
| 1971 | 41 | 0 | 41 | 348 |
| 1972 | 296 | 0 | 296 | 644 |
| 1973 | 177 | 0 | 177 | 821 |
| 1974 | 67 | 0 | 67 | 888 |
| 1975 | 42 | 0 | 42 | 930 |
| 1976 | 65 | 0 | 65 | 995 |
| 1977 | 131 | 0 | 131 | 1,126 |
| 1978 | 205 | 0 | 205 | 1,331 |
| 1979 | 294 | 0 | 294 | 1,625 |
| 1980 | 167 | 0 | 167 | 1,792 |
| 1981 | 202 | 3 | 199 | 1,994 |
| 1982 | 114 | 0 | 114 | 2,108 |
| 1983 | 137 | 0 | 137 | 2,245 |
| 1984 | 107 | 0 | 107 | 2,352 |
| 1985 | 112 | 0 | 112 | 2,464 |
| 1986 | 120 | 21 | 99 | 2,584 |
| 1987 | 113 | 9 | 104 | 2,697 |
| 1988 | 104 | 5 | 99 | 2,801 |
| 1989 | 99 | 7 | 92 | 2,900 |
| 1990 | 114 | 24 | 90 | 3,014 |
| 1991 | 140 | 31 | 109 | 3,154 |
| 1992 | 146 | 6 | 140 | 3,300 |
| 1993 | 189 | 9 | 180 | 3,489 |
| 1994 | 285 | 32 | 253 | 3,774 |
| 1995 | 284 | 14 | 270 | 4,058 |
| 1996 | 336 | 24 | 312 | 4,394 |
| 1997 | 368 | 56 | 312 | 4,762 |
| 1998 | 380 | 38 | 342 | 5,142 |
| 1999 | 343 | 62 | 281 | 5,485 |
| 2000 | 309 | 36 | 273 | 5,794 |
| 2001 | 304 | 14 | 290 | 6,098 |
| 2002 | 393 | 28 | 365 | 6,491 |
| 2003 | 345 | 12 | 333 | 6,836 |
| 2004 | 201 | 15 | 186 | 7,037 |
| 2005 | 202 | 13 | 189 | 7,239 |
| 2006 | 208 | 8 | 200 | 7,447 |
| 2007 | 270 | 39 | 231 | 7,717 |
| 2008 | 220 | 64 | 156 | 7,937 |
| 2009 | 213 | 73 | 140 | 8,150 |
| 2010 | 128 | 11 | 117 | 8,278 |
| 2011 | 100 | 9 | 91 | 8,378 |
| 2012 | 125 | 11 | 114 | 8,503 |
| 2013 | 125 | 12 | 113 | 8,628 |
| 2014 | 159 | 25 | 134 | 8,787 |
| 2015 | 120 | 7 | 113 | 8,907 |
| 2016 | 165 | 20 | 145 | 9,072 |
| 2017 | 181 | 13 | 168 | 9,253 |
| 2018 | 201 | 8 | 193 | 9,454 |
| 2019 | 244 | 15 | 229 | 9,698 |
| 2020 | 233 | 10 | 223 | 9,931 |
| 2021 | 264 | 8 | 256 | 10,195 |
| 2022 | 191 | 9 | 182 | 10,386 |
| 2023 | 173 | 16 | 157 | 10,559 |
| 2024 | 166 | 4 | 162 | 10,725 |
| 2025 | 140 | 12 | 128 | 10,865 |
| 2026 | 117 | 4 | 113 | 10,982 |
Every district in the file on one scale · the whole file, one year at a time · Plate 4 of the Driller’s Atlas.
What drillers reached, township by township
38 PLSS townships here where at least 5 water-supply permits naming the same aquifer filed a depth (9,018 permits in all; the 24 most-drilled are drawn, every one is in the table). Each column is one township, six miles square, on one scale to 600 ft below ground: a faint lane spans the 10th to 90th percentile of where the permits naming that aquifer stopped, the solid band their screens, the tick the median. This is the permit file’s view of the ground — the aquifer is the name the driller wrote, the band is where those holes ended — not a geologic map, and a township is as fine as it gets. Monitoring holes are left out. 5 of these townships straddle a district line and are filed here because most of their permits are.
1,082
805
714
676
620
598
535
481
414
408
384
345
330
302
202 · 89% here
174
131
122
98
82 · 51% here
69
62
62
56
unnamed alluvium faint = where the permits naming it stopped (10th–90th pct) · solid = their screens · tick = median · ft below ground as filed
Every township here, as a table
| Township | Share of its permits in this district | Aquifer named | Permits with a depth | Drilled depth p10 / p50 / p90, ft | Screen top p10 / p50 / p90, ft | Screen bottom p10 / p50 / p90, ft |
|---|---|---|---|---|---|---|
| T14S R78W 6th PM | 100% | unnamed | 1,074 | 32 / 65 / 160 | 20 / 46 / 120 | 35 / 80 / 180 |
| T14S R78W 6th PM | 100% | alluvium | 7 | 92 / 120 / 120 | 48 / 60 / 80 | 88 / 100 / 120 |
| T50N R8E New Mexico PM | 100% | unnamed | 770 | 50 / 120 / 324 | 25 / 65 / 220 | 60 / 136 / 325 |
| T50N R8E New Mexico PM | 100% | alluvium | 35 | 100 / 145 / 353 | 40 / 105 / 259 | 100 / 155 / 328 |
| T14S R79W 6th PM | 100% | unnamed | 706 | 42 / 103 / 220 | 30 / 76 / 166 | 55 / 110 / 222 |
| T14S R79W 6th PM | 100% | alluvium | 6 | 27 / 150 / 225 | — | — |
| T50N R9E New Mexico PM | 100% | unnamed | 666 | 42 / 124 / 250 | 25 / 70 / 176 | 60 / 141 / 256 |
| T50N R9E New Mexico PM | 100% | alluvium | 10 | 100 / 150 / 273 | 60 / 100 / 194 | 100 / 160 / 282 |
| T49N R8E New Mexico PM | 100% | unnamed | 605 | 32 / 80 / 300 | 20 / 43 / 187 | 40 / 100 / 346 |
| T49N R8E New Mexico PM | 100% | alluvium | 14 | 100 / 150 / 482 | 48 / 245 / 304 | 92 / 370 / 504 |
| T49N R9E New Mexico PM | 97% | unnamed | 579 | 30 / 81 / 320 | 20 / 60 / 220 | 40 / 140 / 352 |
| T49N R9E New Mexico PM | 97% | alluvium | 19 | 20 / 125 / 584 | 41 / 160 / 304 | 110 / 290 / 468 |
| T15S R78W 6th PM | 100% | unnamed | 514 | 48 / 114 / 339 | 35 / 70 / 239 | 60 / 121 / 340 |
| T15S R78W 6th PM | 100% | alluvium | 21 | 100 / 180 / 350 | 60 / 160 / 236 | 100 / 240 / 336 |
| T9S R80W 6th PM | 100% | unnamed | 467 | 56 / 140 / 221 | 45 / 102 / 172 | 79 / 143 / 227 |
| T9S R80W 6th PM | 100% | alluvium | 14 | 104 / 144 / 218 | 57 / 88 / 165 | 100 / 140 / 225 |
| T15S R79W 6th PM | 99% | unnamed | 410 | 44 / 130 / 400 | 29 / 96 / 300 | 49 / 145 / 440 |
| T13S R79W 6th PM | 100% | unnamed | 402 | 73 / 148 / 350 | 46 / 110 / 290 | 80 / 152 / 369 |
| T10S R80W 6th PM | 100% | unnamed | 373 | 40 / 80 / 169 | 22 / 50 / 138 | 44 / 83 / 178 |
| T10S R80W 6th PM | 100% | alluvium | 11 | 80 / 122 / 199 | 37 / 65 / 152 | 78 / 106 / 199 |
| T11S R80W 6th PM | 100% | unnamed | 321 | 45 / 145 / 550 | 33 / 150 / 444 | 55 / 207 / 560 |
| T11S R80W 6th PM | 100% | alluvium | 24 | 81 / 340 / 499 | 42 / 291 / 418 | 81 / 346 / 498 |
| T50N R7E New Mexico PM | 100% | unnamed | 312 | 41 / 125 / 440 | 25 / 82 / 260 | 50 / 125 / 440 |
| T50N R7E New Mexico PM | 100% | alluvium | 18 | 94 / 242 / 530 | 40 / 140 / 230 | 100 / 180 / 560 |
| T51N R8E New Mexico PM | 100% | unnamed | 281 | 70 / 236 / 460 | 40 / 148 / 340 | 99 / 245 / 466 |
| T51N R8E New Mexico PM | 100% | alluvium | 21 | 240 / 300 / 400 | 165 / 225 / 348 | 246 / 280 / 400 |
| T8S R80W 6th PM | 89% | unnamed | 200 | 42 / 90 / 195 | 30 / 63 / 140 | 48 / 96 / 210 |
| T15S R80W 6th PM | 100% | unnamed | 172 | 40 / 126 / 245 | 25 / 104 / 201 | 52 / 139 / 242 |
| T12S R79W 6th PM | 100% | unnamed | 131 | 38 / 120 / 262 | 24 / 104 / 204 | 47 / 152 / 264 |
| T13S R78W 6th PM | 99% | unnamed | 122 | 89 / 192 / 357 | 55 / 116 / 240 | 87 / 212 / 362 |
| T10S R79W 6th PM | 100% | unnamed | 96 | 70 / 164 / 340 | 49 / 100 / 255 | 84 / 170 / 342 |
| T48N R8E New Mexico PM | 51% | unnamed | 79 | 30 / 128 / 342 | 28 / 85 / 290 | 66 / 145 / 365 |
| T51N R7E New Mexico PM | 100% | unnamed | 67 | 48 / 130 / 331 | 20 / 55 / 185 | 56 / 135 / 325 |
| T11S R81W 6th PM | 99% | unnamed | 59 | 39 / 73 / 300 | 27 / 48 / 185 | 42 / 85 / 300 |
| T8S R79W 6th PM | 98% | unnamed | 62 | 40 / 54 / 148 | 25 / 41 / 124 | 42 / 64 / 154 |
| T49N R7E New Mexico PM | 100% | unnamed | 53 | 28 / 85 / 281 | 19 / 40 / 128 | 32 / 88 / 300 |
| T50N R6E New Mexico PM | 100% | unnamed | 47 | 61 / 180 / 275 | 40 / 110 / 177 | 91 / 180 / 275 |
| T51N R9E New Mexico PM | 98% | unnamed | 42 | 58 / 295 / 500 | 42 / 190 / 380 | 135 / 300 / 500 |
| T11S R79W 6th PM | 100% | unnamed | 32 | 18 / 44 / 289 | 22 / 61 / 234 | 41 / 92 / 414 |
| T48N R7E New Mexico PM | 97% | unnamed | 26 | 60 / 80 / 332 | 20 / 45 / 206 | 60 / 80 / 326 |
| T14S R77W 6th PM | 100% | unnamed | 22 | 43 / 170 / 543 | 23 / 115 / 276 | 44 / 180 / 555 |
| T9S R81W 6th PM | 100% | unnamed | 22 | 56 / 105 / 236 | 36 / 91 / 188 | 63 / 155 / 280 |
| T9S R79W 6th PM | 100% | unnamed | 18 | 29 / 42 / 413 | 22 / 39 / 434 | 34 / 53 / 484 |
| T49N R6E New Mexico PM | 91% | unnamed | 10 | 39 / 127 / 200 | — | — |
| T51N R6E New Mexico PM | 100% | unnamed | 10 | 21 / 30 / 40 | 14 / 18 / 22 | 28 / 30 / 40 |
| T10S R81W 6th PM | 100% | unnamed | 8 | 34 / 50 / 80 | 18 / 43 / 60 | 33 / 63 / 80 |
| T12S R80W 6th PM | 100% | unnamed | 6 | 34 / 50 / 108 | — | — |
| T14S R80W 6th PM | 100% | unnamed | 6 | 96 / 135 / 296 | 49 / 90 / 224 | 104 / 160 / 309 |
| T15S R77W 6th PM | 92% | unnamed | 6 | 120 / 270 / 578 | 70 / 210 / 492 | 110 / 270 / 578 |
| T51N R5E New Mexico PM | 89% | unnamed | 5 | 187 / 350 / 424 | — | — |
These columns on the map · Plate 6 of the Driller’s Atlas.
The Driller’s Atlas · Plate 2 A cross-section nobody surveyed
Every permitted well within a few miles of the line, drawn from the ground to its drilled depth as the driller filed it. The bright part of each stroke is the perforated casing — where the well actually takes water — coloured by the aquifer named on the permit. Nobody arranged these; the aquifers arrange themselves.
The ground each well hangs from is a 1-km elevation model sampled at the point the permit was spotted, so the profile is real topography smoothed to about a kilometre — peaks are shaved, valleys filled a little — and the depths are the driller’s, measured down from that ground.
Hover or arrow through the strokes to read a well.
The same corridor as a table
| Miles from A | Wells drawn | Median depth (ft) | With a screen | Most-named aquifer | No depth filed | Ground, ft above sea level (median) |
|---|
Bins run from end A to end B of the line. “Most-named aquifer” is the family most often named on permits in the bin, with its count; permits naming no aquifer are the majority of the file and are not a family.
Reservoirs
Source DWR administrative record · verify at DWR structure records ↗
9 reservoir(s) with 17,935 storage measurement(s), 1949–2018. Basin storage as of 2018-04-30 (the record's own end — reservoir records publish ~annually): 103,958 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) | |
|---|---|---|---|---|---|
| ▸ BEAR LAKE (CHAFFEE CTY) MIN LEVEL (1103927) | 102,989 | 1979-10-31 | — | — | dossier → |
| ▸ TURQUOISE RESERVOIR (1103500) | 95,794 | 2018-01-23 | — | — | dossier → |
| ▸ TWIN LAKES RESERVOIR (1103503) | 80,503 | 1984-10-31 | — | — | dossier → |
| ▸ CLEAR CREEK RESERVOIR (1103504) | 8,164 | 2018-04-30 | — | — | dossier → |
| ▸ NORTH FORK RESERVOIR (1103300) | 583 | 2010-10-31 | — | — | dossier → |
| ▸ O'HAVER RESERVOIR (1103921) | 168 | 2010-09-30 | — | — | dossier → |
| ▸ COTTONWOOD LAKE (1104005) | 102 | 2010-10-31 | — | — | dossier → |
| ▸ RAINBOW LAKE (M COTTONWD CRK) (1103535) | 59 | 2010-10-31 | — | — | dossier → |
Snow and runoff
Source Independent agency measurement · fetched 2026-10-14 · 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 2 of 2 sites (0.3 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.
| SNOTEL site | Elev (ft) | SWE (in) | Median (in) | % of median | Typical peak |
|---|---|---|---|---|---|
| Brumley | 10570 | 0.1 | 0.0 | — | April 19 (11.8 in) |
| Saint Elmo | 10420 | 0.3 | 0.0 | — | April 9 (11.5 in) |
NRCS SNOTEL, daily. Sites are assigned to the district whose boundary contains them — the snow that feeds this district can also sit in a neighboring headwater district.
Two ways a snow year goes wrong (1981–2026)
A bad snow year here comes in two flavors (both called snow 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 46 winters the snow never came — the pack peaked below 80% of its median. In 0 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, 1992, 2002, 2004, 2012, 2026.
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 — Chalk Ck nr Nathrop
NRCS's final issue (2026-06-01) calls it even odds that at least 7 kAF arrives over 06-01 to 09-30 — 43% of a normal season; almost certainly at least 2, probably not more than 13. 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 70 replayed seasons (25% typical miss unadjusted vs 28% adjusted), so none is shown — NRCS’s own forecast, unadjusted, is the best April benchmark available for this river. Why we test →
| 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 |
|---|---|---|---|---|---|
| 2 | 5 | 7 | 10 | 13 | 17 |
Runoff outlook — Arkansas R at Salida
NRCS's final issue (2026-06-01) calls it even odds that at least 68 kAF arrives over 06-01 to 09-30 — 35% of a normal season; almost certainly at least 30, probably not more than 106. Our own record at this gage shows 56 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 88 replayed seasons (17% typical miss unadjusted vs 20% adjusted), so none is shown — NRCS’s own forecast, unadjusted, is the best April benchmark available for this river. Why we test →
| 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 |
|---|---|---|---|---|---|---|
| 30 | 53 | 68 | 83 | 106 | 197 | 56 |
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 — 74 seasons: the median miss of the 50% forecast is 17%, with a low bias of 10%, and the observed volume landed inside the stated 10–90% band 65% 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 46 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 72% 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).
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 2026-10-06 · verify at U.S. Drought Monitor ↗
Right now
This is the 3rd-driest week 39 in 117 years of record at ARKANSAS RIVER AT SALIDA, CO. (as of 2026-09-21; this week’s flow sits at the 3rd 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, Chaffee County is 75% in D4 exceptional drought (2026-10-06). The law agrees: the most senior active call leaves 92% of this district’s decreed flow rights junior to the calling right this week.
Every year since 1909, week by week
Each thin row is a year at ARKANSAS RIVER AT SALIDA, 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 11.6 percentile points; next closest 1931 (16.3), 2004 (17.0)). 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 Chaffee, Eagle, Lake, Saguache 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 (563 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
| Drought | Span | Weeks | Trough percentile | Flows recovered | Water table back |
|---|---|---|---|---|---|
| unnamed dry spell | 2025-09-29 → 2026-02-23 | 21 | 27th (2025-10-13) | not yet | — |
| the 2020-22 drought | 2021-03-15 → 2022-04-04 | 55 | 18th (2021-12-13) | 0 weeks | 3 yr (16 wells, 7 still below) |
| the 2018 drought | 2018-08-27 → 2019-05-27 | 39 | 5th (2018-12-03) | 2 weeks | 1 yr (12 wells, 3 still below) |
| the 2012-13 drought | 2012-08-13 → 2013-12-02 | 68 | 6th (2012-11-19) | 2 weeks | 2 yr (13 wells, 1 still below) |
| unnamed dry spell | 2004-08-16 → 2005-12-26 | 71 | 15th (2005-02-21) | 4 weeks | 4 yr (22 wells, 6 still below) |
| the 2002 drought | 2002-07-22 → 2004-02-23 | 83 | 2nd (2002-12-02) | 5 weeks | 6 yr (22 wells, 6 still below) |
| unnamed dry spell | 1990-04-30 → 1990-12-03 | 31 | 21st (1990-05-28) | 5 weeks | 2 yr (19 wells, 3 still below) |
| unnamed dry spell | 1988-10-10 → 1989-03-06 | 21 | 23rd (1988-11-14) | 5 weeks | 4 yr (16 wells, 3 still below) |
| the 1981 drought | 1981-05-25 → 1981-12-07 | 28 | 13th (1981-07-13) | 5 weeks | 2 yr (21 wells) |
| unnamed dry spell | 1978-12-18 → 1979-07-23 | 31 | 7th (1979-03-05) | 0 weeks | 1 yr (12 wells, 2 still below) |
| the 1977 drought | 1977-04-11 → 1978-09-11 | 74 | 2nd (1978-03-20) | 43 weeks | — |
| unnamed dry spell | 1975-02-03 → 1975-08-18 | 28 | 21st (1975-04-07) | 0 weeks | 5 yr (10 wells, 1 still below) |
| unnamed dry spell | 1973-01-29 → 1973-09-03 | 31 | 16th (1973-05-07) | 0 weeks | 9 yr (20 wells, 3 still below) |
| unnamed dry spell | 1959-01-19 → 1959-11-23 | 44 | 17th (1959-03-30) | 35 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 2018, federal crop insurance has paid $16,321 in drought-caused claims across Chaffee, Eagle, Lake, Saguache counties — 0.0% of all insured crop losses there. The worst year was 2018 ($16,321).
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 (1,325 rights across 118 years of shared record), colored by that year’s wetness from the barcode above. Here the correlation is -0.04 — 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.
Legal
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 ↗
15 systems touch this district (15 community systems reporting 21,513 people served, a figure that counts a wholesaler's customers twice); none carries an open health-based violation on EPA's record.
| System | Serves | Source | Here |
|---|---|---|---|
| PARKVILLE WD | 7,500 | Surface water | 100% of its area |
| SALIDA CITY OF | 5,666 | Surface water | 100% of its area |
| BUENA VISTA TOWN OF | 3,776 | Groundwater under the influence of surface water | 100% of its area |
| PONCHA SPRINGS TOWN OF | 2,118 | Groundwater | 100% of its area |
| LAKE FORK MHP | 487 | Groundwater | 100% of its area |
| GAME TRAIL ASSOCIATION INC | 480 | Groundwater | 100% of its area |
| MESA ANTERO SUBD | 250 | Groundwater | 100% of its area |
| TRAIL WEST ASSOC | 249 | Groundwater | 100% of its area |
and 7 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 ↗
92 reaches over 409.0 miles and 46 natural lake levels, held by the Colorado Water Conservation Board so that water stays in the stream. Every reach, with its schedule and case →
- Browns Creek, 13.0 mi: 2 (10/1 - 4/30), 5 (5/1 - 9/30) cfs (appropriated 1975, 75W4287) · dossier
- Chalk Creek, 10.0 mi: 18 (1/1 - 12/31) cfs (appropriated 1977, 77W4662) · dossier
- East Fork Arkansas River, 10.0 mi: 15 (1/1 - 12/31) cfs (appropriated 1977, 77W4646) · dossier
- Silver Creek, 10.0 mi: 4 (1/1 - 12/31) cfs (appropriated 1977, 77W4656) · dossier
- South Cottonwood Creek, 10.0 mi: 10 (1/1 - 12/31) cfs (appropriated 1977, 77W4665) · dossier
- Middle Cottonwood Creek, 9.0 mi: 10 (1/1 - 12/31) cfs (appropriated 1977, 77W4667) · dossier
and 132 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 2023-08-30. Of the 20 structures with a yield estimate, the median one’s senior right was in priority 0% of a median irrigation season and 0% in a dry one. 25 abandonment screens and 179 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: 1939 across 1491 structure(s); 310 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.
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 | 365 | 419 | 1866-05-01 |
| 2015 | 365 | 222 | 1865-10-07 |
| 2016 | 366 | 355 | 1862-04-30 |
| 2017 | 365 | 260 | 1866-10-31 |
| 2018 | 365 | 401 | 1862-04-30 |
| 2019 | 365 | 389 | 1862-03-20 |
| 2020 | 366 | 340 | 1861-05-31 |
| 2021 | 365 | 362 | 1862-04-30 |
| 2022 | 365 | 370 | 1862-11-15 |
| 2023 | 365 | 369 | 1862-04-30 |
| 2024 | 366 | 359 | 1862-04-30 |
| 2025 | 365 | 384 | 1862-04-30 |
Why diversions stopped — call-based explanations
Sustained diversion stops matched to senior administrative calls.
- YOUNG & SMITH DITCH (1100516) DWR↗ stopped 2025-09-30 (8+ days) — call at MARTIN DITCH curtailing 100% of its decreed rate [heuristic-strong]
- WELLS & STARR DITCH (1100526) DWR↗ stopped 2025-09-21 (17+ days) — call at HOEHNE DITCH curtailing 100% of its decreed rate [heuristic-strong]
- YOUNGER DITCH NO 2 (1100521) DWR↗ stopped 2025-08-03 (89+ days) — call at TITSWORTH DITCH curtailing 100% of its decreed rate [heuristic-strong]
- SUNNYSIDE PARK DITCH (1100539) DWR↗ stopped 2025-04-03 (59+ days) — call at HOWARD DITCH(W FOURMILE) curtailing 100% of its decreed rate [heuristic-strong]
- HARRINGTON DITCH (1100550) DWR↗ stopped 2025-02-06 (35+ days) — call at CHILILI DITCH curtailing 100% of its decreed rate [heuristic-strong]
- YOUNGER DITCH NO 2 (1100521) DWR↗ stopped 2024-11-01 (197+ days) — call at MODEL DITCH curtailing 100% of its decreed rate [heuristic-strong]
- KRAFT DITCH (1100530) DWR↗ stopped 2024-11-01 (186+ days) — call at MODEL DITCH curtailing 100% of its decreed rate [heuristic-strong]
- SUNNYSIDE PARK DITCH (1100539) DWR↗ stopped 2024-11-01 (114+ days) — call at MODEL DITCH curtailing 100% of its decreed rate [heuristic-strong]
- DEL MONTE IRRIG DITCH (1100548) DWR↗ stopped 2024-11-01 (132+ days) — call at MODEL DITCH curtailing 100% of its decreed rate [heuristic-strong]
- BURNETT DITCH (1100552) DWR↗ stopped 2024-11-01 (157+ days) — call at MODEL DITCH curtailing 100% of its decreed rate [heuristic-strong]
- PINON DITCH (1100553) DWR↗ stopped 2024-11-01 (173+ days) — call at MODEL DITCH curtailing 100% of its decreed rate [heuristic-strong]
- NOLAND DITCH (1100555) DWR↗ stopped 2024-11-01 (163+ days) — call at MODEL 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 |
|---|---|---|---|
| MT ELBERT CONDUIT (1101123) DWR↗ | 1939-02-10 | 0.0% / 0.0% | 0.0% / 0.0% |
| HALFMOON DIVERSION (1102057) DWR↗ | 1881-05-07 | 0.0% / 0.0% | 0.0% / 0.0% |
| D & C PIPELINE NO 3 (1100887) DWR↗ | 1908-07-05 | 0.0% / 0.0% | 0.0% / 0.0% |
| SETHMAN PIPELINE HDGT 1 (1100804) DWR↗ | 1904-06-01 | 0.0% / 0.0% | 0.0% / 0.0% |
| MISSOURI PARK DITCH (1100570) DWR↗ | 1880-11-15 | 0.0% / 0.0% | 0.0% / 0.0% |
| STARR DITCH (LOWER PT) (1100786) DWR↗ | 1860-05-01 | 100.0% / 100.0% | 100.0% / 100.0% |
| BOWEN DITCH (1100691) DWR↗ | 1888-09-24 | 0.0% / 0.0% | 0.0% / 0.0% |
| SUNNYSIDE PARK DITCH (1100539) DWR↗ | 1884-01-03 | 0.0% / 0.0% | 0.0% / 0.0% |
| HELENA DITCH (1100535) DWR↗ | 1882-03-01 | 0.0% / 0.0% | 0.0% / 0.0% |
| PIONEER DITCH (BROWNS) (1100632) DWR↗ | 1866-05-17 | 26.9% / 0.0% | 0.0% / 0.0% |
| RIVERSIDE-ALLEN DITCH (1100534) DWR↗ | 1872-11-01 | 0.0% / 0.0% | 0.0% / 0.0% |
| STEVENS & LEITER DITCH (1100751) DWR↗ | 1873-09-01 | 0.0% / 0.0% | 0.0% / 0.0% |
Abandonment radar (25 screens)
Absolute rights with 10+ years of no recorded diversions. Screens only — storage, alternate points, and plan operations can explain nonuse lawfully. And diversion REPORTING itself only reached its modern level ~1973 — idleness that begins before then may be unreported use, not nonuse (flagged † below).
- BLOW DITCH - EMPIRE CREEK (1100729) DWR↗ (1890-12-01, 2.0 cfs decreed): last active 1912 — 113 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1973) -- early absence of record is weak evidence of nonuse
- IRON SILVER MINING CO-EVANS GULCH BRANCH (1100757) DWR↗ (1904-06-02, 0.3 cfs decreed): last active 1912 — 113 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1973) -- early absence of record is weak evidence of nonuse
- RESURRECTION DITCH (1100758) DWR↗ (1904-06-01, 3.3 cfs decreed): last active 1912 — 113 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1973) -- early absence of record is weak evidence of nonuse
- EGGLESTON DITCH (1100846) DWR↗ (1885-04-20, 1.0 cfs decreed): last active 1913 — 112 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1973) -- early absence of record is weak evidence of nonuse
- PINON CANON DITCH (1100847) DWR↗ (1886-09-01, 3.4 cfs decreed): last active 1913 — 112 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1973) -- early absence of record is weak evidence of nonuse
- ROCK CLIFF DITCH (1100852) DWR↗ (1890-01-30, 2.0 cfs decreed): last active 1913 — 112 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1973) -- early absence of record is weak evidence of nonuse
- LIPPARD DITCH (1100853) DWR↗ (1895-05-01, 2.0 cfs decreed): last active 1913 — 112 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1973) -- early absence of record is weak evidence of nonuse
- TOWN DITCH (1100854) DWR↗ (1895-05-01, 1.5 cfs decreed): last active 1913 — 112 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1973) -- early absence of record is weak evidence of nonuse
- SCANGA DITCH (1100856) DWR↗ (1896-07-01, 2.8 cfs decreed): last active 1913 — 112 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1973) -- early absence of record is weak evidence of nonuse
- WILLIAMS DITCH (1100876) DWR↗ (1877-04-30, 1.0 cfs decreed): last active 1913 — 112 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1973) -- early absence of record is weak evidence of nonuse
Compliance screens (179 advisory flags)
Screened 261 of 1491 structures with rights (283 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.
- TURQUOISE RESERVOIR (1103500) DWR↗: Observed p99 daily rate 773.1 cfs (max 1260.9) exceeds total decreed absolute 3.0 cfs across 14068 recorded day(s).
- OTERO PUMP STATION (1100529) DWR↗: Observed p99 daily rate 180.5 cfs (max 180.7) exceeds total decreed absolute 1.7 cfs across 4079 recorded day(s).
- SALIDA "OLD" GALLERY (1100882) DWR↗: Observed p99 daily rate 76.5 cfs (max 110.2) exceeds total decreed absolute 2.5 cfs across 3126 recorded day(s).
- CHAMP DITCH (ARK) (1100517) DWR↗: Observed p99 daily rate 52.8 cfs (max 52.8) exceeds total decreed absolute 5.0 cfs across 10846 recorded day(s).
- BOWEN DITCH (1100691) DWR↗: Observed p99 daily rate 50.0 cfs (max 55.5) exceeds total decreed absolute 44.5 cfs across 7674 recorded day(s).
- BUSK-IVANHOE SYSTEM (1104612) DWR↗: Observed p99 daily rate 48.6 cfs (max 74.7) exceeds total decreed absolute 17.5 cfs across 15739 recorded day(s).
- HELENA DITCH (1100535) DWR↗: Observed p99 daily rate 40.0 cfs (max 50.5) exceeds total decreed absolute 36.0 cfs across 17198 recorded day(s).
- MCFARLAND DITCH (1100702) DWR↗: Observed p99 daily rate 40.0 cfs (max 40.0) exceeds total decreed absolute 0.4 cfs across 6452 recorded day(s).
- STEVENS & LEITER WELL (1100759) DWR↗: Observed p99 daily rate 36.0 cfs (max 36.0) exceeds total decreed absolute 1.1 cfs across 4698 recorded day(s).
- FISH DITCH (1100546) DWR↗: Observed p99 daily rate 25.0 cfs (max 25.0) exceeds total decreed absolute 0.2 cfs across 7432 recorded day(s).
Seniority (top structures by decreed rate)
| Structure | Senior priority date | Rights | Decreed abs (cfs) | Decreed abs (AF) | Conditional? |
|---|---|---|---|---|---|
| MT ELBERT CONDUIT (1101123) DWR↗ | 1939-02-10 | 1 | 370.0 | 0 | — |
| HALFMOON DIVERSION (1102057) DWR↗ | 1881-05-07 | 4 | 150.0 | 0 | — |
| D & C PIPELINE NO 3 (1100887) DWR↗ | 1908-07-05 | 1 | 72.8 | 0 | — |
| SETHMAN PIPELINE HDGT 1 (1100804) DWR↗ | 1904-06-01 | 1 | 63.8 | 0 | — |
| MISSOURI PARK DITCH (1100570) DWR↗ | 1880-11-15 | 3 | 55.0 | 0 | — |
| STARR DITCH (LOWER PT) (1100786) DWR↗ | 1860-05-01 | 1 | 51.0 | 0 | — |
| BOWEN DITCH (1100691) DWR↗ | 1888-09-24 | 1 | 44.5 | 0 | — |
| SUNNYSIDE PARK DITCH (1100539) DWR↗ | 1884-01-03 | 3 | 39.2 | 0 | — |
| HELENA DITCH (1100535) DWR↗ | 1882-03-01 | 3 | 36.0 | 0 | — |
| PIONEER DITCH (BROWNS) (1100632) DWR↗ | 1866-05-17 | 3 | 31.0 | 0 | — |
| RIVERSIDE-ALLEN DITCH (1100534) DWR↗ | 1872-11-01 | 4 | 29.0 | 0 | — |
| STEVENS & LEITER DITCH (1100751) DWR↗ | 1873-09-01 | 1 | 27.6 | 0 | — |
| WILLOWDALE DITCH (1100684) DWR↗ | 1867-05-31 | 9 | 24.9 | 0 | — |
| WOLF & NEERLAND DITCH (1100651) DWR↗ | 1877-04-01 | 6 | 21.4 | 0 | — |
| WILLIAMS & HAMM DITCH (1100531) DWR↗ | 1875-12-31 | 3 | 20.0 | 0 | — |
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)
3 applications in the 2026-08 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 2026-10-31 (17 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 3 filings, with excerpts
| Case | What it asks | County | Excerpt |
|---|---|---|---|
2025CW3012
|
plan for augmentation, new underground right | — | CASE NO. 2025CW3012; TITAN AU, INC., 8480 E. Orchard Rd., Suite 4900, Greenwood Village, CO 80111 (Please address all pleadings and inquiries regarding this matter to Applicant’s attorney: John T. Howe, Hoskin, Farina & Kampf, P.C., 200 Grand Avenue, Suite 400… |
2026CW3037
1603718 |
— | — | CASE NO. 2026CW3037; MARIA LAKES GRAZING ASSOCIATION, LLC, c/o Donald E. Siecke, Manager, 7343 S. Alton Way, Ste. 100, Centennial, CO 80122 (Please address all pleadings and inquiries regarding this matter to Applicant’s attorneys: Karl D. Ohlsen, Beth Ann J. … |
2026CW3138
|
reasonable diligence | OF REASONABLE DILIGENCE IN PARK | CASE NUMBER 2026CW3138 MICHAEL STALL, 77 Sugar Creek Center Blvd., # 210, Sugar Land, TX, 77478. Philip E. Lopez, Eric K. Trout, Fairfield and Woods, P.C., 1801 California St, Suite 2600, Denver, CO, 80202. APPLICATION FOR A FINDING OF REASONABLE DILIGENCE IN … |
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.
| Plan | Type | Status | Expires | Structure | Documents |
|---|---|---|---|---|---|
| LAVWCD LARKSPUR DITCH | 37-92-308(5) PLANS LESS THAN 5 YEARS | Approved | 2026-03-31 | 1107127 | plan file |
| BOX CREEK PLACER MINE COMBINED SITES | 37-92-308(5) PLANS LESS THAN 5 YEARS | Approved | 2026-04-30 | 1107821 | plan file |
| WILLOW CREEK MINE ON CORSKE CREEK | 37-92-308(5) PLANS LESS THAN 5 YEARS | Approved | 2027-02-28 | 1107819 | plan file |
| BARN POND | 37-92-308(5) PLANS LESS THAN 5 YEARS | Approved | 2027-04-30 | 1107136 | plan file |
| CPW HARRINGTON DITCH | 37-92-308(4) PLAN PENDING COURT APPLICATION | Pending | — | 1107128 | plan file |
| LEADVILLE NATIONAL FISH HATCHERY GROUNDWATER WELL | 37-92-308(5) PLANS LESS THAN 5 YEARS | Additional Info Needed | — | 1107137 | plan file |
Water quality
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 2026-10-14 · 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.
| Site | Temp °C | Cond µS/cm | DO mg/L | Turb FNU | As of |
|---|---|---|---|---|---|
| ARKANSAS RIVER AT GRANITE, CO. | 8.0 | 180 | 2026-10-14 17:45 | ||
| HALFMOON CREEK NEAR MALTA, CO | 5.8 | 2026-10-14 17:30 |
Where water has been sampled
Source Register of another agency · fetched 2026-10-08 · verify at Water Quality Portal ↗
The portal lists 6,859 sampling stations in this district's watershed (Arkansas Headwaters 11020001), of which 176 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 (79), Colorado River Watch (45), USGS Colorado Water Science Center (36). Most-sampled groups: Inorganics, Major, Metals, Physical, Biological, Counts, 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 ↗
15 community systems touch this district. None carries an open health-based violation on EPA's record. EPA sampled 3 of them for PFAS in 2023–25; none had PFOA or PFOS at or above the 2024 limit.
| System | Serves | EPA record | PFAS (UCMR 5) | Lead, latest 90th pct |
|---|---|---|---|---|
| PARKVILLE WD | 7,500 | 11 of 12 quarters with a violation | none detected | 0.003 mg/L |
| SALIDA CITY OF | 5,666 | 4 of 12 quarters with a violation | none detected | 0.0 mg/L |
| BUENA VISTA TOWN OF | 3,776 | clean, last 12 quarters | none detected | 0.001 mg/L |
| PONCHA SPRINGS TOWN OF | 2,118 | 3 of 12 quarters with a violation | not sampled | 0.0 mg/L |
| LAKE FORK MHP | 487 | 6 of 12 quarters with a violation | not sampled | 0.0005 mg/L |
| GAME TRAIL ASSOCIATION INC | 480 | 1 of 12 quarters with a violation | not sampled | 0.001 mg/L |
| MESA ANTERO SUBD | 250 | 10 of 12 quarters with a violation | not sampled | 0.0025 mg/L |
| TRAIL WEST ASSOC | 249 | clean, last 12 quarters | not sampled | 0.0015 mg/L |
| CHATEAU CHAPARREL CG | 240 | clean, last 12 quarters | not sampled | 0.0 mg/L |
| GLENVIEW OWNERS ASSOC | 195 | 1 of 12 quarters with a violation | not sampled | 0.0005 mg/L |
and 5 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.
Call cascade
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
DWR administration numbers encode appropriation and adjudication dates; lower is more senior.
This week's diagnostic
Loading…
System status
Loading…
Active river calls
Loading…
Hydrographs vs. historical envelope
Loading…
Anomaly flags
Loading…
Snowpack — no snow on the ground at 2 SNOTEL sites — normal for the date; the snow year begins in October and typically peaks around April 19. Runoff outlook — Chalk Ck nr Nathrop: even odds of at least 7 kAF over 06-01 to 09-30 — 43% of a normal season, per NRCS, issued 2026-06-01 — the season’s final; new forecasts begin in January. Runoff outlook — Arkansas R at Salida: even odds of at least 68 kAF over 06-01 to 09-30 — 35% 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 |
|---|---|---|---|---|---|
| Brumley | 10570 | 0.1 | 0.0 | — | April 19 (11.8 in) |
| Saint Elmo | 10420 | 0.3 | 0.0 | — | April 9 (11.5 in) |
Chalk Ck nr Nathrop — 06-01 to 09-30 volume, thousand acre-feet (chance the volume is AT LEAST this):
| 90% | 70% | 50% | 30% | 10% | Normal |
|---|---|---|---|---|---|
| 2 | 5 | 7 | 10 | 13 | 17 |
Arkansas R at Salida — 06-01 to 09-30 volume, thousand acre-feet (chance the volume is AT LEAST this):
| 90% | 70% | 50% | 30% | 10% | Normal |
|---|---|---|---|---|---|
| 30 | 53 | 68 | 83 | 106 | 197 |
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: 8 parent disagreements, 20 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 27 streams, 19 agree. Know this water? Tell us →
| Stream | This site routes it to | DWR routes it to |
|---|---|---|
| Chalk Creek | the mainstem | Delmonica Gulch |
| West Tennessee Creek | the mainstem | Tennessee Creek |
| Longs Gulch | the mainstem | Tennessee Creek |
| Middle Cottonwood Creek | the mainstem | Cottonwood Creek |
| South Cottonwood Creek | the mainstem | Cottonwood Creek |
| North Cottonwood Creek | the mainstem | Cottonwood Creek |
| Browns Creek | the mainstem | Stumpy Creek |
| Box Creek | the mainstem | Poncha Creek |
Sizable streams DWR maps here that this network does not carry:
Lake Fork (14 mi) · Lake Creek (14 mi) · Clear Creek (13 mi) · Pine Creek (12 mi) · Iowa Gulch (11 mi) · Big Union Creek (11 mi) · Fourmile Creek (10 mi) · Tennessee Creek (10 mi)