Hydrohistorian
Blue River Basin
Who may take water from the Blue River Basin, who is calling for it today, and how it is running, compiled from Colorado Division of Water Resources records. Click anything on the map for its record.
Blue River Basin on the ground — the ditches, wells, reservoirs and gages of Water District 36 · 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 Blue River is critically low for late September -- 10% of normal flow, its 9th-driest such week in 89 years of record. No call that the record places on it is active right now. DWR's statements do not settle whether 26 more calls reach it.
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 2026-09-29 (the newest reading on file), flows at the 12 ranked gages are running at a median 68% of their own long-term norm for this window — 12 below a typical year, 0 at or above. Driest relative to its record: ELLIOTT CREEK FEEDER CANAL TO GREEN MTN RES, CO, ranking 2nd lowest of 24 years.
How this comparison is made
Each gage's mean flow over the 3 days either side of 2026-09-29, 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 20:21 from 46 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 46 gages with enough record, 2 are trending down and 0 up, and 3 carry a detected shift. The clearest is Blue River at Dillon, its annual mean flow changing -7.76 cfs per decade (-7.1% of its median annual flow) over 50 years (p=0.0052). The other 43 show no clear signal either way.
| Gage | Trend | Change / decade cfs · % of median annual flow | Significance | Years | Changepoint |
|---|---|---|---|---|---|
|
▸
Blue River at Dillon BLUADICO |
↓ decreasing | -7.76 cfs -7.1% | p=0.005 | 50 | ~1930 |
|
▸
Blue River below Green Mountain Reservoir BLUGRECO |
↓ decreasing | -15.42 cfs -3.6% | p=0.017 | 88 | ~1962 |
|
▸
Tenmile Creek at Dillon TENDILCO |
no clear trend | -6.44 cfs -5.5% | p=0.095 | 39 | ~1930 |
43 other gage(s) show no significant trend or changepoint (not shown).
3 of those show a significant trend once extended backwards from a retired neighbour's record: Blue River near Dillon (116 yr, decreasing); Tenmile Creek Bl North Tenmile Creek, at Frisco (116 yr, decreasing); Blue River below Dillon (106 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. 15 gage(s) and 211 structure(s) report in 2026, but structure reporting only reached half its modern level around ~1969. 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 | 3 | 0 |
| 1920s | 1 | 0 |
| 1930s | 3 | 0 |
| 1940s | 15 | 0 |
| 1950s | 14 | 0 |
| 1960s | 14 | 66 |
| 1970s | 15 | 184 |
| 1980s | 16 | 227 |
| 1990s | 16 | 176 |
| 2000s | 15 | 184 |
| 2010s | 15 | 173 |
| 2020s | 15 | 204 |
Mass-balance (network closure) trend
Structure divrec-history backfill coverage as of the last check: 12% of 1744 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 (3195 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.
- BLUE RIVER BELOW GREEN MOUNTAIN RESERVOIR, CO: reach shifted from +268 cfs to +587 cfs summer mean (more gaining, p=0.043, 77 yr) [sedimentary uplands: moderate groundwater connectivity -- gain/loss shifts can be real aquifer response; corroborate with nearby well records]
- TENMILE CREEK BELOW WEST TENMILE CREEK, CO: reach shifted from -55 cfs to -48 cfs summer mean (more gaining, p=0.043, 11 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]
- BLUE RIVER BELOW DILLON, CO.: reach shifted from +207 cfs to -52 cfs summer mean (more losing, p=0.001, 67 yr) [sedimentary uplands: moderate groundwater connectivity -- gain/loss shifts can be real aquifer response; corroborate with nearby well records] [5 alluvial wells within 2 mi of the gage; pooled water table -2.0 ft (1973–2011, no_trend)]
- BOULDER CREEK AT UPPER STATION, NEAR DILLON, CO.: reach shifted from -15 cfs to -5 cfs summer mean (more gaining, p=0.049, 27 yr) [sedimentary uplands: moderate groundwater connectivity -- gain/loss shifts can be real aquifer response; corroborate with nearby well records]
Groundwater now has its own tab: 29 monitored well(s), water-table trends, stream corridors, and the advisory depletion screen.
Reservoirs now has its own tab: 64 reservoir(s), end-of-year storage back to 1964, click-to-chart histories.
Cross-gage pattern fingerprint
Over the 69-year window with full coverage (1958–2026), the dominant shared pattern across 4 gage(s) explains 84% of year-to-year variance (almost certainly a basin-wide climate/snowpack driver).
All gages in this window move with the shared pattern -- no localized outlier.
Structures most implicated by reconciliation (as of 2026-09-01)
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.
- COUNTRY BOY MINE SPRING (return): +2.3 cfs (14% of that reach's correction)
- BRECKENRIDGE PIPELINE - AP (diversion): +2.3 cfs (14% of that reach's correction)
- BRECKENRIDGE SKI AREA PUMP PLANT & PIPEL (diversion): +2.3 cfs (14% of that reach's correction)
- CHRISTIE HEIGHTS D NO 1 (diversion): +2.3 cfs (14% of that reach's correction)
- ELYRIA DITCH (diversion): +2.3 cfs (14% of that reach's correction)
- ATKINS DITCH (diversion): +2.3 cfs (14% of that reach's correction)
- BRADDOCK DITCH (diversion): +2.3 cfs (14% of that reach's correction)
- TIGER RUN - BLUE RIVER DIVERSION (diversion): +2.1 cfs (25% of that reach's correction)
- GETZ POND (diversion): +2.1 cfs (25% of that reach's correction)
- VER PLOEG SPRING (return): +2.1 cfs (25% of that reach's correction)
Data provenance & quality
Where these numbers come from and how far they can be trusted. Grade D (2/6 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 12 day(s) old (target 7) |
| diversion record | stale | newest diversion record is 711 day(s) old (DWR publishes ~1 year in arrears) |
| structure coverage | sparse | 12% of schematic structures have data |
Independent check: PASS — 100.0000% agreement across 37,314 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 — 99.89% day-level agreement with USGS's own published records for the same gages, across 40 co-listed station(s) and 414,582 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.
46 gage(s) / 441,518 daily values (1904-08-01–2026-09-29); 525 structure(s) with diversion records; 1247 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 ↗
104 water-level measurements across 29 monitored well(s) — 27 alluvial, 0 bedrock — plus 25 administered well(s) reporting metered pumping.
What is being counted
Observation wells and pumping wells are different populations and are never conflated: water levels come from monitored observation wells, and metered pumping comes from administered wells reporting through diversion records. Click any well to chart its own record.
Well map
3D aquifer x-ray
Every aquifer unit as its own head surface, animated through time.
How the surfaces are built, and what they are not
Alluvial water table on top, Denver Basin members (Dawson, Denver, Arapahoe, Laramie–Fox Hills) stacked beneath where measured, interpolated from measured water levels. Units are never mixed; a surface exists only inside its own unit's well coverage, with no extrapolation; thin epochs are suppressed and say why. Vertical scale is exaggerated for readability and z is head elevation in feet. These are measured heads, not a calibrated groundwater model.
Water-table trends
Of 0 well(s) with enough record for a trend test: 0 declining, 0 rising.
Stream corridors — the surface connection
Where a reach's gain or loss has shifted, the wells within two miles of its anchoring gage and what their water table did over the same era.
How the corridor is assembled
For each reach whose gain/loss has shifted (Trends tab): the wells within 2 miles of its anchoring gage, their pooled water-table history over the same era, and an advisory Glover screen of lagged stream depletion from nearby metered pumping. v1 proximity = distance to the reach's anchoring gage; segment-based reach join is a flagged upgrade.
TENMILE CREEK BELOW WEST TENMILE CREEK, CO: 0 alluvial well(s) nearby. Glover screen: 0.7 cfs of nearby metered alluvial pumping → est. lagged depletion 0.6–0.7 cfs (uncalibrated T/S ranges; flagged for SPDSS calibration, AWAS cross-check, and expert review — DWR's AWAS is the authority).
BLUE RIVER BELOW DILLON, CO.: 5 alluvial well(s) nearby; pooled water table -2.0 ft (1973–2011, no_trend, p=0.9641)
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.
51% 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
6,659 located water-supply permits with an issue date, 1955 to 2026; half of them had been issued by 1996, and the busiest year was 1994 with 219. The district’s 1,021 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 8,753 above counts every permit on file here; 1,073 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
The counts by year, as a table
| Year | Issued | Monitoring holes | Water-supply | Issued through that year |
|---|---|---|---|---|
| 1955 | 1 | 0 | 1 | 1 |
| 1956 | 2 | 0 | 2 | 3 |
| 1957 | 2 | 0 | 2 | 5 |
| 1959 | 10 | 0 | 10 | 15 |
| 1960 | 22 | 0 | 22 | 37 |
| 1961 | 29 | 0 | 29 | 66 |
| 1962 | 29 | 0 | 29 | 95 |
| 1963 | 35 | 0 | 35 | 130 |
| 1964 | 45 | 0 | 45 | 175 |
| 1965 | 38 | 0 | 38 | 213 |
| 1966 | 50 | 0 | 50 | 263 |
| 1967 | 39 | 0 | 39 | 302 |
| 1968 | 41 | 0 | 41 | 343 |
| 1969 | 44 | 0 | 44 | 387 |
| 1970 | 35 | 0 | 35 | 422 |
| 1971 | 58 | 0 | 58 | 480 |
| 1972 | 186 | 0 | 186 | 666 |
| 1973 | 100 | 0 | 100 | 766 |
| 1974 | 57 | 0 | 57 | 823 |
| 1975 | 42 | 0 | 42 | 865 |
| 1976 | 44 | 0 | 44 | 909 |
| 1977 | 68 | 0 | 68 | 977 |
| 1978 | 119 | 0 | 119 | 1,096 |
| 1979 | 150 | 0 | 150 | 1,246 |
| 1980 | 94 | 0 | 94 | 1,340 |
| 1981 | 126 | 0 | 126 | 1,466 |
| 1982 | 75 | 0 | 75 | 1,541 |
| 1983 | 84 | 2 | 82 | 1,625 |
| 1984 | 101 | 0 | 101 | 1,726 |
| 1985 | 92 | 9 | 83 | 1,818 |
| 1986 | 106 | 0 | 106 | 1,924 |
| 1987 | 82 | 3 | 79 | 2,006 |
| 1988 | 92 | 13 | 79 | 2,098 |
| 1989 | 135 | 22 | 113 | 2,233 |
| 1990 | 183 | 32 | 151 | 2,416 |
| 1991 | 209 | 43 | 166 | 2,625 |
| 1992 | 197 | 25 | 172 | 2,822 |
| 1993 | 226 | 31 | 195 | 3,048 |
| 1994 | 254 | 35 | 219 | 3,302 |
| 1995 | 216 | 48 | 168 | 3,518 |
| 1996 | 254 | 71 | 183 | 3,772 |
| 1997 | 175 | 35 | 140 | 3,947 |
| 1998 | 262 | 70 | 192 | 4,209 |
| 1999 | 195 | 48 | 147 | 4,404 |
| 2000 | 199 | 39 | 160 | 4,603 |
| 2001 | 189 | 46 | 143 | 4,792 |
| 2002 | 173 | 25 | 148 | 4,965 |
| 2003 | 185 | 66 | 119 | 5,150 |
| 2004 | 231 | 24 | 207 | 5,381 |
| 2005 | 146 | 32 | 114 | 5,527 |
| 2006 | 136 | 7 | 129 | 5,663 |
| 2007 | 217 | 15 | 202 | 5,880 |
| 2008 | 155 | 17 | 138 | 6,035 |
| 2009 | 69 | 3 | 66 | 6,104 |
| 2010 | 54 | 4 | 50 | 6,158 |
| 2011 | 65 | 11 | 54 | 6,223 |
| 2012 | 51 | 8 | 43 | 6,274 |
| 2013 | 81 | 9 | 72 | 6,355 |
| 2014 | 103 | 12 | 91 | 6,458 |
| 2015 | 96 | 9 | 87 | 6,554 |
| 2016 | 109 | 20 | 89 | 6,663 |
| 2017 | 114 | 11 | 103 | 6,777 |
| 2018 | 81 | 6 | 75 | 6,858 |
| 2019 | 94 | 14 | 80 | 6,952 |
| 2020 | 139 | 54 | 85 | 7,091 |
| 2021 | 96 | 13 | 83 | 7,187 |
| 2022 | 122 | 39 | 83 | 7,309 |
| 2023 | 161 | 4 | 157 | 7,470 |
| 2024 | 69 | 11 | 58 | 7,539 |
| 2025 | 74 | 20 | 54 | 7,613 |
| 2026 | 67 | 15 | 52 | 7,680 |
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
17 PLSS townships here where at least 5 water-supply permits naming the same aquifer filed a depth (4,642 permits in all). Each column is one township, six miles square, on one scale to 500 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. 2 of these townships straddle a district line and are filed here because most of their permits are.
1,484
861
615
346
252
246
214
169 · 73% here
131
111
69
52
32
30
20
5
5 · 87% here
unnamed alluvium other named 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 |
|---|---|---|---|---|---|---|
| T7S R77W 6th PM | 100% | unnamed | 1,474 | 60 / 132 / 282 | 27 / 75 / 188 | 60 / 132 / 280 |
| T7S R77W 6th PM | 100% | alluvium | 10 | 98 / 184 / 324 | 63 / 96 / 204 | 96 / 154 / 261 |
| T6S R77W 6th PM | 100% | unnamed | 857 | 59 / 160 / 300 | 29 / 90 / 190 | 60 / 160 / 290 |
| T5S R78W 6th PM | 100% | alluvium | 8 | 55 / 69 / 176 | 31 / 48 / 61 | 52 / 69 / 214 |
| T5S R78W 6th PM | 100% | unnamed | 606 | 35 / 74 / 180 | 25 / 51 / 130 | 40 / 80 / 190 |
| T5S R77W 6th PM | 100% | unnamed | 338 | 46 / 155 / 323 | 25 / 105 / 243 | 45 / 175 / 343 |
| T5S R77W 6th PM | 100% | other named | 6 | 150 / 236 / 312 | — | — |
| T4S R78W 6th PM | 100% | unnamed | 248 | 35 / 82 / 236 | 25 / 60 / 194 | 38 / 115 / 278 |
| T3S R78W 6th PM | 100% | unnamed | 245 | 64 / 222 / 500 | 38 / 145 / 330 | 70 / 240 / 500 |
| T6S R78W 6th PM | 100% | unnamed | 214 | 36 / 100 / 240 | 21 / 60 / 150 | 41 / 118 / 240 |
| T8S R77W 6th PM | 73% | unnamed | 168 | 73 / 140 / 280 | 26 / 80 / 200 | 72 / 140 / 280 |
| T5S R76W 6th PM | 100% | unnamed | 131 | 35 / 75 / 210 | 30 / 62 / 168 | 45 / 95 / 262 |
| T2S R80W 6th PM | 100% | unnamed | 108 | 60 / 150 / 386 | 34 / 85 / 239 | 67 / 160 / 448 |
| T1S R80W 6th PM | 98% | unnamed | 68 | 60 / 314 / 472 | 67 / 180 / 320 | 143 / 325 / 456 |
| T7S R78W 6th PM | 100% | unnamed | 49 | 46 / 117 / 280 | 20 / 65 / 169 | 54 / 114 / 337 |
| T2S R79W 6th PM | 100% | unnamed | 32 | 46 / 98 / 170 | 28 / 55 / 145 | 68 / 108 / 185 |
| T6S R76W 6th PM | 98% | unnamed | 30 | 49 / 152 / 425 | 24 / 85 / 317 | 60 / 145 / 411 |
| T3S R79W 6th PM | 100% | unnamed | 20 | 42 / 80 / 211 | 34 / 61 / 182 | 66 / 128 / 306 |
| T4S R77W 6th PM | 100% | unnamed | 5 | 45 / 54 / 104 | — | — |
| T6S R79W 6th PM | 87% | unnamed | 5 | 40 / 203 / 306 | — | — |
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 ↗
64 reservoir(s) with 6,955 storage measurement(s), 1964–2025. Basin storage as of 2024-10-31 (the record's own end — reservoir records publish ~annually): 295,455 AF across 4 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) | |
|---|---|---|---|---|---|
| ▸ DILLON RESERVOIR (3604512) | 217,354 | 2024-10-31 | — | — | dossier → |
| ▸ GREEN MOUNTAIN RESERVOIR (3603543) | 76,976 | 2024-10-31 | — | — | dossier → |
| ▸ CLINTON GULCH RESERVOIR (3603575) | 4,205 | 2021-10-31 | — | — | dossier → |
| ▸ BLACK LAKE AND RESERVOIR (3603533) | 1,997 | 2010-10-31 | — | — | dossier → |
| ▸ CATARACT LAKE AND RESERVOIR (3603538) | 1,653 | 2010-10-31 | — | — | dossier → |
| ▸ GOOSE PASTURE TARN (3603542) | 805 | 2024-10-31 | — | — | dossier → |
| ▸ MIN LAKE MOHAWK NO 2 (3603586) | 444 | 1992-10-31 | — | — | dossier → |
| ▸ LOWER BLACK CREEK RESERVOIR (3603556) | 400 | 1988-09-22 | — | — | dossier → |
Snow and runoff
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
| SNOTEL site | Elev (ft) | SWE (in) | Median (in) | % of median | Typical peak |
|---|---|---|---|---|---|
| Copper Mountain | 10500 | 0.0 | 0.0 | — | April 26 (17.4 in) |
| Elliot Ridge | 10550 | 0.0 | 0.0 | — | April 25 (23.2 in) |
| Fremont Pass | 11310 | 0.2 | 0.6 | — | May 11 (20.8 in) |
| Grizzly Peak | 11110 | 0.1 | 0.3 | — | April 21 (19.6 in) |
| Hoosier Pass | 11600 | 0.8 | 0.4 | — | April 27 (17.3 in) |
| Summit Ranch | 9350 | 0.2 | 0.0 | — | April 9 (11.4 in) |
NRCS SNOTEL, daily. Sites are assigned to the district whose boundary contains them — the snow that feeds this district can also sit in a neighboring headwater district.
Two ways a snow year goes wrong (1979–2026)
A bad snow year here comes in two flavors (both called snow droughtA winter that shorts the snowpack. It happens two ways: a dry one, where the snow never comes, and a warm one, where near-normal snow falls but melts off weeks early -- and the river feels them differently.), and the river feels them differently. In 8 of the last 48 winters the snow never came — the pack peaked below 80% of its median. In 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, 1987, 1991, 2002, 2004, 2012, 2021, 2026.
Computed by this site from 6 SNOTEL sites’ full daily records (NRCS AWDB, back to 1979). Each year is measured against each site’s own multi-decade median — not the 1991–2020 normal the chart above uses — so the 1980s grade against a fair baseline. Peak and melt-out need 85% of the season’s days on the record; thin years are dropped, not guessed. Derived from snow measurements alone — it cannot tell dry-from-warm causes apart, only what the snowpack did.
Runoff outlook — Dillon Reservoir Inflow
NRCS's final issue (2026-06-01) calls it even odds that at least 25 kAF arrives over 06-01 to 07-31 — 25% of a normal season; almost certainly at least 12, probably not more than 46. Our own record at this gage shows 7 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 54 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 24 kAF. The river delivered 14 kAF.
Computed by this site — not an NRCS number, and shown only because it earned it: replayed over 58 past seasons here (1974–2025), never seeing the year it predicts, the adjustment cut the typical April miss from 85% to 44%. At points where it does not beat NRCS, no adjusted number appears. Coefficients are frozen each August; the model never changes mid-season. Method and honest limits →
| 90% chance of at least | 70% chance of at least | 50% chance of at least | 30% chance of at least | 10% chance of at least | Normal | Observed |
|---|---|---|---|---|---|---|
| 12 | 18 | 25 | 34 | 46 | 101 | 7 |
How good are these forecasts here? (1973–2026)
Grading every April issue against what the river then delivered, measured at this gage’s own record — 53 seasons: the median miss of the 50% forecast is 86%, with a high bias of 86%, and the observed volume landed inside the stated 10–90% band 24% of the time (a calibrated forecast would say 80%).
Computed by this site: NRCS's archived April issues (their period as issued each year) against the observed volume in DWR’s published record; years with under 90% daily coverage are dropped, not summed. A grade of the forecast, never of the forecasters — these are hard rivers. How this point ranks among every graded Colorado forecast point →
What April snow has meant for this river (1979–2026)
Across 48 measured years, the season’s water has closely followed the April snowpack: a year opening April with 80% of median snow has typically gone on to deliver about 60% 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 2.5).
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 — Green Mountain Reservoir Inflow
NRCS's final issue (2026-06-01) calls it even odds that at least 44 kAF arrives over 06-01 to 07-31 — 27% of a normal season; almost certainly at least 25, probably not more than 70. Our own record at this gage shows 56 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 98 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 39 kAF. The river delivered 85 kAF.
Computed by this site — not an NRCS number, and shown only because it earned it: replayed over 63 past seasons here (1962–2025), never seeing the year it predicts, the adjustment cut the typical April miss from 91% to 39%. At points where it does not beat NRCS, no adjusted number appears. Coefficients are frozen each August; the model never changes mid-season. Method and honest limits →
| 90% chance of at least | 70% chance of at least | 50% chance of at least | 30% chance of at least | 10% chance of at least | Normal | Observed |
|---|---|---|---|---|---|---|
| 25 | 35 | 44 | 55 | 70 | 163 | 56 |
How good are these forecasts here? (1950–2026)
Grading every April issue against what the river then delivered, measured at this gage’s own record — 76 seasons: the median miss of the 50% forecast is 73%, with a high bias of 73%, and the observed volume landed inside the stated 10–90% band 12% of the time (a calibrated forecast would say 80%).
Computed by this site: NRCS's archived April issues (their period as issued each year) against the observed volume in DWR’s published record; years with under 90% daily coverage are dropped, not summed. A grade of the forecast, never of the forecasters — these are hard rivers. How this point ranks among every graded Colorado forecast point →
What April snow has meant for this river (1979–2026)
Across 48 measured years, the season’s water has closely followed the April snowpack: a year opening April with 80% of median snow has typically gone on to deliver about 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 2.3).
Computed by this site: the district’s April 1 SWE (% of each SNOTEL site’s own-record median) against the observed April–July volume at this gage (% of its median season) — a fixed window every year, unlike the forecast grades above, which use each issue’s own period. The slope is fit so single wild years can’t steer it (Theil–Sen, log space); years missing 10% of their days are dropped.
Drought
Source Our computation, no independent reference · computed here from the screened DWR record Source Independent agency measurement · fetched 2026-10-13 · verify at U.S. Drought Monitor ↗
Right now
This is the 9th-driest week 39 in 89 years of record at BLUE RIVER BELOW GREEN MOUNTAIN RESERVOIR, CO (as of 2026-09-21; this week’s flow sits at the 10th 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, Grand County is 54% in D4 exceptional drought (2026-10-13). The law agrees: the most senior active call leaves 0% of this district’s decreed flow rights junior to the calling right this week.
Every year since 1937, week by week
Each thin row is a year at BLUE RIVER BELOW GREEN MOUNTAIN RESERVOIR, 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 15.2 percentile points; next closest 1991 (17.9), 1964 (18.7)). 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 Grand, Summit counties — the counties this district’s gages sit in, which overlap the district imperfectly. The Drought Monitor weighs soils, vegetation and local reports; it is CONTEXT beside the river’s own record above, not the water-rights picture.
The law’s own drought gauge
When water runs short, administration answers: calls reach further back in time, and more decreed rights go junior to the calling right. This is that response, weekly since 2002 — the share of this district’s decreed flow rights junior to the most senior active call. Watch it spike in the named droughts below, and linger after the river recovers.
Computed from DWR’s call record (137 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 | 2026-02-16 → 2026-08-17 | 26 | 23rd (2026-04-20) | not yet | — |
| the 2020-22 drought | 2022-07-04 → 2023-02-20 | 33 | 22nd (2022-10-10) | 31 weeks | — |
| the 2020-22 drought | 2021-03-08 → 2021-09-27 | 29 | 23rd (2021-05-17) | 104 weeks | — |
| the 2018 drought | 2019-02-18 → 2019-07-22 | 22 | 21st (2019-03-11) | 1 week | — |
| the 2012-13 drought | 2012-07-02 → 2013-12-16 | 76 | 14th (2013-07-15) | 1 week | — |
| unnamed dry spell | 2010-03-29 → 2010-09-27 | 26 | 15th (2010-05-03) | 2 weeks | — |
| unnamed dry spell | 2005-05-02 → 2005-11-07 | 27 | 19th (2005-06-20) | 4 weeks | — |
| the 2002 drought | 2004-04-12 → 2005-02-07 | 43 | 12th (2004-07-19) | 43 weeks | — |
| the 2002 drought | 2002-04-01 → 2003-12-08 | 88 | 13th (2003-01-27) | 104 weeks | — |
| the 2002 drought | 2001-04-16 → 2001-11-05 | 29 | 22nd (2001-08-13) | 213 weeks | — |
| unnamed dry spell | 1990-04-23 → 1990-10-01 | 23 | 27th (1990-07-23) | 8 weeks | — |
| unnamed dry spell | 1989-03-06 → 1989-09-11 | 27 | 25th (1989-04-03) | 3 weeks | — |
| the 1981 drought | 1981-06-08 → 1982-05-24 | 50 | 14th (1981-11-16) | 30 weeks | — |
| the 1977 drought | 1978-04-10 → 1978-12-25 | 37 | 21st (1978-08-14) | 5 weeks | 1 yr (5 wells, 1 still below) |
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.
When this basin claimed its water
Every bar is a year’s new appropriations (1,696 rights across 90 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.
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 ↗
19 systems touch this district (19 community systems reporting 70,980 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 |
|---|---|---|---|
| BRECKENRIDGE TOWN OF | 28,315 | Surface water | 100% of its area |
| SNAKE RIVER WD | 9,900 | Groundwater | 100% of its area |
| SILVERTHORNE TOWN OF | 8,400 | Groundwater | 100% of its area |
| COPPER MOUNTAIN CONSOLIDATED MD | 5,785 | Groundwater | 100% of its area |
| FRISCO TOWN OF | 4,495 | Surface water | 100% of its area |
| DILLON TOWN OF | 3,254 | Surface water | 100% of its area |
| DILLON VALLEY DISTRICT | 3,063 | Surface water | 100% of its area |
| BUFFALO MOUNTAIN MD | 2,650 | Groundwater | 100% of its area |
and 11 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 ↗
60 reaches over 245.9 miles and 15 natural lake levels, held by the Colorado Water Conservation Board so that water stays in the stream. Every reach, with its schedule and case →
- Blue River, 15.4 mi: 60 (5/1 - 7/15), 85 (7/16 - 4/30) cfs (appropriated 1987, 87CW0299) · dossier
- Slate Creek, 7.0 mi: 3 (10/1 - 4/30), 7 (5/1 - 9/30) cfs (appropriated 1977, 77W3648) · dossier
- Blue River, 6.92 mi: 0.02 (5/1 - 5/31), 0.45 (6/1 - 6/30), 0.35 (7/1 - 7/31), 0.24 (8/1 - 8/31), 0.14 (9/1 - 9/30) cfs (appropriated 1904, 05CW0264) · dossier
- Blue River, 6.9 mi: 90 (10/1 - 11/30), 85 (12/1 - 2/29), 125 (5/1 - 9/30), 90 (3/1 - 4/30) cfs (appropriated 1987, 87CW0298) · dossier
- Blue River, 6.9 mi: 0.02 (5/1 - 5/31), 0.45 (6/1 - 6/30), 0.35 (7/1 - 7/31), 0.24 (8/1 - 8/31), 0.14 (9/1 - 9/30) cfs (appropriated 1904, 05CW0264) · dossier
- Straight Creek, 6.9 mi: 2.5 (1/1 - 12/31) cfs (appropriated 1985, 85CW0648) · dossier
and 69 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 1869-07-01 to 2022-08-29. Of the 20 structures with a yield estimate, the median one’s senior right was in priority 6% of a median irrigation season and 0% in a dry one. 6 abandonment screens and 171 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: 2640 across 1247 structure(s); 392 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.
The three measures, year by year
One row per whole calendar year inside the call record's coverage (38 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 | 184 | 1884-04-07 |
| 2015 | 365 | 256 | 1885-07-28 |
| 2016 | 366 | 237 | 1884-04-26 |
| 2017 | 365 | 330 | 1884-05-01 |
| 2018 | 365 | 290 | 1884-03-02 |
| 2019 | 365 | 165 | 1886-08-09 |
| 2020 | 366 | 221 | 1883-03-30 |
| 2021 | 365 | 218 | 1883-03-15 |
| 2022 | 365 | 201 | 1885-06-01 |
| 2023 | 365 | 120 | 1885-07-28 |
| 2024 | 366 | 164 | 1886-08-09 |
| 2025 | 365 | 232 | 1885-06-16 |
Why diversions stopped — call-based explanations
Sustained diversion stops matched to senior administrative calls.
- BROWN ACORN DITCH (3600540) DWR↗ stopped 2024-07-22 (95+ days) — call at BULL CREEK DITCH curtailing 100% of its decreed rate [heuristic-strong]
- DOMESTIC SUPPLY DITCH (3600591) DWR↗ stopped 2024-07-22 (95+ days) — call at BULL CREEK DITCH curtailing 100% of its decreed rate [heuristic-strong]
- C M OMER DITCH (3600569) DWR↗ stopped 2024-07-18 (99+ days) — call at EAST DIVIDE CREEK DITCH curtailing 100% of its decreed rate [heuristic-strong]
- BRUSH CREEK DITCH (3600541) DWR↗ stopped 2024-07-17 (70+ days) — call at EAST DIVIDE CREEK DITCH curtailing 73% of its decreed rate [heuristic-partial]
- ALBER DITCH (3600507) DWR↗ stopped 2024-07-14 (66+ days) — call at EAST DIVIDE CREEK DITCH curtailing 100% of its decreed rate [heuristic-strong]
- BELLS BLUE RIVER DITCH (3600520) DWR↗ stopped 2024-07-05 (15+ days) — call at ATKINSON DITCH curtailing 100% of its decreed rate [heuristic-strong]
- BELL DITCH (3600517) DWR↗ stopped 2024-06-27 (23+ days) — call at EAST DIVIDE CREEK DITCH curtailing 100% of its decreed rate [heuristic-strong]
- BELL NO 2 DITCH (3600519) DWR↗ stopped 2024-06-26 (10+ days) — call at EAST DIVIDE CREEK DITCH curtailing 100% of its decreed rate [heuristic-strong]
- DRY CREEK DITCH - HEADGATE NO 1 (3600593) DWR↗ stopped 2024-06-14 (25+ days) — call at BAKER DITCH curtailing 100% of its decreed rate [heuristic-strong]
- DRY CREEK NO 1 DITCH (3600594) DWR↗ stopped 2024-05-29 (114+ days) — call at HALKOWEIZ DITCH curtailing 100% of its decreed rate [heuristic-strong]
- DRY CREEK NO 2 DITCH (3600595) DWR↗ stopped 2024-05-29 (114+ days) — call at HALKOWEIZ DITCH curtailing 100% of its decreed rate [heuristic-strong]
- DRY CREEK NO 3 DITCH (3600596) DWR↗ stopped 2024-05-29 (114+ days) — call at HALKOWEIZ 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 |
|---|---|---|---|
| GREEN MTN HYDRO-ELECTRIC (3600881) DWR↗ | 1935-08-01 | 30.2% / 0.0% | 30.2% / 0.0% |
| BLUE RIVER DIVERSION PROJECT (3604684) DWR↗ | 1946-06-24 | 6.3% / 0.0% | 6.3% / 0.0% |
| TOWN OF BRECKENRIDGE WHITEWATER PARK (3607293) DWR↗ | 2000-12-21 | 2.8% / 0.0% | 2.8% / 0.0% |
| CLIMAX INTEGRATED WATER SYSTEM (3604923) DWR↗ | 1903-01-01 | 31.6% / 0.0% | 6.3% / 0.0% |
| CON-HOOSIER SYS BLUE RIVER DITCH (3604683) DWR↗ | 1948-05-13 | 6.3% / 0.0% | 2.8% / 0.0% |
| BLUE VALLEY RANCH HYDRO (3600985) DWR↗ | 1981-03-09 | 4.9% / 0.0% | 4.9% / 0.0% |
| MIN FLOW BLUE RIVER 9 - BOULDER CK TO SL (3602047) DWR↗ | 1904-05-23 | 67.5% / 0.0% | 4.9% / 0.0% |
| MIN FLOW BLUE RIVER 10 - SLATE CK TO GMR (3602048) DWR↗ | 1904-05-23 | 67.5% / 0.0% | 4.9% / 0.0% |
| MIN FLOW BLUE RIVER 8 - ROCK CK TO BOULD (3602046) DWR↗ | 1987-10-02 | 4.9% / 0.0% | 4.9% / 0.0% |
| CON-HOOSIER EAST HOOSIER DITCH (3604689) DWR↗ | 1929-08-05 | 30.2% / 0.0% | 6.3% / 0.0% |
| ELLIOTT CREEK FEEDER (3600606) DWR↗ | 1935-08-01 | 30.2% / 0.0% | 30.2% / 0.0% |
| MIN FLOW BLUE RIVER 11 - GMR TO COLORADO (3602049) DWR↗ | 1987-10-02 | 4.9% / 0.0% | 4.9% / 0.0% |
Abandonment radar (6 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 ~1969 — idleness that begins before then may be unreported use, not nonuse (flagged † below).
- SODA CREEK DITCH (3600809) DWR↗ (1900-07-01, 2.7 cfs decreed): last active 1969 — 11 years idle
- BENTON CREEK NO 1 DITCH (3600522) DWR↗ (1912-10-06, 4.2 cfs decreed): last active 1970 — 10 years idle
- BENTON CREEK NO 2 DITCH (3600523) DWR↗ (1904-10-30, 2.2 cfs decreed): last active 1970 — 10 years idle
- COULTER NO 1 DITCH (3600575) DWR↗ (1904-08-31, 0.8 cfs decreed): last active 1970 — 10 years idle
- COULTER NO 2 DITCH (3600576) DWR↗ (1913-04-24, 0.2 cfs decreed): last active 1970 — 10 years idle
- ENGLE DITCH (3600614) DWR↗ (1942-09-25, 4.1 cfs decreed): last active 1970 — 10 years idle
Compliance screens (171 advisory flags)
Screened 279 of 1247 structures with rights (341 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.
- MIN FLOW BLUE RIVER 5 - DILLON TO STRAIG (3602043) DWR↗: Observed p99 daily rate 947.0 cfs (max 1900.0) exceeds total decreed absolute 50.0 cfs across 5100 recorded day(s).
- MIN FLOW BLUE RIVER 4 - SWAN RIVER TO DI (3602037) DWR↗: Observed p99 daily rate 528.4 cfs (max 715.0) exceeds total decreed absolute 32.0 cfs across 4986 recorded day(s).
- BLUE VALLEY RANCH HYDRO (3600985) DWR↗: Observed p99 daily rate 222.0 cfs (max 222.0) exceeds total decreed absolute 129.0 cfs across 14666 recorded day(s).
- MIN FLOW BLUE RIVER 3 - SWAN RIVER UP TO (3602030) DWR↗: Observed p99 daily rate 177.0 cfs (max 339.0) exceeds total decreed absolute 20.0 cfs across 5822 recorded day(s).
- ELLIOTT CREEK FEEDER (3600606) DWR↗: Observed p99 daily rate 118.0 cfs (max 200.0) exceeds total decreed absolute 90.0 cfs across 17164 recorded day(s).
- MIN FLOW SNAKE RIVER LOW - NORTH FORK TO (3602033) DWR↗: Observed p99 daily rate 107.0 cfs (max 108.0) exceeds total decreed absolute 12.0 cfs across 4350 recorded day(s).
- MIN FLOW STRAIGHT CREEK (3602040) DWR↗: Observed p99 daily rate 90.6 cfs (max 125.0) exceeds total decreed absolute 2.5 cfs across 3580 recorded day(s).
- CON-HOOSIER SYS MCCULLOUGH DITCH (3604690) DWR↗: Observed p99 daily rate 76.0 cfs (max 128.4) exceeds total decreed absolute 60.0 cfs across 8214 recorded day(s).
- CON-HOOSIER TUNNEL (3604699) DWR↗: Observed p99 daily rate 65.7 cfs (max 163.5) exceeds total decreed absolute 20.0 cfs across 26128 recorded day(s).
- HOAGLAND CANAL (ELLIOT) (3600662) DWR↗: Observed p99 daily rate 65.0 cfs (max 69.9) exceeds total decreed absolute 25.0 cfs across 9969 recorded day(s).
Seniority (top structures by decreed rate)
| Structure | Senior priority date | Rights | Decreed abs (cfs) | Decreed abs (AF) | Conditional? |
|---|---|---|---|---|---|
| GREEN MTN HYDRO-ELECTRIC (3600881) DWR↗ | 1935-08-01 | 1 | 1726.0 | 0 | — |
| BLUE RIVER DIVERSION PROJECT (3604684) DWR↗ | 1946-06-24 | 1 | 654.0 | 0 | yes |
| TOWN OF BRECKENRIDGE WHITEWATER PARK (3607293) DWR↗ | 2000-12-21 | 1 | 500.0 | 0 | — |
| CLIMAX INTEGRATED WATER SYSTEM (3604923) DWR↗ | 1903-01-01 | 13 | 416.5 | 103 | yes |
| CON-HOOSIER SYS BLUE RIVER DITCH (3604683) DWR↗ | 1948-05-13 | 3 | 200.0 | 0 | — |
| BLUE VALLEY RANCH HYDRO (3600985) DWR↗ | 1981-03-09 | 1 | 129.0 | 0 | — |
| MIN FLOW BLUE RIVER 9 - BOULDER CK TO SL (3602047) DWR↗ | 1904-05-23 | 3 | 125.0 | 0 | — |
| MIN FLOW BLUE RIVER 10 - SLATE CK TO GMR (3602048) DWR↗ | 1904-05-23 | 2 | 125.0 | 0 | — |
| MIN FLOW BLUE RIVER 8 - ROCK CK TO BOULD (3602046) DWR↗ | 1987-10-02 | 1 | 115.0 | 0 | — |
| ELLIOTT CREEK FEEDER (3600606) DWR↗ | 1935-08-01 | 1 | 90.0 | 0 | — |
| CON-HOOSIER EAST HOOSIER DITCH (3604689) DWR↗ | 1929-08-05 | 2 | 90.0 | 0 | — |
| MIN FLOW BLUE RIVER 11 - GMR TO COLORADO (3602049) DWR↗ | 1987-10-02 | 1 | 85.0 | 0 | — |
| LOBACK DITCH (3600709) DWR↗ | 1930-12-31 | 4 | 75.8 | 0 | — |
| MIN FLOW BLUE RIVER 7 - ROCK CK TO WILLO (3602045) DWR↗ | 1987-10-02 | 1 | 75.0 | 0 | — |
| CON-HOOSIER SYS MCCULLOUGH DITCH (3604690) DWR↗ | 1948-05-13 | 3 | 60.0 | 0 | — |
Recent inventory & legal-document changes
- 2026-10-09 — call released: 39534
- 2026-10-08 — call set: GRAND VALLEY CANAL (39690)
- 2026-10-08 — call released: 36734
- 2026-10-08 — call released: 38588
- 2026-10-08 — call released: 39264
- 2026-10-07 — call set: CORNELL DITCH (39681)
- 2026-10-07 — call set: MOCKING BIRD DITCH (39686)
- 2026-10-07 — call released: 39636
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 (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.
All 10 filings, with excerpts
| Case | What it asks | County | Excerpt |
|---|---|---|---|
2026CW3048
|
— | — | CASE NO. 2026CW3048; Previous Case Nos. 20CW3005, 13CW3044, 01CW68 and 84CW178 – BOARD OF WATER WORKS OF PUEBLO, COLORADO, Attention: Executive Director, 319 West Fourth Street, Pueblo, Colorado 81003 (Please address all pleadings and inquiries regarding this … |
26CW3086
|
change of water right | GRAND | 26CW3086 GRAND COUNTY -RECTOR FAMILY LIMITED LIABILITY LIMITED PARTNERSHIP, MIKE RECTOR, GENERAL PARTNER (5 Inverness Dr. East, Englewood, CO 80112; mhr@rimop.com; 303-570-5174), c/o Valissa Tsoucaris, Esq., Tsoucaris Law, LLC, 3000 Holly Street, Denver, CO 80… |
26CW3097
|
reasonable diligence | PITKIN | 26CW3097 PITKIN COUNTY, COLORADO; COLORADO RIVER OR ITS TRIBUTARIES. WOODY CREEK COMMUNE 1, LLC; WOODY CREEK COMMUNE 2, LLC; WOODY CREEK COMMUNE 3, LLC; and WOODY CREEK COMMUNE 4, LLC, Colorado limited liability companies; c/o Danielle L. Van Arsdale, Esq., Wo… |
26CW3098
|
reasonable diligence | GRAND | 26CW3098 GRAND COUNTY. Ritschard Springs Association, P.O. Box 1594, Kremmling, CO 80459, c/o Kaitlin Randall and Kent Whitmer, JVAM PLLC, PO Box 878, Glenwood Springs, CO 81602, (970) 922 -2122. APPLICATION FOR FINDING OF SEPTEMBER 2026 RESUME WATER DIVISION … |
26CW3099
|
reasonable diligence | GARFIELD | 26CW3099 GARFIELD COUNTY, COLORADO, A SPRING TRIBUTARY TO THE COLORADO RIVER . S Bar Lazy S Enterprises LLC, P.O. Box 809, Silt, Colorado 81652. Please direct all correspondence to Jeffrey J. Conklin and Danielle T. Skinner of Karp Neu Hanlon, P.C., P.O. Drawe… |
26CW3100
|
reasonable diligence | PITKIN | 26CW3100 PITKIN COUNTY – ROARING FORK RIVER AND ITS TRIBUTARIES. RUSSELL WIGHT c/o Paul L. Noto and John Sittler, Patrick, Miller & Noto, P.C., 229 Midland Ave., Basalt, CO 81621 (970) 920-1030. APPLICATION FOR FINDINGS OF REASONABLE DILIGENCE. First Claim: Wi… |
26CW3101
|
reasonable diligence, make absolute | GARFIELD | 26CW3101 GARFIELD COUNTY, CANYON CRK, COLORADO RIVER. App for Reasonable Diligence and To Make Absolute. Ross Jeffery c/o Sherry Caloia, PO Box 443, Glenwood Sprgs 81602. Name: Ross Hydro, decreed in 20CW002 on 10/11/2020. Desc: 1 or more pipelines in NW¼ NE¼ … |
26CW3102
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— | GRAND | 26CW3102 GRAND COUNTY . Moose Ridge Association, c/o Robin Tieman, President, 4075 Nassau Pl., Boulder, CO 80301. Applicant is represented by Kaitlin Randall and Kent Whitmer, JVAM PLLC, PO Box 878, Glenwood Springs, CO 81602, (970) 922 - 2122. APPLICATION FOR… |
26CW3105
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reasonable diligence | PITKIN | 26CW3105 PITKIN COUNTY, COLORADO. WATER RIGHT TRIBUTARY TO THE ROARING FORK RIVER. Application for Findings of Reasonable Diligence. Aspen Skiing Company, LLC, c/o Kylie J. Crandall, Esq., Mark E. Hamilton, Esq., HOLLAND & HART LLP, 600 E. Main St., Suite 104,… |
26CW3107
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reasonable diligence | EAGLE | 26CW3107 EAGLE COUNTY, COLORADO, GROUNDWATER TRIBUTARY TO LAKE CREEK, TRIBUTARY TO THE EAGLE RIVER, TRIBUTARY TO THE COLORADO RIVER. WLC1003 LLC, 1003 Lake Creek Road, Edwards, Colorado 81632. Please direct all correspondence to Michael J. Sawyer and Erika S. … |
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 |
|---|---|---|---|---|---|
| CLIMAX MOLYBDENUM COMPANY EMERGENCY | 37-92-308(7) PLAN EMERGENCY | Approved | 2026-06-27 | — | plan file |
| COLORADO RIVER DISTRICT EMERGENCY 2026 | 37-92-308(7) PLAN EMERGENCY | Approved | 2026-10-31 | 3807128 | plan file |
| SUMMIT COUNTY LANDFILL | 37-92-308(5) PLANS LESS THAN 5 YEARS | Approved | 2026-12-31 | — | plan file |
| GALLOWAY BLUE VALLEY RANCH | 37-92-308(5) PLANS LESS THAN 5 YEARS | Pending | — | — | plan file |
| MARYLAND CREEK (M1996049) | 37-90-137(11) GRAVEL PIT PLAN | Division Review | — | — | plan file |
| SILVERTHORNE, TOWN OF - UNION WELLS 25CW3161 | 37-92-308(4) PLAN PENDING COURT APPLICATION | Division Review | — | — | plan file |
| BRECKENRIDGE SKI AREA RESTAURANTS | 37-92-308(5) PLANS LESS THAN 5 YEARS | Withdrawn | — | — | plan file |
| CLIMAX MOLYBDENUM COMPANY (12CW0176) | 37-92-308(4) PLAN PENDING COURT APPLICATION | Unacceptable | — | — | 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 2026-10-17 · 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.
| Site | Temp °C | Cond µS/cm | DO mg/L | Turb FNU | As of |
|---|---|---|---|---|---|
| BLUE RIVER BELOW DILLON, CO. | 6.5 | 274 | 2026-10-17 02:15 | ||
| BLUE RIVER NEAR DILLON, CO | 8.3 | 215 | 2026-10-17 03:00 |
Where water has been sampled
Source Register of another agency · fetched 2026-10-08 · verify at Water Quality Portal ↗
The portal lists 835 sampling stations in this district's watershed (Blue 14010002), of which 57 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 (46), Colorado River Watch (8), USGS Colorado Water Science Center (3). Most-sampled groups: Nutrient, Physical, Inorganics, Major, Metals, Inorganics, Minor, 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 ↗
19 community systems touch this district. None carries an open health-based violation on EPA's record. EPA sampled 5 of them for PFAS in 2023–25; 1 had PFOA or PFOS at or above the 2024 limit.
| System | Serves | EPA record | PFAS (UCMR 5) | Lead, latest 90th pct |
|---|---|---|---|---|
| SNAKE RIVER WD | 9,900 | 2 of 12 quarters with a violation | PFOA, PFOS at or over the limit | 0.0009 mg/L |
| BRECKENRIDGE TOWN OF | 28,315 | 9 of 12 quarters with a violation | none detected | 0.002 mg/L |
| SILVERTHORNE TOWN OF | 8,400 | 5 of 12 quarters with a violation | 2 detected, under the limits | 0.0 mg/L |
| COPPER MOUNTAIN CONSOLIDATED MD | 5,785 | clean, last 12 quarters | none detected | 0.005 mg/L |
| FRISCO TOWN OF | 4,495 | 4 of 12 quarters with a violation | none detected | 0.004 mg/L |
| DILLON TOWN OF | 3,254 | 1 of 12 quarters with a violation | not sampled | 0.005 mg/L |
| DILLON VALLEY DISTRICT | 3,063 | 2 of 12 quarters with a violation | not sampled | 0.003 mg/L |
| BUFFALO MOUNTAIN MD | 2,650 | clean, last 12 quarters | not sampled | 0.001 mg/L |
| EAST DILLON WD | 2,501 | 1 of 12 quarters with a violation | not sampled | 0.0042 mg/L |
| KEYSTONE RANCH | 670 | 2 of 12 quarters with a violation | not sampled | 0.006 mg/L |
and 9 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
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System status
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Active river calls
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Hydrographs vs. historical envelope
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Anomaly flags
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Snowpack — 6 SNOTEL sites report here. Runoff outlook — Dillon Reservoir Inflow: even odds of at least 25 kAF over 06-01 to 07-31 — 25% of a normal season, per NRCS, issued 2026-06-01 — the season’s final; new forecasts begin in January. Runoff outlook — Green Mountain Reservoir Inflow: even odds of at least 44 kAF over 06-01 to 07-31 — 27% of a normal season, per NRCS, issued 2026-06-01 — the season’s final; new forecasts begin in January. Full snow & runoff picture — charts, forecast history and how the forecasts have verified →
Sites, exceedance bands and sources
| SNOTEL site | Elev (ft) | SWE (in) | Median (in) | % of median | Typical peak |
|---|---|---|---|---|---|
| Copper Mountain | 10500 | 0.0 | 0.0 | — | April 26 (17.4 in) |
| Elliot Ridge | 10550 | 0.0 | 0.0 | — | April 25 (23.2 in) |
| Fremont Pass | 11310 | 0.2 | 0.6 | — | May 11 (20.8 in) |
| Grizzly Peak | 11110 | 0.1 | 0.3 | — | April 21 (19.6 in) |
| Hoosier Pass | 11600 | 0.8 | 0.4 | — | April 27 (17.3 in) |
| Summit Ranch | 9350 | 0.2 | 0.0 | — | April 9 (11.4 in) |
Dillon Reservoir Inflow — 06-01 to 07-31 volume, thousand acre-feet (chance the volume is AT LEAST this):
| 90% | 70% | 50% | 30% | 10% | Normal |
|---|---|---|---|---|---|
| 12 | 18 | 25 | 34 | 46 | 101 |
Green Mountain Reservoir Inflow — 06-01 to 07-31 volume, thousand acre-feet (chance the volume is AT LEAST this):
| 90% | 70% | 50% | 30% | 10% | Normal |
|---|---|---|---|---|---|
| 25 | 35 | 44 | 55 | 70 | 163 |
Snow-water equivalent and medians (1991–2020) from NRCS SNOTEL; seasonal volume forecasts from the NRCS National Water and Climate Center. Sites and forecast points are assigned to the district whose boundary contains them — snowpack that feeds this district can also sit in a neighboring headwater district. Toggle the Snow chip on the map above to see the sites.
Topology cross-check: 2 parent disagreements, 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, 25 agree. Know this water? Tell us →
| Stream | This site routes it to | DWR routes it to |
|---|---|---|
| West Tenmile Creek | the mainstem | Tenmile Creek |
| Soda Creek | the mainstem | Snake River |
Sizable streams DWR maps here that this network does not carry:
Cataract Creek (12 mi) · Slate Creek (10 mi) · Elliott Creek (9 mi) · Boulder Creek (9 mi) · French Gulch (8 mi) · Elliott Creek (7 mi) · Otter Creek (7 mi) · Beaver Creek (6 mi)