Hydrohistorian
Los Pinos River Basin
Who may take water from the Los Pinos 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.
Los Pinos River Basin on the ground — the ditches, wells, reservoirs and gages of Water District 31 · 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 Los Pinos River is critically low for late September -- 18% of normal flow. No call that the record places on it is active right now. DWR's statements do not settle whether 3 more calls reach it. This year's runoff outlook, issued 2026-06-01, called for 24% 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 6 ranked gages are running at a median 152% of their own long-term norm for this window — 3 below a typical year, 3 at or above. Driest relative to its record: SPRING CREEK DITCH (PINE RIVER CANAL) NEAR BAYFIELD, CO, ranking 3rd lowest of 15 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 21:12 from 8 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 8 gages with enough record, 0 are trending down and 0 up, and 1 carries a detected shift. The other 7 show no clear signal either way.
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 |
|---|---|---|---|---|---|
|
▸
Spring Creek at La Boca SPRILACO |
no clear trend | +0.73 cfs +2.2% | p=0.350 | 60 | ~1968 |
7 other gage(s) show no significant trend or changepoint (not shown).
How the measurement network itself changed
This basin was not always measured the way it is today — the API-era record is dense and recent, the early record sparse. 6 gage(s) and 36 structure(s) report in 2026, but structure reporting only reached half its modern level around ~1967. 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) |
|---|---|---|
| 1920s | 1 | 0 |
| 1930s | 1 | 0 |
| 1940s | 1 | 0 |
| 1950s | 3 | 49 |
| 1960s | 4 | 24 |
| 1970s | 4 | 100 |
| 1980s | 4 | 115 |
| 1990s | 4 | 124 |
| 2000s | 5 | 120 |
| 2010s | 5 | 92 |
| 2020s | 6 | 32 |
Mass-balance (network closure) trend
Structure divrec-history backfill coverage as of the last check: 10% of 1202 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 (1951–2026)
Mass-balance kinks computed for every summer month back to 1951 (746 reach-snapshots) — which reaches gain or lose water, and how that has shifted across decades. Each shift is cross-checked against the observation record above: as more diversions became metered, "unaccounted" water shrinks mechanically, which can masquerade as a hydrologic shift.
No reach shows a statistically significant long-term gain/loss shift.
Groundwater now has its own tab: 120 monitored well(s), water-table trends, stream corridors, and the advisory depletion screen.
Reservoirs now has its own tab: 30 reservoir(s), end-of-year storage back to 1951, click-to-chart histories.
Cross-gage pattern fingerprint
Over the 41-year window with full coverage (1986–2026), the dominant shared pattern across 3 gage(s) explains 88% of year-to-year variance (almost certainly a basin-wide climate/snowpack driver).
All gages in this window move with the shared pattern -- no localized outlier.
Structures most implicated by reconciliation (as of 2026-09-27)
Which structures' data absorbed the most correction when the current mass-balance snapshot was reconciled -- see the Historical tab for the full picture on any date.
- IGNACIO INTAKE GALLERY (diversion): +5.5 cfs (2% of that reach's correction)
- TOWN OF IGNACIO PL (diversion): +5.5 cfs (2% of that reach's correction)
- SP-1301 (return): +5.5 cfs (2% of that reach's correction)
- MCCATHRON SPRINGS (return): +5.5 cfs (2% of that reach's correction)
- HALLSTED SEPG DITCH NO 2 (diversion): +5.5 cfs (2% of that reach's correction)
- HALLSTED SEPG DITCH NO 1 (diversion): +5.5 cfs (2% of that reach's correction)
- DR MORRISON D (IGNACIO) (diversion): +5.5 cfs (2% of that reach's correction)
- KELSALL PINE RIVER PUMP (diversion): +5.5 cfs (2% of that reach's correction)
- LAPLAWD PINE RIVER DIVR AP PT 2 (diversion): +5.5 cfs (2% of that reach's correction)
- KELSALL PUMP (diversion): +5.5 cfs (2% 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 | 10% of schematic structures have data |
Independent check: PASS — 100.0000% agreement across 626,697 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 — 99.12% day-level agreement with USGS's own published records for the same gages, across 6 co-listed station(s) and 107,336 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.
Upstream revisions: DWR's HydroBase_CO_20260928 image changed 200 previously-published historical value(s) across 1 structure(s) in this basin. The revised record now governs; every change is logged, none swapped silently.
8 gage(s) / 126,857 daily values (1927-10-01–2026-09-27); 204 structure(s) with diversion records; 1037 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 ↗
181 water-level measurements across 120 monitored well(s) — 86 alluvial, 0 bedrock — plus 4 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 1 well(s) with enough record for a trend test: 0 declining, 0 rising.
Wells labeled by administrative world before anything else is said about them: tributary alluvium participates in the priority system; designated-basin and Denver Basin bedrock aquifers are governed differently and are excluded from stream-connection reasoning. Read bedrock declines differently too: deep bedrock aquifers recharge negligibly on human timescales, so a falling bedrock level is storage mining — effectively permanent — not a drought response that a wet year undoes. All screens advisory.
70% are constructed wells; 10% 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 located water-supply permits with an issue date, 1984 to 2026; half of them had been issued by 1995, and the busiest year was 2026 with 3. A permit is not a well, and the year is the date the paper was issued, not a drilling date.
water-supply permits issued that year
The counts by year, as a table
| Year | Issued | Monitoring holes | Water-supply | Issued through that year |
|---|---|---|---|---|
| 1984 | 2 | 0 | 2 | 2 |
| 1994 | 2 | 0 | 2 | 4 |
| 1995 | 1 | 0 | 1 | 5 |
| 2005 | 1 | 0 | 1 | 6 |
| 2024 | 1 | 0 | 1 | 7 |
| 2026 | 3 | 0 | 3 | 10 |
Every district in the file on one scale · the whole file, one year at a time · Plate 4 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 ↗
30 reservoir(s) with 2,048 storage measurement(s), 1951–2012. Basin storage as of 2011-10-19 (the record's own end — reservoir records publish ~annually): 58,940 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) | |
|---|---|---|---|---|---|
| ▸ VALLECITO RESERVOIR (3103518) | 58,751 | 2010-10-31 | — | — | dossier → |
| ▸ VALLECITO RESERVOIR (3103529) | 350 | 1980-08-07 | — | — | dossier → |
| ▸ EMERALD LAKE RESERVOIR (3103516) | 220 | 1951-09-01 | — | — | dossier → |
| ▸ WOMMER RESERVOIR NO 1 (3103517) | 189 | 2011-10-19 | — | — | dossier → |
| ▸ VALLECITO RESERVOIR (3103532) | 90 | 1980-07-10 | — | — | dossier → |
| ▸ BELLFLOWER RETENTION RES (3103520) | 60 | 1990-10-31 | — | — | dossier → |
| ▸ GOSNEY GRAVEL PIT NO. 1 (3103805) | 47 | 2003-10-31 | — | — | dossier → |
| ▸ VALLECITO RESERVOIR (3103531) | 37 | 1980-08-07 | — | — | dossier → |
Snow and runoff
Source Independent agency measurement · fetched 2026-10-17 · verify at NRCS report generator ↗ Source Our computation, scored against a reference · NRCS forecast, graded here against the gage record
Snow-water equivalent, WY2027
No snow on the ground — normal for the date; 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 |
|---|---|---|---|---|---|
| Vallecito | 10740 | 0.0 | 0.0 | — | April 5 (14.8 in) |
NRCS SNOTEL, daily. Sites are assigned to the district whose boundary contains them — the snow that feeds this district can also sit in a neighboring headwater district.
Two ways a snow year goes wrong (1987–2026)
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 7 of the last 40 winters the snow never came — the pack peaked below 80% of its median. In 2 more, the snow came but left early — a near-normal peak melted out two weeks or more ahead of its usual date, sending the water down before the season needed it.
The snow never came: 1988, 2002, 2007, 2015, 2018, 2025, 2026. The snow left early: 2012, 2022.
Computed by this site from 1 SNOTEL site’ full daily records (NRCS AWDB, back to 1987). 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 — Vallecito Reservoir Inflow
NRCS's final issue (2026-06-01) calls it even odds that at least 19 kAF arrives over 06-01 to 07-31 — 24% of a normal season; almost certainly at least 10, probably not more than 44. New forecasts begin in January. How to read these numbers →
| 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 |
|---|---|---|---|---|---|
| 10 | 14 | 19 | 29 | 44 | 79 |
How good are these forecasts here? (1950–1986)
Grading every April issue against what the river then delivered, measured at this gage’s own record — 37 seasons: the median miss of the 50% forecast is 14%, with a high bias of 1%.
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 →
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 14th-driest week 39 in 76 years of record at LOS PINOS RIVER AT LA BOCA, CO. (as of 2026-09-21; this week’s flow sits at the 18th 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, La Plata County is 6% in D2 severe 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 1951, week by week
Each thin row is a year at LOS PINOS RIVER AT LA BOCA, 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 37 weeks recorded so far, 2026’s weekly trace most resembles 1951 (mean gap 12.3 percentile points; next closest 2003 (13.0), 2002 (13.5)). The analog’s remainder is drawn as context — its ending is what happened to it, not a forecast for this year.
The Drought Monitor’s view since 2000
Mean share of area in each class across La Plata county — 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 (409 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 | 2025-02-03 → 2026-09-21 | 85 | 10th (2025-08-18) | not yet | — |
| unnamed dry spell | 2023-11-13 → 2024-11-04 | 51 | 11th (2024-04-08) | not yet | — |
| the 2020-22 drought | 2020-02-10 → 2023-06-05 | 173 | 5th (2021-04-05) | 0 weeks | — |
| the 2018 drought | 2018-02-05 → 2019-07-01 | 73 | 2nd (2019-01-21) | 0 weeks | — |
| the 2012-13 drought | 2012-08-27 → 2014-02-24 | 78 | 9th (2013-05-06) | 6 weeks | — |
| the 2002 drought | 2002-03-25 → 2004-06-14 | 116 | 3rd (2002-10-07) | 6 weeks | — |
| unnamed dry spell | 1990-02-19 → 1990-08-27 | 27 | 22nd (1990-04-09) | 4 weeks | — |
| the 1977 drought | 1977-05-02 → 1978-06-05 | 57 | 11th (1977-10-03) | 25 weeks | 9 yr (9 wells, 2 still below) |
| the 1963-64 drought | 1963-09-30 → 1965-02-22 | 73 | 20th (1964-05-18) | 10 weeks | — |
| unnamed dry spell | 1959-06-01 → 1960-05-02 | 48 | 16th (1959-09-21) | 1 week | — |
| the 1950s drought | 1956-09-17 → 1957-03-11 | 25 | 27th (1956-10-08) | 11 weeks | — |
| the 1950s drought | 1954-06-14 → 1954-11-22 | 23 | 28th (1954-06-21) | 54 weeks | — |
| the 1950s drought | 1953-08-03 → 1954-04-05 | 35 | 23rd (1953-09-28) | 87 weeks | — |
| the 1950s drought | 1951-03-26 → 1952-05-12 | 59 | 7th (1951-09-24) | 0 weeks | — |
Detected mechanically: the 26-week smoothed percentile below the 30th for at least 20 weeks; recovered on regaining the 50th. The water-table clock compares each monitoring well against its own pre-drought median (the 3 years before onset) and dates the year the median well got back — the aquifer remembers longest, and “still below” is a finding, not a gap. The knobs are stated because the episode list depends on them — a different reasonable choice merges or splits episodes at the edges. Names are attached where an episode overlaps a drought Colorado already talks about.
What drought has cost here
Since 1994, federal crop insurance has paid $689,401 in drought-caused claims across La Plata county — 18.3% of all insured crop losses there. The worst year was 2002 ($75,597).
USDA crop-insurance indemnities where the recorded cause of loss is drought, summed over the counties this district's gages sit in. Counties overlap water districts imperfectly, and insured-crop claims are a floor on drought damage, not a total. Source: USDA RMA cause-of-loss files.
When this basin claimed its water
Every bar is a year’s new appropriations (588 rights across 76 years of shared record), colored by that year’s wetness from the barcode above. Here the correlation is +0.32 — this basin tended to claim water after wet years, when the supply had just shown itself. 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 ↗
8 systems touch this district (8 community systems reporting 5,924 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 |
|---|---|---|---|
| BAYFIELD TOWN OF | 2,300 | Surface water | 100% of its area |
| FOREST LAKES MD | 1,699 | Groundwater | 100% of its area |
| IGNACIO TOWN OF | 800 | Purchased surface water | 100% of its area |
| LA PLATA ARCHULETA WATER DISTRICT | 510 | Purchased surface water | 100% of its area |
| HOMESTEAD TRAILS | 258 | Groundwater | 100% of its area |
| HAPPY SCENES WS INC | 209 | Groundwater | 100% of its area |
| FREEMAN CREEK | 88 | Groundwater under the influence of surface water | 100% of its area |
| HEARTWOOD CO OP HOUSING | 60 | Groundwater | 100% of its area |
Instream-flow rights held by the state
Source Register of another agency · fetched 2026-10-11 · verify at CWCB instream flow program ↗
5 reaches over 52.6 miles and 26 natural lake levels, held by the Colorado Water Conservation Board so that water stays in the stream. Every reach, with its schedule and case →
- Los Pinos River, 23.4 mi: 50 (10/1 - 5/9) cfs (appropriated 2006, 07CW0089)
- Los Pinos River, 14.9 mi: 136 (5/10 - 9/30) cfs (appropriated 2006, 07CW0089)
- Los Pinos River, 9.3 mi: 32 (1/1 - 12/31) cfs (appropriated 1984, 84CW0283) · dossier
- Los Pinos River, 4.47 mi: 1.2 (11/01 - 04/30), 2.8 (05/01 - 10/31) cfs (appropriated 2021, 21CW3049)
- Vallecito Creek, 0.51 mi: 20 (01/01 - 03/15), 33 (03/16 - 04/15), 92 (04/16 - 08/31), 70 (09/01 - 10/31), 45 (11/01 - 11/15), 31 (11/16 - 12/14), 25 (12/15 - 12/31) cfs (appropriated 2017, 17CW3045) · dossier
- ANNIE LAKE (appropriated 1976, W-1540-76) · dossier
and 25 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 1868-03-02 to 2025-10-01. Of the 20 structures with a yield estimate, the median one’s senior right was in priority 56% of a median irrigation season and 27% in a dry one. 25 abandonment screens and 102 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: 1122 across 1037 structure(s); 93 structure(s) carry 1 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: 1 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 | 319 | 117 | 1883-05-15 |
| 2015 | 316 | 90 | 1899-05-13 |
| 2016 | 273 | 94 | 1888-02-08 |
| 2017 | 297 | 98 | 1904-01-02 |
| 2018 | 285 | 164 | 1878-05-15 |
| 2019 | 186 | 53 | 1880-06-01 |
| 2020 | 240 | 171 | 1986-11-23 |
| 2021 | 246 | 143 | 1876-11-01 |
| 2022 | 261 | 161 | 1888-03-20 |
| 2023 | 198 | 82 | 1880-06-01 |
| 2024 | 231 | 114 | 1876-10-10 |
| 2025 | 281 | 169 | 1888-03-20 |
Why diversions stopped — call-based explanations
Sustained diversion stops matched to senior administrative calls.
- ROBERT MORRISON DITCH (3100547) DWR↗ stopped 2025-10-22 (9+ days) — call at LA PLATA RIVER BASIN curtailing 100% of its decreed rate [heuristic-partial]
- CATLIN DITCH (3100545) DWR↗ stopped 2025-09-11 (50+ days) — call at SPRING CREEK DITCH curtailing 100% of its decreed rate [heuristic-strong]
- DUNHAM IRRIGATION DITCH (3100550) DWR↗ stopped 2025-09-09 (52+ days) — call at SPRING CREEK DITCH curtailing 100% of its decreed rate [heuristic-strong]
- HIGBEE IRRIGATION DITCH (3100516) DWR↗ stopped 2025-09-07 (54+ days) — call at SPRING CREEK DITCH curtailing 100% of its decreed rate [heuristic-strong]
- BUHMAN DITCH (3100531) DWR↗ stopped 2025-08-19 (73+ days) — call at SPRING CREEK DITCH curtailing 100% of its decreed rate [heuristic-strong]
- BUHMAN DITCH (3100531) DWR↗ stopped 2025-07-01 (12+ days) — call at HENRY BOLEN DITCH curtailing 100% of its decreed rate [heuristic-strong]
- DUNHAM IRRIGATION DITCH (3100550) DWR↗ stopped 2025-06-18 (22+ days) — call at HENRY BOLEN DITCH curtailing 100% of its decreed rate [heuristic-strong]
- BUHMAN DITCH (3100531) DWR↗ stopped 2024-09-15 (9+ days) — call at HENRY BOLEN DITCH curtailing 100% of its decreed rate [heuristic-strong]
- HIGBEE IRRIGATION DITCH (3100516) DWR↗ stopped 2024-09-03 (9+ days) — call at HENRY BOLEN DITCH curtailing 100% of its decreed rate [heuristic-strong]
- PALMER DITCH (3100522) DWR↗ stopped 2024-07-06 (117+ days) — call at HENRY BOLEN DITCH curtailing 100% of its decreed rate [heuristic-strong]
- DUNHAM IRRIGATION DITCH (3100550) DWR↗ stopped 2024-06-25 (334+ days) — call at HENRY BOLEN DITCH curtailing 100% of its decreed rate [heuristic-strong]
- BUHMAN DITCH (3100531) DWR↗ stopped 2024-06-23 (30+ days) — call at CONLEY 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 |
|---|---|---|---|
| VALLECITO HYDROELECTRIC (3100844) DWR↗ | 1979-06-01 | 2.3% / 0.0% | 2.3% / 0.0% |
| SPRING CREEK DITCH (3101045) DWR↗ | 1868-07-25 | 100.0% / 100.0% | 1.4% / 0.0% |
| ROBERT MORRISON DITCH (3100547) DWR↗ | 1890-10-01 | 23.4% / 0.0% | 1.4% / 0.0% |
| KING DITCH (3100519) DWR↗ | 1881-05-01 | 51.4% / 22.0% | 2.3% / 0.0% |
| VALLECITO CREEK INSTREAM FLOW WATER RIGH (3101901) DWR↗ | 2017-03-23 | 1.4% / 0.0% | 1.4% / 0.0% |
| DR MORRISON DITCH (3101044) DWR↗ | 1868-07-25 | 100.0% / 100.0% | 16.8% / 0.0% |
| SCHRODER IRRIGATION DITCH (3100523) DWR↗ | 1881-09-01 | 48.1% / 19.2% | 1.4% / 0.0% |
| PORTER DITCH (3100583) DWR↗ | 1936-06-15 | 2.3% / 0.0% | 2.3% / 0.0% |
| WEMINUCHE PASS DITCH (3104637) DWR↗ | 1934-07-28 | 2.3% / 0.0% | 2.3% / 0.0% |
| THOMPSON-EPPERSON DITCH (3100511) DWR↗ | 1877-12-31 | 60.7% / 31.3% | 9.8% / 0.0% |
| LOS PINOS RIVER (3101900) DWR↗ | 1984-07-13 | 2.3% / 0.0% | 2.3% / 0.0% |
| PINE R WEMINUCHE PASS D (3104638) DWR↗ | 1934-10-11 | 2.3% / 0.0% | 2.3% / 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 ~1967 — idleness that begins before then may be unreported use, not nonuse (flagged † below).
- EMERALD LAKE RESERVOIR (3103516) DWR↗ (1976-05-12, 0.0 cfs decreed): last active 1951 — 74 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1967) -- early absence of record is weak evidence of nonuse
- LEIGH PIPELINE (3100738) DWR↗ (1973-06-01, 0.1 cfs decreed): last active 1969 — 56 years idle
- COUCH D NO 1 & PUMP PLT (3100602) DWR↗ (1969-03-01, 1.0 cfs decreed): last active 1972 — 53 years idle
- GEORGE B JONES DITCH (3100565) DWR↗ (1911-05-01, 2.5 cfs decreed): last active 1973 — 52 years idle
- COUCH D NO 2 & PUMP PLT (3100603) DWR↗ (1969-03-01, 1.0 cfs decreed): last active 1973 — 52 years idle
- MONTGOMERY DITCH (3100610) DWR↗ (1920-04-23, 4.0 cfs decreed): last active 1973 — 52 years idle
- LOWER WOMMER DITCH NO 1 (3100623) DWR↗ (1900-07-31, 3.0 cfs decreed): last active 1973 — 52 years idle
- LOWER WOMMER DITCH NO 2 (3100624) DWR↗ (1900-07-31, 2.0 cfs decreed): last active 1973 — 52 years idle
- CALMETT NO 1 PUMP AND PL (3100631) DWR↗ (1952-12-31, 0.7 cfs decreed): last active 1973 — 52 years idle
- CURRIE-JACK CREEK PL (3100643) DWR↗ (1965-07-06, 0.0 cfs decreed): last active 1973 — 52 years idle
Compliance screens (102 advisory flags)
Screened 139 of 1037 structures with rights (151 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.
- VALLECITO HYDROELECTRIC (3100844) DWR↗: Observed p99 daily rate 725.0 cfs (max 850.0) exceeds total decreed absolute 720.0 cfs across 40124 recorded day(s).
- KING DITCH (3100519) DWR↗: Observed p99 daily rate 116.0 cfs (max 758.6) exceeds total decreed absolute 106.2 cfs across 47452 recorded day(s).
- SCHRODER IRRIGATION DITCH (3100523) DWR↗: Observed p99 daily rate 64.9 cfs (max 82.0) exceeds total decreed absolute 63.5 cfs across 44216 recorded day(s).
- ROBT MORRISON D HEAIR EX (3100645) DWR↗: Observed p99 daily rate 54.0 cfs (max 56.0) exceeds total decreed absolute 2.5 cfs across 7116 recorded day(s).
- THOMPSON-EPPERSON DITCH (3100511) DWR↗: Observed p99 daily rate 45.0 cfs (max 66.0) exceeds total decreed absolute 35.4 cfs across 41129 recorded day(s).
- BEAR CREEK AND PINE RIVER DITCH (3100514) DWR↗: Observed p99 daily rate 22.6 cfs (max 110.0) exceeds total decreed absolute 14.0 cfs across 47111 recorded day(s).
- CEANABOO DITCH (3100502) DWR↗: Observed p99 daily rate 19.5 cfs (max 26.7) exceeds total decreed absolute 9.8 cfs across 34987 recorded day(s).
- LOS PINOS IRRIGATING DITCH (3100512) DWR↗: Observed p99 daily rate 19.0 cfs (max 35.8) exceeds total decreed absolute 11.5 cfs across 73215 recorded day(s).
- LA BOCA DITCH (3100507) DWR↗: Observed p99 daily rate 18.0 cfs (max 31.7) exceeds total decreed absolute 14.3 cfs across 22127 recorded day(s).
- KIRKPATRICK DITCH (3100535) DWR↗: Observed p99 daily rate 16.5 cfs (max 22.6) exceeds total decreed absolute 6.5 cfs across 10832 recorded day(s).
Seniority (top structures by decreed rate)
| Structure | Senior priority date | Rights | Decreed abs (cfs) | Decreed abs (AF) | Conditional? |
|---|---|---|---|---|---|
| VALLECITO HYDROELECTRIC (3100844) DWR↗ | 1979-06-01 | 1 | 720.0 | 0 | — |
| SPRING CREEK DITCH (3101045) DWR↗ | 1868-07-25 | 9 | 321.2 | 0 | yes |
| ROBERT MORRISON DITCH (3100547) DWR↗ | 1890-10-01 | 6 | 108.5 | 0 | — |
| KING DITCH (3100519) DWR↗ | 1881-05-01 | 4 | 106.2 | 0 | — |
| VALLECITO CREEK INSTREAM FLOW WATER RIGH (3101901) DWR↗ | 2017-03-23 | 1 | 92.0 | 0 | — |
| DR MORRISON DITCH (3101044) DWR↗ | 1868-07-25 | 2 | 72.6 | 0 | yes |
| SCHRODER IRRIGATION DITCH (3100523) DWR↗ | 1881-09-01 | 4 | 63.5 | 0 | — |
| PORTER DITCH (3100583) DWR↗ | 1936-06-15 | 2 | 48.0 | 0 | — |
| WEMINUCHE PASS DITCH (3104637) DWR↗ | 1934-07-28 | 4 | 40.0 | 0 | — |
| THOMPSON-EPPERSON DITCH (3100511) DWR↗ | 1877-12-31 | 6 | 35.4 | 0 | — |
| LOS PINOS RIVER (3101900) DWR↗ | 1984-07-13 | 1 | 32.0 | 0 | — |
| PINE R WEMINUCHE PASS D (3104638) DWR↗ | 1934-10-11 | 3 | 18.0 | 0 | — |
| DRY CREEK DITCH (3100660) DWR↗ | 1900-12-31 | 1 | 15.4 | 0 | — |
| LA BOCA DITCH (3100507) DWR↗ | 1868-07-25 | 1 | 14.3 | 0 | yes |
| BEAR CREEK AND PINE RIVER DITCH (3100514) DWR↗ | 1878-05-01 | 1 | 14.0 | 0 | — |
Recent inventory & legal-document changes
- 2026-10-01 — call released: 39556
- 2026-10-01 — call released: 37181
- 2026-09-30 — call released: 39596
- 2026-09-29 — call set: LA PLATA RIVER BASIN (39596)
- 2026-09-29 — call released: 38755
- 2026-09-26 — call released: 39564
- 2026-09-25 — call set: COTTONWOOD DITCH NO 2 (39564)
- 2026-09-25 — call released: 39537
Water-court filings this month (division-wide)
4 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 (44 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 4 filings, with excerpts
| Case | What it asks | County | Excerpt |
|---|---|---|---|
2026CW3027
|
— | LA PLATA | 2026CW3027 La Plata County, Water District No. 7 1. Name, address, and telephone number of applicant: Hermosa Sanitation District, PO Box 2217, Durango, CO 81302, 970-759-0185; Attorney: Floyd L. Smith, 48 CR 250, Suite 5, Durango, CO 81301; 2. Name of structu… |
2026CW3028
|
— | MINERAL | 2026CW3028 Mineral County, (18CW3051)… |
2026CW3029
|
reasonable diligence, make absolute, new underground right | ARCHULETA | 2026CW3029 Archuleta County, Application for Alternate Points of Diversion, To Make Absolute, and for a Finding of Reasonable Diligence for Surface and Underground Water Rights. 1. Applicants: Alpine Lakes Ranch Property Owners Association, Inc. and Alpine Lak… |
2026CW8
|
— | LA PLATA | 2026CW8 La Plata County, Brett A. Vuyk and Barbara L. Vuyk, 697 Sunrise Ln. Durango, CO 81301, Date of Original Decree: 7/18/2007 Case No. 06CW88, Subsequent decrees: Date of Decree: 1/10/2014 Case No. 13CW23, Date of Decree: 9/2/2020 Case No. 20CW1: Long Draw… |
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 |
|---|---|---|---|---|---|
| NORTHERN SAN JUAN BASIN FRUITLAND FORMATION PINE RIVER (10CW6) | 37-92-308(4) PLAN PENDING COURT APPLICATION | Pending | — | — | 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 ↗
1 USGS sensor reports 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 |
|---|---|---|---|---|---|
| VALLECITO CREEK NEAR BAYFIELD, CO. | 4.7 | 2026-10-17 14:45 |
Where water has been sampled
Source Register of another agency · fetched 2026-10-08 · verify at Water Quality Portal ↗
The portal lists 670 sampling stations in this district's watershed (Upper San Juan 14080101), of which 78 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: Southern Ute Tribe (37), Colorado Dept. of Public Health & Environment-WQCD (16), Mountain Studies Institute (MSI) (14). Most-sampled groups: Inorganics, Major, Metals, Physical, Nutrient, Organics, Other. 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 ↗
8 community systems touch this district. None carries an open health-based violation on EPA's record. EPA sampled 0 of them for PFAS in 2023–25.
| System | Serves | EPA record | PFAS (UCMR 5) | Lead, latest 90th pct |
|---|---|---|---|---|
| BAYFIELD TOWN OF | 2,300 | clean, last 12 quarters | not sampled | 0.0027 mg/L |
| FOREST LAKES MD | 1,699 | clean, last 12 quarters | not sampled | 0.0017 mg/L |
| IGNACIO TOWN OF | 800 | 9 of 12 quarters with a violation | not sampled | 0.0008 mg/L |
| LA PLATA ARCHULETA WATER DISTRICT | 510 | 1 of 12 quarters with a violation | not sampled | 0.0105 mg/L |
| HOMESTEAD TRAILS | 258 | clean, last 12 quarters | not sampled | 0.0017 mg/L |
| HAPPY SCENES WS INC | 209 | clean, last 12 quarters | not sampled | 0.0027 mg/L |
| FREEMAN CREEK | 88 | 4 of 12 quarters with a violation | not sampled | 0.0 mg/L |
| HEARTWOOD CO OP HOUSING | 60 | 5 of 12 quarters with a violation | not sampled | 0.0004 mg/L |
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 1 SNOTEL site — normal for the date; the snow year begins in October and typically peaks around April 5. Runoff outlook — Vallecito Reservoir Inflow: even odds of at least 19 kAF over 06-01 to 07-31 — 24% 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 |
|---|---|---|---|---|---|
| Vallecito | 10740 | 0.0 | 0.0 | — | April 5 (14.8 in) |
Vallecito Reservoir Inflow — 06-01 to 07-31 volume, thousand acre-feet (chance the volume is AT LEAST this):
| 90% | 70% | 50% | 30% | 10% | Normal |
|---|---|---|---|---|---|
| 10 | 14 | 19 | 29 | 44 | 79 |
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: 7 parent disagreements, 10 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 20 streams, 13 agree. Know this water? Tell us →
| Stream | This site routes it to | DWR routes it to |
|---|---|---|
| Grimes Creek | the mainstem | Vallecito Creek |
| Ignacio Creek | the mainstem | Rock Creek |
| Trail Canyon | the mainstem | no parent named |
| Tiffany Draw | the mainstem | Spring Creek |
| Rock Creek | the mainstem | Vallecito Creek |
| Pump Canyon | the mainstem | no parent named |
| Self Arroyo | the mainstem | Dry Creek |
Sizable streams DWR maps here that this network does not carry:
Bear Creek (11 mi) · Lake Creek (8 mi) · Flint Creek (7 mi) · Red Creek (7 mi) · East Creek (7 mi) · Sierra Vandera Creek (4 mi) · Indian Creek (4 mi) · Lion Creek (4 mi)