Rio Grande

Division 3 · Water District 20 · As of 2026-09-18 05:23 MDT · 4 weeks ago

Who may take water from the Rio Grande, 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.

Live · machine-built

Rio Grande on the ground — the ditches, wells, reservoirs and gages of Water District 20 · 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.

4% of normal flow, week of 2026-09-21

1 call the record places on it, 8 unsettled

The Rio Grande is critically low for late September -- 4% of normal flow, its 6th-driest such week in 129 years of record. 1 call stands against it right now; the most senior right calling dates to 1881. DWR's statements do not settle whether 8 more calls reach it. This year's runoff outlook, issued 2026-06-01, called for 25% of normal.

Schematic

Historical

Reconstruct conditions as of

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 60 ranked gages are running at a median 100% of their own long-term norm for this window — 26 below a typical year, 34 at or above. Driest relative to its record: BASSI NORTH FARM ROAD GRAVEL PIT, ranking 1st lowest of 2 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 20:06 from 98 gage(s) with cached period-of-record data. The series is each gage's annual mean flow in cfs (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 98 gages with enough record, 10 are trending down and 0 up, and 14 carry a detected shift. The clearest is Closed Basin Project Canal near Alamosa, its annual mean flow changing -6.03 cfs per decade (-27.9% of its median annual flow) over 37 years (p<0.0001). The other 80 show no clear signal either way. 4 transbasin gages meter imported or exported water — marked ⇆ below and kept out of these counts, because that flow is an operator's decision, not the basin's hydrology (all transbasin diversions).

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

Gage	Trend	Change / decade cfs · % of median annual flow	Significance	Years	Changepoint
▸ Closed Basin Project Canal near Alamosa CBPALACO	↓ decreasing	-6.03 cfs -27.9%	p<0.001	37	~2009
▸ ⚠️ ⇆ William's Creek-Squaw Pass Ditch at Grizzly Pass WCSDITCO	↑ increasing	+0.08 cfs	p<0.001	54	~1983
▸ Rio Grande near Lobatos RIOLOBCO	↓ decreasing	-34.74 cfs -8.6%	p<0.001	126	~1949
▸ Rio Grande at Embudo, Nm. RIOEMBNM	↓ decreasing	-36.56 cfs -4.8%	p<0.001	127	~1949
▸ ⚠️ San Marcial Conveyance Channel on Rio Grande, Nm SMCRIONM	↓ decreasing	-40.23 cfs -15.9%	p<0.001	71	~1975
▸ Rio Grande below Elephant Butte Dam, Nm RIOELENM	↓ decreasing	-39.58 cfs -4.3%	p<0.001	109	~1949
▸ Rio Grande at Wason, below Creede RIOWASCO	↓ decreasing	-58.17 cfs -9.2%	p=0.007	46	~1929
▸ Rio Grande at Otowi Bridge near San Ildefonso, Nm. RIOOTANM	↓ decreasing	-39.58 cfs -3.3%	p=0.009	122	~1945
▸ Rio Grande at Thirty Mile Bridge near Creede RIOMILCO	↓ decreasing	-5.13 cfs -2.6%	p=0.010	111	~1949
▸ Rio Grande near Del Norte RIODELCO	↓ decreasing	-18.67 cfs -2.1%	p=0.016	127	~1929
▸ ⚠️ ⇆ Weminuche Pass Ditch at Weminuche Pass WEMDITCO	↓ decreasing	-0.26 cfs -18.5%	p=0.024	56	~1986
▸ Rio Grande at Albuquerque, Nm. RIOALBNM	↓ decreasing	-90.81 cfs -9.7%	p=0.026	60	~1999
▸ ⚠️ ⇆ Treasure Pass Ditch at Wolf Creek Pass TREDITCO	no clear trend	-0.02 cfs	p=0.189	56	~1986
▸ ⚠️ Rio Grande Floodway at San Acacia, Nm RGFSANNM	no clear trend	+59.05 cfs +10.0%	p=0.199	67	~1978
▸ ⚠️ Rio Grande Floodway at San Marcial, Nm SMFRIONM	no clear trend	+29.86 cfs +7.3%	p=0.295	76	~1974
▸ ⚠️ ⇆ Don La Font Ditch No. 1 at Piedra Pass DLFDT1CO	no clear trend	-0.00 cfs	p=0.305	46	~1992
▸ Rio Chama below El Vado Dam, Nm RCHELVNM	no clear trend	+6.19 cfs +1.6%	p=0.393	90	~1978
▸ Rio Grande at Alamosa RIOALACO	no clear trend	-4.73 cfs -2.7%	p=0.423	113	~1929

⚠️ 7 gages flagged: their records may have quietly shifted against their neighbours, so treat their trends with caution.

How drift is detected

Every gage's annual flows are compared against each neighbour's as a double-mass curve (Searcy & Hardison, USGS WSP 1541-B); a Pettitt step test looks for a break in the ratio. A gage is flagged only when the breaks AGREE across its references, and a break against an already-suspect gage is never counted against a healthy one. A double-mass break means the ratio between two gages changed, not that either gage is faulty: a new diversion, a reservoir, or an import changes that ratio exactly as a rating shift does. Screening aid for expert review, never a measurement verdict.

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

2 of those show a significant trend once extended backwards from a retired neighbour's record: Rio Grande below Taos Junction Bridge near Taos, Nm (127 yr, decreasing); Rio Grande at Wagon Wheel Gap (118 yr, decreasing, suspect). Those are reconstructions, not measurements — each gage's page shows both.

How the measurement network itself changed

This basin was not always measured the way it is today — the API-era record is dense and recent, the early record sparse. 73 gage(s) and 311 structure(s) report in 2026, but structure reporting only reached half its modern level around ~1957. 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)
1880s	1	0
1890s	2	0
1900s	3	0
1910s	9	0
1920s	11	0
1930s	14	0
1940s	18	0
1950s	28	140
1960s	32	184
1970s	36	194
1980s	34	208
1990s	37	272
2000s	45	262
2010s	51	286
2020s	48	273

Mass-balance (network closure) trend

Structure divrec-history backfill coverage as of the last check: 9% of 2958 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 (4600 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.

RIO GRANDE AT MONTE VISTA: reach shifted from -934 cfs to +377 cfs summer mean (more gaining, p=0.000, 77 yr) [sedimentary uplands: moderate groundwater connectivity -- gain/loss shifts can be real aquifer response; corroborate with nearby well records] [measurement-evolution caution: this shift co-moves with the growth of the gage/metering network (rho=0.64) -- part of it may be unaccounted water becoming accounted, not hydrologic change] [3 alluvial wells within 2 mi of the gage; pooled water table -1.4 ft (1946–1975, no_trend)]
PRAIRIE DITCH NEAR SEVEN-MILE PLAZA: reach shifted from -239 cfs to -91 cfs summer mean (more gaining, p=0.004, 17 yr) [sedimentary uplands: moderate groundwater connectivity -- gain/loss shifts can be real aquifer response; corroborate with nearby well records] [4 alluvial wells within 2 mi of the gage; pooled water table -5.6 ft (1947–2005, no_trend)]
RIO GRANDE AT ALAMOSA: reach shifted from -291 cfs to +194 cfs summer mean (more gaining, p=0.002, 77 yr) [sedimentary uplands: moderate groundwater connectivity -- gain/loss shifts can be real aquifer response; corroborate with nearby well records] [measurement-evolution caution: this shift co-moves with the growth of the gage/metering network (rho=0.62) -- part of it may be unaccounted water becoming accounted, not hydrologic change] [2 alluvial wells within 2 mi of the gage; pooled water table +1.2 ft (1949–2021, increasing)]
PINOS CREEK NEAR DEL NORTE, CO.: reach shifted from -369 cfs to +30 cfs summer mean (more gaining, p=0.000, 77 yr) [mountain crystalline canyon: minimal groundwater storage -- large or shifting unaccounted losses here are more consistent with data/measurement issues or unmodeled plumbing than with aquifer exchange] [measurement-evolution caution: this shift co-moves with the growth of the gage/metering network (rho=0.63) -- part of it may be unaccounted water becoming accounted, not hydrologic change]
RIO GRANDE ABOVE TRINCHERA CREEK NEAR LA SAUSES: reach shifted from +43 cfs to +206 cfs summer mean (more gaining, p=0.003, 77 yr) [sedimentary uplands: moderate groundwater connectivity -- gain/loss shifts can be real aquifer response; corroborate with nearby well records] [measurement-evolution caution: this shift co-moves with the growth of the gage/metering network (rho=0.66) -- part of it may be unaccounted water becoming accounted, not hydrologic change]
BEAVER CREEK BELOW BEAVER CREEK RESERVOIR: reach shifted from -70 cfs to -40 cfs summer mean (more gaining, p=0.009, 29 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: 605 monitored well(s), water-table trends, stream corridors, and the advisory depletion screen.

Reservoirs now has its own tab: 66 reservoir(s), end-of-year storage back to 1975, click-to-chart histories.

Cross-gage pattern fingerprint

Over the 115-year window with full coverage (1912–2026), the dominant shared pattern across 3 gage(s) explains 94% 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.

SONDLES D (diversion): -33.0 cfs (25% of that reach's correction)
HEILMAN SLOUGH D (diversion): -33.0 cfs (25% of that reach's correction)
BLANCA CNL (diversion): -33.0 cfs (25% of that reach's correction)
KENILWORTH CNL (diversion): -33.0 cfs (25% of that reach's correction)
ORR WASTE D (diversion): +22.0 cfs (6% of that reach's correction)
EHROWITZ D (diversion): +22.0 cfs (6% of that reach's correction)
WILLOW ROAD SPRING (return): +22.0 cfs (6% of that reach's correction)
WILLOW SPRING (return): +22.0 cfs (6% of that reach's correction)
UPPER HORSE CANYON SPR (return): +22.0 cfs (6% of that reach's correction)
LOG CANYON SPRING (return): +22.0 cfs (6% of that reach's correction)

Data provenance & quality

Where these numbers come from and how far they can be trusted. Grade C (3/6 points) — the components below are the finding; the letter alone is not. Sources: DWR HydroBase snapshot HydroBase_CO_20260928 (imported 2026-10-04) for history, plus the CDSS REST API for current conditions.

Check	State	What was measured
gage freshness	stale	newest gage reading is 14 day(s) old (target 7)
diversion record	expected-lag	newest diversion record is 346 day(s) old (DWR publishes ~1 year in arrears)
structure coverage	sparse	9% of schematic structures have data

Independent check: PASS — 100.0000% agreement across 262,508 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 — 99.67% day-level agreement with USGS's own published records for the same gages, across 31 co-listed station(s) and 777,166 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.

98 gage(s) / 1,211,596 daily values (1889-01-01–2026-09-27); 619 structure(s) with diversion records; 8023 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 ↗

52,552 water-level measurements across 605 monitored well(s) — 350 alluvial, 117 bedrock — plus 2 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 149 well(s) with enough record for a trend test: 95 declining, 7 rising.

Fastest-declining wells	Setting	ft / decade	Span	p
▸ NA04000732CCC	alluvial	-10.46	14 yr	0.0228
▸ NA04100636DDD RG33B	alluvial	-10.45	25 yr	0.0
▸ NA04000801AAD1 RG29A	alluvial	-10.37	10 yr	0.0006
▸ NA04000931BAB1	unknown	-8.34	34 yr	0.0001
▸ NA04101032ABB1 EW-40U	alluvial	-8.2	33 yr	0.0012
▸ NA04101032ABB2 EW-40C	alluvial	-7.96	33 yr	0.0007
▸ NA04100936DDA RG28A	alluvial	-7.53	42 yr	0.0
▸ NA04000804BCC2	alluvial	-7.17	56 yr	0.0

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.

RIO GRANDE AT MONTE VISTA: 3 alluvial well(s) nearby; pooled water table -1.4 ft (1946–1975, no_trend, p=0.2643). Glover screen: 0.4 cfs of nearby metered alluvial pumping → est. lagged depletion 0.2–0.3 cfs (uncalibrated T/S ranges; flagged for SPDSS calibration, AWAS cross-check, and expert review — DWR's AWAS is the authority).

PRAIRIE DITCH NEAR SEVEN-MILE PLAZA: 4 alluvial well(s) nearby; pooled water table -5.6 ft (1947–2005, no_trend, p=0.0892)

RIO GRANDE AT ALAMOSA: 2 alluvial well(s) nearby; pooled water table +1.2 ft (1949–2021, increasing, p=0.0)

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.

21,691 well permits on file — not decreed rights

55% household or domestic use

100 ft median depth, 15,403 wells reporting

62% are constructed wells; 32% 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

15,458 located water-supply permits with an issue date, 1915 to 2026; half of them had been issued by 1994, and the busiest year was 1972 with 1,895. The district’s 1,300 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 21,691 above counts every permit on file here; 4,933 of them have no usable location or no issue date and are not in this chart.

Show the monitoring holes too (1,300; the scale changes)

water-supply permits issued that year monitoring holes, when shown 3 issued before 1950 are in the table, not the bars

The counts by year, as a table

Located well permits with an issue date in this district, by issue year. Monitoring holes are the two DWR monitoring categories; water-supply is everything else.
Year	Issued	Monitoring holes	Water-supply	Issued through that year
1915	1	0	1	1
1935	1	0	1	2
1945	1	0	1	3
1950	1	0	1	4
1953	26	0	26	30
1954	92	0	92	122
1955	147	0	147	269
1956	136	0	136	405
1957	63	0	63	468
1958	81	0	81	549
1959	242	0	242	791
1960	381	0	381	1,172
1961	35	0	35	1,207
1962	15	0	15	1,222
1963	41	0	41	1,263
1964	63	0	63	1,326
1965	125	0	125	1,451
1966	35	0	35	1,486
1967	55	0	55	1,541
1968	49	0	49	1,590
1969	48	0	48	1,638
1970	38	0	38	1,676
1971	118	0	118	1,794
1972	1,895	0	1,895	3,689
1973	223	0	223	3,912
1974	135	0	135	4,047
1975	112	0	112	4,159
1976	210	0	210	4,369
1977	252	0	252	4,621
1978	274	0	274	4,895
1979	214	0	214	5,109
1980	178	0	178	5,287
1981	239	0	239	5,526
1982	179	0	179	5,705
1983	168	0	168	5,873
1984	148	0	148	6,021
1985	151	0	151	6,172
1986	118	0	118	6,290
1987	132	0	132	6,422
1988	148	26	122	6,570
1989	166	2	164	6,736
1990	235	57	178	6,971
1991	186	13	173	7,157
1992	162	11	151	7,319
1993	332	70	262	7,651
1994	339	59	280	7,990
1995	346	65	281	8,336
1996	432	74	358	8,768
1997	434	59	375	9,202
1998	471	67	404	9,673
1999	388	29	359	10,061
2000	385	43	342	10,446
2001	380	30	350	10,826
2002	552	24	528	11,378
2003	507	39	468	11,885
2004	334	30	304	12,219
2005	213	15	198	12,432
2006	233	20	213	12,665
2007	215	17	198	12,880
2008	150	3	147	13,030
2009	169	9	160	13,199
2010	153	2	151	13,352
2011	133	6	127	13,485
2012	158	14	144	13,643
2013	194	22	172	13,837
2014	173	9	164	14,010
2015	191	67	124	14,201
2016	173	43	130	14,374
2017	207	41	166	14,581
2018	175	23	152	14,756
2019	186	49	137	14,942
2020	185	9	176	15,127
2021	285	34	251	15,412
2022	273	31	242	15,685
2023	280	74	206	15,965
2024	303	102	201	16,268
2025	228	11	217	16,496
2026	262	1	261	16,758

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

53 PLSS townships here where at least 5 water-supply permits naming the same aquifer filed a depth (14,085 permits in all; the 24 most-drilled are drawn, every one is in the table). Each column is one township, six miles square, on one scale to 1,500 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. 5 of these townships straddle a district line and are filed here because most of their permits are.

T40N R8E New Mexico PM
914

T39N R7E New Mexico PM
843

T39N R8E New Mexico PM
752

T37N R10E New Mexico PM
701

T40N R3E New Mexico PM
678

T40N R7E New Mexico PM
674

T40N R4E New Mexico PM
654

T39N R10E New Mexico PM
643

T38N R8E New Mexico PM
627

T40N R10E New Mexico PM
622

T40N R9E New Mexico PM
581

T39N R9E New Mexico PM
578

T37N R9E New Mexico PM
534

T41N R1W New Mexico PM
450

T38N R9E New Mexico PM
425

T36N R9E New Mexico PM
416 · 61% here

T40N R6E New Mexico PM
395

T37N R8E New Mexico PM
389

T38N R10E New Mexico PM
365

T38N R11E New Mexico PM
289 · 77% here

T40N R5E New Mexico PM
276

T37N R11E New Mexico PM
269

T36N R8E New Mexico PM
263 · 66% here

T39N R3E New Mexico PM
251

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

Water-supply permits by PLSS township and the aquifer named on them, where at least 5 filed a depth: percentiles of the depth drilled to and of the screen top and bottom (where at least 5 filed a screen), feet below ground as filed. The permit file’s view, not a geologic map.
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
T40N R8E New Mexico PM	100%	unnamed	699	53 / 100 / 169	10 / 20 / 46	60 / 98 / 115
T40N R8E New Mexico PM	100%	other named	215	70 / 100 / 199	20 / 40 / 179	79 / 100 / 200
T39N R7E New Mexico PM	100%	unnamed	607	44 / 100 / 180	16 / 70 / 151	54 / 110 / 184
T39N R7E New Mexico PM	100%	other named	236	50 / 110 / 200	30 / 80 / 166	60 / 110 / 200
T39N R8E New Mexico PM	100%	unnamed	518	36 / 87 / 250	8 / 20 / 59	40 / 82 / 125
T39N R8E New Mexico PM	100%	other named	234	50 / 97 / 300	20 / 46 / 201	55 / 88 / 272
T37N R10E New Mexico PM	100%	other named	248	40 / 158 / 758	20 / 102 / 442	40 / 156 / 525
T37N R10E New Mexico PM	100%	unnamed	453	27 / 300 / 950	8 / 65 / 890	30 / 137 / 1,526
T40N R3E New Mexico PM	100%	alluvium	5	30 / 49 / 229	—	—
T40N R3E New Mexico PM	100%	other named	56	32 / 50 / 72	24 / 38 / 55	34 / 50 / 150
T40N R3E New Mexico PM	100%	unnamed	617	34 / 60 / 478	25 / 50 / 307	40 / 95 / 514
T40N R7E New Mexico PM	100%	unnamed	495	60 / 107 / 177	18 / 40 / 100	81 / 110 / 177
T40N R7E New Mexico PM	100%	other named	179	80 / 120 / 184	20 / 60 / 140	87 / 117 / 190
T40N R4E New Mexico PM	100%	other named	42	29 / 56 / 172	20 / 40 / 113	29 / 52 / 173
T40N R4E New Mexico PM	100%	unnamed	611	36 / 70 / 360	24 / 50 / 257	40 / 78 / 365
T39N R10E New Mexico PM	100%	other named	380	40 / 70 / 120	18 / 20 / 60	40 / 60 / 113
T39N R10E New Mexico PM	100%	unnamed	263	49 / 80 / 522	10 / 20 / 55	50 / 66 / 120
T38N R8E New Mexico PM	100%	unnamed	318	30 / 64 / 533	5 / 15 / 349	30 / 50 / 589
T38N R8E New Mexico PM	100%	other named	309	42 / 140 / 361	20 / 100 / 320	40 / 120 / 400
T40N R10E New Mexico PM	99%	other named	278	60 / 80 / 120	19 / 34 / 61	60 / 80 / 120
T40N R10E New Mexico PM	99%	unnamed	344	63 / 100 / 457	12 / 20 / 50	70 / 98 / 134
T40N R9E New Mexico PM	100%	unnamed	398	63 / 90 / 250	10 / 20 / 42	61 / 86 / 125
T40N R9E New Mexico PM	100%	other named	183	70 / 90 / 109	17 / 30 / 60	70 / 85 / 100
T39N R9E New Mexico PM	100%	other named	206	60 / 80 / 216	18 / 30 / 60	60 / 80 / 115
T39N R9E New Mexico PM	100%	unnamed	371	53 / 88 / 325	10 / 20 / 45	50 / 80 / 116
T37N R9E New Mexico PM	99%	other named	270	50 / 222 / 623	30 / 170 / 450	50 / 200 / 581
T37N R9E New Mexico PM	99%	unnamed	263	125 / 500 / 1,462	33 / 300 / 790	122 / 540 / 1,716
T41N R1W New Mexico PM	100%	unnamed	414	53 / 98 / 198	42 / 80 / 140	60 / 100 / 190
T41N R1W New Mexico PM	100%	other named	36	64 / 100 / 186	51 / 74 / 124	63 / 99 / 164
T38N R9E New Mexico PM	100%	other named	242	40 / 60 / 300	20 / 34 / 160	40 / 60 / 200
T38N R9E New Mexico PM	100%	unnamed	183	35 / 230 / 898	12 / 40 / 800	35 / 78 / 900
T36N R9E New Mexico PM	61%	other named	164	90 / 240 / 536	59 / 178 / 312	90 / 230 / 408
T36N R9E New Mexico PM	61%	unnamed	252	47 / 249 / 600	10 / 225 / 429	144 / 455 / 685
T40N R6E New Mexico PM	100%	unnamed	359	25 / 74 / 160	19 / 50 / 114	40 / 100 / 182
T40N R6E New Mexico PM	100%	other named	33	45 / 100 / 180	18 / 40 / 65	45 / 100 / 133
T37N R8E New Mexico PM	100%	other named	140	60 / 200 / 450	40 / 150 / 320	60 / 200 / 446
T37N R8E New Mexico PM	100%	unnamed	249	75 / 280 / 655	24 / 113 / 328	117 / 300 / 806
T38N R10E New Mexico PM	99%	other named	195	40 / 60 / 734	19 / 30 / 482	40 / 58 / 726
T38N R10E New Mexico PM	99%	unnamed	170	28 / 122 / 966	14 / 40 / 904	41 / 108 / 1,543
T38N R11E New Mexico PM	77%	other named	197	40 / 200 / 610	20 / 180 / 520	40 / 254 / 619
T38N R11E New Mexico PM	77%	unnamed	92	45 / 300 / 773	22 / 160 / 492	42 / 285 / 606
T40N R5E New Mexico PM	100%	unnamed	255	31 / 100 / 380	28 / 117 / 300	50 / 164 / 400
T40N R5E New Mexico PM	100%	other named	21	40 / 120 / 140	30 / 100 / 100	51 / 120 / 127
T37N R11E New Mexico PM	97%	other named	141	39 / 60 / 300	20 / 30 / 196	40 / 50 / 220
T37N R11E New Mexico PM	97%	unnamed	128	77 / 234 / 700	15 / 80 / 540	35 / 155 / 586
T36N R8E New Mexico PM	66%	other named	68	50 / 163 / 478	20 / 146 / 203	55 / 175 / 585
T36N R8E New Mexico PM	66%	unnamed	195	60 / 300 / 676	9 / 189 / 340	60 / 320 / 700
T39N R3E New Mexico PM	100%	other named	22	40 / 50 / 103	26 / 34 / 62	40 / 50 / 86
T39N R3E New Mexico PM	100%	unnamed	228	39 / 145 / 363	30 / 120 / 290	50 / 190 / 382
T39N R5E New Mexico PM	100%	other named	16	52 / 100 / 320	18 / 39 / 287	54 / 93 / 307
T39N R5E New Mexico PM	100%	unnamed	140	20 / 200 / 505	21 / 140 / 321	60 / 216 / 501
T38N R7E New Mexico PM	99%	unnamed	114	60 / 159 / 398	40 / 120 / 376	93 / 166 / 418
T38N R7E New Mexico PM	99%	other named	40	41 / 196 / 242	27 / 153 / 200	45 / 193 / 237
T41N R3W New Mexico PM	100%	unnamed	130	30 / 65 / 300	22 / 58 / 274	35 / 96 / 303
T41N R3W New Mexico PM	100%	other named	14	41 / 114 / 185	26 / 58 / 161	41 / 114 / 185
T41N R1E New Mexico PM	100%	other named	6	45 / 124 / 290	34 / 102 / 250	45 / 122 / 290
T41N R1E New Mexico PM	100%	unnamed	121	35 / 125 / 325	25 / 125 / 277	43 / 164 / 324
T40N R1W New Mexico PM	100%	other named	14	34 / 60 / 83	24 / 45 / 71	34 / 60 / 83
T40N R1W New Mexico PM	100%	unnamed	84	41 / 80 / 120	33 / 61 / 113	40 / 80 / 123
T39N R11E New Mexico PM	79%	other named	75	40 / 60 / 238	20 / 30 / 242	40 / 60 / 286
T39N R11E New Mexico PM	79%	unnamed	20	49 / 72 / 209	20 / 40 / 68	46 / 60 / 97
T41N R4W New Mexico PM	100%	unnamed	85	30 / 52 / 122	21 / 36 / 68	34 / 50 / 135
T39N R6E New Mexico PM	100%	unnamed	84	50 / 220 / 417	36 / 162 / 360	60 / 214 / 412
T41N R2W New Mexico PM	100%	unnamed	67	35 / 44 / 262	22 / 30 / 178	35 / 43 / 259
T40N R2E New Mexico PM	100%	other named	8	45 / 60 / 90	40 / 48 / 76	45 / 60 / 89
T40N R2E New Mexico PM	100%	unnamed	57	38 / 79 / 302	39 / 60 / 81	50 / 80 / 300
T40N R11E New Mexico PM	52%	other named	40	86 / 114 / 140	19 / 41 / 54	75 / 85 / 98
T40N R11E New Mexico PM	52%	unnamed	16	86 / 137 / 385	34 / 43 / 180	76 / 84 / 235
T37N R7E New Mexico PM	98%	other named	15	91 / 120 / 169	73 / 90 / 120	89 / 120 / 161
T37N R7E New Mexico PM	98%	unnamed	33	65 / 150 / 209	28 / 90 / 180	100 / 157 / 454
T41N R2E New Mexico PM	100%	unnamed	39	31 / 52 / 170	20 / 40 / 160	35 / 56 / 170
T38N R5E New Mexico PM	100%	unnamed	35	14 / 80 / 421	17 / 84 / 372	36 / 268 / 425
T39N R2E New Mexico PM	100%	unnamed	31	25 / 80 / 100	14 / 62 / 97	29 / 80 / 117
T42N R1W New Mexico PM	100%	unnamed	33	10 / 100 / 898	7 / 155 / 768	22 / 195 / 968
T40N R2W New Mexico PM	100%	unnamed	32	30 / 60 / 317	20 / 84 / 300	39 / 104 / 360
T41N R5E New Mexico PM	100%	unnamed	21	100 / 240 / 344	92 / 180 / 274	112 / 240 / 398
T38N R6E New Mexico PM	100%	unnamed	11	220 / 340 / 640	196 / 280 / 593	264 / 340 / 673
T38N R4E New Mexico PM	100%	unnamed	11	12 / 47 / 370	—	—
T39N R4E New Mexico PM	100%	unnamed	12	98 / 190 / 600	26 / 120 / 560	97 / 223 / 600
T41N R3E New Mexico PM	100%	unnamed	10	30 / 50 / 173	13 / 45 / 147	40 / 65 / 182
T41N R4E New Mexico PM	100%	unnamed	9	14 / 60 / 340	28 / 140 / 356	48 / 200 / 412
T41N R5W New Mexico PM	100%	unnamed	9	100 / 345 / 473	85 / 182 / 300	140 / 372 / 485
T40N R3W New Mexico PM	100%	unnamed	8	21 / 44 / 92	—	—
T37N R6E New Mexico PM	100%	unnamed	7	49 / 365 / 741	—	—
T38N R2E New Mexico PM	100%	unnamed	7	25 / 70 / 149	—	—
T40N R1E New Mexico PM	100%	unnamed	5	72 / 260 / 360	—	—
T40N R4W New Mexico PM	100%	unnamed	6	32 / 100 / 245	—	—

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.

Line Corridor

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 ↗

66 reservoir(s) with 27,950 storage measurement(s), 1975–2026. Basin storage as of 2025-10-31 (the record's own end — reservoir records publish ~annually): 48,114 AF across 16 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)
▸ RIO GRANDE RES (2003554)	23,219	2025-10-31	—	—	dossier →
▸ CONTINENTAL RES (2003536)	12,320	2025-10-31	—	—	dossier →
▸ SANTA MARIA RES (2003558)	5,176	2025-10-31	—	—	dossier →
▸ BEAVER PARK RES (2003532)	2,714	2025-10-31	—	—	dossier →
▸ BIG MEADOWS RES (2003589)	2,269	2025-10-31	—	—	dossier →
▸ ROAD CANYON RES (2003555)	1,281	2010-10-31	—	—	dossier →
▸ LOST LAKES RESERVOIR (2003546)	835	2025-10-29	—	—	dossier →
▸ LAKE HUMPHREYS RES (2003587)	715	2010-10-31	—	—	dossier →

Snow and runoff

Source Independent agency measurement · fetched 2026-10-15 · verify at NRCS report generator ↗ Source Our computation, scored against a reference · NRCS forecast, graded here against the gage record

Snow-water equivalent, WY2027

A trace of snow at 5 of 5 sites (3.4 in of water at most); the median for the date is zero, so there is no percent to show yet. The snow year begins in October. The new water year began October 1; the chart fills in a day at a time as NRCS publishes each reading.

SNOTEL site	Elev (ft)	SWE (in)	Median (in)	% of median	Typical peak
Beartown	11580	3.4	0.0	—	April 17 (23.2 in)
Grayback	11620	0.4	—	—	—
Middle Creek	11260	2.2	0.0	—	April 15 (19.2 in)
Rat Creek	11680	2.2	—	—	—
Upper Rio Grande	9370	0.1	0.0	—	March 18 (6.6 in)

NRCS SNOTEL, daily. Sites are assigned to the district whose boundary contains them — the snow that feeds this district can also sit in a neighboring headwater district.

Two ways a snow year goes wrong (1981–2026)

A bad snow year here comes in two flavors (both called snow drought), and the river feels them differently. In 7 of the last 46 winters the snow never came — the pack peaked below 80% of its median. In 3 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, 1996, 2002, 2003, 2018, 2025, 2026. The snow left early: 2006, 2012, 2022.

Computed by this site from 5 SNOTEL sites’ full daily records (NRCS AWDB, back to 1981). Each year is measured against each site’s own multi-decade median — not the 1991–2020 normal the chart above uses — so the 1980s grade against a fair baseline. Peak and melt-out need 85% of the season’s days on the record; thin years are dropped, not guessed. Derived from snow measurements alone — it cannot tell dry-from-warm causes apart, only what the snowpack did.

Runoff outlook — Rio Grande at Thirty Mile Bridge

NRCS's final issue (2026-06-01) calls it even odds that at least 19 kAF arrives over 06-01 to 09-30 — 26% of a normal season; almost certainly at least 10, probably not more than 43. Our own record at this gage shows 22 kAF actually delivered. New forecasts begin in January. How to read these numbers →

We test a record-based adjustment of the April benchmark at every graded point. Here it did not beat NRCS over 81 replayed seasons (13% typical miss unadjusted vs 16% adjusted), so none is shown — NRCS’s own forecast, unadjusted, is the best April benchmark available for this river. Why we test →

90% chance of at least	70% chance of at least	50% chance of at least	30% chance of at least	10% chance of at least	Normal	Observed
10	15	19	29	43	72	22

How good are these forecasts here? (1962–2025)

Grading every April issue against what the river then delivered, measured at this gage’s own record — 62 seasons: the median miss of the 50% forecast is 14%, with a low bias of 4%, and the observed volume landed inside the stated 10–90% band 84% of the time (a calibrated forecast would say 80%).

Computed by this site: NRCS's archived April issues (their period as issued each year) against the observed volume in DWR’s published record; years with under 90% daily coverage are dropped, not summed. A grade of the forecast, never of the forecasters — these are hard rivers. How this point ranks among every graded Colorado forecast point →

What April snow has meant for this river (1981–2026)

Across 46 measured years, the season’s water has closely followed the April snowpack: a year opening April with 80% of median snow has typically gone on to deliver about 84% of a normal season (a snow-to-runoff elasticity of 0.6). In warm, early-melt years the river delivered a median of 70% of a normal season, against 108% in typical years — the timing of the melt matters, not just its size.

Computed by this site: the district’s April 1 SWE (% of each SNOTEL site’s own-record median) against the observed April–July volume at this gage (% of its median season) — a fixed window every year, unlike the forecast grades above, which use each issue’s own period. The slope is fit so single wild years can’t steer it (Theil–Sen, log space); years missing 10% of their days are dropped.

Runoff outlook — Rio Grande at Wagon Wheel Gap

NRCS's final issue (2026-06-01) calls it even odds that at least 45 kAF arrives over 06-01 to 09-30 — 25% of a normal season; almost certainly at least 22, probably not more than 81. Our own record at this gage shows 54 kAF actually delivered. New forecasts begin in January. How to read these numbers →

We test a record-based adjustment of the April benchmark at every graded point. Here it did not beat NRCS over 41 replayed seasons (12% typical miss unadjusted vs 17% adjusted), so none is shown — NRCS’s own forecast, unadjusted, is the best April benchmark available for this river. Why we test →

90% chance of at least	70% chance of at least	50% chance of at least	30% chance of at least	10% chance of at least	Normal	Observed
22	33	45	60	81	182	54

How good are these forecasts here? (1982–2025)

Grading every April issue against what the river then delivered, measured at this gage’s own record — 42 seasons: the median miss of the 50% forecast is 12%, with a low bias of 6%, and the observed volume landed inside the stated 10–90% band 81% of the time (a calibrated forecast would say 80%).

What April snow has meant for this river (1981–2026)

Across 46 measured years, the season’s water has closely followed the April snowpack: a year opening April with 80% of median snow has typically gone on to deliver about 84% of a normal season (a snow-to-runoff elasticity of 0.8). In warm, early-melt years the river delivered a median of 76% of a normal season, against 116% in typical years — the timing of the melt matters, not just its size.

Runoff outlook — SF Rio Grande at South Fork

NRCS's final issue (2026-06-01) calls it even odds that at least 17 kAF arrives over 06-01 to 09-30 — 35% of a normal season; almost certainly at least 8, probably not more than 29. Our own record at this gage shows 15 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 31 kAF over 04-01 to 09-30. 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 34 kAF. The river delivered 50 kAF.

Computed by this site — not an NRCS number, and shown only because it earned it: replayed over 62 past seasons here (1962–2025), never seeing the year it predicts, the adjustment cut the typical April miss from 14% to 13%. 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
8	12	17	22	29	49	15

How good are these forecasts here? (1950–2025)

Grading every April issue against what the river then delivered, measured at this gage’s own record — 74 seasons: the median miss of the 50% forecast is 16%, with a low bias of 0%, and the observed volume landed inside the stated 10–90% band 90% of the time (a calibrated forecast would say 80%).

What April snow has meant for this river (1981–2026)

Across 46 measured years, the season’s water has closely followed the April snowpack: a year opening April with 80% of median snow has typically gone on to deliver about 73% of a normal season (a snow-to-runoff elasticity of 1.0). In warm, early-melt years the river delivered a median of 75% of a normal season, against 110% in typical years — the timing of the melt matters, not just its size.

Runoff outlook — Rio Grande nr Del Norte

NRCS's final issue (2026-06-01) calls it even odds that at least 65 kAF arrives over 06-01 to 09-30 — 25% of a normal season; almost certainly at least 25, probably not more than 117. Our own record at this gage shows 68 kAF actually delivered. New forecasts begin in January. How to read these numbers →

We test a record-based adjustment of the April benchmark at every graded point. Here it did not beat NRCS over 63 replayed seasons (12% typical miss unadjusted vs 13% adjusted), so none is shown — NRCS’s own forecast, unadjusted, is the best April benchmark available for this river. Why we test →

90% chance of at least	70% chance of at least	50% chance of at least	30% chance of at least	10% chance of at least	Normal	Observed
25	45	65	86	117	255	68

How good are these forecasts here? (1950–2025)

Grading every April issue against what the river then delivered, measured at this gage’s own record — 75 seasons: the median miss of the 50% forecast is 13%, with a low bias of 2%, and the observed volume landed inside the stated 10–90% band 84% of the time (a calibrated forecast would say 80%).

What April snow has meant for this river (1981–2026)

Across 46 measured years, the season’s water has closely followed the April snowpack: a year opening April with 80% of median snow has typically gone on to deliver about 73% of a normal season (a snow-to-runoff elasticity of 0.9). In warm, early-melt years the river delivered a median of 64% of a normal season, against 108% in typical years — the timing of the melt matters, not just its size.

Drought

Source Our computation, no independent reference · computed here from the screened DWR record Source Independent agency measurement · fetched 2026-10-06 · verify at U.S. Drought Monitor ↗

Right now

This is the 6th-driest week 39 in 129 years of record at RIO GRANDE AT EMBUDO, NM. (as of 2026-09-21; this week’s flow sits at the 4th percentile for the date). On this week’s US Drought Monitor, Conejos County is 86% in D3 extreme drought (2026-10-06). The law agrees: the most senior active call leaves 96% of this district’s decreed flow rights junior to the calling right this week.

Every year since 1889, week by week

Each thin row is a year at RIO GRANDE AT EMBUDO, NM.; 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 6.2 percentile points; next closest 2018 (7.4), 1956 (10.7)). 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 Alamosa, Conejos, Costilla, Elbert, Hinsdale, La Plata, Mineral, Rio Grande, Saguache counties — the counties this district’s gages sit in, which overlap the district imperfectly. The Drought Monitor weighs soils, vegetation and local reports; it is CONTEXT beside the river’s own record above, not the water-rights picture.

The law’s own drought gauge

When water runs short, administration answers: calls reach further back in time, and more decreed rights go junior to the calling right. This is that response, weekly since 1968 — 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 (3235 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	2025-06-30 → 2026-01-05	27	20th (2025-10-06)	5 weeks	—
unnamed dry spell	2024-01-08 → 2024-07-15	27	21st (2024-03-18)	22 weeks	—
the 2020-22 drought	2022-01-31 → 2022-09-26	34	24th (2022-06-06)	2 weeks	not yet (41 of 69 wells still below)
the 2020-22 drought	2020-07-20 → 2021-10-04	63	6th (2020-11-16)	53 weeks	not yet (44 of 70 wells still below)
the 2018 drought	2018-06-11 → 2019-07-22	58	2nd (2018-11-26)	0 weeks	2 yr (74 wells, 33 still below)
the 2012-13 drought	2012-08-27 → 2013-12-16	68	11th (2013-07-01)	2 weeks	not yet (50 of 86 wells still below)
unnamed dry spell	2006-06-05 → 2006-10-23	20	24th (2006-07-24)	0 weeks	1 yr (97 wells, 15 still below)
the 2002 drought	2002-01-28 → 2004-07-19	129	2nd (2002-10-07)	37 weeks	not yet (89 of 129 wells still below)
unnamed dry spell	2000-07-24 → 2001-06-25	48	10th (2000-11-06)	7 weeks	not yet (66 of 110 wells still below)
unnamed dry spell	1996-08-12 → 1997-03-10	30	19th (1996-10-14)	3 weeks	5 yr (136 wells, 56 still below)
unnamed dry spell	1989-11-20 → 1990-08-06	37	25th (1990-04-23)	11 weeks	16 yr (89 wells, 39 still below)
the 1981 drought	1981-02-09 → 1981-12-21	45	12th (1981-07-06)	32 weeks	2 yr (83 wells, 9 still below)
the 1977 drought	1977-01-10 → 1978-10-02	90	6th (1978-03-27)	35 weeks	7 yr (77 wells, 16 still below)
unnamed dry spell	1974-07-29 → 1975-07-28	52	11th (1975-01-06)	0 weeks	7 yr (61 wells, 13 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.

What drought has cost here

Since 1991, federal crop insurance has paid $19,952,790 in drought-caused claims across Alamosa, Conejos, Costilla, Elbert, Hinsdale, La Plata, Mineral, Rio Grande, Saguache counties — 6.3% of all insured crop losses there. The worst year was 2012 ($2,373,752).

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 (8,123 rights across 131 years of shared record), colored by that year’s wetness from the barcode above. Here the correlation is -0.05 — 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 ↗

11 systems touch this district (11 community systems reporting 24,405 people served, a figure that counts a wholesaler's customers twice); 1 of them carries an open health-based violation on EPA's record.

System	Serves	Source	Here
ALAMOSA CITY OF	11,271	Groundwater	100% of its area
MONTE VISTA CITY OF	4,600	Groundwater	100% of its area
CENTER TOWN OF	2,575	Groundwater	100% of its area
CREEDE CITY OF	1,965	Groundwater	100% of its area
EAST ALAMOSA	1,453	Purchased groundwater	100% of its area
DEL NORTE TOWN OF	1,429	Groundwater	100% of its area
SOUTH FORK WEST MUNICIPAL TOWN OF	566	Groundwater	100% of its area
RIO GRANDE WATER COMPANY	265	Groundwater under the influence of surface water	100% of its area

and 3 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 ↗

78 reaches over 523.1 miles and 13 natural lake levels, held by the Colorado Water Conservation Board so that water stays in the stream. Every reach, with its schedule and case →

Rio Grande, 21.2 mi: 65 (10/1 - 4/30), 150 (5/1 - 9/30) cfs (appropriated 1982, 83CW0039) · dossier
Goose Creek, 18.5 mi: 8 (10/1 - 4/30), 15 (5/1 - 9/30) cfs (appropriated 1982, 83CW0038) · dossier
Park Creek, 15.1 mi: 6 (10/1 - 4/30), 8 (5/1 - 9/30) cfs (appropriated 1980, 80CW0091) · dossier
Embargo Creek, 15.0 mi: 5 (1/1 - 12/31) cfs (appropriated 1976, 76W3647) · dossier
Rio Grande, 14.4 mi: 80 (10/1 - 4/30), 160 (5/1 - 9/30) cfs (appropriated 1982, 83CW0042) · dossier
Beaver Creek, 14.3 mi: 8 (10/1 - 4/30), 14 (5/1 - 9/30) cfs (appropriated 1980, 80CW0095) · dossier

and 85 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 1850-12-31 to 2015-09-24. 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. 16 abandonment screens and 184 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: 9243 across 8023 structure(s); 338 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 1969–2025, administration on this district has been tightening: 3 of 3 measures (days under call, calls set, seniority 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 (57 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	61	8	1870-03-01
2015	365	373	1854-03-31
2016	366	344	1850-01-01
2017	365	307	1855-04-30
2018	365	427	1855-06-01
2019	365	547	1850-01-01
2020	366	523	1854-03-31
2021	365	533	1854-03-31
2022	365	291	1854-03-31
2023	365	136	1854-03-31
2024	366	105	1854-03-31
2025	365	117	1854-03-31

Why diversions stopped — call-based explanations

Sustained diversion stops matched to senior administrative calls.

BAUER D (2000528) DWR↗ stopped 2025-10-22 (5+ days) — call at SANGRE CRISTO TRINCHERA curtailing 100% of its decreed rate [heuristic-strong]
CADLE D 3 (2000559) DWR↗ stopped 2025-09-07 (35+ days) — call at RIO GRANDE COMPACT - LOBATOS curtailing 100% of its decreed rate [heuristic-strong]
BILLINGS D (2000546) DWR↗ stopped 2025-08-29 (7+ days) — call at RIO GRANDE COMPACT - LOBATOS curtailing 96% of its decreed rate [heuristic-partial]
BREY D (2000552) DWR↗ stopped 2025-08-28 (44+ days) — call at RIO GRANDE COMPACT - LOBATOS curtailing 100% of its decreed rate [heuristic-strong]
CADLE D 1 (2000557) DWR↗ stopped 2025-08-17 (56+ days) — call at RIO GRANDE COMPACT - LOBATOS curtailing 100% of its decreed rate [heuristic-strong]
BUTLER IRR D (2000556) DWR↗ stopped 2025-08-11 (7+ days) — call at RIO GRANDE COMPACT - LOBATOS curtailing 100% of its decreed rate [heuristic-strong]
BELLOWS CR D 1 (2000531) DWR↗ stopped 2025-07-28 (21+ days) — call at RIO GRANDE COMPACT - LOBATOS curtailing 100% of its decreed rate [heuristic-strong]
BAUER D (2000528) DWR↗ stopped 2025-07-27 (5+ days) — call at RIO GRANDE COMPACT - LOBATOS curtailing 100% of its decreed rate [heuristic-strong]
BARCLAY D (2000524) DWR↗ stopped 2025-07-14 (106+ days) — call at RIO GRANDE COMPACT - LOBATOS curtailing 75% of its decreed rate [heuristic-partial]
BREENE MYERS D (2000551) DWR↗ stopped 2025-06-30 (110+ days) — call at RIO GRANDE COMPACT - LOBATOS curtailing 57% of its decreed rate [heuristic-partial]
BEVAN D 4 (2000541) DWR↗ stopped 2025-06-19 (116+ days) — call at RIO GRANDE COMPACT - LOBATOS curtailing 56% of its decreed rate [heuristic-partial]
BENNETT CR D (2000535) DWR↗ stopped 2025-06-18 (29+ days) — call at RIO GRANDE COMPACT - LOBATOS curtailing 80% of its decreed rate [heuristic-partial]

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
USFS QP37N (2001965) DWR↗	1905-06-03	5.6% / 0.0%	5.6% / 0.0%
RIO GRANDE CNL (2000812) DWR↗	1879-11-30	50.0% / 0.0%	5.6% / 0.0%
RGWUA RECHARGE PROJECT (2001675) DWR↗	1959-11-01	5.6% / 0.0%	5.6% / 0.0%
USFS QP37K (2001964) DWR↗	1905-06-03	5.6% / 0.0%	5.6% / 0.0%
USFS QP39F (2001984) DWR↗	1907-03-02	5.6% / 0.0%	5.6% / 0.0%
FARMERS UNION CNL (2000631) DWR↗	1887-04-01	16.4% / 0.0%	5.6% / 0.0%
EMPIRE CNL (2000623) DWR↗	1882-08-10	32.7% / 0.0%	5.6% / 0.0%
SAN LUIS VALLEY CNL (2000829) DWR↗	1885-01-05	24.3% / 0.0%	5.6% / 0.0%
USFS QP37D (2001958) DWR↗	1905-06-03	5.6% / 0.0%	5.6% / 0.0%
USFS QP39D (2001979) DWR↗	1905-06-03	5.6% / 0.0%	5.6% / 0.0%
USFS QP31F (2001929) DWR↗	1905-06-03	5.6% / 0.0%	5.6% / 0.0%
PRAIRIE D (2000798) DWR↗	1872-05-01	51.4% / 0.0%	5.6% / 0.0%

Abandonment radar (16 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 ~1957 — idleness that begins before then may be unreported use, not nonuse (flagged † below).

EAGLE D (2000613) DWR↗ (1875-05-05, 5.3 cfs decreed): last active 1962 — 34 years idle
LOHR OVERFLOW SEPG D #1 (2000718) DWR↗ (1897-06-28, 9.0 cfs decreed): last active 1962 — 34 years idle
WINTZ D (2000908) DWR↗ (1910-10-14, 2.1 cfs decreed): last active 1962 — 34 years idle
MEADOW LAKE RES (2003547) DWR↗ (1916-06-01, 0.0 cfs decreed): last active 1965 — 31 years idle
LARICK D 5 (2000708) DWR↗ (1874-05-01, 2.0 cfs decreed): last active 1966 — 30 years idle
MACLEOD D 2 (2000724) DWR↗ (1882-05-31, 1.0 cfs decreed): last active 1970 — 26 years idle
MACLEOD D 5 (2000727) DWR↗ (1878-04-01, 1.0 cfs decreed): last active 1970 — 26 years idle
SHERIDAN NORTH D (2000841) DWR↗ (1883-04-01, 2.0 cfs decreed): last active 1970 — 26 years idle
SHERIDAN SOUTH D (2000842) DWR↗ (1882-09-30, 3.0 cfs decreed): last active 1970 — 26 years idle
BOWEN DRAIN DIST LAT SYS (2000549) DWR↗ (1922-06-21, 53.5 cfs decreed): last active 1974 — 22 years idle

Compliance screens (184 advisory flags)

Screened 342 of 8023 structures with rights (413 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.

EMPIRE CNL (2000623) DWR↗: Observed p99 daily rate 516.0 cfs (max 613.0) exceeds total decreed absolute 505.9 cfs across 49601 recorded day(s).
RIO GRANDE RES (2003554) DWR↗: Observed p99 daily rate 224.0 cfs (max 2039.3) exceeds total decreed absolute 3.7 cfs across 250131 recorded day(s).
PRAIRIE DRAIN D (2000799) DWR↗: Observed p99 daily rate 188.0 cfs (max 216.0) exceeds total decreed absolute 40.0 cfs across 2199 recorded day(s).
COSTILLA D (2000587) DWR↗: Observed p99 daily rate 134.0 cfs (max 191.0) exceeds total decreed absolute 103.3 cfs across 28368 recorded day(s).
SANTA MARIA RES (2003558) DWR↗: Observed p99 daily rate 109.4 cfs (max 1696.0) exceeds total decreed absolute 3.7 cfs across 146061 recorded day(s).
EXCELSIOR D (2000627) DWR↗: Observed p99 daily rate 106.0 cfs (max 154.0) exceeds total decreed absolute 89.7 cfs across 40685 recorded day(s).
CENTENNIAL D (2000566) DWR↗: Observed p99 daily rate 97.0 cfs (max 132.0) exceeds total decreed absolute 82.4 cfs across 35085 recorded day(s).
CONTINENTAL RES (2003536) DWR↗: Observed p99 daily rate 95.3 cfs (max 1647.6) exceeds total decreed absolute 3.7 cfs across 162004 recorded day(s).
CHICAGO D (2000575) DWR↗: Observed p99 daily rate 85.0 cfs (max 196.0) exceeds total decreed absolute 66.4 cfs across 33392 recorded day(s).
WESTSIDE D (2000903) DWR↗: Observed p99 daily rate 50.0 cfs (max 80.0) exceeds total decreed absolute 35.8 cfs across 22621 recorded day(s).

Seniority (top structures by decreed rate)

Structure	Senior priority date	Rights	Decreed abs (cfs)	Decreed abs (AF)	Conditional?
USFS QP37N (2001965) DWR↗	1905-06-03	1	2044.0	0	—
RIO GRANDE CNL (2000812) DWR↗	1879-11-30	23	1648.5	0	—
RGWUA RECHARGE PROJECT (2001675) DWR↗	1959-11-01	1	1018.0	0	yes
USFS QP37K (2001964) DWR↗	1905-06-03	1	960.0	0	—
USFS QP39F (2001984) DWR↗	1907-03-02	1	880.0	0	—
FARMERS UNION CNL (2000631) DWR↗	1887-04-01	10	801.4	0	—
EMPIRE CNL (2000623) DWR↗	1882-08-10	6	505.9	0	—
SAN LUIS VALLEY CNL (2000829) DWR↗	1885-01-05	13	501.0	0	yes
USFS QP37D (2001958) DWR↗	1905-06-03	1	447.0	0	—
USFS QP39D (2001979) DWR↗	1905-06-03	1	390.2	0	—
USFS QP31F (2001929) DWR↗	1905-06-03	1	373.2	0	—
PRAIRIE D (2000798) DWR↗	1872-05-01	20	367.0	487	—
MONTE VISTA CNL (2000753) DWR↗	1882-05-31	12	340.8	0	—
USFS QP37B (2001956) DWR↗	1905-06-03	1	324.6	0	—
USFS QP37H (2001962) DWR↗	1907-03-02	1	293.4	0	—

Recent inventory & legal-document changes

2026-10-08 — call set: CHICAGO D (39692)
2026-10-08 — call released: 39674
2026-10-08 — call set: VALDEZ D (39691)
2026-10-08 — call released: 39668
2026-10-05 — call set: CHICAGO D (39674)
2026-10-05 — call released: 39667
2026-10-05 — call set: NEWTON D 2 (39673)
2026-10-05 — call released: 39639

Water-court filings this month (division-wide)

2 applications in the 2026-08 resume for this basin's division — new rights, changes, augmentation plans — from the water clerk's statutory monthly notice (C.R.S. 37-92-302), the earliest public signal of a new claim. Filings are division-wide, not district-filtered: check the county column. Full resume PDF at the Judicial Branch →

Anyone affected may file a statement of opposition until 2026-10-31 (16 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 2 filings, with excerpts

Case	What it asks	County	Excerpt
`2026CW5` 2505063	—	TRIBUTARIES IN SAGUACHE	Case No. 2026CW5: Applicant Kiana Creek Holdings II 3450 Big Bear Drive Sedalia, CO. 80135. jerry@kianacreekfarms.com (719) 588-0908. In the Rio Grande River or its Tributaries In Saguache County. APPLICATION FOR CORRECTION FOR AN ESTABLISHED BUT ERRONEOUSLY D…
`2026CW6`	change of water right	IN ALAMOSA	Case No. 2026CW6: Applicant KJRC Investments, LLC Splashland, LLC c/o Aaron and Tiffanie Polkowske 14099 County Road U La Jara, CO. 81140 no phone number, no email. In Alamosa County. APPLICATION FOR CHANGE OF WATER RIGHT Decreed water right for which change i…

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
BASSI NORTH FARM LLC	37-92-308(5) PLANS LESS THAN 5 YEARS	Approved	2026-03-31	—	plan file
PINE RIVER WEMINUCHE PASS DITCH SD 2 3 6	37-92-308(5) PLANS LESS THAN 5 YEARS	Approved	2026-04-30	—	plan file
SUBDISTRICT NO 2 SQUAW PASS	37-92-308(4) PLAN PENDING COURT APPLICATION	Approved	—	—	plan file
COBLENTZ WELLS	37-92-308(4) PLAN PENDING COURT APPLICATION	Division Review	—	—	plan file
DEACON FAMILY INVESTMENTS LP	37-92-308(5) PLANS LESS THAN 5 YEARS	Division Review	—	—	plan file
MEADOW GLEN DITCH - WEBB	37-92-308(5) PLANS LESS THAN 5 YEARS	Division Review	—	—	plan file
SUSTAINABLE WATER AUGMENTATION GROUP (SWAG) - CASE NO 23CW3015	37-92-308(4) PLAN PENDING COURT APPLICATION	Additional Info Needed	—	—	plan file
MONTE VISTA WATER USERS ASSN	37-92-308(5) PLANS LESS THAN 5 YEARS	Withdrawn	—	—	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 2026-10-16 · verify at USGS current conditions ↗

No USGS continuous water-quality sensor reports from inside this district. Statewide sensors →

Where water has been sampled

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

The portal lists 2,728 sampling stations in this district's watersheds (Rio Grande Headwaters 13010001, 55% of the district; Alamosa-Trinchera 13010002, 28% of the district; San Luis 13010003, 15% of the district; Saguache 13010004, 3% of the district), of which 107 reported a sample in the last 5 years on the state and tribal side (USGS activity is in the station count, not in that figure). Most active: Colorado Dept. of Public Health & Environment-WQCD (79), Colorado River Watch (25), USGS Colorado Water Science Center (3). Most-sampled groups: Inorganics, Major, Metals, Physical, Nutrient, Inorganics, Minor, Metals. Every station as a file ↗

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

Drinking water

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

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

System	Serves	EPA record	PFAS (UCMR 5)	Lead, latest 90th pct
VALLEY MOBILE HOME LLC	85	1 open health-based	not sampled	0.0 mg/L
ALAMOSA CITY OF	11,271	clean, last 12 quarters	none detected	0.0 mg/L
MONTE VISTA CITY OF	4,600	clean, last 12 quarters	none detected	0.0 mg/L
CENTER TOWN OF	2,575	2 of 12 quarters with a violation	not sampled	0.0 mg/L
CREEDE CITY OF	1,965	4 of 12 quarters with a violation	none detected	0.0 mg/L
EAST ALAMOSA	1,453	clean, last 12 quarters	not sampled	0.001 mg/L
DEL NORTE TOWN OF	1,429	9 of 12 quarters with a violation	not sampled	0.001 mg/L
SOUTH FORK WEST MUNICIPAL TOWN OF	566	4 of 12 quarters with a violation	not sampled	0.0 mg/L
RIO GRANDE WATER COMPANY	265	3 of 12 quarters with a violation	not sampled	0.003 mg/L
INDIAN TRAILS WATER LLC	110	clean, last 12 quarters	not sampled	0.0015 mg/L

and 1 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

Administration number

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 5 SNOTEL sites — normal for the date; the snow year begins in October and typically peaks around April 17. Runoff outlook — Rio Grande at Thirty Mile Bridge: even odds of at least 19 kAF over 06-01 to 09-30 — 26% of a normal season, per NRCS, issued 2026-06-01 — the season’s final; new forecasts begin in January. Runoff outlook — Rio Grande at Wagon Wheel Gap: even odds of at least 45 kAF over 06-01 to 09-30 — 25% of a normal season, per NRCS, issued 2026-06-01 — the season’s final; new forecasts begin in January. Runoff outlook — SF Rio Grande at South Fork: even odds of at least 17 kAF over 06-01 to 09-30 — 35% of a normal season, per NRCS, issued 2026-06-01 — the season’s final; new forecasts begin in January. Runoff outlook — Rio Grande nr Del Norte : even odds of at least 65 kAF over 06-01 to 09-30 — 25% 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
Beartown	11580	3.4	0.0	—	April 17 (23.2 in)
Grayback	11620	0.4	—	—	—
Middle Creek	11260	2.2	0.0	—	April 15 (19.2 in)
Rat Creek	11680	2.2	—	—	—
Upper Rio Grande	9370	0.1	0.0	—	March 18 (6.6 in)

Rio Grande at Thirty Mile Bridge — 06-01 to 09-30 volume, thousand acre-feet (chance the volume is AT LEAST this):

90%	70%	50%	30%	10%	Normal
10	15	19	29	43	72

Rio Grande at Wagon Wheel Gap — 06-01 to 09-30 volume, thousand acre-feet (chance the volume is AT LEAST this):

90%	70%	50%	30%	10%	Normal
22	33	45	60	81	182

SF Rio Grande at South Fork — 06-01 to 09-30 volume, thousand acre-feet (chance the volume is AT LEAST this):

90%	70%	50%	30%	10%	Normal
8	12	17	22	29	49

Rio Grande nr Del Norte — 06-01 to 09-30 volume, thousand acre-feet (chance the volume is AT LEAST this):

90%	70%	50%	30%	10%	Normal
25	45	65	86	117	255

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: 15 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 48 streams, 33 agree. Know this water? Tell us →

Stream	This site routes it to	DWR routes it to
Spring Creek	the mainstem	Owl Creek
Spring Creek	the mainstem	North Clear Creek
Willow Creek	the mainstem	Spring Creek
Lone Rock Creek	the mainstem	Baughman Creek
Pinos Creek	the mainstem	no parent named
San Francisco Creek	the mainstem	no parent named
Beaver Creek	the mainstem	South Fork Rio Grande
Castle Rock Creek	the mainstem	West Fork Pinos Creek

Sizable streams DWR maps here that this network does not carry:

Red Mountain Creek (14 mi) · Miners Creek (14 mi) · Old Woman Creek (13 mi) · Squaw Creek (12 mi) · Waverly Drainage Ditch (12 mi) · Lost Trail Creek (10 mi) · Texas Creek (10 mi) · Bear Creek (10 mi)

Something wrong on this page? Tell us →

Rio Grande

Schematic

Historical

Evolution of the network

Trends

This year, in context

Gage flow trend & changepoints

How the measurement network itself changed

Mass-balance (network closure) trend

Reach gain/loss shifts (1950–2026)

Cross-gage pattern fingerprint

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

Data provenance & quality

Groundwater

Well map

3D aquifer x-ray

Water-table trends

Stream corridors — the surface connection

Permits issued here, by year

What drillers reached, township by township

Reservoirs

Reservoir map — how full is each vessel?

Basin storage, end of each water year

Largest reservoirs on record

Snow and runoff

Snow-water equivalent, WY2027

Two ways a snow year goes wrong (1981–2026)

Runoff outlook — Rio Grande at Thirty Mile Bridge

How good are these forecasts here? (1962–2025)

What April snow has meant for this river (1981–2026)

Runoff outlook — Rio Grande at Wagon Wheel Gap

How good are these forecasts here? (1982–2025)

What April snow has meant for this river (1981–2026)

Runoff outlook — SF Rio Grande at South Fork

The record-adjusted April benchmark

How good are these forecasts here? (1950–2025)

What April snow has meant for this river (1981–2026)

Runoff outlook — Rio Grande nr Del Norte

How good are these forecasts here? (1950–2025)

What April snow has meant for this river (1981–2026)

Drought

Right now

Every year since 1889, week by week

This year against its analogs

The Drought Monitor’s view since 2000

The law’s own drought gauge

This basin’s droughts, by its own record

What drought has cost here

When this basin claimed its water

Legal

Who serves it, who protects it

Public water systems here

Instream-flow rights held by the state

Is the river getting harder to divert from?

Why diversions stopped — call-based explanations

Right yield — how often could these rights actually divert?

Abandonment radar (16 screens)

Compliance screens (184 advisory flags)

Seniority (top structures by decreed rate)

Recent inventory & legal-document changes

Water-court filings this month (division-wide)

Active substitute water supply plans in this district

Water quality

The water itself, in this district

Right now

Where water has been sampled

Drinking water

Impaired waters

Call cascade

Pick a calling right

This week's diagnostic

System status

Active river calls

Hydrographs vs. historical envelope

Anomaly flags

Keep track of Colorado’s water?