Upper Colorado/Fraser Rivers

Division 5 · Water District 51

Draft - NLDI/CDSS verified

Full diagnostic snapshot pending — this district's weekly-style report (system status, active calls, hydrographs, anomaly flags) is produced by the nightly rotation and appears here after its first run. The tabs above are live now.

Bootstrap review report — d5_wd51_upper_colorado_fraser_rivers

Generated 2026-08-14 09:06 UTC for Division 5 / Water District 51.

This is a review checklist, not a finished config. Everything below is a suggestion from live DWR data — confirm or correct each section in config.yaml before running this basin for real.

1. Stream-name patterns

Assumed mainstem pattern: COLORADO RIVER (highest-count waterSource value). Candidates below by structure count — decide which are real tributaries worth their own centerline vs. noise, and add them to longitudinal.tributary_stream_patterns in priority order (more-specific names, e.g. "WEST FORK X", must precede substrings of themselves, e.g. "X").

waterSource	structure count
COLORADO RIVER (assumed mainstem)	236
FRASER RIVER	149
WILLIAMS FORK	59
RANCH CREEK	58
WILLOW CREEK	52
CROOKED CREEK	50
TENMILE CREEK	43
POLE CREEK	42
SMITH CREEK	41
HAMILTON CREEK	33
SKUNK CREEK	31
BATTLE CREEK	27
CORRAL CREEK	26
SAINT LOUIS CREEK	24
TRAIL CREEK	21
REEDER CREEK	20
LITTLE MUDDY CREEK	15
ROCK CREEK	15
SKYLARK CREEK	14
EIGHTMILE CREEK	13
NINEMILE CREEK	13
SODA CREEK	12
STILLWATER CREEK	12
LITTLE COLUMBINE CREEK	11
BULL RUN	10
COPPER CREEK	10
JOHNSON GULCH	10
ELK CREEK	8
VASQUEZ CREEK	8
SPRING BRANCH	8

2. Diversion / return classification

Auto-classified from structureType + name patterns: 835 diversions, 197 returns, 972 unclassified (neither pattern matched — these render as neither on the schematic unless added to return_flow_wdids/force_diversion_wdids or a type is added to the diversion/return type lists).

This layer needs the least manual work — it's the same heuristic the engine uses at runtime. Spot-check a sample rather than reviewing every row; if you have a water-year accounting spreadsheet for this basin, cross-reference it against the 'other' bucket specifically (that's where a real augmentation return with an unusual DWR structureType will hide).

2b. Cross-checked against decreed water rights (CDSS)

12 structure(s) have a decreed water right (CDSS waterrights/netamount) that disagrees with the structureType/name-pattern classification above. Same-agency evidence (DWR/HydroBase), not independent of DWR the way the NLDI topology check is — worth a glance, not an automatic correction.

wdid	structure	currently	decreed uses suggest	decreed uses
5101069	HENDERSON MINE RAILWAY TUNNEL	other	diversion	Domestic, Fishery, Industrial, Irrigation, Municipal, Recreation
5101237	WILLIAMS FORK POWER CONDUIT	other	diversion	Power Generation
5101245	WINTER PARK BASE DIVERSION POINT 1	other	diversion	Commercial, Fire, Irrigation
5101246	WINTER PARK BASE DIVERSION POINT 2	other	diversion	Commercial, Fire, Irrigation
5101277	VAGABOND RANCH HYDRO DIVERSION	other	diversion	Power Generation
5101322	HENDERSON SHAFT NO 2	other	diversion	Industrial
5101370	ELK VALLEY GALLERY	other	diversion	Commercial, Domestic, Fire, Irrigation
5101435	BYERS PEAK RENEWABLE ENERGY FACILITY	other	diversion	Power Generation
5103592	WPCC STORAGE TANK	other	return	Augmentation, Fire
5103627	CRESTVIEW RANCH RECHARGE SITE	other	return	Augmentation
5103639	JAMES PEAK RANCH LOWER POND	other	return	Augmentation, Fishery, Recreation, Wildlife
5103645	BRODERICK MILL POND PUMP & PIPELINE	other	diversion	Fire, Fishery, Industrial

3. Suspected nested tributaries

40 flag(s) confirmed connected by USGS NLDI — real surveyed stream-network topology, not a distance guess (see VERIFICATION-PLAN.md). This confirms the two candidates' channels really do merge (ruling out a coincidental-proximity false flag) but NOT auto-applied to tributary_parent_overrides — NLDI's overlap test can't reliably tell which side is upstream once two streams have already merged near DWR's own recorded structures, only that they connect. Confirm the direction (which one is the tributary, which is the parent) from local knowledge or the evidence below, then set it yourself.

pair	NLDI evidence
WILLOW CREEK <-> MAINSTEM	tributary's downstream NHD trace (comid 1234513) first overlaps MAINSTEM's own downstream trace at index 0 (next-nearest candidate: ('TRAIL CREEK', 1))
ELK CREEK <-> FRASER RIVER	tributary's downstream NHD trace (comid 1239327) first overlaps FRASER RIVER's own downstream trace at index 1 (next-nearest candidate: ('MAINSTEM', 19))
WILLIAMS FORK <-> MAINSTEM	tributary's downstream NHD trace (comid 1232803) first overlaps MAINSTEM's own downstream trace at index 2 (next-nearest candidate: none)
EIGHTMILE CREEK <-> NINEMILE CREEK	tributary's downstream NHD trace (comid 1234337) first overlaps NINEMILE CREEK's own downstream trace at index 1 (next-nearest candidate: ('MAINSTEM', 7))
BULL RUN <-> WILLIAMS FORK	tributary's downstream NHD trace (comid 1236785) first overlaps WILLIAMS FORK's own downstream trace at index 5 (next-nearest candidate: ('MAINSTEM', 9))
HAMILTON CREEK <-> HURD CREEK	tributary's downstream NHD trace (comid 1239589) first overlaps HURD CREEK's own downstream trace at index 1 (next-nearest candidate: ('MAINSTEM', 18))
MULE CREEK <-> WILLIAMS FORK	tributary's downstream NHD trace (comid 1237443) first overlaps WILLIAMS FORK's own downstream trace at index 2 (next-nearest candidate: ('MAINSTEM', 19))
BATTLE CREEK <-> BULL RUN	tributary's downstream NHD trace (comid 1236819) first overlaps BULL RUN's own downstream trace at index 1 (next-nearest candidate: ('MAINSTEM', 9))
SAINT LOUIS CREEK <-> FRASER RIVER	tributary's downstream NHD trace (comid 1239243) first overlaps FRASER RIVER's own downstream trace at index 2 (next-nearest candidate: ('MAINSTEM', 13))
COPPER CREEK <-> WILLIAMS FORK	tributary's downstream NHD trace (comid 1236747) first overlaps WILLIAMS FORK's own downstream trace at index 4 (next-nearest candidate: ('MAINSTEM', 8))
ROHRACHER CREEK <-> EIGHTMILE CREEK	tributary's downstream NHD trace (comid 1232455) first overlaps EIGHTMILE CREEK's own downstream trace at index 2 (next-nearest candidate: ('MAINSTEM', 10))
RASBERRY CREEK <-> EIGHTMILE CREEK	tributary's downstream NHD trace (comid 1232455) first overlaps EIGHTMILE CREEK's own downstream trace at index 2 (next-nearest candidate: ('MAINSTEM', 10))
POLE CREEK <-> CROOKED CREEK	tributary's downstream NHD trace (comid 1239289) first overlaps CROOKED CREEK's own downstream trace at index 0 (next-nearest candidate: ('MAINSTEM', 15))
NINEMILE CREEK <-> TENMILE CREEK	tributary's downstream NHD trace (comid 1234353) first overlaps TENMILE CREEK's own downstream trace at index 1 (next-nearest candidate: ('MAINSTEM', 12))
VASQUEZ CREEK <-> FRASER RIVER	tributary's downstream NHD trace (comid 1239617) first overlaps FRASER RIVER's own downstream trace at index 1 (next-nearest candidate: ('MAINSTEM', 21))
CROOKED CREEK <-> SILVER CREEK	tributary's downstream NHD trace (comid 1234371) first overlaps SILVER CREEK's own downstream trace at index 1 (next-nearest candidate: ('MAINSTEM', 12))
RANCH CREEK <-> FRASER RIVER	tributary's downstream NHD trace (comid 1239231) first overlaps FRASER RIVER's own downstream trace at index 0 (next-nearest candidate: ('MAINSTEM', 13))
BEAVER CREEK <-> MAINSTEM	tributary's downstream NHD trace (comid 1232273) first overlaps MAINSTEM's own downstream trace at index 4 (next-nearest candidate: ('LITTLE MUDDY CREEK', 5))
SKYLARK CREEK <-> WILLIAMS FORK	tributary's downstream NHD trace (comid 1238679) first overlaps WILLIAMS FORK's own downstream trace at index 1 (next-nearest candidate: ('MAINSTEM', 16))
TENMILE CREEK <-> FRASER RIVER	tributary's downstream NHD trace (comid 1234297) first overlaps FRASER RIVER's own downstream trace at index 1 (next-nearest candidate: ('MAINSTEM', 5))
FISHER CREEK <-> TENMILE CREEK	tributary's downstream NHD trace (comid 1234365) first overlaps TENMILE CREEK's own downstream trace at index 1 (next-nearest candidate: ('MAINSTEM', 11))
CABIN CREEK <-> RANCH CREEK	tributary's downstream NHD trace (comid 1239271) first overlaps RANCH CREEK's own downstream trace at index 0 (next-nearest candidate: ('MAINSTEM', 16))
MULLER CREEK <-> ROCKWELL CREEK	tributary's downstream NHD trace (comid 1234317) first overlaps ROCKWELL CREEK's own downstream trace at index 3 (next-nearest candidate: ('MAINSTEM', 6))
LOST CREEK <-> WILLIAMS FORK	tributary's downstream NHD trace (comid 1237275) first overlaps WILLIAMS FORK's own downstream trace at index 1 (next-nearest candidate: ('MAINSTEM', 18))
TONAHUTU CREEK <-> NORTH INLET	tributary's downstream NHD trace (comid 1234053) first overlaps NORTH INLET's own downstream trace at index 1 (next-nearest candidate: ('MAINSTEM', 5))
JOHNSON GULCH <-> WILLIAMS FORK	tributary's downstream NHD trace (comid 1238577) first overlaps WILLIAMS FORK's own downstream trace at index 6 (next-nearest candidate: ('MAINSTEM', 9))
REED CREEK <-> ROCK CREEK	tributary's downstream NHD trace (comid 1234303) first overlaps ROCK CREEK's own downstream trace at index 1 (next-nearest candidate: ('MAINSTEM', 3))
TRAIL CREEK <-> HURD CREEK	tributary's downstream NHD trace (comid 1239239) first overlaps HURD CREEK's own downstream trace at index 0 (next-nearest candidate: ('MAINSTEM', 17))
JONES CREEK <-> WILLIAMS FORK	tributary's downstream NHD trace (comid 1239681) first overlaps WILLIAMS FORK's own downstream trace at index 0 (next-nearest candidate: none)
SKUNK CREEK <-> POLE CREEK	tributary's downstream NHD trace (comid 1239283) first overlaps POLE CREEK's own downstream trace at index 1 (next-nearest candidate: ('MAINSTEM', 16))
DROWSY WATER CREEK <-> MAINSTEM	tributary's downstream NHD trace (comid 1231705) first overlaps MAINSTEM's own downstream trace at index 1 (next-nearest candidate: ('KINNEY CREEK', 2))
ROCKWELL CREEK <-> ROCK CREEK	tributary's downstream NHD trace (comid 1234303) first overlaps ROCK CREEK's own downstream trace at index 1 (next-nearest candidate: ('MAINSTEM', 3))
SPRING BRANCH <-> CROOKED CREEK	tributary's downstream NHD trace (comid 1239289) first overlaps CROOKED CREEK's own downstream trace at index 0 (next-nearest candidate: ('MAINSTEM', 15))
CLINES SLOUGH <-> FRASER RIVER	tributary's downstream NHD trace (comid 1234371) first overlaps FRASER RIVER's own downstream trace at index 0 (next-nearest candidate: ('MAINSTEM', 12))
WALDEN HOLLOW CREEK <-> MAINSTEM	tributary's downstream NHD trace (comid 1234667) first overlaps MAINSTEM's own downstream trace at index 3 (next-nearest candidate: ('POLE CREEK', 9))
IRVING HALE CREEK <-> MAINSTEM	tributary's downstream NHD trace (comid 1234599) first overlaps MAINSTEM's own downstream trace at index 4 (next-nearest candidate: ('STRAWBERRY CREEK', 12))
SILVER CREEK <-> FRASER RIVER	tributary's downstream NHD trace (comid 1234371) first overlaps FRASER RIVER's own downstream trace at index 0 (next-nearest candidate: ('MAINSTEM', 12))
DARLING CREEK <-> WILLIAMS FORK	tributary's downstream NHD trace (comid 1238529) first overlaps WILLIAMS FORK's own downstream trace at index 1 (next-nearest candidate: none)
UTE CREEK <-> WILLIAMS FORK	tributary's downstream NHD trace (comid 1238707) first overlaps WILLIAMS FORK's own downstream trace at index 5 (next-nearest candidate: ('MAINSTEM', 30))
DEBERARD DRAW <-> FRASER RIVER	tributary's downstream NHD trace (comid 1234331) first overlaps FRASER RIVER's own downstream trace at index 1 (next-nearest candidate: ('MAINSTEM', 9))

Still need a human decision — these tributary pairs are comparably close to EACH OTHER as to the mainstem — one may actually join the other rather than the mainstem directly (like Leavenworth Creek -> South Clear Creek in the Clear Creek basin). NLDI couldn't resolve these (no nearby flowline, or ambiguous/no downstream overlap within range) — if you know the real topology, set it in longitudinal.tributary_parent_overrides.

tributary	possible parent	dist to possible parent (mi)	dist to mainstem (mi)	NLDI result
KINNEY CREEK	SMITH CREEK	0.0	0.27	ambiguous -- tied earliest overlap at index 1: ['SMITH CREEK', 'MAINSTEM']
GARDINER CREEK	ROCK CREEK	0.11	0.29	ambiguous -- tied earliest overlap at index 1: ['ROCK CREEK', 'MAINSTEM']
COYOTE CREEK	SMITH CREEK	0.82	0.57	ambiguous -- tied earliest overlap at index 1: ['SMITH CREEK', 'MAINSTEM']
CORRAL CREEK	ROCK CREEK	0.15	0.16	ambiguous -- tied earliest overlap at index 3: ['ROCK CREEK', 'MAINSTEM']
STRAWBERRY CREEK	TRAIL CREEK	0.44	0.75	ambiguous -- tied earliest overlap at index 10: ['TRAIL CREEK', 'MAINSTEM']
HURD CREEK	TRAIL CREEK	0.14	0.11	ambiguous -- tied earliest overlap at index 16: ['TRAIL CREEK', 'MAINSTEM']
MEADOW CREEK	TRAIL CREEK	0.06	2.23	ambiguous -- tied earliest overlap at index 16: ['TRAIL CREEK', 'MAINSTEM']

4. Gage placement risk

None — every gage with a resolvable position is within the placement cutoff.

98 more gage(s) pass but are within 2x the cutoff distance — worth a glance if the structure dataset changes later.

Next steps

Fill in tributary_stream_patterns from section 1.
Resolve section 3's flags (or confirm none apply).
Resolve section 4's at-risk gages.
Cross-reference return_flow_wdids/force_diversion_wdids against any local accounting source you have for this basin.
Review the rendered schematic for this district before relying on it.

Reconstruct conditions as of

Evolution of the network

Computed 2026-08-20 09:14 from 84 gage(s) with cached period-of-record data. Statistical tests (Mann-Kendall trend, Pettitt changepoint) require at least 8 years spanning at least 10 years of record -- gages below that report no signal, not "no change."

Data provenance & quality

Where these numbers come from and how far they can be trusted. Grade D (2/6 points) — the components below are the finding; the letter alone is not. Sources: DWR HydroBase snapshot HydroBase_CO_20260707 (imported 2026-08-19) for history, plus the CDSS REST API for current conditions.

Check	State	What was measured
gage freshness	stale	newest gage reading is 45 day(s) old (target 7)
diversion record	stale	newest diversion record is 658 day(s) old (DWR publishes ~1 year in arrears)
structure coverage	sparse	8% of schematic structures have data

Independent check: PASS — 100.0000% agreement across 103,104 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 — 99.81% day-level agreement with USGS's own published records for the same gages, across 61 co-listed station(s) and 601,272 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.

84 gage(s) / 758,219 daily values (1904-10-01–2026-07-06); 628 structure(s) with diversion records; 2208 with decreed rights. Methodology has not yet had independent expert review — treat every figure as an advisory screen, not an administrative or legal conclusion.

Read this first: the measurement network itself evolved

This basin was not always measured the way it is today — the API-era record is dense and recent, the early record sparse. 36 gage(s) and 276 structure(s) report in 2026, but structure reporting only reached half its modern level around ~1976. Every historical claim below is checked against this: long-term shifts that co-move with the growth of the network carry an explicit measurement-evolution caution, and abandonment screens whose idleness begins before the modern reporting era are flagged †.

Decade	Gages with data (median yr)	Structures reporting (median yr)
1900s	3	0
1910s	4	0
1920s	2	0
1930s	13	0
1940s	16	0
1950s	26	0
1960s	23	0
1970s	22	50
1980s	22	250
1990s	23	300
2000s	28	262
2010s	32	253
2020s	36	276

Gage flow trend & changepoints

Of the 84 gages with enough record, 10 are trending down and 5 up, and 12 carry a detected shift. The clearest is RANCH CREEK DITCH NEAR WINTER PARK, CO, +56.7 points of its long-term median per decade over 32 years (p=0.0000). The other 69 show no clear signal either way.

Every located gage with a period of record — dot size scales with the strength of its flow trend (|Sen slope| in points of median per decade, the same statistic as the table below), color with direction. An amber ring marks a detected Pettitt changepoint. Click a gage to chart its trend and shift.

Gage	Trend	Change / decade points of median	Significance	Years	Changepoint
▸ RANCH CREEK DITCH NEAR FRASER COLO RANDIFCO	↑ increasing	+97.7	p=0.000	18	~1954
▸ RANCH CREEK DITCH NEAR WINTER PARK, CO RANCRKCO	↑ increasing	+56.7	p=0.000	32	~1962
▸ COLORADO RIVER AT GRAND LAKE (NORTH FORK) COLGRAND	↓ decreasing	-48.0	p=0.027	16	—
▸ COLORADO RIVER NEAR GRANBY, CO COLNGBCO	↓ decreasing	-38.6	p=0.001	32	~1949
▸ FRASER-JIM CREEK DITCH AT FLUME NEAR FRAJDICO	↑ increasing	+32.0	p=0.001	44	~1963
▸ WINDY GAP BYPASS FLUME WGPBPFCO	↓ decreasing	-30.8	p=0.009	20	~2018
▸ EAST INLET CREEK EASINLET	↓ decreasing	-20.2	p=0.017	16	—
▸ WILLIAMS FORK BELOW STEELMAN CREEK, CO. WILSTECO	↓ decreasing	-10.4	p=0.003	69	~2000
▸ FRASER RIVER AT WINTER PARK, CO. FRAWINCO	↓ decreasing	-10.1	p=0.000	115	~1938
▸ ST. LOUIS CREEK NEAR FRASER, CO. SLOFRACO	↓ decreasing	-7.7	p=0.000	91	~1958
▸ COLORADO RIVER NEAR GRAND LAKE, CO. COLGRACO	↓ decreasing	-7.7	p=0.003	66	~1918
▸ RANCH CREEK NEAR FRASER, CO. RANFRACO	↓ decreasing	-5.7	p=0.004	92	~1953
▸ WILLIAMS FORK NEAR PARSHALL, CO WILPARCO	↓ decreasing	-4.5	p=0.000	113	~1952
▸ COLORADO RIVER BELOW LAKE GRANBY, CO. COLGBYCO	↑ increasing	+4.0	p=0.009	34	—
▸ VASQUEZ CREEK AT WINTER PARK, CO VASWINCO	↑ increasing	+3.7	p=0.023	92	~1992

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

Mass-balance (network closure) trend

Structure divrec-history backfill coverage as of the last check: 8% of 689 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 (2481 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.

RANCH CREEK NEAR TABERNASH, CO.: reach shifted from -129 cfs to -138 cfs summer mean (more losing, p=0.029, 11 yr) [mountain crystalline canyon: minimal groundwater storage -- large or shifting unaccounted losses here are more consistent with data/measurement issues or unmodeled plumbing than with aquifer exchange]
WILLIAMS FORK BELOW WILLIAMS FORK RESERVOIR, CO: reach shifted from +137 cfs to -146 cfs summer mean (more losing, p=0.000, 73 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=-0.67) -- part of it may be unaccounted water becoming accounted, not hydrologic change]
WILLOW CREEK BELOW WILLOW CREEK RESERVOIR: reach shifted from -36 cfs to -133 cfs summer mean (more losing, p=0.001, 68 yr) [alluvial valley: real alluvial aquifer -- a decades-long shift toward losing is the classic signature of alluvial pumping and urbanization]

Groundwater now has its own tab: 74 monitored well(s), water-table trends, stream corridors, and the advisory depletion screen.

Reservoirs now has its own tab: 126 reservoir(s), end-of-year storage back to 1975, click-to-chart histories.

Cross-gage pattern fingerprint

Over the 92-year window with full coverage (1935–2026), the dominant shared pattern across 4 gage(s) explains 65% 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.

The basin's aquifer story, from 1,051 water-level measurements across 74 monitored well(s) (65 alluvial, 0 bedrock, rest unclassified) — plus 19 administered well(s) reporting metered pumping through diversion records. Observation wells and pumping wells are different populations and are never conflated. Click a well to chart its record.

Well map

Every monitored well with a location — hover for identity, click to chart its water-level record below. ● alluvial ● bedrock / confined (Denver Basin, High Plains, etc. — one-way, no human-timescale recharge) ● unclassified — marker size scales with the strength of the well's water-level trend (|Sen slope| in ft/decade — the same Mann-Kendall/Sen statistic as the trends table below); the smallest, faintest dots have too little record to test.

3D aquifer x-ray

Every aquifer unit as its own 3D head surface — alluvial water table on top, Denver Basin members (Dawson, Denver, Arapahoe, Laramie–Fox Hills) stacked beneath where measured — interpolated from measured water levels and animated through time. Units are never mixed; surfaces exist only inside each unit's well coverage (no extrapolation); thin epochs are suppressed with their reason shown. Vertical scale exaggerated for readability; z is head elevation in feet. Advisory — measured heads, not a calibrated model.

Water-table trends

Of 0 well(s) with enough record for a trend test: 0 declining, 0 rising.

Stream corridors — the surface connection

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.

RANCH CREEK NEAR TABERNASH, CO.: 1 alluvial well(s) nearby; pooled water table — ft (1996–2011, no_trend, p=0.7105)

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.

126 reservoir(s) with 11,152 storage measurement(s), 1975–2025. Basin storage as of 2024-10-31 (the record's own end — reservoir records publish ~annually): 569,595 AF across 33 reservoir(s). 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?

Each reservoir drawn as a vessel: bubble size ∝ its record-high storage, fill level = 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 of its own record high otherwise (a wrong capacity would be worse than an honest record high, so only confident joins upgrade). Hover for numbers, click to chart its history below the map. A dashed teal ring marks reservoirs reporting live DWR telemetry — their fill reflects yesterday's storage, drawn as a dotted tail on charts and treated as provisional until the next verified HydroBase snapshot supersedes it. ● <25% ● 25–60% ● 60–90% ● >90%

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 reservoir to chart its full storage history.

Reservoir	Last recorded storage (AF)	As of
▸ CBT GRANBY RESERVOIR (5104055)	462,484	2024-10-31
▸ WILLIAMS FORK RESERVOIR (5103709)	81,431	2024-10-31
▸ CBT SHADOW MOUNTAIN LAKE (5103695)	16,969	2024-10-31
▸ CBT WILLOW CREEK RESERVOIR (5103710)	6,970	2024-10-31
▸ EAST BRANCH RESERVOIR (5103715)	1,738	2016-10-31
▸ MEADOW CREEK RESERVOIR (5103686)	611	2024-10-31
▸ SYLVAN RESERVOIR (5103701)	300	2024-09-10
▸ JACK ORR RESERVOIR (5104009)	245	1994-10-31

Decrees, seniority, and administrative calls connected to this basin's flow network. Advisory reading aids on public DWR data — not administrative or legal conclusions. Rights on file: 3490 across 2208 structure(s); 65 structure(s) carry 0 court-case references.

Decreed rights on this network run from 1864-06-01 to 2024-11-30. 25 abandonment screens and 332 compliance flags are listed below as leads for review — a screen is not an abandonment and a flag is not a violation.

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 ~1976 — idleness that begins before then may be unreported use, not nonuse (flagged † below).

GRAND LAKE PIPELINE (5100679) (1945-03-15, 6.0 cfs decreed): last active 1976 — 35 years idle
HOLZWARTH DITCH NO 3 (5100713) (1920-06-01, 1.0 cfs decreed): last active 1976 — 35 years idle
KIMSEY NO 1 DITCH (5100762) (1891-05-01, 1.6 cfs decreed): last active 1976 — 35 years idle
MILLS GULCH DITCH (5100797) (1864-06-01, 0.5 cfs decreed): last active 1976 — 35 years idle
WOOD PIPELINE (5100969) (1931-01-01, 0.0 cfs decreed): last active 1976 — 35 years idle
BUNTE RESERVOIR (5103646) (1911-04-18, 0.0 cfs decreed): last active 1976 — 35 years idle
F W LINKE RESERVOIR (5103659) (1948-05-13, 0.0 cfs decreed): last active 1976 — 35 years idle
F W LINKE NO 2 RESERVOIR (5103660) (1950-10-11, 0.0 cfs decreed): last active 1976 — 35 years idle
HANKINSON RESERVOIR (5103665) (1949-01-27, 0.0 cfs decreed): last active 1976 — 35 years idle
LINKE RESERVOIR (5103680) (1910-10-20, 0.0 cfs decreed): last active 1976 — 35 years idle

Compliance screens (332 advisory flags)

Screened 442 of 2208 structures with rights (526 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.

CBT WILLOW CREEK FEEDER (5100958): Observed p99 daily rate 444.0 cfs (max 551.0) exceeds total decreed absolute 400.0 cfs across 36486 recorded day(s).
KINNEY BARRIGER DITCH (5100763): Observed p99 daily rate 96.1 cfs (max 114.0) exceeds total decreed absolute 65.0 cfs across 12282 recorded day(s).
RED TOP VALLEY DITCH - STILLWATER CREEK (5101315): Observed p99 daily rate 92.0 cfs (max 120.0) exceeds total decreed absolute 12.0 cfs across 3495 recorded day(s).
FRASER RIVER DIVERSION PROJECT - LITTLE (5101265): Observed p99 daily rate 60.0 cfs (max 107.0) exceeds total decreed absolute 0.7 cfs across 8394 recorded day(s). Structure holds an Augmentation-use decree -- diversions above the direct-flow decree can be lawful under plan operations; interpret with care.
BUNTE HIGHLINE DITCH (5100546): Observed p99 daily rate 50.0 cfs (max 54.0) exceeds total decreed absolute 45.0 cfs across 9915 recorded day(s). Structure holds an Augmentation-use decree -- diversions above the direct-flow decree can be lawful under plan operations; interpret with care.
SOPHRONIA DAY DITCH (5100893): Observed p99 daily rate 40.5 cfs (max 48.2) exceeds total decreed absolute 24.1 cfs across 8932 recorded day(s).
OSTRANDER DITCH (5100826): Observed p99 daily rate 31.0 cfs (max 32.1) exceeds total decreed absolute 16.0 cfs across 7031 recorded day(s). Structure holds an Augmentation-use decree -- diversions above the direct-flow decree can be lawful under plan operations; interpret with care.
HAMILTON-CABIN CREEK EXTENSION (5101250): Observed p99 daily rate 29.0 cfs (max 63.0) exceeds total decreed absolute 25.0 cfs across 24685 recorded day(s).
MUSGRAVE DITCH (5100810): Observed p99 daily rate 27.8 cfs (max 50.5) exceeds total decreed absolute 25.0 cfs across 17386 recorded day(s).
SHERIFF DITCH (COLORADO RIVER) (5100883): Observed p99 daily rate 25.4 cfs (max 25.4) exceeds total decreed absolute 18.8 cfs across 6849 recorded day(s).

Seniority (top structures by decreed rate)

Structure	Senior priority date	Rights	Decreed abs (cfs)	Conditional?
CBT GRANBY PUMP CANAL (5100678)	1935-08-01	1	1100.0	—
MOFFAT WATER TUNNEL (5104655)	1921-07-04	1	928.0	yes
WINDY GAP PUMP PIPELINE CANAL (5104700)	1967-06-22	3	600.0	—
CBT ALVA B ADAMS TUNNEL (5104634)	1935-08-01	1	550.0	—
GRAND RIVER DITCH (5104601)	1890-09-01	1	524.6	—
CBT WILLOW CREEK FEEDER (5100958)	1935-08-01	1	400.0	—
WILLIAMS FORK POWER CONDUIT (5101237)	1933-10-15	3	311.0	yes
FRASER RIVER DIVERSION PROJECT - FRASER (5100639)	1921-07-04	6	275.7	yes
WILLIAMS FORK TUNNEL (5104603)	1921-07-04	1	254.0	yes
BIG LAKE DITCH (5100529)	1903-02-06	3	231.0	yes
FRASER RIVER DIVERSION PROJECT - VASQUEZ (5101310)	1921-07-04	6	175.0	yes
RED TOP VALLEY DITCH (5100848)	1901-11-10	2	150.0	yes
MIN FLOW COLORADO RIVER TROUBLESOME-BLUE (5102036)	1980-07-08	1	150.0	—
MIN FLOW COLORADO RIVER WILLIAMS FK-TROU (5102037)	1980-07-08	1	135.0	—
WILLIAMS FORK DIVERSION PROJECT - SOUTH (5101279)	1921-07-04	3	115.0	yes

No inventory or legal-document changes detected since the daily watch began.

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.