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CBT WILLOW CREEK RESERVOIR

Structure dossier · WDID 5103710 · RESERVOIR · WILLOW CREEK · DWR record

Source DWR administrative record · verify at DWR structure ↗ Source DWR administrative record · verify at DWR diversion records ↗ Source Our computation, scored against a reference · scored against DWR's call analysis, see /methods

Where this page's figures come from

Generated 2026-10-13 17:53 by Hydrohistorian. Sources: DWR HydroBase snapshot HydroBase_CO_20260928 (history) + CDSS REST (current), USGS NWIS cross-checks. Engine v0.5.0 (dd58e60) — every figure regenerates from this named code version and data image.

Who owns it

DWR’s own records name no owner for a ditch, reservoir or well, so this comes from the source shown and can be out of date. Organisations only: a private landowner’s name is never listed.

The record and the river

Where this structure is measured

GageFlowing nowRecordHow we know
WILLOW CREEK RESERVOIR WILRESCO — — co-located, 1 m
WILLOW CREEK BELOW WILLOW CREEK RESERVOIR WILWCRCO 25.7 cfs 1953–2026, 24,046 days co-located, 233 m

A green link is DWR's own: either its telemetry inventory maps this WDID to that station, or the station is named for this WDID (0700553 → 0700553A). An amber one is ours — the station sits within 250 m and shares a distinctive word with this structure's name, which is a strong hint rather than a DWR statement that this gage meters this structure. Wrong? Tell us.

In short

CBT WILLOW CREEK RESERVOIR holds 1 decreed right on WILLOW CREEK. No active call senior to its rights reaches its district today (30 active calls checked), so it is in priority now. 25 further calls state no district and sit outside this one, so they are counted here rather than assumed either way. That is today's position; the weeks ahead cannot be projected for it: only 0 analog year(s) have both flow and a complete administration record; 4 needed. In a median year over its last 15 recorded years it diverts 12,492 acre-feet. It was a party to 1 court cases that also touched 5 other structures.

Assembled from the figures on this page — every number above is checked against them before it is shown (9 checked). The detail, with its method, is in the cards below.

Download this structure

Everything on this page as data you can work with — and a README that makes it citable: the HydroBase snapshot it was built from, the build commit, what every column means, the method behind each derived figure, and that method's stated limits.

⇩ Full record (.zip) Print / save as PDF

Or one table at a time: rights.csv · annual_use.csv · curtailment_now.csv · court_cases.csv · co_parties.csv · call_climatology.csv

What is in the bundle
  • rights.csv — every decreed right, most senior first, with admin numbers, dates, amounts, uses and case numbers.
  • annual_use.csv — recorded diversion by year, with releases accounted separately.
  • curtailment_now.csv — each right's current priority status and how often it was out across analog years.
  • court_cases.csv — the cases attached to its rights.
  • co_parties.csv — the other structures that were parties to those cases. Not available anywhere else.
  • call_climatology.csv — how often each right has been out of priority by week of season, with confidence intervals and the seasons the record could actually judge.
  • README.txt — provenance, methods, limits, disclaimer, and links back to DWR's own records for verification.

Where it sits

Location as DWR records it (storage). Faint dots are the neighbouring water; click any to open it.

Dam safety

Dam WILLOW CREEK (completed 1953)
Hazard class High
Condition at last inspection Conditionally Satisfactory (2019-07-22)
Storage restriction None on file
Normal storage 10,600 AF
Physical status Active
Emergency action plan Yes

Source: DWR Dam Safety’s jurisdictional-dam inventory (damsafety/damsafetydaminfojd), refreshed weekly. Joined on this structure’s own WDID as DWR records it on the dam. Hazard class describes the consequence of failure, not the likelihood of it. DWR’s dam record.

Current administration

● In priority — no active call senior to this structure's rights affects its district (30 active call(s) checked).

25 further calls state no district and sit outside this one, so they are counted here rather than assumed either way.

Which of its rights are out of priority?

The outlook for the weeks ahead is not computable for this structure: only 0 analog year(s) have both flow and a complete administration record; 4 needed. Today’s position is a separate question, and it is answered in Current administration above — that screen reads the district’s active calls and needs no reference gage.

Where it sits in line

Priority 1935-08-01 — 426th most senior of the 2208 structures with decreed rights in this water districtDWR's administrative subdivision of a river basin; the unit calls are usually stated in..

Under prior appropriationColorado's rule for sharing water: first in time, first in right. Age decides, not proximity or need., everything ahead of it in this line is satisfied in full before it receives any water. Immediately ahead: CBT SHADOW MOUNTAIN LAKE (1935-08-01). Immediately behind: CBT GRANBY RESERVOIR (1935-08-01).

On WILLOW CREEK at river mile 42.4, it is 48th of 64 down the reach. Immediately upstream: HUDLER RESERVOIR NO 4. Immediately downstream: MCQUEARY DITCH 6.

Position on the modelled network, not a claim about whose water this is — a stream carries water from many rights at once, and diverted water returns to it.

Decreed rights (1)

Admin noDWR's numeric encoding of a water right's seniority. Smaller is more senior; the integer part counts days from 1849-12-31 to the date that ranks the right. AppropriatedWhen water was first put to beneficial use. It sets seniority unless a prior adjudication date is later. AdjudicatedWhen the water court confirmed the right. A use decreed in 1975 was not a decreed use in 1955, however old the appropriation is. AbsoluteA right actually put to use, as opposed to conditional -- a placeholder for a use not yet made. ConditionalA right reserving a place in line for a use not yet made; it must be diligently pursued or it lapses. Alt-pointAn absolute amount decreed at another structure that may be diverted here instead -- an alternate point of diversion or an exchange. DWR calls this the APEX amount; a right showing 0.0 absolute but an alt-point amount is exercised here under another structure's decree. Decreed forWhat the court said this water may be used for -- irrigation, municipal supply, augmentation and so on.Case
31258.00000 1935-08-011955-10-12 10553.0 AF 0.0 — Irrigation, Industrial +1 CA2782

Amounts marked cfs are flow rates; AF are stored volumes (storage rights are decreed in acre-feet). An absolute amount of 0.0 beside an alt-point amount is not a dead right: the water is decreed at another structure, and that row records permission to divert it here instead (an alternate point or exchange). A case listing several numbers reflects the original decree plus later change cases.

Recorded use (last 15 years on record)

Years far under the decreed amount? That gap has a name — paper water vs. wet water, explained on this structure.

In a median year this structure has a recorded diversion of 12,492 AF. Its most recent year on record, 2024, came in at 11,115 AF — 89% of that, and 5th lowest of the 15 years with a recorded volume.

This structure records both diversions and reservoir releases — they are separate water movements and are accounted separately below.

YearDiverted (AFA volume: one acre covered a foot deep, about 326,000 gallons -- roughly a suburban household's outdoor use for a year.)Compared with its own recordReleased (AF)Days recordedPeak (cfs)
2010 13,698 12th lowest of 15 · 110% of median 10,999 365 327.7
2011 10,243 4th lowest of 15 · 82% of median 10,018 365 331.2
2012 11,656 7th lowest of 15 · 93% of median 11,239 366 154.8
2013 12,866 9th lowest of 15 · 103% of median 12,000 365 331.7
2014 14,364 13th lowest of 15 · 115% of median 15,109 304 293.0
2015 21,025 15th lowest of 15 · 168% of median 25,694 154 345.0
2016 12,492 8th lowest of 15 · 100% of median 8,717 366 251.6
2017 9,532 1st lowest of 15 · 76% of median 12,432 365 229.9
2018 9,682 3rd lowest of 15 · 78% of median 8,449 365 228.4
2019 13,634 11th lowest of 15 · 109% of median 12,703 365 218.1
2020 9,636 2nd lowest of 15 · 77% of median 9,669 366 169.3
2021 13,242 10th lowest of 15 · 106% of median 12,577 365 188.9
2022 14,378 14th lowest of 15 · 115% of median 13,439 365 202.5
2023 11,140 6th lowest of 15 · 89% of median 12,337 365 337.3
2024 11,115 5th lowest of 15 · 89% of median 9,076 305 210.8

How good is our record of it?

Grade A (9/10 points) — the components below are the finding; the letter alone is not.

The rubric, component by component
CheckStateDetail
identity complete name, type, and water source all on file
decreed rights on file 1 right(s), seniority decoded
diversion record stale 17469 measured days, but newest is 699 day(s) before the data's end (target 450)
record continuity continuous 100% of the irrigation seasons in 1974-2024 carry measured days
published-record stability stable no upstream revisions recorded against this structure

Advisory reading aid on public data — not an administrative or legal conclusion, not a title opinion, and not a substitute for DWR administration or an engineer's analysis. Methodology review status is disclosed at hydrohistorian's basin pages.

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