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GUANELLA RESERVOIR

Structure dossier · WDID 0704030 · RESERVOIR · WEST FORK CLEAR CREEK · DWR record · probably GOLDEN CITY OF’s (matched on DWR’s contact or an EPA intake name; verify below)

Guanella Reservoir is a reservoir on West Fork Clear Creek in Colorado. This page is its public record: the water it has a right to, whether it may take it today, and its history, compiled from the Colorado Division of Water Resources.

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 2026-10-15 03:16 by Hydrohistorian. Sources: DWR HydroBase snapshot HydroBase_CO_20260928 (history) + CDSS REST (current), USGS NWIS cross-checks. Engine v0.5.0 (c7f5ca1) — every figure regenerates from this named code version and data image.

The record and the river

Where this structure is measured

GageFlowing nowRecordHow we know
GUANELLA RESERVOIR INFLOW GUAINFCO 3.6 cfs 2005–2026, 7,462 days DWR telemetry mapping
GUANELLA RESERVOIR (OUTFLOW) GUAOUTCO 0.36 cfs 2005–2026, 7,760 days DWR telemetry mapping

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.

Flowing now

3.6 cfs as of 2026-10-15 00:00 (3.3 h ago)

Provisional 15-minute telemetry from GUAINFCO ↗ (GUANELLA RESERVOIR INFLOW). Raw, not the approved record — it is never merged into the diversion history below. DWR publishes the official diversion record after the water year closes and is approved, which is why that record ends months back while this reads minutes ago.

In short

GUANELLA RESERVOIR holds 12 decreed rights on WEST FORK CLEAR CREEK. As of 2026-10-01, 9 of them are out of priority under a call at admin 7449.00000 placed by WANNAMAKER DITCH. Its 3 most senior rights, back to 1863-04-17, keep diverting. 7 further calls state no district and sit outside this one, so they are counted here rather than assumed either way. In a median year over its last 15 recorded years it diverts 1,569 acre-feet. It was a party to 10 court cases that also touched 22 other structures.

Assembled from the figures on this page — every number above is checked against them before it is shown (11 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 GUANELLA (completed 2004)
Hazard class High
Condition at last inspection Satisfactory (2026-09-01)
Storage restriction None on file
Normal storage 1,340 AF
Physical status Active
Emergency action plan Yes

Source: DWR Dam Safety’s jurisdictional-dam inventory (damsafety/damsafetydaminfojd), refreshed weekly. DWR’s record for this dam carries no WDID and no matched NID id, so it is joined by name and position: “GUANELLA” 0.248 mi away. More than half of Colorado’s jurisdictional dams can be reached no other way; judge the match before relying on it. Hazard class describes the consequence of failure, not the likelihood of it. DWR’s dam record.

Current administration

● Junior rights called out — call at WANNAMAKER DITCH (CLEAR CREEK, priority 1870-05-23).

Which of its rights are out of priority?

Under today's controlling call (WANNAMAKER DITCH, priority 1870-05-23): 9 of this structure's 12 rights are out of priority now. (7 call(s) state no district and sit outside this one — not judged, not assumed.) In the 5 past years most like this one (2023, 2017, 2022, 2021, 2015), 12 of the rights shown below were out at least one week in at least one analog year.

Right (priority)NowAnalog years outMajority out by
1863-04-17 4855 ● in priority 3 of 5 —
1868-02-23 6628 ● in priority 4 of 5 2026-10-01
1869-03-31 7030 ● in priority 4 of 5 2026-10-01
1871-04-13 7773 ● out 4 of 5 2026-10-01
1902-03-04 19055 ● out 5 of 5 2026-10-01
1977-06-08 48212 ● out 5 of 5 2026-10-01
1987-04-02 53326 ● out 5 of 5 2026-10-01
2000-12-28 55149 ● out 5 of 5 2026-10-01
2003-10-28 56183 ● out 5 of 5 2026-10-01
2004-07-05 56434 ● out 5 of 5 2026-10-01
2006-02-14 57023 ● out 5 of 5 2026-10-01
2018-05-24 61727 ● out 5 of 5 2026-10-01
How this table is built, and what it is not

“Now” compares each right's admin number with today's most senior applicable active call. The outlook uses flows at GUANELLA RESERVOIR INFLOW around 2026-10-01 (the newest reading on file) — currently 196% of that gage's own median for this window — to pick the 5 most similar past years with complete administration records (2015–2026). Only calls that verifiably apply count: DWR's own district statements in the call's set comments, a caller located in this district, or — on the same stream, where DWR records both stream miles (measured from the mouth) — a caller DOWNSTREAM of this structure. An upstream senior cannot demand water this diversion never deprives it of. Calls that state nothing and sit elsewhere are counted as unjudged rather than assumed, which also means the verified record is shorter than the raw one: early calls rarely state districts. For each week it finds the most senior call then in force; a right is out in that week exactly when that call is senior to it, which is why one line prices every right and juniors can be out while seniors keep diverting. “Majority out by” is the first week out in more than half the analog years. A frequency among named historical years, not a probability from a model, and not a forecast of what the division engineer will do. It says how often years whose flow resembled this one were under a call senior to this right in a given week. Snowpack, storage, and the actual administrative decisions of a given season are not modelled. Check the analog years listed: if they do not resemble this year to you, the outlook does not either.

Where it sits in line

Priority 1863-04-17 — 59th most senior of the 1815 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: LOWER URAD RES (1863-04-17). Immediately behind: 0704031 (1863-04-17).

On WEST FORK CLEAR CREEK at river mile 13.5, it is 4th of 4 down the reach. Immediately upstream: LINDSTROM NO 2 DITCH. Nothing modelled downstream of it on this reach.

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 (13)

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
4855.00000 1863-04-171884-10-04 0.0 cfs 0.0 0.2975 cfs Storage, Municipal +1 94CW0087
6628.00000 1868-02-231884-10-04 0.0 cfs 0.0 0.5868 cfs Storage, Municipal +1 94CW0087
7030.00000 1869-03-311884-10-04 0.0 cfs 0.0 2.6978 cfs Storage, Municipal +1 94CW0087
7773.00000 1871-04-131884-10-04 0.0 cfs 0.0 0.947 cfs Storage, Municipal +1 94CW0087
19055.00000 1902-03-041936-05-13 0.0 AF 0.0 6735.938 AF Irrigation, Municipal +8 96CW1117
48212.46545 1977-06-081982-12-31 2325.0 AF 0.0 — Irrigation, Municipal +6 10CW0078, 17CW3070 +1
53325.50130 1987-04-021996-12-31 0.0 cfs 0.0 25.0 cfs Irrigation, Municipal +8 05CW0154, 96CW1117
55149.00000 2000-12-282002-12-31 0.0 cfs 0.0 38.0 cfs Irrigation, Municipal +6 02CW0379
56183.00000 2003-10-282003-12-31 0.0 cfs 0.0 35.0 cfs Augmentation 03CW0361, 12CW0127
56434.00000 2004-07-052004-12-31 0.0 cfs 0.0 6.0 cfs Commercial, Fire +1 04CW0323
57023.00000 2006-02-142005-12-31 0.0 cfs 0.0 15.0 cfs Augmentation, All beneficial uses 20CW3082, 05CW0302
61726.61505 2018-05-242019-12-31 0.0 AF 0.0 1.0 AF Augmentation 19CW3255
61726.61505 2018-05-242019-12-31 0.0 cfs 0.0 1.0 cfs Augmentation 19CW3255

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.

How often is it out of priority?

Across the 11 seasons whose call record is complete enough to judge this structure (2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024, 2025, 2026), week by week from April.

most senior right · admin 4855.00000 · peaks at 9 of 11 seasons
AprMayJunJulAugSep
middle right · admin 53325.50130 · peaks at 11 of 11 seasons
AprMayJunJulAugSep
most junior right · admin 61726.61505 · peaks at 11 of 11 seasons
AprMayJunJulAugSep

Snow sets the clock here. In the driest third of snow years (3 seasons), the call was on all season, every season. In the middle third (5 seasons), the call settled in for the season around May 27; in 4 of them it never lifted at all. In the wettest third (3 seasons), the call settled in for the season around June 24 (June 17 to July 8 across those years).

Snow years ranked by the district’s April 1 snow-water percentile across 1 SNOTEL site; 11 seasons carry both a snow reading and a judgeable call record. How the past played out, not a forecast.

Why only 11 seasons, and what the bars mean

Each bar is one week: how many of those seasons that right was out of priority under a call this site can lawfully attribute to this structure. Green is never, red is every season on record.

The short record is a property of DWR's data, not of the river. A call only counts against a structure when we can establish it applies — by the districts named in its set comments, or by stream mile on the same source. DWR did not begin stating affected districts routinely until about 2015: fewer than one call in ten can be judged before then, against roughly two in three since. A season we cannot judge is not a season without calls, so it is dropped rather than counted as quiet — 12 seasons dropped here.

This is a frequency over past seasons, not a forecast. It says nothing about what the division engineer will do this year.

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 1,569 AF. Its most recent year on record, 2025, came in at 39 AF — 2% of that, and 1st 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)
2011 232 3rd lowest of 15 · 15% of median 86 61 2.0
2012 654 5th lowest of 15 · 42% of median 1,109 142 6.2
2013 63 2nd lowest of 15 · 4% of median 162 37 2.7
2014 1,099 7th lowest of 15 · 70% of median 3,198 203 13.4
2015 1,983 11th lowest of 15 · 126% of median 2,710 336 14.7
2016 2,216 12th lowest of 15 · 141% of median 4,208 366 16.8
2017 2,217 13th lowest of 15 · 141% of median 4,576 365 14.1
2018 2,582 14th lowest of 15 · 165% of median 1,817 365 12.7
2019 4,380 15th lowest of 15 · 279% of median 328 365 31.0
2020 1,668 9th lowest of 15 · 106% of median 825 366 14.0
2021 1,842 10th lowest of 15 · 117% of median 4,588 347 4.7
2022 1,569 8th lowest of 15 · 100% of median 6,639 304 24.1
2023 345 4th lowest of 15 · 22% of median 4,634 61 3.0
2024 750 6th lowest of 15 · 48% of median 4,904 306 6.4
2025 39 1st lowest of 15 · 2% of median 2,630 62 4.0

How good is our record of it?

Grade A (10/10 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 13 right(s), seniority decoded
diversion record current 5528 measured days, newest 335 day(s) before the data's end (DWR publishes ~1 year in arrears)
record continuity continuous 100% of the irrigation seasons in 2004-2025 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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