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THORNTON HAMMER PIT

Structure dossier · WDID 0203913 · RESERVOIR · SOUTH PLATTE RIVER · DWR record · probably THORNTON CITY OF’s (matched on DWR’s contact or an EPA intake name; verify below)

Thornton Hammer Pit is a reservoir on South Platte River 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 17:36 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.

The record and the river

In short

THORNTON HAMMER PIT holds 1 decreed right on SOUTH PLATTE RIVER. A call at BURLINGTON D RIVER HEADGATE on SOUTH PLATTE RIVER (1885-11-20) currently reaches it: fully called out. 7 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 3 analog year(s) have both flow and a complete administration record; 4 needed. In a median year over its last 8 recorded years it diverts 321 acre-feet. It was a party to 2 court cases that also touched 6 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.

Current administration

● Fully called out — call at BURLINGTON D RIVER HEADGATE (SOUTH PLATTE RIVER, priority 1885-11-20).

Which of its rights are out of priority?

The outlook for the weeks ahead is not computable for this structure: only 3 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 1991-12-31 — 10694th most senior of the 21886 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: THORNTON COOLEY EAST PIT (1991-12-31). Immediately behind: ROGERS RES (1991-12-31).

On MAINSTEM at river mile 126.3, it is 791st of 890 down the reach. Immediately upstream: UNITED DIVERSION FACILITY NO 3. Immediately downstream: KEN MITCHELL LAKES SEC 11 PUMP STATION.

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
51864.00000 1991-12-311991-12-31 0.0 AF 2116.1 AF — Irrigation, Municipal +8 18CW3158, 91CW0126

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 51864.00000 · peaks at 10 of 11 seasons
AprMayJunJulAugSep
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 8 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 321 AF. Its most recent year on record, 2025, came in at 334 AF — 104% of that, and 6th lowest of the 8 years with a recorded volume.

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 recordDays recordedPeak (cfs)
2018 20 1st lowest of 8 · 6% of median 61 1.3
2019 577 8th lowest of 8 · 180% of median 365 9.5
2020 331 5th lowest of 8 · 103% of median 366 11.6
2021 115 2nd lowest of 8 · 36% of median 365 1.2
2022 388 7th lowest of 8 · 121% of median 365 14.4
2023 311 4th lowest of 8 · 97% of median 365 13.7
2024 265 3rd lowest of 8 · 83% of median 366 7.1
2025 334 6th lowest of 8 · 104% of median 304 5.7

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 1 right(s), seniority decoded
diversion record current 2557 measured days, newest 336 day(s) before the data's end (DWR publishes ~1 year in arrears)
record continuity continuous 100% of the irrigation seasons in 2018-2025 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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