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IRWIN DITCH
Structure dossier · WDID 2800593 · 1 · LOS PINOS CREEK · DWR record
Where this page's figures come from
Generated 2026-08-27 22:50 by Hydrohistorian. Sources: DWR HydroBase snapshot HydroBase_CO_20260707 (history) + CDSS REST (current), USGS NWIS cross-checks. Engine v0.5.0 (2deb1d7) — every figure regenerates from this named code version and data image.
Where it sits
Location as DWR records it. Faint dots are the neighbouring water; click any to open it.
Which of its rights are out of priority?
Not computable for this structure: this structure is not on the modelled flow network, so no reference gage can honestly stand in for it.
Where it sits in line
Priority 1881-05-31 — 65th most senior of the 1505 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: MCDOWELL VAN TUYL NO 2 D (1881-05-15). Immediately behind: BENNETT NO 2 DITCH (1881-06-01).
Decreed rights (4)
| 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. | Units | UsesWhat the court said this water may be used for -- irrigation, municipal supply, augmentation and so on. | Case |
|---|---|---|---|---|---|---|---|
| 16192.11474 | 1881-05-31 | 1904-04-29 | 1.6 | 0.0 | C | IRR | 53 |
| 17684.0 | 1898-06-01 | 1904-04-29 | 1.6 | 0.0 | C | IRR | 122 |
| 38822.11474 | 1881-05-31 | 1961-12-15 | 4.23 | 0.0 | C | IRR | 373 |
| 38822.17684 | 1898-06-01 | 1961-12-15 | 5.77 | 0.0 | C | IRR | 379 |
Legal record & documents
4 decreed actions on record across
2 court cases:
CA5591, CA1266.
Every case, dated
| Case | Actions | Latest adjudication | Types |
|---|---|---|---|
CA5591 | 2 | 1961-12-15 | S |
CA1266 | 2 | 1904-04-29 | S |
DWR's own records for this structure: net amounts · transactions & adjudication history · scanned decrees (search a case number there for the imaged document). On this site: the district's full legal picture →
Recorded use (last 15 years on record)
In a median year this structure has a recorded diversion of 609 AF. Its most recent year on record, 2025, came in at 1,179 AF — 194% of that, and 13th lowest of the 15 years with a recorded volume.
| Year | Diverted (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 record | Days recorded | Peak (cfs) |
|---|---|---|---|---|
| 2011 | 331 | 4th lowest of 15 · 54% of median | 87 | 2.7 |
| 2012 | 229 | 2nd lowest of 15 · 38% of median | 80 | 2.1 |
| 2013 | 110 | 1st lowest of 15 · 18% of median | 38 | 1.8 |
| 2014 | 363 | 6th lowest of 15 · 60% of median | 50 | 3.8 |
| 2015 | 641 | 9th lowest of 15 · 105% of median | 58 | 5.9 |
| 2016 | 813 | 11th lowest of 15 · 134% of median | 91 | 5.9 |
| 2017 | 555 | 7th lowest of 15 · 91% of median | 69 | 8.0 |
| 2018 | 345 | 5th lowest of 15 · 57% of median | 61 | 3.0 |
| 2019 | 1,169 | 12th lowest of 15 · 192% of median | 82 | 10.6 |
| 2020 | 609 | 8th lowest of 15 · 100% of median | 80 | 4.6 |
| 2021 | 282 | 3rd lowest of 15 · 46% of median | 39 | 4.5 |
| 2022 | 786 | 10th lowest of 15 · 129% of median | 73 | 5.7 |
| 2023 | 1,237 | 14th lowest of 15 · 203% of median | 87 | 8.5 |
| 2024 | 1,472 | 15th lowest of 15 · 242% of median | 96 | 12.0 |
| 2025 | 1,179 | 13th lowest of 15 · 194% of median | 60 | 10.6 |
Trends for this structure
Recorded use is rising over its last 15 recorded years (+74 AF/yr, Mann-Kendall p=0.006).
How good is our record of it?
Grade B (7/10 points) — the components below are the finding; the letter alone is not.
The rubric, component by component
| Check | State | Detail |
|---|---|---|
| identity | complete | name, type, and water source all on file |
| decreed rights | on file | 4 right(s), seniority decoded |
| diversion record | present | 4173 measured days; currency unknown (no data-coverage date to compare against) |
| record continuity | sparse | 35% of the irrigation seasons in 1970-2025 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.