← My Water  ·  All ditches in this district  ·  Print / save as PDF  · 

 ·  every download of this record carries its certificate id

OLYMPUS TUNNEL

Structure dossier · WDID 0401000 · PIPELINE · BIG THOMPSON RIVER · 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 05:06 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

Where this structure is measured

GageFlowing nowRecordHow we know
OLYMPUS TUNNEL (ESTES FOOTHILLS CANAL) OLYTUNCO 79.2 cfs 1953–2026, 25,873 days DWR telemetry mapping
OLYMPUS DAM AT LAKE ESTES OLYDAMCO — — co-located, 47 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.

Flowing now

79.2 cfs as of 2026-10-13 03:05 (2.0 h ago)

Provisional 15-minute telemetry from OLYTUNCO ↗ (OLYMPUS TUNNEL (ESTES FOOTHILLS CANAL)). 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

OLYMPUS TUNNEL holds 20 decreed rights on BIG THOMPSON RIVER. As of 2026-09-27, 8 of them are out of priority under a call at admin 8522.00000 placed by FARMERS IRRIGATION CANAL. Its 12 most senior rights, back to 1861-11-10, keep diverting. 6 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 272,711 acre-feet. It was a party to 3 court cases that also touched 12 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 (diversion). Faint dots are the neighbouring water; click any to open it.

Current administration

● Junior rights called out — call at FARMERS IRRIGATION CANAL (BIG THOMPSON RIVER, priority 1873-04-30).

Which of its rights are out of priority?

Under today's controlling call (FARMERS IRRIGATION CANAL, priority 1873-04-30): 8 of this structure's 20 rights are out of priority now. (6 call(s) state no district and sit outside this one — not judged, not assumed.) In the 5 past years most like this one (2010, 2021, 2016, 2019, 2023), 7 of the rights shown below were out at least one week in at least one analog year.

Right (priority)NowAnalog years outMajority out by
1861-11-10 4332 ● in priority 0 of 5 —
1863-04-01 4839 ● in priority 0 of 5 —
1864-05-01 5235 ● in priority 0 of 5 —
… 7 more rights between these …
1872-05-01 8157 ● in priority 3 of 5 2026-09-27
1873-05-01 8522 ● in priority 4 of 5 2026-09-27
1873-06-23 8575 ● out 4 of 5 2026-09-27
1873-10-25 8699 ● out 4 of 5 2026-09-27
… 3 more rights between these …
1883-09-17 12313 ● out 5 of 5 2026-09-27
2002-12-30 55881 ● out 5 of 5 2026-09-27
1956-06-06 60630 ● out 5 of 5 2026-09-27
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 BIG THOMPSON RIVER BELOW LAKE ESTES around 2026-09-27 (the newest reading on file) — currently 82% of that gage's own median for this window — to pick the 5 most similar past years with complete administration records (2004–2026). 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 1861-11-10 — 16th most senior of the 1296 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: VIESTENZ-SMITH PARK PUMP (1861-11-10). Immediately behind: LAKE ESTES (1861-11-10).

On MAINSTEM at river mile 20.5, it is 99th of 487 down the reach. Immediately upstream: ESTES PARK DITCH 4. Immediately downstream: HARRISON SPRING NO 1.

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 (21)

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
4332.00000 1861-11-101883-05-28 0.0 AF 0.0 222.6 AF Irrigation, Municipal +7 02CW0392, 89CW0128 +1
4332.00000 1861-11-101883-05-28 0.0 cfs 0.0 9.0208 cfs Irrigation, Municipal +7 02CW0392, 89CW0128 +1
4839.00000 1863-04-011883-05-28 0.0 cfs 0.0 4.6971 cfs Irrigation, Municipal +7 89CW0128, 02CW0392
5235.00000 1864-05-011883-05-28 0.0 cfs 0.0 6.6141 cfs Irrigation, Municipal +7 02CW0392, 89CW0128
5772.00000 1865-10-201883-05-28 0.0 cfs 0.0 11.0097 cfs Irrigation, Municipal +7 89CW0128, 03CW0354 +1
5784.00000 1865-11-011883-05-28 0.0 cfs 0.0 5.0126 cfs Municipal 03CW0354, 02CW0392
5923.00000 1866-03-201883-05-28 0.0 cfs 0.0 2.134 cfs Irrigation, Municipal +7 89CW0128
6269.00000 1867-03-011883-05-28 0.0 cfs 0.0 9.0232 cfs Irrigation, Municipal +7 89CW0128, 02CW0392
6361.00000 1867-06-011883-05-28 0.0 cfs 0.0 7.154 cfs Irrigation, Municipal +7 03CW0354, 02CW0392 +1
7598.00000 1870-10-201883-05-28 0.0 cfs 0.0 32.9643 cfs Irrigation, Municipal +7 89CW0128, 03CW0354 +1
7944.00000 1871-10-011883-05-28 0.0 cfs 0.0 14.484 cfs Irrigation, Municipal +7 02CW0392, 89CW0128
8157.00000 1872-05-011883-05-28 0.0 cfs 0.0 1.3379 cfs Irrigation, Municipal +7 89CW0128, 02CW0392
8522.00000 1873-05-011883-05-28 0.0 cfs 0.0 34.7846 cfs Irrigation, Municipal +7 02CW0392, 89CW0128
8575.00000 1873-06-231883-05-28 0.0 cfs 0.0 11.8224 cfs Irrigation, Municipal +7 89CW0128, 03CW0354 +1
8699.00000 1873-10-251883-05-28 0.0 cfs 0.0 29.9753 cfs Irrigation, Municipal +7 02CW0392, 03CW0354 +1
10167.00000 1877-11-011883-05-28 0.0 cfs 0.0 44.6283 cfs Irrigation, Municipal +7 89CW0128, 02CW0392
10532.00000 1878-11-011883-05-28 0.0 cfs 0.0 12.8344 cfs Irrigation, Municipal +7 03CW0354, 02CW0392 +1
11269.00000 1880-11-071883-05-28 0.0 cfs 0.0 9.7207 cfs Irrigation, Municipal +7 89CW0128
12313.00000 1883-09-171883-05-28 0.0 cfs 0.0 0.0022 cfs Irrigation, Municipal +7 89CW0128
55881.00000 2002-12-302002-12-31 0.0 cfs 0.0 388.5 cfs Municipal 02CW0393, 02CW0394
60630.38873 1956-06-062016-12-31 566.0 cfs 0.0 — Power generation 16CW3193

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 much of this decree was in priority, by day

A right is in priority on a day when it is senior to every call administering this structure. Of its 566.0 cfs decreed rate, the average day over the last 6 year(s) had 23.248 cfs in priority (4% of the decree). No call in effect is a free river — that was 3.8% of days.

On 10 days some rights were in priority and others were not — seniority splits a decree rather than switching it off. Calls are set and released at a time of day, not at midnight, so a day is counted by the hour: a call setting at 4pm costs that day a third of its rate, not all of it. A call began or ended mid-day on 10 of these days.

This is paper water. It is the decreed rate that was in priority — not water that was physically in the stream, and not water this structure diverted. A ditch can be in priority for 50 cfs on a day the creek carries five. What that distinction means →

YearMean in priority (Apr–Sep) Share of decreeFree-river days Days fully out
2026 0.0 cfs 0% 0 285
2025 0.0 cfs 0% 0 365
2024 22.17 cfs 4% 29 330
2023 123.72 cfs 22% 41 321
2022 0.0 cfs 0% 0 365
2021 0.0 cfs 0% 0 80
Show the last 120 days, day by day
DateIn priorityControlling call
2026-10-12 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-10-11 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-10-10 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-10-09 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-10-08 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-10-07 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-10-06 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-10-05 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-10-04 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-10-03 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-10-02 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-10-01 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-30 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-29 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-28 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-27 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-26 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-25 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-24 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-23 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-22 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-21 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-20 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-19 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-18 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-17 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-16 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-15 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-14 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-13 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-12 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-11 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-10 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-09 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-08 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-07 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-06 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-05 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-04 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-03 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-02 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-09-01 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-08-31 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-08-30 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-08-29 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-08-28 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-08-27 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-08-26 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-08-25 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-08-24 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-08-23 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-08-22 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-08-21 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-08-20 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-08-19 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-08-18 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-08-17 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-08-16 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-08-15 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-08-14 0.0 cfs (0%) HILLSBOROUGH DITCH, 1861-11-10 · Big Thompson River · same source, at or above the calling point
2026-08-13 0.0 cfs (0%) HILLSBOROUGH DITCH, 1861-11-10 · Big Thompson River · same source, at or above the calling point
2026-08-12 0.0 cfs (0%) HILLSBOROUGH DITCH, 1861-11-10 · Big Thompson River · same source, at or above the calling point
2026-08-11 0.0 cfs (0%) HILLSBOROUGH DITCH, 1861-11-10 · Big Thompson River · same source, at or above the calling point
2026-08-10 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-08-09 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-08-08 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-08-07 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-04-01 · Big Thompson River · same source, at or above the calling point
2026-08-06 0.0 cfs (0%) HILLSBOROUGH DITCH, 1864-05-01 · Big Thompson River · same source, at or above the calling point
2026-08-05 0.0 cfs (0%) HILLSBOROUGH DITCH, 1864-05-01 · Big Thompson River · same source, at or above the calling point
2026-08-04 0.0 cfs (0%) HILLSBOROUGH DITCH, 1864-05-01 · Big Thompson River · same source, at or above the calling point
2026-08-03 0.0 cfs (0%) HILLSBOROUGH DITCH, 1864-05-01 · Big Thompson River · same source, at or above the calling point
2026-08-02 0.0 cfs (0%) HILLSBOROUGH DITCH, 1865-02-25 · Big Thompson River · same source, at or above the calling point
2026-08-01 0.0 cfs (0%) HILLSBOROUGH DITCH, 1865-10-20 · Big Thompson River · same source, at or above the calling point
2026-07-31 0.0 cfs (0%) HILLSBOROUGH DITCH, 1865-10-20 · Big Thompson River · same source, at or above the calling point
2026-07-30 0.0 cfs (0%) HILLSBOROUGH DITCH, 1865-02-25 · Big Thompson River · same source, at or above the calling point
2026-07-29 0.0 cfs (0%) HILLSBOROUGH DITCH, 1865-02-25 · Big Thompson River · same source, at or above the calling point
2026-07-28 0.0 cfs (0%) HILLSBOROUGH DITCH, 1865-10-20 · Big Thompson River · same source, at or above the calling point
2026-07-27 0.0 cfs (0%) HILLSBOROUGH DITCH, 1865-10-20 · Big Thompson River · same source, at or above the calling point
2026-07-26 0.0 cfs (0%) HILLSBOROUGH DITCH, 1865-11-01 · Big Thompson River · same source, at or above the calling point
2026-07-25 0.0 cfs (0%) BIG T PLATTE R DITCH, 1865-11-18 · Big Thompson River · same source, at or above the calling point
2026-07-24 0.0 cfs (0%) HILLSBOROUGH DITCH, 1865-10-20 · Big Thompson River · same source, at or above the calling point
2026-07-23 0.0 cfs (0%) HILLSBOROUGH DITCH, 1864-05-01 · Big Thompson River · same source, at or above the calling point
2026-07-22 0.0 cfs (0%) HILLSBOROUGH DITCH, 1864-05-01 · Big Thompson River · same source, at or above the calling point
2026-07-21 0.0 cfs (0%) HILLSBOROUGH DITCH, 1864-05-01 · Big Thompson River · same source, at or above the calling point
2026-07-20 0.0 cfs (0%) HILLSBOROUGH DITCH, 1864-05-01 · Big Thompson River · same source, at or above the calling point
2026-07-19 0.0 cfs (0%) HILLSBOROUGH DITCH, 1864-05-01 · Big Thompson River · same source, at or above the calling point
2026-07-18 0.0 cfs (0%) HILLSBOROUGH DITCH, 1864-05-01 · Big Thompson River · same source, at or above the calling point
2026-07-17 0.0 cfs (0%) HILLSBOROUGH DITCH, 1864-05-01 · Big Thompson River · same source, at or above the calling point
2026-07-16 0.0 cfs (0%) HILLSBOROUGH DITCH, 1864-05-01 · Big Thompson River · same source, at or above the calling point
2026-07-15 0.0 cfs (0%) HILLSBOROUGH DITCH, 1864-05-01 · Big Thompson River · same source, at or above the calling point
2026-07-14 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-05-01 · Big Thompson River · same source, at or above the calling point
2026-07-13 0.0 cfs (0%) HILLSBOROUGH DITCH, 1863-05-01 · Big Thompson River · same source, at or above the calling point
2026-07-12 0.0 cfs (0%) HILLSBOROUGH DITCH, 1864-05-01 · Big Thompson River · same source, at or above the calling point
2026-07-11 0.0 cfs (0%) HILLSBOROUGH DITCH, 1864-05-01 · Big Thompson River · same source, at or above the calling point
2026-07-10 0.0 cfs (0%) HILLSBOROUGH DITCH, 1864-05-01 · Big Thompson River · same source, at or above the calling point
2026-07-09 0.0 cfs (0%) HILLSBOROUGH DITCH, 1864-05-01 · Big Thompson River · same source, at or above the calling point
2026-07-08 0.0 cfs (0%) HILLSBOROUGH DITCH, 1864-05-01 · Big Thompson River · same source, at or above the calling point
2026-07-07 0.0 cfs (0%) HILLSBOROUGH DITCH, 1864-05-01 · Big Thompson River · same source, at or above the calling point
2026-07-06 0.0 cfs (0%) HILLSBOROUGH DITCH, 1864-05-01 · Big Thompson River · same source, at or above the calling point
2026-07-05 0.0 cfs (0%) HILLSBOROUGH DITCH, 1864-05-01 · Big Thompson River · same source, at or above the calling point
2026-07-04 0.0 cfs (0%) HILLSBOROUGH DITCH, 1864-05-01 · Big Thompson River · same source, at or above the calling point
2026-07-03 0.0 cfs (0%) HILLSBOROUGH DITCH, 1864-05-01 · Big Thompson River · same source, at or above the calling point
2026-07-02 0.0 cfs (0%) HILLSBOROUGH DITCH, 1865-02-25 · Big Thompson River · same source, at or above the calling point
2026-07-01 0.0 cfs (0%) HILLSBOROUGH DITCH, 1865-10-20 · Big Thompson River · same source, at or above the calling point
2026-06-30 0.0 cfs (0%) BIG T PLATTE R DITCH, 1866-06-30 · Big Thompson River · same source, at or above the calling point
2026-06-29 0.0 cfs (0%) BIG T PLATTE R DITCH, 1867-03-01 · Big Thompson River · same source, at or above the calling point
2026-06-28 0.0 cfs (0%) BIG T PLATTE R DITCH, 1867-03-01 · Big Thompson River · same source, at or above the calling point
2026-06-27 0.0 cfs (0%) BIG T PLATTE R DITCH, 1867-03-01 · Big Thompson River · same source, at or above the calling point
2026-06-26 0.0 cfs (0%) BIG T PLATTE R DITCH, 1867-03-01 · Big Thompson River · same source, at or above the calling point
2026-06-25 0.0 cfs (0%) BIG T PLATTE R DITCH, 1867-03-01 · Big Thompson River · same source, at or above the calling point
2026-06-24 0.0 cfs (0%) BIG T PLATTE R DITCH, 1867-03-01 · Big Thompson River · same source, at or above the calling point
2026-06-23 0.0 cfs (0%) BIG T PLATTE R DITCH, 1867-03-01 · Big Thompson River · same source, at or above the calling point
2026-06-22 0.0 cfs (0%) BIG T PLATTE R DITCH, 1867-06-01 · Big Thompson River · same source, at or above the calling point
2026-06-21 0.0 cfs (0%) BIG T PLATTE R DITCH, 1867-06-01 · Big Thompson River · same source, at or above the calling point
2026-06-20 0.0 cfs (0%) BIG T PLATTE R DITCH, 1870-10-20 · Big Thompson River · same source, at or above the calling point
2026-06-19 0.0 cfs (0%) BIG T PLATTE R DITCH, 1870-10-20 · Big Thompson River · same source, at or above the calling point
2026-06-18 0.0 cfs (0%) BIG T PLATTE R DITCH, 1870-10-20 · Big Thompson River · same source, at or above the calling point
2026-06-17 0.0 cfs (0%) BIG T PLATTE R DITCH, 1870-10-20 · Big Thompson River · same source, at or above the calling point
2026-06-16 0.0 cfs (0%) BIG T PLATTE R DITCH, 1871-10-01 · Big Thompson River · same source, at or above the calling point
2026-06-15 0.0 cfs (0%) BIG T PLATTE R DITCH, 1871-10-01 · Big Thompson River · same source, at or above the calling point
How this is worked out, and what it cannot tell you
  • This is a decreed rate that was in priority -- paper water, not water that was available or diverted.
  • Augmentation plans, exchanges and substitute supply plans let a structure divert lawfully while out of priority; none are modelled.
  • Calls on the river this source flows into are included without a position test, so curtailment can be over-reported where the calling point sits above the confluence.
  • DWR's administration is the authority. Scored against DWR's own call analysis, this method agreed on 95.5% of 85,822 structure-days (2026-08-29).
  • Calls considered for this structure: 3994, of which 2690 sit on a river it flows into.

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 4332.00000 · never out of priority in these seasons
AprMayJunJulAugSep
middle right · admin 8157.00000 · peaks at 11 of 11 seasons
AprMayJunJulAugSep
most junior right · admin 60630.38873 · peaks at 11 of 11 seasons
AprMayJunJulAugSep

Snow sets the clock here. In the driest third of snow years (3 seasons), 2 seasons stayed under call throughout and 0 ended free. In the middle third (5 seasons), the call settled in for the season around June 10 (June 3 to June 24 across those years); in 2 of them it never lifted at all. In the wettest third (3 seasons), the call settled in for the season around July 8 (June 17 to July 8 across those years); in 1 of them it never lifted at all.

Snow years ranked by the district’s April 1 snow-water percentile across 2 SNOTEL sites; 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 272,711 AF. Its most recent year on record, 2025, came in at 244,941 AF — 90% of that, and 7th lowest of the 15 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)
2011 294,576 12th lowest of 15 · 108% of median 306 806.0
2012 277,779 10th lowest of 15 · 102% of median 305 596.7
2013 73,794 1st lowest of 15 · 27% of median 192 599.4
2014 316,088 15th lowest of 15 · 116% of median 364 922.3
2015 212,280 3rd lowest of 15 · 78% of median 349 901.2
2016 272,711 8th lowest of 15 · 100% of median 333 554.0
2017 215,761 5th lowest of 15 · 79% of median 237 552.0
2018 276,095 9th lowest of 15 · 101% of median 333 553.6
2019 305,737 14th lowest of 15 · 112% of median 355 559.0
2020 206,561 2nd lowest of 15 · 76% of median 335 560.0
2021 296,678 13th lowest of 15 · 109% of median 365 553.0
2022 215,544 4th lowest of 15 · 79% of median 338 552.0
2023 281,274 11th lowest of 15 · 103% of median 339 553.0
2024 234,391 6th lowest of 15 · 86% of median 277 552.0
2025 244,941 7th lowest of 15 · 90% of median 304 553.0

Call-derived yield: senior right divertible 100.0% of a median season / 61.2% dry-year.

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 21 right(s), seniority decoded
diversion record current 5216 measured days, newest 331 day(s) before the data's end (DWR publishes ~1 year in arrears)
record continuity continuous 76% of the irrigation seasons in 1993-2025 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.

Hydrohistorian is free, with no ads — one server and a lot of public records. If it earns its keep, you can help keep it running.