Hydrohistorian
Apishapa River on the ground — the ditches, wells, reservoirs and gages of Water District 18 · clicktap anything for its record
Browse this district’s ditches, gages, reservoirs, wells and springs as a list.
Full diagnostic snapshot pending — this district's weekly-style report (system status, active calls, hydrographs, anomaly flags) is produced by the nightly rotation and appears here after its first run. The tabs above are live now.
Schematic
Historical
Evolution of the network
Trends
This year, in context
In the weeks around 1981-09-30 (the newest reading on file), flows at the 1 ranked gage are running at a median 395% of their own long-term norm for this window — 0 below a typical year, 1 at or above. Driest relative to its record: APISHAPA RIVER AT AGUILAR, CO., ranking 6th lowest of 6 years.
How this comparison is made
Each gage's mean flow over the 3 days either side of 1981-09-30, compared with the same window in every year of its own record — so a gage is only ever measured against itself, and gages with no record in the window are counted out rather than guessed.
Gage flow trend & changepoints
What counts as a trend here
Computed 2026-08-30 19:37 from 2 gage(s) with cached period-of-record data. The series is each gage's annual mean flow in cfs (years with ≥300 days of record). Mann-Kendall (trend, with the Hamed–Rao correction for serial correlation — persistence can otherwise fake significance) and Pettitt (changepoint) both require at least 8 years spanning at least 10 years of record. A gage below that reports no signal — which is not the same as “no change.” The %-per-decade figure is the same Sen slope divided by the gage's median annual flow, for comparing across streams of very different size; it is omitted for near-ephemeral channels where the median is too small to divide by honestly.
None of the 2 gages with enough record shows a significant trend or a detected shift — which is itself the finding.
No gage shows a statistically significant trend or changepoint yet.
2 other gage(s) show no significant trend or changepoint (not shown).
How the measurement network itself changed
This basin was not always measured the way it is today — the API-era record is dense and recent, the early record sparse. 0 gage(s) and 33 structure(s) report in 2025, but structure reporting only reached half its modern level around ~1916. Every historical claim below is checked against this: long-term shifts that co-move with the growth of the network carry an explicit measurement-evolution caution, and abandonment screens whose idleness begins before the modern reporting era are flagged †.
| Decade | Gages with data (median yr) | Structures reporting (median yr) |
|---|---|---|
| 1880s | 0 | 2 |
| 1900s | 0 | 1 |
| 1910s | 0 | 22 |
| 1920s | 0 | 20 |
| 1930s | 0 | 12 |
| 1940s | 1 | 10 |
| 1950s | 0 | 24 |
| 1960s | 0 | 22 |
| 1970s | 0 | 18 |
| 1980s | 0 | 24 |
| 1990s | 0 | 20 |
| 2000s | 0 | 27 |
| 2010s | 0 | 26 |
| 2020s | 0 | 30 |
Mass-balance (network closure) trend
Structure divrec-history backfill coverage as of the last check: 2% of 1658 schematic-relevant structures. 0 year(s) clear the 30% coverage gate so far -- the trend activates automatically once qualifying years span a full decade. No action needed; the nightly backfill keeps extending the record.
Reach gain/loss shifts (–)
Mass-balance kinks computed for every summer month back to (0 reach-snapshots) — which reaches gain or lose water, and how that has shifted across decades. Each shift is cross-checked against the observation record above: as more diversions became metered, "unaccounted" water shrinks mechanically, which can masquerade as a hydrologic shift.
No reach shows a statistically significant long-term gain/loss shift.
Groundwater now has its own tab: 39 monitored well(s), water-table trends, stream corridors, and the advisory depletion screen.
Reservoirs now has its own tab: 2 reservoir(s), end-of-year storage back to 1979, click-to-chart histories.
Cross-gage pattern fingerprint
Not enough gages with a long enough common-coverage window yet to fingerprint shared patterns.
Data provenance & quality
Where these numbers come from and how far they can be trusted. Grade D (2/6 points) — the components below are the finding; the letter alone is not. Sources: DWR HydroBase snapshot HydroBase_CO_20260707 (imported 2026-08-19) for history, plus the CDSS REST API for current conditions.
| Check | State | What was measured |
|---|---|---|
| gage freshness | stale | newest gage reading is 16405 day(s) old (target 7) |
| diversion record | expected-lag | newest diversion record is 304 day(s) old (DWR publishes ~1 year in arrears) |
| structure coverage | sparse | 2% of schematic structures have data |
Independent check: PASS — 100.0000% agreement across 141,066 stored values re-checked against DWR's authoritative record (HydroBase_CO_20260707), over 20 structures. 0 disagreement(s) beyond a 0.01 cfs tolerance. Checked 2026-08-19; a rotating sample covers the whole basin across successive runs, and the structures this report cites are checked every time.
Federal cross-check: PASS — 100.00% day-level agreement with USGS's own published records for the same gages, across 2 co-listed station(s) and 5,782 overlapping days (within max(2%, 0.5 cfs) daily). Pre-1950 records at some gages carry known between-agency day-stamp and transcription differences — scored at each year's best ±1-day alignment; residual disagreement is real historical divergence, flagged for review.
2 gage(s) / 5,785 daily values (1938-03-01–1981-09-30); 53 structure(s) with diversion records; 367 with decreed rights. Methodology has not yet had independent expert review — treat every figure as an advisory screen, not an administrative or legal conclusion.
Groundwater
40 water-level measurements across 39 monitored well(s) — 21 alluvial, 0 bedrock — plus 2 administered well(s) reporting metered pumping.
What is being counted
Observation wells and pumping wells are different populations and are never conflated: water levels come from monitored observation wells, and metered pumping comes from administered wells reporting through diversion records. Click any well to chart its own record.
Well map
3D aquifer x-ray
Every aquifer unit as its own head surface, animated through time.
How the surfaces are built, and what they are not
Alluvial water table on top, Denver Basin members (Dawson, Denver, Arapahoe, Laramie–Fox Hills) stacked beneath where measured, interpolated from measured water levels. Units are never mixed; a surface exists only inside its own unit's well coverage, with no extrapolation; thin epochs are suppressed and say why. Vertical scale is exaggerated for readability and z is head elevation in feet. These are measured heads, not a calibrated groundwater model.
Water-table trends
Of 0 well(s) with enough record for a trend test: 0 declining, 0 rising.
Wells labeled by administrative world before anything else is said about them: tributary alluvium participates in the priority system; designated-basin and Denver Basin bedrock aquifers are governed differently and are excluded from stream-connection reasoning. Read bedrock declines differently too: deep bedrock aquifers recharge negligibly on human timescales, so a falling bedrock level is storage mining — effectively permanent — not a drought response that a wet year undoes. All screens advisory.
Reservoirs
2 reservoir(s) with 67 storage measurement(s), 1979–2009. Basin storage as of 2008-10-01 (the record's own end — reservoir records publish ~annually): 5 AF across 1 reservoir(s).
Why storage matters to the flow network
Storage change is real water the mass balance must credit — a losing reach beside a filling reservoir isn't losing water, it's banking it.
Reservoir map — how full is each vessel?
What “full” is measured against
Bubble size is proportional to a reservoir's record-high storage. Fill is its last recorded storage as a share of its surveyed capacity (USACE National Inventory of Dams) where a confident NID match exists — the tooltip names the matched dam — and as a share of its own record high otherwise. A wrong capacity would be worse than an honest record high, so only confident joins upgrade.
A dashed teal ring marks reservoirs reporting live DWR telemetry: their fill reflects yesterday's storage, is drawn as a dotted tail on charts, and is treated as provisional until the next verified HydroBase snapshot supersedes it.
A dashed red ring marks a dam under an active storage restriction from DWR's Dam Safety branch — the State Engineer has limited how much it may legally store, so a low fill can be an order, not a drought. Hazard class and inspection condition come from the same record, joined only where the dam carries this reservoir's WDID or a confident NID match — a wrong dam's restriction would be worse than none shown.
Basin storage, end of each water year
End-of-water-year totals; per-year reservoir counts shown because reporting coverage varies -- a total is only comparable to years with similar counts.
Largest reservoirs on record
Click a row to chart its full storage history, or open its dossier for rights, documents and dam-safety facts.
| Reservoir | Last recorded storage (AF) | As of | Full | Dam (DWR Dam Safety) | |
|---|---|---|---|---|---|
| ▸ SEVEN LAKES RESERVOIR (1803780) | 1,222 | 1987-09-01 | — | — | dossier → |
| ▸ SPANISH PEAKS POND NO 13 (1803513) | 5 | 2008-10-01 | — | — | dossier → |
Legal
Decreed rights on this network run from 1866-10-31 to 2017-01-24. Of the 20 structures with a yield estimate, the median one’s senior right was in priority 1% of a median irrigation season and 0% in a dry one. 7 abandonment screens and 13 compliance flags are listed below as leads for review — a screen is not an abandonment and a flag is not a violation.
Rights on file: 402 across 367 structure(s); 34 structure(s) carry 0 court-case references. Advisory reading aids on public DWR data — not administrative or legal conclusions.
Is the river getting harder to divert from?
Over 2003–2025, administration on this district has been tightening: 3 of 3 measures (days under call, calls set, seniority of the controlling call) are moving toward more administration, none the other way.
The three measures, year by year
One row per whole calendar year inside the call record's coverage (23 years); partly-covered years are omitted rather than reported as quiet. Trend is Mann-Kendall with the same significance gate as every other trend on this site. Counted from DWR's published call record, which begins in the early 2000s: earlier years are absent, not quiet. A rise in the number of calls set can also reflect how finely an administrator records one episode, which is why days under call -- insensitive to that -- is the component to read first. Advisory summary of the public record, not an administrative finding.
| Year | Days under call | Calls set | Controlling priority (median) |
|---|---|---|---|
| 2014 | 365 | 419 | 1866-05-01 |
| 2015 | 365 | 222 | 1865-10-07 |
| 2016 | 366 | 355 | 1862-04-30 |
| 2017 | 365 | 260 | 1866-10-31 |
| 2018 | 365 | 401 | 1862-04-30 |
| 2019 | 365 | 389 | 1862-03-20 |
| 2020 | 366 | 340 | 1861-05-31 |
| 2021 | 365 | 362 | 1862-04-30 |
| 2022 | 365 | 370 | 1862-11-15 |
| 2023 | 365 | 369 | 1862-04-30 |
| 2024 | 366 | 359 | 1862-04-30 |
| 2025 | 365 | 384 | 1862-04-30 |
Why diversions stopped — call-based explanations
Sustained diversion stops matched to senior administrative calls.
- GONZALES DITCH (1800503) DWR↗ stopped 2025-07-02 (23+ days) — call at TITSWORTH DITCH curtailing 100% of its decreed rate [heuristic-strong]
- GONZALES DITCH (1800503) DWR↗ stopped 2024-06-25 (116+ days) — call at HARRINGTON DITCH curtailing 67% of its decreed rate [heuristic-partial]
- GONZALES DITCH (1800503) DWR↗ stopped 2023-10-31 (143+ days) — call at BURROUGHS DITCH curtailing 100% of its decreed rate [heuristic-strong]
- LUCERO DITCH (1800506) DWR↗ stopped 2023-10-31 (159+ days) — call at BURROUGHS DITCH curtailing 100% of its decreed rate [heuristic-strong]
Right yield — how often could these rights actually divert?
Share of irrigation-season days each structure's rights were not called out, derived from the 22-year district-scoped call record (senior right = floor, junior right = ceiling constraint). Call-record-derived; DWR's own analysis governs where available.
| Structure | Senior priority | Senior right: median / dry yr | Junior right: median / dry yr |
|---|---|---|---|
| SALISBURY NORTHSIDE (1800527) DWR↗ | 1869-05-31 | 0.5% / 0.0% | 0.0% / 0.0% |
| ESCONDIDA DITCH (1800536) DWR↗ | 1908-01-08 | 0.0% / 0.0% | 0.0% / 0.0% |
| WIDDERFIELD COMBINED (1800550) DWR↗ | 1868-04-01 | 5.1% / 0.0% | 0.0% / 0.0% |
| GONZALES DITCH (1800503) DWR↗ | 1866-10-31 | 25.2% / 0.0% | 0.5% / 0.0% |
| BORREGO DITCH (1800502) DWR↗ | 1870-02-15 | 0.0% / 0.0% | 0.0% / 0.0% |
| ANTONIA SAIS DITCH (1800513) DWR↗ | 1890-12-15 | 0.0% / 0.0% | 0.0% / 0.0% |
| GUADALUPE APODACA DITCH (1800519) DWR↗ | 1872-05-01 | 0.0% / 0.0% | 0.0% / 0.0% |
| LUCERO DITCH (1800506) DWR↗ | 1867-03-31 | 17.3% / 0.0% | 17.3% / 0.0% |
| FELIX CRUZ DITCH (1800517) DWR↗ | 1868-05-30 | 3.3% / 0.0% | 3.3% / 0.0% |
| PAIS DITCH (1800525) DWR↗ | 1869-04-10 | 1.4% / 0.0% | 1.4% / 0.0% |
| JOSE RAMON GONZALEZ (1800505) DWR↗ | 1868-06-21 | 1.4% / 0.0% | 1.4% / 0.0% |
| JOSE MARIE VIGIL DITCH 2 (1800538) DWR↗ | 1867-10-05 | 9.3% / 0.0% | 9.3% / 0.0% |
Abandonment radar (7 screens)
Absolute rights with 10+ years of no recorded diversions. Screens only — storage, alternate points, and plan operations can explain nonuse lawfully. And diversion REPORTING itself only reached its modern level ~1916 — idleness that begins before then may be unreported use, not nonuse (flagged † below).
- SLEVEC CONDER WELL NO 1 (1805000) DWR↗ (1953-10-31, 0.2 cfs decreed): last active 1979 — 44 years idle
- SOUTHSIDE VIGIL DITCH (1800540) DWR↗ (1868-05-31, 4.5 cfs decreed): last active 2005 — 18 years idle
- SPANISH PEAKS POND NO 13 (1803513) DWR↗ (1957-11-30, 0.0 cfs decreed): last active 2005 — 18 years idle
- SPANISH PEAKS RANCH DITCH NO 1 (1800544) DWR↗ (1957-11-30, 3.5 cfs decreed): last active 2009 — 14 years idle
- ANTONIA SAIS DITCH (1800513) DWR↗ (1890-12-15, 17.6 cfs decreed): last active 2010 — 13 years idle
- SPANISH PEAKS P/L NO 1 (1800543) DWR↗ (1932-12-31, 0.5 cfs decreed): last active 2010 — 13 years idle
- GUADALUPE APODACA DITCH (1800519) DWR↗ (1872-05-01, 13.7 cfs decreed): last active 2013 — 10 years idle
Compliance screens (13 advisory flags)
Screened 25 of 367 structures with rights (29 have diversion history on file). A flag is a lead for expert review — augmentation plans, exchanges, and free-river conditions can make over-decree diversions lawful and are deliberately not modeled.
- ESCONDIDA DITCH (1800536) DWR↗: Observed p99 daily rate 44.1 cfs (max 165.0) exceeds total decreed absolute 27.0 cfs across 4454 recorded day(s).
- LUCERO DITCH (1800506) DWR↗: Observed p99 daily rate 10.9 cfs (max 18.2) exceeds total decreed absolute 10.8 cfs across 17362 recorded day(s).
- FELIX CRUZ DITCH (1800517) DWR↗: Observed p99 daily rate 10.3 cfs (max 11.6) exceeds total decreed absolute 10.3 cfs across 7284 recorded day(s).
- JOSE RAMON GONZALEZ (1800505) DWR↗: Observed p99 daily rate 9.1 cfs (max 9.1) exceeds total decreed absolute 9.1 cfs across 7988 recorded day(s).
- MAURICIO APODACA DITCH (1800524) DWR↗: Observed p99 daily rate 5.5 cfs (max 9.1) exceeds total decreed absolute 5.5 cfs across 6490 recorded day(s).
- NORTHSIDE VIGIL DITCH (1800539) DWR↗: Observed p99 daily rate 5.5 cfs (max 8.0) exceeds total decreed absolute 5.5 cfs across 8652 recorded day(s).
- JULIAN LUCERO DITCH (1800520) DWR↗: Observed p99 daily rate 5.0 cfs (max 8.5) exceeds total decreed absolute 2.1 cfs across 8540 recorded day(s).
- SOUTHSIDE VIGIL DITCH (1800540) DWR↗: Observed p99 daily rate 5.0 cfs (max 5.1) exceeds total decreed absolute 4.5 cfs across 6480 recorded day(s).
- MARTINEZ DITCH (1800523) DWR↗: Observed p99 daily rate 4.0 cfs (max 4.0) exceeds total decreed absolute 2.5 cfs across 4858 recorded day(s).
- CORDOVA DITCH (1800529) DWR↗: Observed p99 daily rate 4.0 cfs (max 4.5) exceeds total decreed absolute 1.5 cfs across 3982 recorded day(s).
Seniority (top structures by decreed rate)
| Structure | Senior priority date | Rights | Decreed abs (cfs) | Decreed abs (AF) | Conditional? |
|---|---|---|---|---|---|
| SALISBURY NORTHSIDE (1800527) DWR↗ | 1869-05-31 | 4 | 42.8 | 0 | — |
| ESCONDIDA DITCH (1800536) DWR↗ | 1908-01-08 | 1 | 27.0 | 0 | — |
| WIDDERFIELD COMBINED (1800550) DWR↗ | 1868-04-01 | 4 | 26.1 | 0 | — |
| GONZALES DITCH (1800503) DWR↗ | 1866-10-31 | 2 | 22.0 | 0 | — |
| BORREGO DITCH (1800502) DWR↗ | 1870-02-15 | 1 | 20.5 | 0 | — |
| ANTONIA SAIS DITCH (1800513) DWR↗ | 1890-12-15 | 1 | 17.6 | 0 | — |
| GUADALUPE APODACA DITCH (1800519) DWR↗ | 1872-05-01 | 1 | 13.7 | 0 | — |
| LUCERO DITCH (1800506) DWR↗ | 1867-03-31 | 1 | 10.8 | 0 | — |
| FELIX CRUZ DITCH (1800517) DWR↗ | 1868-05-30 | 1 | 10.3 | 0 | — |
| PAIS DITCH (1800525) DWR↗ | 1869-04-10 | 1 | 9.7 | 0 | — |
| JOSE RAMON GONZALEZ (1800505) DWR↗ | 1868-06-21 | 1 | 9.1 | 0 | — |
| JOSE MARIE VIGIL DITCH 2 (1800538) DWR↗ | 1867-10-05 | 1 | 7.0 | 0 | — |
| MAURICIO APODACA DITCH (1800524) DWR↗ | 1868-06-15 | 1 | 5.5 | 0 | — |
| NORTHSIDE VIGIL DITCH (1800539) DWR↗ | 1868-05-20 | 1 | 5.5 | 0 | — |
| SOUTHSIDE VIGIL DITCH (1800540) DWR↗ | 1868-05-31 | 1 | 4.5 | 0 | — |
No inventory or legal-document changes detected since the daily watch began.
Water-court filings this month (division-wide)
6 applications in the 2026-07 resume for this basin's division — new rights, changes, augmentation plans — from the water clerk's statutory monthly notice (C.R.S. 37-92-302), the earliest public signal of a new claim. Filings are division-wide, not district-filtered: check the county column. Full resume PDF at the Judicial Branch →
Anyone affected may file a statement of opposition until 2026-09-30 (25 days left). C.R.S. 37-92-302(3): due by the last day of the second month following the filing month — computed, not legal advice; confirm with the water clerk.
All 6 filings, with excerpts
| Case | What it asks | County | Excerpt |
|---|---|---|---|
2026CW3032
|
— | — | CASE NO. 2026CW3032; Previous Case Nos. 20CW3003, 13CW3008, 97CW83 – EMPIRE LODGE HOMEOWNER’S ASSOCIATION, INC. c/o Tim Ratterman, President, 585 Empire Valley Drive, Leadville, CO 80461 (Please address all pleadings and inquiries regarding this matter to Appl… |
2026CW3033
1205090 1205091 |
reasonable diligence | — | CASE NO. 2026CW3033; Previous Case No. 2019CW3032 – SANGRE DE CRISTO RANCH, LLC c/o Stephanie Stolba, 44301 E Iliff Trail, Bennett, CO 80102 (Please address all pleadings and inquiries regarding this matter to Applicant’s attorney: Jennifer M. DiLalla, #40319,… |
2026CW3034
|
— | HUERFANO | CASE NO. 2026CW 3034; (2017CW3075); CUCHARAS SANITATION & WATER DISTRICT, 16925 Highway 12, Cucharas, Colorado 81055 (“CSWD”); Huerfano County Water Conservancy District, c/o/ Administrator, P.O. Pox 442, La Veta, Colorado 81055 (“Huerfano”); Town of La Veta, … |
2026CW3035
|
plan for augmentation | — | CASE NO. 2026CW3035; GUM FAMILY TRUST AND JACOB GUM, TRUSTEE AND INDIVIDUALLY, 8580 Forest Line Point, Colorado Springs, CO, 80908 (Please address all pleadings a nd inquiries regarding this matter to Applicant’s attorney s: Philip E. Lopez, Eric K. Trout, Fai… |
2026CW3036
1406622 1406637 1406670 |
plan for augmentation | — | CASE NO. 2026CW3036; Previous Case No. 2017CW3009 – SILOAM WELL ASSOCIATION, 46 Glenroyal Dr., Pueblo, CO 81005 (Please address all pleadings and inquiries regarding this matter to Applicant’s attorney: Steven L. Jasnssen, Esq., 1937 Juniper St., Longmont, CO … |
2026CW7
|
— | — | CASE NO. 2026CW7; COLORADO DIVISION OF PARKS AND WILDLIFE AND THE PARKS AND WILDLIFE COMMISSION (“CPW”), Attn: Pete Conovitz, Water Rights Program Administrator, 6060 Broadway, Denver, Colorado 80216 (Please address all pleadings and inquiries regarding this m… |
Call cascade
If a call were placed at a given seniority, which structures in this basin would be out of priority, and how much of their decreed rate would be curtailed? Computed from this basin's cached decrees.
What this does and doesn't model. Seniority arithmetic only: every right junior to the call is treated as curtailed. It does not model reach applicability — structures downstream of the calling point are not administered by it — and it applies no futile-call judgment. Read it as “who is junior to this date, and by how much,” not as a prediction of what the Division Engineer would actually order.
Pick a calling right
Real decrees from this basin, ordered by administration number — that is, by actual seniority. The years will look out of order, and that is correct: an administration number encodes the adjudication date as well as the appropriation date, so a right appropriated in 1970 can be administered ahead of one from 1950. A senior call curtails almost everything; a junior one curtails almost nothing.
Or enter an administration number directly
DWR administration numbers encode appropriation and adjudication dates; lower is more senior.
Topology cross-check: 0 parent disagreements, 6 sizable streams not on this network (vs DWR's route framework — under review)
This flow network was built mechanically; DWR's Source Water Route Framework disagrees with it in the places below. Each row is a question a human reviewer has not yet answered — not an error verdict. Checked 5 streams, 5 agree. Know this water? Tell us →
Sizable streams DWR maps here that this network does not carry:
Salado Creek (28 mi) · Del Aqua Arroyo (14 mi) · Sorgs Arroyo (5 mi) · Elmore Arroyo (5 mi) · Bates Lake Arroyo (5 mi) · Herlick Canyon (4 mi)