Hydrohistorian
← Basin trends · All gages in this district
William's Creek-Squaw Pass Ditch at Grizzly Pass
Transbasin diversion gage · WCSDITCO · USGS 09348000 · Division 3 · Water District 20 · Hinsdale County
Live gage at DWR ↗ · USGS monitoring location ↗ · Download daily record (CSV)
Source DWR administrative record · verify at DWR station ↗ Source Independent agency measurement · verify at USGS ↗ Source Our computation, no independent reference · computed here from the screened record
Two different numbers, deliberately: Flowing now is raw 15-minute telemetry, provisional and unreviewed. Latest cached reading is the end of the verified daily record. They are never merged, and the verified series is the one the trend is computed on.
What this gage meters
This is not a natural stream record. The Williams Creek-Squaw Pass Ditch moves water from Williams Creek, San Juan basin (Div 7) into Squaw Creek, Rio Grande basin (Div 3) — so this record is a ledger of those deliveries. Trends here reflect operational and demand decisions, not the basin's hydrology, and the basin trends page marks it accordingly (⇆). All of Colorado's curated transbasin diversions are collected at /transbasin.
The record
Readings come from the weekly-refreshed cache, never fetched live — the date beside the value says exactly how fresh it is. The live gage is one click up.
Annual flow & trend
Chart: annual mean flow at William's Creek-Squaw Pass Ditch at Grizzly Pass, water years 1948 to 2026. The measured record is increasing at 0.08 cubic feet per second per decade. A Pettitt changepoint is detected around 1983. The underlying yearly values are available as a CSV download linked at the top of this page.
This gage measures the Williams Creek-Squaw Pass Ditch, water carried across the Continental Divide. It is taken from Williams Creek, San Juan basin (Div 7) and delivered to Squaw Creek, Rio Grande basin (Div 3) — so what this gage reads leaves one river basin for good and arrives in another.
The two ends: Williams Cr Sq Pass Divr (source, on Williams Creek); Williams Squaw Pass (receiving, on Transbasin Water)
- Decree in case CA0308 ↗ · imaged 2008-04-24 · filed under the source end, Williams Cr Sq Pass Divr
- Decree in case 87CW0007 ↗ · imaged 2007-02-21 · filed under the receiving end, Williams Squaw Pass
- Decree in case 96CW0032 ↗ · imaged 2006-03-17 · filed under the receiving end, Williams Squaw Pass
The ditch’s mapped channel is drawn on the map below where the USGS has surveyed it. Every crossing →
Where it sits
Location as DWR records it (5.0).
Provenance
DWR station abbreviation WCSDITCO; recorded station name “WILLIAM'S CREEK-SQUAW PASS DITCH AT GRIZZLY PASS”; operated by DWR. Daily flows from the DWR HydroBase snapshot plus CDSS REST updates, refreshed on the weekly cycle. Trend statistics are Mann-Kendall (Hamed-Rao corrected) with Sen's slope in native cfs, the same numbers as the basin Trends tab.