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Grand River Ditch at La Poudre Pass

Transbasin diversion gage · GRNDRDCO · USGS 09010000 · Division 1 · Water District 3 · Larimer 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 Grand River Ditch moves water from Colorado River headwaters at La Poudre Pass (Div 5) into Cache la Poudre River via Long Draw (Div 1), operated by Water Supply & Storage Co. — 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

Period of record
1929-04-30 → 2026-09-27
Daily values
37,015
Flowing now
2.49 cfs 2026-10-12 23:45, 3.6 h ago
Latest cached reading
4.8 cfs (2026-09-27)
Trend
decreasing, -1.73 cfs/decade (-6.7% of median)
Pettitt changepoint
~1964

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 Grand River Ditch at La Poudre Pass, water years 1929 to 2026. The measured record is decreasing at -1.73 cubic feet per second per decade. A Pettitt changepoint is detected around 1964. The underlying yearly values are available as a CSV download linked at the top of this page.

Loading chart…

This gage measures the Grand River Ditch, water carried across the Continental Divide. It is taken from Colorado River headwaters at La Poudre Pass (Div 5) and delivered to Cache la Poudre River via Long Draw (Div 1) — so what this gage reads leaves one river basin for good and arrives in another.

The two ends: Grand River Ditch (source, on Colorado River); Grand River Ditch North Feeder (source, on Colorado River); Grand River Ditch South Feeder (source, on Specimen Creek); Grand River Ditch Release Structure (receiving, on La Poudre Pass Creek)

Decrees:

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 GRNDRDCO; recorded station name “GRAND RIVER DITCH AT LA POUDRE 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.