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Boulder Creek

Division 1 · Water District 6 · As of 2026-08-31 00:36 MDT
Full analysis
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Boulder Creek on the ground — the ditches, wells, reservoirs and gages of Water District 6 · clicktap anything for its record

Snowpack — no snow on the ground at 3 SNOTEL sites — normal for the date; the snow year begins in October and typically peaks around April 9. Runoff outlook — Boulder Ck nr Orodell: even odds of at least 28 kAF over 06-01 to 09-30 — 62% of a normal season, per NRCS, issued 2026-06-01 — the season’s final; new forecasts begin in January. Runoff outlook — South Boulder Ck nr Eldorado Springs: even odds of at least 15 kAF over 06-01 to 09-30 — 56% of a normal season, per NRCS, issued 2026-06-01 — the season’s final; new forecasts begin in January. Full snow & runoff picture — charts, forecast history and how the forecasts have verified →

Sites, exceedance bands and sources
SNOTEL siteElev (ft)SWE (in)Median (in)% of medianTypical peak
Lake Eldora9700 0.00.0 April 9 (14.0 in)
Niwot9940 0.00.0 April 19 (15.0 in)
University Camp10330 0.20.0 May 7 (19.9 in)

Boulder Ck nr Orodell — 06-01 to 09-30 volume, thousand acre-feet (chance the volume is AT LEAST this):

90%70%50%30%10%Normal
2326283034 45

South Boulder Ck nr Eldorado Springs — 06-01 to 09-30 volume, thousand acre-feet (chance the volume is AT LEAST this):

90%70%50%30%10%Normal
912151619 27

Snow-water equivalent and medians (1991–2020) from NRCS SNOTEL; seasonal volume forecasts from the NRCS National Water and Climate Center. Sites and forecast points are assigned to the district whose boundary contains them — snowpack that feeds this district can also sit in a neighboring headwater district. Toggle the Snow chip on the map above to see the sites.

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 9 streams, 9 agree. Know this water? Tell us →

Sizable streams DWR maps here that this network does not carry:

Fourmile Creek (15 mi) · Bear Canyon Creek (8 mi) · Dry Creek (6 mi) · Bummers Gulch (4 mi) · Johnson Gulch (3 mi) · Bullhead Gulch (3 mi)

Snow and runoff

Snow-water equivalent, WY2026

No snow on the ground — normal for the date; the snow year begins in October. The chart shows the full water year just ending.

SNOTEL siteElev (ft)SWE (in)Median (in)% of medianTypical peak
Lake Eldora9700 0.00.0 April 9 (14.0 in)
Niwot9940 0.00.0 April 19 (15.0 in)
University Camp10330 0.20.0 May 7 (19.9 in)

NRCS SNOTEL, daily. Sites are assigned to the district whose boundary contains them — the snow that feeds this district can also sit in a neighboring headwater district.

Two ways a snow year goes wrong (1979–2026)

A bad snow year here comes in two flavors (both called snow droughtA winter that shorts the snowpack. It happens two ways: a dry one, where the snow never comes, and a warm one, where near-normal snow falls but melts off weeks early -- and the river feels them differently.), and the river feels them differently. In 8 of the last 48 winters the snow never came — the pack peaked below 80% of its median. In 1 more, the snow came but left early — a near-normal peak melted out two weeks or more ahead of its usual date, sending the water down before the season needed it. This year was one of the dry ones: the pack peaked at 56% of median.

The snow never came: 1981, 1985, 1991, 2001, 2002, 2004, 2012, 2026. The snow left early: 2006.

Computed by this site from 3 SNOTEL sites’ full daily records (NRCS AWDB, back to 1979). Each year is measured against each site’s own multi-decade median — not the 1991–2020 normal the chart above uses — so the 1980s grade against a fair baseline. Peak and melt-out need 85% of the season’s days on the record; thin years are dropped, not guessed. Derived from snow measurements alone — it cannot tell dry-from-warm causes apart, only what the snowpack did.

Runoff outlook — Boulder Ck nr Orodell

NRCS's final issue (2026-06-01) calls it even odds that at least 28 kAF arrives over 06-01 to 09-30 — 62% of a normal season; almost certainly at least 23, probably not more than 34. Our own record at this gage shows 10 kAF so far this period (partial record: 73 of 92 days). New forecasts begin in January. How to read these numbers →

90% chance of at least70% chance of at least50% chance of at least30% chance of at least10% chance of at leastNormalObserved
2326283034 45 10*

How good are these forecasts here? (1950–2025)

Grading every April issue against what the river then delivered, measured at this gage’s own record — 75 seasons: the median miss of the 50% forecast is 24%, with a high bias of 16%, and the observed volume landed inside the stated 10–90% band 56% of the time (a calibrated forecast would say 80%).

Computed by this site: NRCS's archived April issues (their period as issued each year) against the observed volume in DWR’s published record; years with under 90% daily coverage are dropped, not summed. A grade of the forecast, never of the forecasters — these are hard rivers. How this point ranks among every graded Colorado forecast point →

What April snow has meant for this river (1979–2026)

Across 48 measured years, the season’s water has loosely followed the April snowpack: a year opening April with 80% of median snow has typically gone on to deliver about 77% of a normal season (a snow-to-runoff elasticityHow strongly one number moves with another. A snow-to-runoff elasticity of 1.5 means a 10% shortfall in April snowpack has typically become a 15% shortfall in the season's water. of 0.7). In warm, early-melt years the river delivered a median of 82% of a normal season, against 97% in typical years — the timing of the melt matters, not just its size. This year opened April at 26% of median snow and delivered 36% of a normal season.

Computed by this site: the district’s April 1 SWE (% of each SNOTEL site’s own-record median) against the observed April–July volume at this gage (% of its median season) — a fixed window every year, unlike the forecast grades above, which use each issue’s own period. The slope is fit so single wild years can’t steer it (Theil–Sen, log space); years missing 10% of their days are dropped.

Runoff outlook — South Boulder Ck nr Eldorado Springs

NRCS's final issue (2026-06-01) calls it even odds that at least 15 kAF arrives over 06-01 to 09-30 — 56% of a normal season; almost certainly at least 9, probably not more than 19. New forecasts begin in January. How to read these numbers →

90% chance of at least70% chance of at least50% chance of at least30% chance of at least10% chance of at leastNormal
912151619 27