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North Fork of South Platte

Division 1 · Water District 80 · As of 2026-10-10 05:06 MDT · 6 days ago

Who may take water from the North Fork of South Platte, who is calling for it today, and how it is running, compiled from Colorado Division of Water Resources records. Click anything on the map for its record.

Live · machine-built

North Fork of South Platte on the ground — the ditches, wells, reservoirs and gages of Water District 80 · clicktap anything for its record

Browse this district’s ditches, gages, reservoirs, wells and springs as a list.

14% of normal flow, week of 2026-09-21
1 call the record places on it, 6 unsettled

The South Platte River is critically low for late September -- 14% of normal flow. 1 call stands against it right now; the most senior right calling dates to 1875. DWR's statements do not settle whether 6 more calls reach it.

Snow and runoff

Source Independent agency measurement · fetched 2026-10-16 · verify at NRCS report generator ↗ Source Our computation, scored against a reference · NRCS forecast, graded here against the gage record

Snow-water equivalent, WY2027

SNOTEL siteElev (ft)SWE (in)Median (in)% of medianTypical peak
Jackwhacker Gulch11030 0.60.4 — April 25 (14.4 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 (1999–2026)

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 7 of the last 28 winters the snow never came — the pack peaked below 80% of its median. In 0 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.

The snow never came: 2002, 2004, 2005, 2010, 2012, 2022, 2026.

Computed by this site from 1 SNOTEL site’ full daily records (NRCS AWDB, back to 1999). 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 — Cheesman Lake Inflow

NRCS's final issue (2026-06-01) calls it even odds that at least 31 kAF arrives over 06-01 to 09-30 — 40% of a normal season; almost certainly at least 16, probably not more than 45. 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
1626313745 78

Drought

Source Our computation, no independent reference · computed here from the screened DWR record Source Independent agency measurement · fetched 2026-10-13 · verify at U.S. Drought Monitor ↗

Right now

This is the 14th-driest week 39 in 102 years of record at SOUTH PLATTE RIVER BELOW CHEESMAN RESERVOIR (as of 2026-09-21; this week’s flow sits at the 14th percentileRank against the record: a river at its 5th percentile is lower than it was in 95 of the past 100 years on this same date. for the date). On this week’s US Drought Monitor, Park County is 34% in D4 exceptional drought (2026-10-13). The law agrees: the most senior active call leaves 98% of this district’s decreed flow rights junior to the calling right this week.

Every year since 1924, week by week

Each thin row is a year at SOUTH PLATTE RIVER BELOW CHEESMAN RESERVOIR; each cell is one week’s flow ranked against the same calendar week of every other year — warm means dry for the date, blue wet, so seasonality cancels and droughts appear as warm bands. Gaps are missing record, never a dry river. Click a year to reconstruct it on the Historical tab.

This year against its analogs

Over the 39 weeks recorded so far, 2026’s weekly trace most resembles 1972 (mean gap 14.7 percentile points; next closest 2023 (14.8), 2012 (16.4)). The analog’s remainder is drawn as context — its ending is what happened to it, not a forecast for this year.

The Drought Monitor’s view since 2000

Mean share of area in each class across Douglas, Jefferson, Park counties — the counties this district’s gages sit in, which overlap the district imperfectly. The Drought Monitor weighs soils, vegetation and local reports; it is CONTEXT beside the river’s own record above, not the water-rights picture.

The law’s own drought gauge

When water runs short, administration answers: calls reach further back in time, and more decreed rights go junior to the calling right. This is that response, weekly since 1950 — the share of this district’s decreed flow rights junior to the most senior active call. Watch it spike in the named droughts below, and linger after the river recovers.

Computed from DWR’s call record (929 calls touching this district) against the district’s rights index. Scoping is deliberately coarse — a call’s own district, or districts named in its comments — and this is administration’s RESPONSE, not a per-structure verdict (each dossier’s curtailment card does that, with stream miles). A deepening call can also reflect growing demand, not only shrinking supply.

1685–1987: this river before anyone measured it

Tree rings record wet and dry years centuries before the first gage. This is the published reconstruction of annual flow at North Fork of South Platte River at South Platte — 303 years, with its uncertainty band drawn, not implied. A reconstruction is an estimate, not a measurement: it answers “is this decade unusual in four centuries?”, and nothing in this site’s statistics uses it.

Woodhouse, C.A. and J.J. Lukas (2006), Multi-century tree-ring reconstructions of Colorado streamflow for water resource planning, Climatic Change 78; data via NOAA NCEI World Data Service for Paleoclimatology / TreeFlow. Source data ↗

This basin’s droughts, by its own record

DroughtSpanWeeks Trough percentileFlows recovered Water table back
the 2020-22 drought 2021-07-19 → 2021-12-06 20 27th (2021-09-20) 2 weeks —
the 2012-13 drought 2013-07-29 → 2014-01-06 23 24th (2013-09-09) 0 weeks —
the 2002 drought 2003-07-21 → 2004-02-02 28 18th (2003-08-25) 45 weeks —
the 1981 drought 1981-06-22 → 1982-04-19 43 23rd (1981-11-02) 17 weeks —
the 1977 drought 1978-05-08 → 1979-05-28 55 10th (1978-10-30) 43 weeks —
the 1977 drought 1977-08-29 → 1978-05-01 35 14th (1977-12-12) 99 weeks —
unnamed dry spell 1969-02-10 → 1969-09-22 32 10th (1969-06-02) 3 weeks —
unnamed dry spell 1966-10-31 → 1968-10-07 101 6th (1968-03-25) 53 weeks —
the 1963-64 drought 1964-11-09 → 1965-09-06 43 5th (1965-02-22) 43 weeks —
unnamed dry spell 1960-11-07 → 1961-08-28 42 9th (1961-01-30) 14 weeks —
unnamed dry spell 1959-12-21 → 1960-09-05 37 8th (1960-03-28) 65 weeks —
unnamed dry spell 1958-12-08 → 1959-11-02 47 5th (1959-05-04) 109 weeks —
the 1950s drought 1955-11-07 → 1957-10-21 102 6th (1957-06-10) 3 weeks —
unnamed dry spell 1944-04-10 → 1944-10-09 26 20th (1944-05-08) 63 weeks —

Detected mechanically: the 26-week smoothed percentile below the 30th for at least 20 weeks; recovered on regaining the 50th. The water-table clock compares each monitoring well against its own pre-drought median (the 3 years before onset) and dates the year the median well got back — the aquifer remembers longest, and “still below” is a finding, not a gap. The knobs are stated because the episode list depends on them — a different reasonable choice merges or splits episodes at the edges. Names are attached where an episode overlaps a drought Colorado already talks about.

What drought has cost here

Since 1996, federal crop insurance has paid $1,316 in drought-caused claims across Douglas, Jefferson, Park counties — 0.4% of all insured crop losses there. The worst year was 1996 ($1,113).

USDA crop-insurance indemnities where the recorded cause of loss is drought, summed over the counties this district's gages sit in. Counties overlap water districts imperfectly, and insured-crop claims are a floor on drought damage, not a total. Source: USDA RMA cause-of-loss files.

When this basin claimed its water

Every bar is a year’s new appropriations (1,096 rights across 103 years of shared record), colored by that year’s wetness from the barcode above. Here the correlation is -0.25 — this basin tended to claim water in dry times, under scarcity pressure. Across the state both behaviors exist: ephemeral southwest basins file after wet demonstrations, transbasin-source basins under drought — and the biggest statewide filing waves sat in the 1950s drought and after 2002, not in the wet 1980s–90s.

Appropriation dates are the CLAIMED initiation of a right, not the courthouse filing date; the record is survivor-biased (abandoned claims are absent, so failed dry-era scrambles are undercounted); and the big 1960s and 2000s spikes sit on legal events — the pre-1969-Act adjudication era and 2000s legislation — not on weather. A correlation here is a description, never a cause.

New to how a dry winter becomes a call on the river? Anatomy of a drought walks the chain in four minutes — snow to rivers to reservoirs to calls to the water table.

Snowpack — 1 SNOTEL site report here. Runoff outlook — Cheesman Lake Inflow: even odds of at least 31 kAF over 06-01 to 09-30 — 40% 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
Jackwhacker Gulch11030 0.60.4 — April 25 (14.4 in)

Cheesman Lake Inflow — 06-01 to 09-30 volume, thousand acre-feet (chance the volume is AT LEAST this):

90%70%50%30%10%Normal
1626313745 78

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.

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