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St. Vrain Creek

Division 1 · Water District 5 · As of 2026-08-16 03:15 MDT

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Reconstruct conditions as of

Evolution of the network

Gage flow trend & changepoints

What counts as a trend here

Computed 2026-08-20 08:23 from 65 gage(s) with cached period-of-record data. Mann-Kendall (trend) 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.”

Of the 65 gages with enough record, 7 are trending down and 3 up, and 4 carry a detected shift. The clearest is SOUTH SAINT VRAIN NEAR WARD, -10.3 points of its long-term median per decade over 37 years (p=0.0006). The other 53 show no clear signal either way.

Gage	Trend	Change / decade points of median	Significance	Years	Changepoint
▸ SAINT VRAIN CREEK AT LONGMONT, CO SVLONGCO	↑ increasing	+229.8	p=0.024	12	—
▸ LEFT HAND CREEK AT HOVER ROAD NEAR LONGMONT, CO LEFTHOCO	↓ decreasing	-169.9	p=0.002	13	—
▸ RURAL DITCH TAIL RETURN TO ST. VRAIN CREEK RUTAILCO	↑ increasing	+120.8	p=0.013	11	—
▸ NORTH SAINT VRAIN CREEK BELOW BUTTONROCK (RALPH PRICE) RESERVOIR NSVBBRCO	↓ decreasing	-62.8	p=0.009	14	—
▸ ST. VRAIN CREEK BELOW BOULDER CREEK AT HWY 119 NEAR LONGMONT, CO SVCBBCCO	↓ decreasing	-61.5	p=0.024	13	—
▸ BOULDER RESERVOIR INLET BFCINFCO	↓ decreasing	-60.7	p=0.042	22	—
▸ SOUTH BRANCH ST. VRAIN CREEK SBRSTVCO	↓ decreasing	-47.0	p=0.043	16	—
▸ LONGMONT SUPPLY DITCH LONSUPCO	↓ decreasing	-42.7	p=0.041	18	—
▸ ZWECK AND TURNER DITCH ZWETURCO	no clear trend	+41.8	p=0.058	18	~2015
▸ SOUTH SAINT VRAIN NEAR WARD SSVWARCO	↓ decreasing	-10.3	p=0.001	37	~1998
▸ SAINT VRAIN CREEK AT MOUTH NEAR PLATTEVILLE, CO SVCPLACO	↑ increasing	+4.4	p=0.011	100	~1956
▸ SAINT VRAIN CREEK AT LYONS, CO SVCLYOCO	no clear trend	-1.5	p=0.077	131	~1929

53 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. 50 gage(s) and 121 structure(s) report in 2026, but structure reporting only reached half its modern level around ~1975. 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)
1890s	1	0
1900s	1	0
1910s	1	0
1920s	2	0
1930s	4	0
1940s	4	0
1950s	6	28
1960s	8	33
1970s	7	57
1980s	8	54
1990s	12	70
2000s	16	76
2010s	41	80
2020s	49	98

Mass-balance (network closure) trend

Structure divrec-history backfill coverage as of the last check: 4% of 1542 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 (1950–2026)

Mass-balance kinks computed for every summer month back to 1950 (3761 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.

NORTH SAINT VRAIN CREEK BELOW BUTTONROCK (RALPH PRICE) RESERVOIR: reach shifted from +83 cfs to +32 cfs summer mean (more losing, p=0.037, 14 yr) [crystalline foothills: minimal groundwater storage -- large or shifting unaccounted losses here are more consistent with data/measurement issues or unmodeled plumbing than with aquifer exchange]
NORTH SAINT VRAIN CREEK ABOVE BUTTONROCK RESERVOIR: reach shifted from +1949 cfs to +77 cfs summer mean (more gaining, p=0.000, 21 yr) [crystalline foothills: minimal groundwater storage -- large or shifting unaccounted losses here are more consistent with data/measurement issues or unmodeled plumbing than with aquifer exchange]
BONUS DITCH: reach shifted from +85 cfs to -49 cfs summer mean (more losing, p=0.023, 18 yr) [sedimentary plains/foothills: moderate groundwater connectivity -- gain/loss shifts can be real aquifer response; corroborate with nearby well records] [measurement-evolution caution: this shift co-moves with the growth of the gage/metering network (rho=-0.58) -- part of it may be unaccounted water becoming accounted, not hydrologic change]
JAMES DITCH: reach shifted from -116 cfs to -68 cfs summer mean (more gaining, p=0.049, 18 yr) [sedimentary plains/foothills: moderate groundwater connectivity -- gain/loss shifts can be real aquifer response; corroborate with nearby well records]
MIDDLE SAINT VRAIN AT PEACEFUL VALLEY: reach shifted from -61 cfs to +58 cfs summer mean (more gaining, p=0.002, 29 yr) [alluvial valley: real alluvial aquifer -- a decades-long shift toward losing is the classic signature of alluvial pumping and urbanization]
ST. VRAIN CREEK BELOW LONGMONT, CO.: reach shifted from +153 cfs to +48 cfs summer mean (more losing, p=0.034, 33 yr) [alluvial valley: real alluvial aquifer -- a decades-long shift toward losing is the classic signature of alluvial pumping and urbanization]

Groundwater now has its own tab: 258 monitored well(s), water-table trends, stream corridors, and the advisory depletion screen.

Reservoirs now has its own tab: 83 reservoir(s), end-of-year storage back to 1950, click-to-chart histories.

Cross-gage pattern fingerprint

Over the 23-year window with full coverage (2004–2026), the dominant shared pattern across 3 gage(s) explains 63% of year-to-year variance (almost certainly a basin-wide climate/snowpack driver).

All gages in this window move with the shared pattern -- no localized outlier.

Structures most implicated by reconciliation (as of 2026-08-15)

Which structures' data absorbed the most correction when the current mass-balance snapshot was reconciled -- see the Historical tab for the full picture on any date.

GODDING D CENTRAL AUG RT (return): -48.9 cfs (100% of that reach's correction)
ANDERSON DITCH RT OUTLET (return): +38.7 cfs (100% of that reach's correction)
LONGMONT SEWER RT (return): -6.9 cfs (100% of that reach's correction)
RURAL D CENTRAL AUG RT (return): +6.7 cfs (100% of that reach's correction)

Data provenance & quality

Where these numbers come from and how far they can be trusted. Grade C (3/6 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	current	newest gage reading is 5 day(s) old
diversion record	stale	newest diversion record is 658 day(s) old (DWR publishes ~1 year in arrears)
structure coverage	sparse	4% of schematic structures have data

Independent check: PASS — 100.0000% agreement across 276,352 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 — 99.65% day-level agreement with USGS's own published records for the same gages, across 11 co-listed station(s) and 123,644 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.

65 gage(s) / 510,582 daily values (1895-10-01–2026-08-15); 228 structure(s) with diversion records; 1289 with decreed rights. Methodology has not yet had independent expert review — treat every figure as an advisory screen, not an administrative or legal conclusion.

419 water-level measurements across 258 monitored well(s) — 137 alluvial, 41 bedrock — plus 4 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 1 well(s) with enough record for a trend test: 0 declining, 0 rising.

Stream corridors — the surface connection

Where a reach's gain or loss has shifted, the wells within two miles of its anchoring gage and what their water table did over the same era.

How the corridor is assembled

For each reach whose gain/loss has shifted (Trends tab): the wells within 2 miles of its anchoring gage, their pooled water-table history over the same era, and an advisory Glover screen of lagged stream depletion from nearby metered pumping. v1 proximity = distance to the reach's anchoring gage; segment-based reach join is a flagged upgrade.

BONUS DITCH: 6 alluvial well(s) nearby

JAMES DITCH: 11 alluvial well(s) nearby

MIDDLE SAINT VRAIN AT PEACEFUL VALLEY: 2 alluvial well(s) nearby

ST. VRAIN CREEK BELOW LONGMONT, CO.: 16 alluvial well(s) nearby; pooled water table — ft (1968–1983, no_trend, p=0.1078). Glover screen: 0.2 cfs of nearby metered alluvial pumping → est. lagged depletion 0.2–0.2 cfs (uncalibrated T/S ranges; flagged for SPDSS calibration, AWAS cross-check, and expert review — DWR's AWAS is the authority).

BEAVER CREEK ABOVE BEAVER CREEK RESERVOIR: 1 alluvial well(s) nearby

WEBSTER MCCASLIN DITCH: 10 alluvial well(s) nearby

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.

83 reservoir(s) with 16,614 storage measurement(s), 1950–2025. Basin storage as of 2024-10-31 (the record's own end — reservoir records publish ~annually): 48,992 AF across 27 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.

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 reservoir to chart its full storage history.

Reservoir	Last recorded storage (AF)	As of
▸ BUTTON ROCK RES (0504010)	16,208	2023-10-31
▸ MARLATT RES NO 7 (0503910)	12,053	1986-10-31
▸ UNION RES (0503905)	7,812	2024-10-31
▸ BOULDER RES (0504515)	5,902	2023-10-31
▸ FOOTHILLS RES (0504071)	2,420	2024-10-31
▸ THOMAS RES (0504042)	2,255	1992-10-31
▸ NEW THOMAS RES (0504379)	2,003	2024-10-31
▸ HIGHLAND RES 2 (0504032)	1,771	2024-10-31

Decreed rights on this network run from 1860-01-01 to 2021-12-07. Of the 20 structures with a yield estimate, the median one’s senior right was in priority 100% of a median irrigation season and 56% in a dry one. 3 abandonment screens and 30 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: 2401 across 1289 structure(s); 0 structure(s) carry 0 court-case references. Advisory reading aids on public DWR data — not administrative or legal conclusions.

Why diversions stopped — call-based explanations

Sustained diversion stops matched to senior administrative calls.

MEADOW DITCH (0500521) stopped 2024-09-25 (7+ days) — call at HAGERS MEADOW DITCH curtailing 100% of its decreed rate [heuristic-strong, district-confirmed]
JAMES DITCH (0500539) stopped 2024-09-24 (16+ days) — call at HAGERS MEADOW DITCH curtailing 100% of its decreed rate [heuristic-partial, district-confirmed]
CHAPMAN MCCASLIN DITCH (0500546) stopped 2024-09-02 (14+ days) — call at JONES DONNELLY DITCH curtailing 100% of its decreed rate [heuristic-strong]
OLIGARCHY DITCH (0500547) stopped 2024-08-31 (13+ days) — call at HAGERS MEADOW DITCH curtailing 100% of its decreed rate [heuristic-partial, district-confirmed]
ROUGH READY DITCH (0500527) stopped 2024-08-26 (20+ days) — call at HAGERS MEADOW DITCH curtailing 100% of its decreed rate [heuristic-partial, district-confirmed]
WEBSTER MCCASLIN DITCH (0500537) stopped 2024-08-05 (22+ days) — call at HAGERS MEADOW DITCH curtailing 100% of its decreed rate [heuristic-strong, district-confirmed]
PECK DITCH (0500550) stopped 2024-07-29 (10+ days) — call at HAGERS MEADOW DITCH curtailing 100% of its decreed rate [heuristic-strong, district-confirmed]
JAMES DITCH (0500539) stopped 2024-07-25 (13+ days) — call at HAGERS MEADOW DITCH curtailing 100% of its decreed rate [heuristic-partial, district-confirmed]
ROUGH READY DITCH (0500527) stopped 2024-07-20 (27+ days) — call at HAGERS MEADOW DITCH curtailing 100% of its decreed rate [heuristic-partial, district-confirmed]
SWEDE DITCH (0500529) stopped 2024-07-11 (28+ days) — call at HAGERS MEADOW DITCH curtailing 100% of its decreed rate [heuristic-partial, district-confirmed]
GOSS PRIVATE DITCH 1 (0500534) stopped 2024-07-04 (24+ days) — call at OSBORNE CAYWOOD DITCH curtailing 100% of its decreed rate [heuristic-strong]
SUPPLY DITCH (0500523) stopped 2024-07-01 (6+ days) — call at HAGERS MEADOW DITCH curtailing 100% of its decreed rate [heuristic-partial, district-confirmed]

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
HIGHLAND DITCH (0500526)	1861-03-08	100.0% / 84.1%	5.6% / 0.0%
OLIGARCHY DITCH (0500547)	1861-03-08	100.0% / 84.1%	5.6% / 0.0%
LEFT HAND DITCH (0500603)	1863-06-01	100.0% / 44.4%	5.6% / 0.0%
ROUGH READY DITCH (0500527)	1861-03-08	100.0% / 84.1%	5.6% / 0.0%
ST VRAIN PALMERTON DITCH (0500528)	1861-03-08	100.0% / 84.1%	5.6% / 0.0%
FOOTHILLS INLET (0500532)	1862-04-15	100.0% / 56.5%	10.7% / 0.0%
SUPPLY DITCH (0500523)	1861-03-08	100.0% / 84.1%	5.6% / 0.0%
LONGMONT WHITE WTR COURSE (0502001)	2001-07-10	5.6% / 0.0%	5.6% / 0.0%
BOULDER RES LEFT HAND CR FDR DITCH (0500640)	1961-12-15	6.1% / 0.0%	6.1% / 0.0%
KURTZ RES (0504000)	2001-08-10	5.6% / 0.0%	5.6% / 0.0%
LAKE DITCH (0500564)	1874-04-15	58.0% / 16.8%	10.7% / 0.0%
TABLE MOUNTAIN DITCH (0500569)	1860-09-01	100.0% / 84.1%	5.6% / 0.0%

Abandonment radar (3 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 ~1975 — idleness that begins before then may be unreported use, not nonuse (flagged † below).

HANSEN DITCH (0500580) (1878-05-01, 1.5 cfs decreed): last active 1952 — 29 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1975) -- early absence of record is weak evidence of nonuse
UPPER BALDWIN DITCH (0500583) (1872-04-01, 9.1 cfs decreed): last active 1956 — 25 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1975) -- early absence of record is weak evidence of nonuse
SPRING GULCH DITCH (0500582) (1884-01-02, 10.0 cfs decreed): last active 1964 — 17 years idle † predates modern reporting era — last recorded activity predates this basin's modern reporting era (~1975) -- early absence of record is weak evidence of nonuse

Compliance screens (30 advisory flags)

Screened 75 of 1289 structures with rights (134 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.

LYONS PIPELINE (0500512): Observed p99 daily rate 134.0 cfs (max 134.0) exceeds total decreed absolute 4.0 cfs across 14104 recorded day(s). Structure holds an Augmentation-use decree -- diversions above the direct-flow decree can be lawful under plan operations; interpret with care.
BEAR GULCH SPRING 3 (0500705): Observed p99 daily rate 100.0 cfs (max 100.0) exceeds total decreed absolute 0.1 cfs across 504 recorded day(s).
COLUMBINE PL (0500507): Observed p99 daily rate 33.5 cfs (max 33.5) exceeds total decreed absolute 0.1 cfs across 12 recorded day(s).
PELLA DITCH (0500551): Observed p99 daily rate 25.0 cfs (max 35.0) exceeds total decreed absolute 2.0 cfs across 26698 recorded day(s). Structure holds an Augmentation-use decree -- diversions above the direct-flow decree can be lawful under plan operations; interpret with care.
LONGMONT SOUTH PIPELINE (0500522): Observed p99 daily rate 24.5 cfs (max 28.2) exceeds total decreed absolute 3.0 cfs across 8750 recorded day(s). Structure holds an Augmentation-use decree -- diversions above the direct-flow decree can be lawful under plan operations; interpret with care.
WILLIAMSON CAVEY DITCH (0500934): Observed p99 daily rate 24.2 cfs (max 28.0) exceeds total decreed absolute 11.9 cfs across 351 recorded day(s). Structure holds an Augmentation-use decree -- diversions above the direct-flow decree can be lawful under plan operations; interpret with care.
PECK DITCH (0500550): Observed p99 daily rate 20.0 cfs (max 43.0) exceeds total decreed absolute 17.0 cfs across 11613 recorded day(s).
DIXON MILL DITCH (0500576): Observed p99 daily rate 20.0 cfs (max 20.0) exceeds total decreed absolute 6.0 cfs across 3079 recorded day(s).
SOUTH FLAT DITCH (0500558): Observed p99 daily rate 15.0 cfs (max 20.0) exceeds total decreed absolute 14.8 cfs across 24374 recorded day(s). Structure holds an Augmentation-use decree -- diversions above the direct-flow decree can be lawful under plan operations; interpret with care.
SPRING GULCH DITCH (0500582): Observed p99 daily rate 14.0 cfs (max 14.0) exceeds total decreed absolute 10.0 cfs across 348 recorded day(s).

Seniority (top structures by decreed rate)

Structure	Senior priority date	Rights	Decreed abs (cfs)	Decreed abs (AF)	Conditional?
HIGHLAND DITCH (0500526)	1861-03-08	75	2959.4	0	yes
OLIGARCHY DITCH (0500547)	1861-03-08	30	664.1	0	yes
LEFT HAND DITCH (0500603)	1863-06-01	6	641.3	0	—
ROUGH READY DITCH (0500527)	1861-03-08	31	430.3	0	—
ST VRAIN PALMERTON DITCH (0500528)	1861-03-08	37	425.8	0	—
FOOTHILLS INLET (0500532)	1862-04-15	10	375.0	0	—
SUPPLY DITCH (0500523)	1861-03-08	47	354.1	0	yes
LONGMONT WHITE WTR COURSE (0502001)	2001-07-10	1	350.0	0	—
BOULDER RES LEFT HAND CR FDR DITCH (0500640)	1961-12-15	1	200.0	0	—
KURTZ RES (0504000)	2001-08-10	2	190.0	3542	yes
LAKE DITCH (0500564)	1874-04-15	5	158.8	0	—
TABLE MOUNTAIN DITCH (0500569)	1860-09-01	40	153.6	0	yes
HALDI DITCH (0500565)	1860-09-01	38	153.0	0	—
SWEDE DITCH (0500529)	1861-03-08	24	116.2	0	—
LAST CHANCE DITCH (0500589)	1872-03-15	6	105.7	0	yes

No inventory or legal-document changes detected since the daily watch began.

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

Administration number

DWR administration numbers encode appropriation and adjudication dates; lower is more senior.

Stream	Gage	R-mile	Predicted (cfs)	Observed (cfs)	Δ (cfs)	Reach (mi)	Hypothesis
MAINSTEM	SAINT VRAIN SUPPLY CANAL NEAR LYONS, CO (SVSLYOCO)	23.6	240.1	0.2	-239.9	0.0	Unaccounted -239.9 cfs loss over 0.0 mi. No structure clearly responsible — possible ungaged diversion, channel seepage / phreatophyte loss, or evapotranspiration.
MAINSTEM	SAINT VRAIN SUPPLY CANAL NEAR LYONS, CO (SVSLYOCO)	23.6	1.2	240.1	+239.0	1.9	Unaccounted +239.0 cfs gain over 1.9 mi. Diversions in this reach with stale data (MCCALL RES, OLIGARCHY RES 1, PELICAN SHORES SOUTH PUMP) — under-reporting could mask an offsetting loss.
MAINSTEM	LYONS BOHN PARK PUMP STATION (BHNPRKCO)	32.2	100.1	0.0	-100.1	0.7	Unaccounted -100.1 cfs loss over 0.7 mi. Likely cause: stale/missing diversion data at CLENNON RES, JOHN F HARTFORD RES, HEWITT RES.
MAINSTEM	BOULDER CREEK FEEDER CANAL NEAR LYONS (BFCLYOCO)	31.5	39.9	135.0	+95.2	0.9	Unaccounted +95.2 cfs gain over 0.9 mi. Diversions in this reach with stale data (MAINTENOMA RES, HIGHLAND LAKE, CRYSTAL LAKE) — under-reporting could mask an offsetting loss.
MAINSTEM	ROUGH AND READY DITCH (ROUREACO)	1.1	69.2	0.0	-69.2	0.6	Unaccounted -69.2 cfs loss over 0.6 mi. Likely cause: stale/missing diversion data at MONTGOMERY PRIVATE DITCH.
MAINSTEM	SAINT VRAIN CREEK AT MOUTH NEAR PLATTEVILLE, CO (SVCPLACO)	30.7	0.5	47.0	+46.5	6.4	Unaccounted +46.5 cfs gain over 6.4 mi. Likely cause: stale/missing return data at LONGEVITY SPRING, ANDERSON DITCH RT OUTLET.
MAINSTEM	UNION RESERVOIR OUTLET (UNIOUTCO)	18.3	5.3	48.9	+43.7	0.0	Unaccounted +43.7 cfs gain over 0.0 mi. No structure clearly responsible — possible ungaged return flow, baseflow from groundwater, or unmodeled tributary inflow.
MAINSTEM	BONUS DITCH (BONDITCO)	11.8	47.1	5.8	-41.3	0.2	Unaccounted -41.3 cfs loss over 0.2 mi. No structure clearly responsible — possible ungaged diversion, channel seepage / phreatophyte loss, or evapotranspiration.
MAINSTEM	BOULDER CREEK FEEDER CANAL NEAR LYONS (BFCLYOCO)	31.5	135.0	100.1	-34.9	0.0	Unaccounted -34.9 cfs loss over 0.0 mi. No structure clearly responsible — possible ungaged diversion, channel seepage / phreatophyte loss, or evapotranspiration.
MAINSTEM	SAINT VRAIN SUPPLY CANAL DELIVERY TO SUPPLY DITCH (SVSSUPCO)	0.5	30.1	0.0	-30.1	0.1	Unaccounted -30.1 cfs loss over 0.1 mi. No structure clearly responsible — possible ungaged diversion, channel seepage / phreatophyte loss, or evapotranspiration.
MAINSTEM	SAINT VRAIN CREEK BELOW KEN PRATT BLVD AT LONGMONT, CO (SVCLOPCO)	14.8	0.6	29.2	+28.5	0.6	Unaccounted +28.5 cfs gain over 0.6 mi. No structure clearly responsible — possible ungaged return flow, baseflow from groundwater, or unmodeled tributary inflow.
MAINSTEM	GOSS DITCH 1 (GODIT1CO)	3.3	18.1	0.0	-18.1	0.4	Unaccounted -18.1 cfs loss over 0.4 mi. Likely cause: stale/missing diversion data at CHAPMAN MCCASLIN DITCH.
MAINSTEM	RURAL DITCH TAIL RETURN TO ST. VRAIN CREEK (RUTAILCO)	21.4	23.4	7.2	-16.2	2.0	Unaccounted -16.2 cfs loss over 2.0 mi. Likely cause: stale/missing diversion data at HOKESTRA CELL 2 RESERVOIR.
MAINSTEM	MIDDLE SAINT VRAIN AT PEACEFUL VALLEY (MIDSTECO)	17.4	29.2	15.6	-13.6	2.6	Unaccounted -13.6 cfs loss over 2.6 mi. Likely cause: stale/missing diversion data at CLOVER BASIN RES.
MAINSTEM	NORTH SAINT VRAIN CREEK BELOW BUTTONROCK (RALPH PRICE) RESERVOIR (NSVBBRCO)	21.6	2.6	14.7	+12.1	0.2	Unaccounted +12.1 cfs gain over 0.2 mi. Likely cause: stale/missing return data at RURAL D CENTRAL AUG RT.
MAINSTEM	SAINT VRAIN CREEK AT HYGIENE, CO (SVCHGICO)	6.3	1.2	12.8	+11.7	0.1	Unaccounted +11.7 cfs gain over 0.1 mi. No structure clearly responsible — possible ungaged return flow, baseflow from groundwater, or unmodeled tributary inflow.
MAINSTEM	UNION RESERVOIR OUTLET (UNIOUTCO)	18.3	15.6	5.3	-10.3	0.9	Unaccounted -10.3 cfs loss over 0.9 mi. Likely cause: stale/missing diversion data at GREEN LAKE, BOULDER CNTY FAIRGRNDS R.
MAINSTEM	LEFT HAND CREEK NEAR BOULDER, CO. (LEFCRECO)	11.5	0.0	10.1	+10.1	4.4	Unaccounted +10.1 cfs gain over 4.4 mi. Likely cause: stale/missing return data at POINT OF PINES SPG NO 1, POINT OF PINES SPG NO 3, CRYSTAL SPRING & PL.
MAINSTEM	SOUTH BRANCH ST. VRAIN CREEK (SBRSTVCO)	2.5	1.7	11.0	+9.3	1.2	Unaccounted +9.3 cfs gain over 1.2 mi. Diversions in this reach with stale data (FOOTHILLS INLET) — under-reporting could mask an offsetting loss.
MAINSTEM	SAINT VRAIN CREEK BELOW SOUTH BRANCH DIVERSION (SVCBSBCO)	2.9	11.0	18.1	+7.2	0.4	Unaccounted +7.2 cfs gain over 0.4 mi. No structure clearly responsible — possible ungaged return flow, baseflow from groundwater, or unmodeled tributary inflow.
MAINSTEM	LONGMONT SUPPLY DITCH (LONSUPCO)	21.6	14.7	8.3	-6.4	0.1	Unaccounted -6.4 cfs loss over 0.1 mi. No structure clearly responsible — possible ungaged diversion, channel seepage / phreatophyte loss, or evapotranspiration.
MAINSTEM	LEFT HAND CREEK AT HOVER ROAD NEAR LONGMONT, CO (LEFTHOCO)	14.2	5.8	0.6	-5.2	2.5	Unaccounted -5.2 cfs loss over 2.5 mi. No structure clearly responsible — possible ungaged diversion, channel seepage / phreatophyte loss, or evapotranspiration.
MAINSTEM	HAGER MEADOWS DITCH (HGRMDWCO)	6.8	5.8	0.8	-5.0	0.5	Unaccounted -5.0 cfs loss over 0.5 mi. Likely cause: stale/missing diversion data at JAMES MASON DITCH.

Gage ⇅	Station ⇅	Avg cfs Aug 03–Aug 09 ⇅	% Hist Median ⇅	Rank ⇅	Δ1wk ⇅	Δ4wk ⇅	Yrs ⇅	Status ⇅
LEFCRECO	LEFT HAND CREEK NEAR BOULDER, CO.	10.1	26%	0	-7	-9	24.1	SHORT_RECORD
LEFTHDCO	LEFT HAND DIVERSION NEAR WARD	10.8	34%	0	-7	-11	18.0	SHORT_RECORD
MIDSTECO	MIDDLE SAINT VRAIN AT PEACEFUL VALLEY	15.6	58%	0	-7	-12	17.3	SHORT_RECORD
OLIDITCO	OLIGARCHY DITCH DIVERSION	0.0	0%	0	-0	-9	17.1	SHORT_RECORD
ROUREACO	ROUGH AND READY DITCH	0.0	0%	0	-0	-1	15.9	SHORT_RECORD
PALDITCO	PALMERTON DITCH	4.0	27%	0	-15	-18	16.0	SHORT_RECORD
SWEDITCO	SWEDE DITCH	0.0	0%	0	+0	+0	16.5	SHORT_RECORD
SMEDITCO	SMEAD DITCH	1.7	46%	0	+0	-1	15.4	SHORT_RECORD
DAVDOWCO	DAVIS AND DOWNING DITCH	0.0	1%	0	+0	-8	15.0	SHORT_RECORD
ZWETURCO	ZWECK AND TURNER DITCH	4.5	44%	0	-4	-1	17.1	SHORT_RECORD
HGRMDWCO	HAGER MEADOWS DITCH	0.8	34%	0	-2	-0	16.0	SHORT_RECORD
NORMUTCO	NORTHWEST MUTUAL DITCH	1.0	67%	0	+0	-0	15.3	SHORT_RECORD
RUNYONCO	RUNYON DITCH	0.0	0%	0	+0	+0	13.6	SHORT_RECORD
SVCLOPCO	SAINT VRAIN CREEK BELOW KEN PRATT BLVD AT LONGMONT, CO	29.2	49%	0	-13	+5	12.0	SHORT_RECORD
NSVBBRCO	NORTH SAINT VRAIN CREEK BELOW BUTTONROCK (RALPH PRICE) RESERVOIR	14.7	41%	0	-1	-22	13.2	SHORT_RECORD
LEFTHOCO	LEFT HAND CREEK AT HOVER ROAD NEAR LONGMONT, CO	0.6	16%	0	+0	-0	12.4	SHORT_RECORD
SVCBBCCO	ST. VRAIN CREEK BELOW BOULDER CREEK AT HWY 119 NEAR LONGMONT, CO	48.9	44%	0	-23	-9	12.9	SHORT_RECORD
BHNPRKCO	LYONS BOHN PARK PUMP STATION	0.0	0%	0	+0	-0	5.9	SHORT_RECORD
0502407A	LOWER BOULDER DITCH AUG RETURN TO GODDING HOLLOW	0.0	0%	0	+0	+0	4.3	SHORT_RECORD
NELDITCO	NELSON DITCH	0.5	100%	0	-0	-0	0.2	SHORT_RECORD
SVSSUPCO	SAINT VRAIN SUPPLY CANAL DELIVERY TO SUPPLY DITCH	0.0	0%	0	-0	-0	4.4	SHORT_RECORD
SBRSTVCO	SOUTH BRANCH ST. VRAIN CREEK	11.0	56%	0	-3	-17	16.6	SHORT_RECORD
NIWDITCO	NIWOT DITCH	2.9	58%	1	-1	-1	15.9	SHORT_RECORD
GODIT1CO	GOSS DITCH 1	0.0	0%	1	-0	-0	16.5	SHORT_RECORD
PCKPELCO	PECK PELLA CLOVER DITCH	1.2	56%	2	-0	-3	14.7	SHORT_RECORD
RUTAILCO	RURAL DITCH TAIL RETURN TO ST. VRAIN CREEK	7.2	56%	10	-4	-5	10.8	SHORT_RECORD
LASDITCO	LAST CHANCE DITCH	23.4	75%	12	-6	-3	15.2	SHORT_RECORD
WEBDITCO	WEBSTER MCCASLIN DITCH	0.3	16%	13	-0	-0	16.2	SHORT_RECORD
TRUDITCO	TRUE AND WEBSTER DITCH	1.0	53%	25	-1	-2	15.4	SHORT_RECORD
SUPDITCO	SUPPLY DITCH	0.2	11%	25	-0	-0	16.9	SHORT_RECORD
HIGHLDCO	HIGHLAND DITCH AT LYONS, CO	100.1	86%	25	+1	+15	19.9	SHORT_RECORD
SVCBSBCO	SAINT VRAIN CREEK BELOW SOUTH BRANCH DIVERSION	18.1	79%	26	-10	-22	3.0	SHORT_RECORD
LONSUPCO	LONGMONT SUPPLY DITCH	8.3	82%	26	-2	-3	16.7	SHORT_RECORD
SVCHGICO	SAINT VRAIN CREEK AT HYGIENE, CO	12.8	89%	30	-2	+3	10.7	SHORT_RECORD
JAMDITCO	JAMES DITCH	1.3	45%	33	-1	-7	16.8	SHORT_RECORD
0500536A	CLOUGH PRIVATE DITCH	0.8	98%	35	-1	-1	4.0	SHORT_RECORD
CLODITCO	CLOUGH AND TRUE DITCH	0.1	100%	50	-2	+0	16.2	SHORT_RECORD
SFLDITCO	SOUTH FLAT DITCH	3.9	117%	65	+3	+3	15.9	SHORT_RECORD
BONDITCO	BONUS DITCH	5.8	170%	76	+1	-2	16.4	SHORT_RECORD
DENTAYCO	DENIO TAYLOR DITCH	3.3	136%	84	+1	-0	15.3	SHORT_RECORD
BFCINFCO	BOULDER RESERVOIR INLET	115.1	302%	100	+4	+12	17.6	SHORT_RECORD
BLDRLHCO	BOULDER RESERVOIR DELIVERY TO BOULDER-LEFT HAND DITCH	4.4	179%	100	+0	+4	5.0	SHORT_RECORD
UNIOUTCO	UNION RESERVOIR OUTLET	5.3	102%	100	-4	-1	1.1	SHORT_RECORD
SVCLYOCO	SAINT VRAIN CREEK AT LYONS, CO	30.1	23%	0	-23	-47	130.2	OK
SSVWARCO	SOUTH SAINT VRAIN NEAR WARD	11.1	30%	0	-6	-10	43.0	OK
SVCPLACO	SAINT VRAIN CREEK AT MOUTH NEAR PLATTEVILLE, CO	47.0	28%	0	-22	-15	99.4	OK
SVSLYOCO	SAINT VRAIN SUPPLY CANAL NEAR LYONS, CO	240.1	114%	59	-14	+41	71.4	OK
BFCLYOCO	BOULDER CREEK FEEDER CANAL NEAR LYONS	135.0	152%	68	-10	+24	70.8	OK