Eldorado Canyon (S. Boulder Cr. in park)

Tailwater/Freestone · Eldorado Canyon SP section of S. Boulder Cr.Class 2Fishing Well

○ Live fetch unavailable — showing sample data

191 cfs

Flow

47°F

Water temp

39.931, -105.296

Location · USGS gauge

40–150

Ideal flow · cfs

Conditions · water 44–50°F

~191 cfs from Gross release (FRA 6/5: 'flows all over, rapidly rising and falling' — see S. Boulder Cr) · spiked above ideal range, wading difficult · fish behind structure

Strategy

Same water as S. Boulder below Gross, but downstream and inside Eldorado Canyon SP — drive-up access via Hwy 170 (no Walker Ranch hike). Park pass required. 8–14" rainbows + brook trout common; browns to 18"+ in deeper holes. ~191 cfs from Gross release now (spiked, wading difficult — stay ankle-deep), fish behind structure — rocks and boulders. Today (Sun Jul 5) ~91°F plains, sunny and hot — the cold release fishes all day; scattered storms Tue–Wed, heat rebuilds late week.

Detailed report

Same Mysis-shrimp playbook as upstream S. Boulder. Spiked to ~191 cfs (FRA 6/5 — above ideal 80-120 range, wading difficult, stay ankle-deep). Best easy-access tailwater close to Brighton. Weekday pattern: today (Sun Jul 5) ~91°F plains, sunny and hot; scattered storms Tue–Wed, heat rebuilds late week. Fish behind structure that blocks current — rocks and boulders.

Report: Front Range Anglers / About Boulder · June 5, 2026 · Front Range Anglers staff

Fly-shop reports

2 shops report on Eldorado Canyon (S. Boulder Cr. in park)

Front Range Anglers

Boulder

Live report

About Boulder / Boulder CVB

Live report

Reports are pulled live from each shop when you open this river. Shop wording varies — tap through for the full, original report.

Fishability Score breakdown

How today's 83 is built. Flow 35% · Water temp 25% · Weather 20% · Hatch 20%.

Flow75/100

Water temp100/100

Weather76/100

Hatch match82/100

Weather & hatch are placeholder factors until wired to live sources.

What to throw — by time of day

Morning

Dawn – 11am

Zebra Midge #20, JuJu Baetis #18, Mysis #16–20, RS-2 #20

MiddayNOW

11am – 5pm

Mole Fly #18, AR's BWO Emerger, Parachute Adams #18, dry-dropper

Evening

5pm – dark

Caddis #16 (warmest days), Griffith's Gnat #20, Hanging Midge #22

Species

Rainbow · Brook · Brown (some 18"+)

USGS gauge 06729500

Seasonal hatch report

In season now

Fall — BWOs & Streamers

Cooling water wakes the fish up. Blue-Winged Olives return on grey afternoons, and pre-spawn browns chase streamers hard.

Morning

Dawn – 11am

Hatching

Midges · BWO nymphs · Trico (early fall)

Flies

Pheasant Tail #18, RS-2 #20, Trico spinner #24

Rig

Nymph deep; streamer the banks early for aggressive browns.

Afternoon

NOW

11am – 5pm

Hatching

Blue-Winged Olives · October caddis (freestone)

Flies

BWO dun #20-22, Parachute Adams #20, October Caddis #10

Rig

Overcast = dry BWOs; otherwise swing/strip streamers for browns.

Evening

5pm – dark

Hatching

BWO spinners · Streamer window

Flies

Sculpin/Woolly Bugger #6-8, RS-2 #20

Rig

Strip big flies through frog water at last light for the biggest fish.

Source: Hatchwise Seasonal Guide · updated Jul 5, 12:00 PM MT. General seasonal patterns — verify against a current local shop report before you go.

Sources & last updated

Source	Feeds	Most recent update
USGS 06729500	Eldorado Canyon (S. Boulder Cr. in park)	Sample data — no live reading
Hatchwise Seasonal Guide	Hatch & fly guidance	Jul 5, 12:00 PM MT · editorial
Front Range Anglers	Shop fly report	Live — see report
About Boulder / Boulder CVB	Shop fly report	Live — see report

Live flow & water temp come straight from the USGS Instantaneous Values service; timestamps are the gauge's own reading times (Mountain Time).