Fly fishing report · West

Tuolumne River below Hetch Hetchy

Tuolumne River below Hetch Hetchy planning with RiverReports flow, official agency sources, NWS weather, access notes, hatch timing, fly picks, and practical safety guidance.

Check flow & weather

Today's river scoreMedium source confidence

Caution

Best option: Float.

A float can fit better than wading only if launches, shuttle, boat skill, wind, and local rules all check out.

Updated Jul 16, 5:41 PM UTCLive sources checked regularly

Recommended approachFloat

Mode scores adjust the river-wide score for the risks of wading, bank fishing, or floating.

Wade29/100

Wading is the most sensitive plan today. Use protected edges only, avoid crossings, and downgrade quickly if clarity or current feels wrong.

Bank / edgeCheck

This report does not describe this as a primary mode. Verify legal access, depth, launches, and retreat options before planning around it.

Float · Best fit55/100

A float can fit better than wading only if launches, shuttle, boat skill, wind, and local rules all check out.

Confirm before you leave

Flow and weather right now.

Use the flow trend to confirm the score before you leave. Weather can change the safest and most productive fishing window.

River strategy

Treat this as a Sierra freestone or canyon-water day.

Tuolumne River below Hetch Hetchy should be planned around flow, legal access, and the specific reach you intend to fish. The best plan is built around safe flow, legal access, water temperature, and short realistic reaches instead of trying to cover the whole drainage.

Use RiverReports for the public chart, then check the listed agency pages because no separate USGS numeric station was verified for this reach.
NPS Hetch Hetchy rules, RiverReports chart, BLM/forest notices, CDFW rules, and weather
NPS Hetch Hetchy rules and BLM Tuolumne Wild and Scenic River context should be checked before assuming any practical access below the dam.
Dam-influenced flow, steep canyon exits, restricted areas, cold water, and remote access

Why this score moved

FlowUse caution

RiverReports is linked for the flow chart, but this page does not have a structured live flow value the score can read automatically. Treat the rating as conservative and open the chart before committing.

Best mode nowUse caution

Float: A float can fit better than wading only if launches, shuttle, boat skill, wind, and local rules all check out.

SeasonHelps score

Summer: Best dry-dropper and attractor window, especially early and late before canyon heat builds.

WeatherHelps score

The NWS forecast is about 74F with Sunny.

Public alertsHelps score

No active NWS alert was returned for this forecast point.

Read the water

What changes the plan.

Best windows come with stable flow, cool water, and access that does not require unsafe crossings. Skip the trip when the gauge rises fast, roads are uncertain, or water is too warm.

Stable release and cool water

Best for careful canyon trout fishing where access is legal.

Changing dam influence

Do not wade if flow or release timing is uncertain.

Restricted access

Treat closures and posted rules as trip-stoppers.

Hot low conditions

Fish early or choose a cooler backup.

Field plan

Fish it with intention.

Best flows

Stable, clear, cool water with safe crossings and enough depth to hold trout in pockets.

When to skip

Skip during sharp rises, hot low water, unsafe crossings, or road and trail uncertainty.

Local plan

Hetch Hetchy, Mather, or Groveland is the practical base. Check nps hetch hetchy rules, riverreports chart, blm/forest notices, cdfw rules, and weather, then pick a short legal access plan instead of trying to cover the whole river.

Backup water

Check nearby BlueStreamFly reports if the gauge, rules, or weather do not fit the plan.

Hatches & flies

Bring a flexible box.

TimingWhat to watchUseful flies

SpringLittle stones, BWOs, caddis, and runoff-edge nymph movementStonefly nymph, BWO emerger, hare's ear, caddis pupa

Reviewed family · report says “Stonefly nymph”Stonefly Nymph PatternsStonefly nymph patterns generally emphasize two tails, a broad thorax, segmented abdomen, and bottom contact; rubber legs, biots, beads, and jig hooks define different exact forms.See family guide

Reviewed family · report says “BWO emerger”Blue-Winged Olive PatternsBWO describes a hatch group, not one fly. Nymph, emerger, dry, cripple, and spinner profiles must stay separate because they occupy different parts of the water column.See family guide + 2 more reviewed guides in the Fly Box

Early summerCaddis, PMDs, yellow sallies, and attractor dry-fly windowsElk hair caddis, PMD emerger, yellow stimulator, perdigon

Reviewed pattern · report says “Elk hair caddis”Elk Hair CaddisLook for a tented elk- or deer-hair wing, clipped hair head, dubbed body, rib, and hackle palmered along the body. The body color should be labeled because tiers often match different natural caddis colors.See photos & how to fish it

Reviewed family · report says “PMD emerger”Pale Morning Dun PatternsPMD names an insect group, not one fly. Pale nymphs, trailing-shuck emergers, upright or low-riding duns, cripples, and spent-wing spinners stay visibly separate.See family guide + 2 more reviewed guides in the Fly Box

Late summerTerrestrials, ants, beetles, hoppers, and evening caddisFoam ant, beetle, hopper, X-caddis, parachute Adams

Reviewed family · report says “Foam ant”Ant PatternsAnt patterns can be foam, fur-bodied, winged, or sunken. The narrow waist and paired body lobes matter more than one material recipe.See family guide

Reviewed family · report says “beetle”Beetle PatternsBeetle flies range from simple foam shells to hair-bodied and sunken forms. A rounded back and compact profile distinguish the family from ants and hoppers.See family guide + 3 more reviewed guides in the Fly Box

FallBWOs, midges, October caddis, and small streamer windowsBWO emerger, zebra midge, October caddis pupa, olive bugger

Reviewed pattern · report says “zebra midge”Zebra MidgeLook for a very slim tapered thread body, evenly spaced contrasting wire rib, a small bead, and no tail or wing. The reviewed classic is black with silver wire and a silver bead. Red, olive, brown, glass-bead, jig-hook, resin-coated, or tailed forms must remain labeled variations rather than replacing the classic identity.See photos & how to fish it + 2 more reviewed guides in the Fly Box

Start with a dry-dropper in broken water before adding weight.

Fish near-bank pockets first; canyon trout often hold closer than expected.

Use small streamers in deeper buckets or slightly colored water.

Move often and avoid wasting the best daylight on unsafe crossings.

Access & responsibility

Know the entry. Know the exit.

Check current CDFW inland trout regulations plus park, forest, or BLM notices before fishing. Rules can vary by reach and season.

Hetch Hetchy area

NPS restrictions and entry rules control the first planning decision.

Downstream Wild and Scenic corridor

BLM and forest context helps, but canyon access is demanding.

Mather / Groveland base

Use as a logistics base, not as proof of easy access.

Transparent sources

Check the facts behind the plan.

Last material review: 2026-05-31

Active maintenance check: Jul 14, 2026. BlueStreamFly checks report sources, links, live fishability inputs, and page rendering on a recurring maintenance schedule. This check does not change the material review date unless public guidance or sources changed.

flowRiverReports: Tuolumne River below Hetch Hetchy safetyNWS forecast point near Tuolumne River below Hetch Hetchy regulationCDFW inland fishing information accessYosemite National Park Hetch Hetchy regulationYosemite National Park fishing accessBLM Tuolumne Wild and Scenic River backgroundGenerated regional Tuolumne River below Hetch Hetchy planning image

Common questions

Before you leave.

Is Tuolumne River below Hetch Hetchy usually open for fly fishing?+

Check current CDFW rules and land-management notices first. This page gives planning context, but legal status comes from current rules.

Should I wade or float?+

Wade-and-move is the baseline. Float only where you have whitewater skill, legal access, and a safe takeout.

Which flow source should I use?+

Use the RiverReports chart for a fast read, then verify conditions with the listed park, forest, or water-management sources before fishing.