Washington Riffe Lake Fishing: Kokanee, Trout, and Tactics

Lewis County’s 11,830-acre reservoir, formed by Mossyrock Dam, stretches 23 miles up a timbered Cowlitz River canyon, holding deep, cold water prized for its kokanee and trout fisheries. Kokanee salmon dominate the lake, supported by a healthy population of landlocked rainbow trout and the occasional landlocked chinook that wanders in from the river below. The Washington Department of Fish and Wildlife (WDFW) stocks both species each year, building the fishery into one of the most reliable kokanee destinations in the Pacific Northwest.

This guide covers what kokanee and trout anglers need to plan a productive trip to Riffe Lake, from seasonal timing and trolling setups to launch access and current WDFW rules.

The Lay of the Lake and What Lives in It

Mossyrock Dam backs the Cowlitz River into a long, narrow reservoir that fills a former river valley, so the lake acts more like a flooded canyon than a broad basin. The main channel runs north toward Taidnapam, with side arms branching off where smaller creeks once met the river. Tacoma Public Utilities draws water down through the turbines to generate power, and those daily fluctuations can shift the shoreline by several feet between morning and evening.

Primary Species and Stocking Program

Kokanee salmon are the headline fishery, and they thrive here because the lake matches their preferences: cold, oxygen-rich water deep enough to stratify in summer, plus a forage base of Daphnia and aquatic insects. WDFW supplements the wild spawn with annual fry plants, and the program has run long enough that natural reproduction now carries much of the load.

Rainbow trout are the secondary target, and they are not just stockers. Some of the rainbows in Riffe are leftovers from past plants that learned to feed on kokanee fry and shiners, which is why a 14-inch rainbow from this lake fights harder than its size suggests. A small number of landlocked chinook show up in odd years, strays from the Cowlitz River hatchery program that found their way upstream before the dam closed to them.

Species	Primary Forage	Typical Size	Stocking Role
Kokanee salmon	Zooplankton, insect larvae	10 to 16 inches	WDFW fry plants, natural spawn
Rainbow trout	Kokanee fry, insects, minnows	10 to 18 inches	WDFW supplemental plants
Landlocked chinook	Small fish, invertebrates	12 to 24 inches	Incidental, no plant

Cowlitz River water carries a mercury advisory, so check the current WDFW fish consumption guidelines before keeping a meal. The advisory thresholds shift by species and water body, and Riffe has carried a partial advisory in past years.

Because those advisories change with the season, knowing when each species is active helps you plan a meal that stays within safe limits.

Seasonal Patterns and When Each Species Bites

Kokanee move with the temperature, and on Riffe that means tracking the thermocline through the year. In spring, the lake turns over and the water column mixes, pushing schools into the upper 30 to 60 feet where warmer, oxygenated water sits. By early summer, a thermocline forms and the fish drop below it, often holding tight to the 50 to 80 foot band.

Spring, Summer, and Fall Windows

April through June is the classic spring bite, with kokanee and the rainbows that follow them feeding aggressively in shallower water. July and August push fish deep, and success depends on running downriggers at the exact depth where the graph marks bait and fish. September cools the surface and pulls schools back up, producing a fall bite that can rival spring for numbers and size.

Winter slows everything down but does not stop it. The lake stays open year-round, and a handful of diehard anglers target rainbows through the cold months when boat traffic disappears and the fish push shallower to follow the few insects still hatching.

“Plan dawn through mid-morning for calm-water trolling. When afternoon wind kicks up, shift the spread higher in the column; kokanee often rise ten feet to chase injured prey pushed by the chop.

Tackle, Lures, and Trolling Setups That Produce

Downrigger trolling is the proven method for this lake, and the standard rig is a two-rod spread that puts dodgers and lures at controlled depths. Most anglers run a wedding cake dodger trailing a Kokanee Killer or P-Line mini-hoochie in pink, orange, or chartreuse behind 18 to 30 inches of leader, with a 4 to 6 ounce sliding sinker ahead of the dodger to keep the bait upright in the strike zone.

Boat Setups That Cover the Column

Light-action kokanee rods in the 7 to 9 foot range, spooled with 8 to 10 pound monofilament or light braid, handle most presentations. Run two downriggers on opposite corners of the boat so you can stack one rod at 40 feet and another at 60, then adjust up or down based on the graph. Speed matters: kokanee bite best at 1.0 to 1.5 mph, slower than most trout trolling.

Shore and Kayak Options

Shore anglers do best near Taidnapam and along the upper Cowlitz arm where the water deepens quickly off the bank. Bubble floats loaded with cured shrimp, worm pieces, or PowerBait catch rainbows reliably from late spring through fall. Kayak and pontoon anglers find productive water in the upper arms, where wind is reduced and fish hold tight to submerged structure and drop-offs.

But the right rig only pays off if you can actually reach productive water without fighting a crowded launch or limited shoreline.

• ▸Dodger color matters: silver and brass work in low light, while chartreuse and pink pop in stained or deep water.
• ▸Scent the bait: a strip of cured shrimp on the hook boosts kokanee bites that will not commit to a bare lure.
• ▸Watch the rod tip: a kokanee bite often shows as a soft tap-tap, not the hard pull of a rainbow.
• ▸Reel weight matters: a 4 to 6 ounce sinker keeps the dodger tracking true without spinning at trolling speed.
• ▸Match line to depth: heavier mono (10 to 12 pound) helps drive a deep presentation when the downrigger weight is heavy.

Boat Launches, Shore Access, and Getting on the Water

Taidnapam Park on the north end is the main hub for Riffe Lake boat launch fishing, with a paved ramp, ample trailer parking, restrooms, and a campground that fills fast on summer weekends. The ramp handles everything from kayaks to large wake boats, and there is a small fee for day use. Siggins Point, on the south end closer to the dam, offers a secondary launch that works well when Taidnapam is crowded.

Access Points and Shoreline Spots

PacifiCorp and Tacoma Power manage parcels of shoreline around the lake, and several of those parcels allow bank fishing, though the rules vary by location. Check the posted access signs before parking or wading; some areas close during high-water drawdowns, and a few require a discover pass or day-use fee.

Kayakers find their best water in the upper Cowlitz arm above Taidnapam, where the wind dies and the water deepens fast. The launch at Taidnapam works for hand-carried craft, and the campground offers easy overnight staging for multi-day trips.

Access Point	Type	Amenities	Best For
Taidnapam Park	Paved boat launch	Restrooms, campground, parking	Full-size boats, families
Siggins Point	Paved boat launch	Parking, vault toilet	Smaller crowds, dam-area fishing
Upper Cowlitz arm	Kayak/cartop launch	Limited, check access rules	Kayak, pontoon, bank fishing

Licensing, Limits, and the Rules Anglers Need to Know

A Washington state fishing license is required for anyone 15 and older, and you can pick one up through WDFW online, at a regional office, or at any sporting goods store in the area. Annual licenses run around $30 to $60 for residents depending on the package, with non-resident options priced higher. A Columbia River Basin endorsement and a steelhead card are not required for Riffe, since the fish are landlocked, but check the current pamphlet before each trip because rules shift.

Bag Limits and Gear Rules

Kokanee limits on Riffe are typically generous, with no minimum size and a daily count that often allows 10 to 16 fish depending on the year’s regulation. Rainbow trout carry a minimum size, often 12 inches, and a daily count of two to five that changes by season. Selective gear rules may apply in sections of the Cowlitz River below the dam, so anglers who plan to drift downstream from the launch need to read the fine print before rigging.

Those rulebook details matter less, though, without recent reports telling you where fish are actually biting this week.

• ▸License: required for anglers 15 and older, available online or in stores.
• ▸Kokanee limit: generous bag, no minimum size, confirm current count in the WDFW pamphlet.
• ▸Rainbow limit: minimum length applies, daily count changes annually.
• ▸River below the dam: selective gear rules and seasonal closures affect boaters drifting downstream.
• ▸Discover pass: required at some PacifiCorp and Tacoma Power shoreline parcels.

“Skim the WDFW Sport Fishing Rules pamphlet the week before each trip. Limits, size slots, and gear rules update each March, and what worked last season may not be legal this one.

Reading Reports, Stocking Data, and Planning a Trip

WDFW publishes annual stocking reports showing how many kokanee fry and rainbow trout went into Riffe, and those numbers predict the coming season better than any rumor mill. A big fry plant two springs ago means a strong year-class now, and the report tells you exactly when those fish were planted and in what quantity. Pull the report from the WDFW website before booking a trip.

Local Reports and Pre-Trip Prep

Local tackle shops near Mossyrock and along Highway 12 share the freshest Riffe Lake fishing report information, often naming the depth, dodger color, and trolling speed that produced recent catches. The WDFW hotline and regional email updates are the next-best source when shops are closed.

Build a pre-trip checklist so nothing important gets left in the truck: license printed or saved on the phone, downriggers tuned and ball weights checked, dodgers and Kokanee Killer rigs in the box, lake elevation checked against the current Tacoma Power release schedule, and a backup plan for windy afternoons when the upper arms become unfishable.

Putting the Plan Together

Run dawn through mid-morning on calm days when the lake is glass and the graph marks clean arches. When the afternoon wind picks up, head for the upper Cowlitz arm where the hills block the chop, or pull the spread shallower where the wave action pushes bait toward the surface. Most successful trips blend both windows, fishing the main lake early and shifting to sheltered water after lunch.

Bottom Line

Riffe Lake rewards anglers who match the season, the depth, and the gear to what the water is actually doing on any given day. The fishery is dominated by kokanee and supported by rainbows that grow fast on a forage-rich diet, and the WDFW stocking program keeps both species self-sustaining year after year. Bring a downrigger, a dodger-and-hoochie combo, and a willingness to adjust depth until the graph fills with marks, and you will have a shot at the best catch the Cowlitz valley can offer.

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