The Landlocked Steelhead Of Thermalito Afterbay   By: Dan Bacher January 15, 2008 More Articles by Dan

The Thermalito Afterbay outlet area of the Feather River is one of the most heavily fished fishing spots in the state, drawing huge crowds in the spring, summer and fall for king salmon and during the fall and winter for steelhead.  Jim Zanoco, local fishing guide, once humorously described it to me as the “Gates of Hell,” alluding to the crowded conditions, raging tempers and bad attitudes that one often finds there during the peak of fishing season.

In contrast, the Thermalito Afterbay above the outlet provides relative solitude for bank anglers and trollers quietly pursuing a variety of species including largemouth bass, smallmouth bass, spotted bass, channel catfish, crappie and other fish. For this time starting in 2007, anglers can add landlocked steelhead to the list of species one can catch at the lake.

In an experiment, the Department of Water Resources teamed up with Department of Fish and Game staff members at the Feather River Fish Hatchery in Oroville to plant catchable steelhead to develop a new inland fishery. 

The hatchery planted 10,000 catchable size steelhead weighing about a half pound each in 2007, but will probably not be able to plant the fish in 2008 because they don’t anticipate having surplus steelhead yearlings then, according to Paula Hoover, hatchery manager #1. Hopefully, they will get enough steelhead in 2009 and ensuing years to continue the experiment. 

To make these fish easily identifiable, they double clipped the fish – clipping both the adipose fin and one of the ventricle fins. The fish are meant to be caught as catchables or holdover trout. So far, the fish haven’t been reported in the screw traps operated on the Feather River by DWR biologists downriver of the afterbay.

The experiment to date appears to be a rousing success, according to the reports of anglers who have caught big, fat landlocked steelhead while bait fishing and trolling in the afterbay.

“My mom and dad, Dell and Dillard,  have been hooking these fish for the past two months, catching limits on some days,” according to John Lackey at Oroville Outdoors River One. “The fishing has slowed down a bit lately, but anglers are still catching some quality fish.”

In addition to catching the steelhead, anglers are also hauling in some quality largemouth bass in the 3 pound class while fishing minnows under bobbers in the afterbay.

“One woman I’ve known for years rarely fishes, but decided to give a try at the afterbay,” said Lackey. “She came back with four steelhead topped by a 3-1/2 pounder while fishing minnows right off the rockwall by the bridge.”

Trollers are also finding solid landlocked steelhead action this fall while using minnows and nightcrawlers behind flashers or an array of minnow imitation lures. “The key is locating the fish, since the steelhead are chasing small minnows on the reservoir,” said Lackey. 

Bob Boucke, owner of Johnson’s Bait and Tackle in Yuba City, reported catching anywhere from 12 to 16 fish per day on his trolling adventures this fall. “I catch and release all of my landlocked steelhead and urge others to do also, since the hatchery doesn’t plan to stock any catchable steelhead this coming year,” he emphasized.

“This is an awesome fishery,” he noted. “These are beautiful fish that fight really hard. The fish my fishing partners and I hooked were in the 2 to 3 pound range, but other anglers reported hooking a few larger fish in the 5 to 6 pound class.” 

Boucke trolls the afterbay with a nightcrawler behind a 4/0 dodger fished at 40 to 60 feet behind the boat with no weight. He prefers to troll at 4 to 5 feet deep at a speed of 1.2 to 1.5 mph.

There are two trolling paths that he utilizes at the afterbay. The first is from the cove at Wilbur boat ramp straight down the deep water channel to the rockwall. The second area is along the rockwall from the Highway 162 Bridge down to just above the release gates.  

Trout also emigrate from Thermalito Forebay into the afterbay The DFG plants about 12,000 pounds of catchable rainbows per year in the forebay, according to Don Ward, manager of the DFG’s American River Fish Hatchery. This forebay is a popular place for anglers to take a break from the faster pace of steelhead fishing and to catch some rainbows while fishing Power Bait, nightcrawlers, spinners and spoons from the bank. 

The afterbay is a big lake, with a water surface area of 4,300 acres and operating storage of  57,040 acre-feet of water when full. Located about six miles southwest of the city of Oroville, Thermalito Afterbay is an off stream reservoir of the State Water Project that stores water from Oroville Lake on the Feather River. 

The lake hosts largemouth and spotted bass, as well as channel catfish, bluegill and crappie, but is largely overlooked because of the close proximity of more popular spots such as Lake Oroville and the Feather River. The bass fishing is much less consistent that nearby Lake Oroville, but anglers who hit the afterbay on the right day can find some superb action on largemouth bass.

“The lake is a tough one for bass, since fishing there is a case of either feast or famine,” said Thompson also at Oroville Outdoors River One. “I caught five fish over 4 pounds on one trip and I’ve been skunked there. Your best bet is to throw a Rat-L-Trap around points and tules when the water level is up.”

When the water level is down, he recommended tossing out swim baits such as Brush Hogs and Basstrix blue/silver Ghost Minnows in one foot of water. “You want to fish the swimbaits fast just like you would a rip bait,” he advised.  “I like to rig my Basstrix as a weedless bait with weighted hooks.”

Most of the fish that anglers catch are largemouths, including good numbers of fish in the 2 pound range, along with a sprinkling of spotted bass.  Though bass fishing is best done from boats here, shore anglers fishing around the Highway 162 Bridge and the Wilbur Road Boat Ramp can also catch bass, in addition to the rainbows. 

According to the Department of Water Resources, the afterbay provides storage for the water required by the pumpback operation to Lake Oroville, helps regulate the power system, produces controlled flow in the Feather River downstream from the Oroville-Thermalito facilities, and provides recreation. It also serves as a warming basin for agricultural water deliver to farms east of the afterbay, in addition to providing fishing, boating, camping and other recreational opportunities.  

For more information about fishing the Thermalito Afterbay and Forebay, call Oroville Outdoors River One at 530-533-8564, Oroville Outdoors at 530-533-4990, Huntington Sportsman’s Store at 530-534-8000 and Oro Dam Bait and Tackle at 530-533-1656.

Thermalito Afterbay/Forebay Facts

Thermalito Afterbay Dam:   the Department of Water Resources constructed the Thermalito Afterbay Dam from 1965 to 1968. The offstream reservoir has a maximum operating storage of 57,040 acre-feet of water. The afterbay features 4,300 surface acres and 26 miles of shoreline. The water surface elevation is 136.5 feet above sea level.

The afterbay provides storage for the water required by the pumpback operation to Lake Oroville, helps regulate the power system, produces controlled flow in the Feather River downstream from the Oroville-Thermalito facilities, and provides recreation. It also serves as a warming basin for agricultural water delivery to farms east of the afterbay. 

Thermalito Afterbay is open for boating, swimming, fishing, picnicking, and limited hunting. There are three boat ramps available. The afterbay is adjacent to the Oroville Wildlife Area and the Feather River Fish Hatchery Annex. 

Thermalito Forebay: Constructed between 1965 and 1968, Thermalito Forebay is an offstream reservoir contained by Thermalito Forebay Dam on the south and east and by Campbell Hills on the north and west. Located at a surface elevation of 225 feet, the forebay has 13,350 acre-feet when full. The water surface area is 3200 acres and the shoreline is 10 miles

The forebay serves an important role in the pumpback operations of the Oroville-Thermalito Complex and offers recreational activities including fishing, boating, hiking and camping. It is located about four miles west of the city of Oroville.  

The North Thermalito Forebay Recreation Area offers a beautiful 300-acre day-use area for a picnic near the water. Facilities are also available for barbecuing, sunning, and swimming as well as camping. Restrooms and phones are available as are dressing rooms, potable water, and parking. Boating is restricted to non-powerboats such as sailboats and canoes.

Thermalito Forebay South has picnic tables, stoves, 4-lane boat launch ramp, chemical toilets, a new swim beach, and fish cleaning station. Power boating and fishing are the forebay's main attractions.

Information: Lake Oroville State Recreation Area, 400 Glen Drive, Oroville, CA 95966, (530) 538-2200  

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