Trout Fishing on The South Platte

Rainbow trout born to run are now cooling their fins in a custom-designed nursery section of the South Platte River below Antero Reservoir in central Colorado. Stocked into the nursery as sub-catchables (5-inch fingerlings), the young rainbows will grow quickly and, in time, will leave the nursery and swim downstream, where they will put the finishing touch on a management plan that began several years back.

The rainbows are offspring of a self-sustaining rainbow trout population that developed in the North Platte River above Lake McConaughy in Nebraska. The rainbows make annual spawning runs from the lake into the river, often swimming upstream more than fifty miles.

If the traveling McConaughys remain true to their nature, they will establish a spawning run in the South Platte traversing the 15-miles of river between Antero and Spinney Mountain reservoirs. Jeff Spohn, Division of Wildlife (DOW) aquatic biologist for South Park and the scientist behind the project, has high expectations that the McConaughys will not only enhance angling opportunities all through the river, but also will fit the management plan for Spinney Mountain Reservoir.

More on that later; but first, a step back to the late 1990s, when DOW aquatic researcher Rod Van Velson studied the stretch river immediately below Antero Reservoir and saw an opportunity to correct a habitat problem and to create something special. The first ? mile of the river, which once had meandered across the valley, was abandoned after a flood in the early 1970s resulted in water spilling out of the river onto the valley. Subsequently, water was diverted into a wide, straight, featureless channel built to expedite outflows from the reservoir. However, evidence of the original streambed remained visible.

Van Velson, now retired from the DOW, said, ?We could see where about two-thousand feet of the old river channel had ran and I decided that we should use that same geometry. It was a fairly sinuous stream and that is what we wanted to reconstruct.?

When reconstructing the stream, Van Velson and his crew created pools for wintering habitat, installed boulders and wood structures for trout holding areas, point bars for filtering sediment from the stream, and gravel riffles for spawning habitat. Unfortunately, when the reconstruction was completed in 2000, a severe drought plagued the region along with the rest of the state. Antero Reservoir eventually was drained and the newly reconstructed stream remained dry until recently.

Now that the reconstructed stream has enough water to sustain a trout population, Spohn has set the plan in motion. He stocked the stream with both sub-catchable McConaughy rainbows and catchable-sized hatchery rainbows. Although Denver Water, who owns and operates the reservoir and the reconstructed portion of the river below, has yet to open the area to public fishing, Spohn wanted the stream to be ready to go for anglers when that time arrives.

Spohn said, ?The reconstructed channel is a great little nursery where the rainbows can feed on scuds coming out of Antero and put on some weight before they migrate down to Spinney Mountain Reservoir. They typically remain in the stream until they reach approximately 11-inches long, which suits our management plan to supply Spinney with larger-sized trout to prevent predation from northern pike.?

The McConaughy rainbows undoubtedly will contribute to the reservoir?s fishing as they fatten and grow in reservoir?s rich environment, but the high point of their mission will come in approximately two years, when they leave the reservoir to make a spawning run back toward Antero.

During the spawning run, the rainbows will provide anglers with opportunities for catching larger trout on many miles of the South Platte River, including stretches of river that served up only mediocre fishing in the past. Public fishing access on the South Platte is abundant at both the Badger Basin and Spinney Mountain state wildlife areas.

Van Velson and his crew also worked to improve stream habitat at locations in these stretches. His work can be seen in strategically placed diamond-shaped clusters of boulders, rock wing dams, point bars, and willow plantings to help stabilize the banks.