RESERVOIR HOGS: Fishing South Park’s Elevenmile Canyon, Antero, and Spinney Mountain Stillwaters
Located in the heart of central Colorado’s Rocky Mountains, the 1,000-square-mile South Park Basin is perhaps best known for the snaking South Platte River and its lunker tailwater trout. But the river also fills and flows from a series of three reservoirs—Antero, Spinney Mountain, and Elevenmile Canyon—that are all remarkable fisheries in their own right. These three reservoirs provide some of Colorado’s finest stillwater fishing. They are home to large trout amid great structure, a healthy forage base, and heavy hatches during the prime spring, summer, and fall months.
Elevation: 8,978 feet
Surface Area: 1,000 acres
Species: Rainbow, brook, cuttbow, cutthroat, brown, and splake
Where: From Colorado Springs, follow U.S. 24 through Hartsel to
the Antero entrance on the right.
Antero Reservoir has a reputation for growing big trout, fast. With maximum depths of about 30 to 35 feet, depending on seasonal snowpack, and plenty of shallower water, it has ideal conditions for anglers to get their flies to the trout from almost anywhere on the water.
Historically, Antero has produced a wealth of quality fish. This all came to a halt in June 2002, when the Hayman Fire escalated into one of the largest and most destructive burns Colorado has ever seen. With severe drought and demands from Denver water users taking a toll on the South Platte water supply, the decision was made to drain Antero—the uppermost reservoir in the system.
This kiss of death sparked a flurry of questions about whether or not Antero could ever return to its full potential. When it reopened in July 2007, the answer was revealed, with anglers catching numerous trout over 7 pounds. Antero had returned. Nevertheless, this success sparked new challenges for the fishery and its fly fishers.
That spring, the Colorado Division of Wildlife (CDOW) introduced slot limits for trout, allowing anglers to keep one fish over 20 inches as well as four smaller fish. These regulations may have been too generous. Antero’s reopening triggered an onslaught by the general angling community and a subsequent sea of dead trout, attributed largely to illegal cull-and-release mortality exacerbated by warm water temperatures and the release of trout hooked deeply with bait.
In an effort to resolve the issue, CDOW instituted emergency regulations, halving legal limits. The current regulations allow for two trout over 20 inches, which gives smaller trout a chance to grow to their full potential. My hope is that bait fishing will also be banned soon, allowing Antero’s giants a fighting chance at survival.
Spinney Mountain Reservoir
Elevation: 8,691 feet
Surface Area: 2,500 acres
Species: Rainbow, brown, cutthroat, cuttbow, and pike
Where: From Colorado Springs, take Highway 24 for about 55
miles over Wilkerson Pass. Turn south on CR 23,
then right on CR 59.
According to CDOW, Spinney Mountain Reservoir is experiencing an upsurge in both its trout and pike populations. Spinney is particularly popular with fly fishers because of its flies-and-lures-only (no bait) special regulations. The fish grow quickly due to an abundance of high-protein scuds, and the regulations keep the trout population robust. See parks.state.co.us/Parks/SpinneyMountain/ParkActivities/Fishing/ for more details.
Similar to Antero, Spinney reaches maximum depths of approximately 35 feet. One clear advantage to these shallow bodies of water is angler accessibility by boat as well as for stalking cruising trout from shore. The reservoir closes to angling when it freezes in early winter, and reopens after ice-off in late April or May. Over the last five years the number and size of trout have increased, and this should continue for years to come. The key to this is managing the pike population for minimal growth, allowing for maximum trout
Elevenmile Canyon Reservoir
Elevation: 8,566 feet
Surface Area: 3,400 acres
Species: Rainbow, brown, cutthroat, cuttbow, pike, Kokanee salmon
Where: From Colorado Springs, drive 38 miles west on U.S. 24
to 1 mile west of the town of Lake George. Turn left (south)
on CR 90 and drive 6 miles to CR 92.
Continue south on 92 for 5 miles to the entrance.
Elevenmile grows some of the biggest fish in the South Park neighborhood—double-digit trout are caught every year. With water depths reaching 100+ feet, deeper-dwelling fish see little angling pressure. These trout migrate annually from the reservoir into the South Platte to spawn and are largely responsible for the river’s Dream Stream nickname.
Elevenmile’s size and overall depth make finding trout sometimes challenging. Concentrate on the limited shallow nearshore areas from the beginning of ice-off until about mid-May. This is when monsters leave the deep water and cruise the warmer shallows in search of food.
As the season progresses, trout disperse throughout the reservoir, and you must focus your efforts on deeper water, sinking lines, and fishing the thermoclines. Also target windswept bays where food concentrates and trout move in to take advantage of the easy pickings.
Despite varying water conditions, weather, and structural elements, all three reservoirs share similar food bases and hatch schedules. You’ll catch more fish when you understand trout behavior based on when and where hatches occur and how best to match and present your flies.
The two most consistent year-round food supplies are scuds and midges. The best midging kicks off in the spring as water temperatures warm into the 50-degree F. range and trout are actively feeding. Midge hatches continues through early summer, when they are joined by damselflies.
Damselfly nymphs swim toward shore, where they crawl and molt into adults on bankside vegetation. They are best imitated with subsurface patterns and presentations.
Callibaetis mayflies are next to join the mix and can be imitated with nymphs, emergers, and drys—depending on the stage of the hatch.
In addition, reservoir trout feed on dragonfly nymphs and adults, baitfish, leeches, eggs, and crayfish. Crayfish are a favorite food item, and trout often cruise the shallows looking for them. Imitate their movements with intermediate and sinking-tip lines and a darting, pulsating retrieve.
Just after ice-off, experiment with crayfish, leeches, and other big-ticket subsurface items along shoreline structure and in and around the shallows. Swimming and twitching a leech pattern suspended under a strike indicator can draw vicious strikes.
On a typical day on a South Park stillwater, I begin with midges and scuds in the early morning, followed by damsels, Callibaetis, and dragonflies into late afternoon. When the hatch is off, experiment with leeches, baitfish, crayfish, eggs, and other imitations of protein-rich foods.
The four main food supplies of the South Park reservoirs are scuds, midges, Callibaetis mayflies, and damselflies. The following selections for each will eliminate some of the guesswork and help you catch more fish every time on the water.
Scuds. South Park scuds are olive, tan, and orange, and range in size from #12-20, although #16-18 are most common. When choosing a pattern, keep in mind that scuds move across the water column at relatively consistent depths and speeds, often on or near the bottom. Unlike mayflies, they do not move from bottom to top through the water column to hatch. Three productive patterns include McClellan’s Hunchback Scud (olive/tan, #14-18), Flashback CDC Scud (olive/tan/orange, #16-18), and Erickson’s Hot Spot Scud (tan/olive, #16-18).
Midges. Midges are an abundant, season-long food source on all three reservoirs. They range in size from #12-18 with three stages of life: larva, pupa, and adult. Midge larvae hug the reservoir bottoms and glow red from the hemoglobin stored in their bodies. Midge pupae (or emergers) are characterized by their segmented bodies, gills, distinct taper, and their propensity to undulate as they ascend toward the surface to hatch. Midge adults hover above the water and eventually skate along the surface while laying their eggs. For fly-fishing purposes, the two most important stages to imitate are the larva and the pupa because of their overall concentrations and vulnerability to trout feeding subsurface.
The two most effective colors are red for larva patterns and black for pupa imitations. Productive flies include Greg Garcia’s Rojo Midge (red/black/green, #12-18), Frostbite Chironomid Pupa (black/red, #12-18), and Frostbite Chironomid Bomber (black, #12-16). For top water, try a Griffith’s Gnat (#14-18).
Callibaetis. All three reservoirs hold high numbers of large Callibaetis mayflies (#12-16)—a reliable food source in the summer months for cruising trout. Imitate Callibaetis with nymphs, emergers, and adults. Unlike some of the other insects dwelling in these reservoirs, trout concentrate on all three stages of the Callibaetis
life cycle. The emerging state is the most productive, and it’s imperative to experiment by varying your presentation depths in order to align your imitations with the moving trout. Trout typically suspend themselves at distinct levels in the water column based on the stage of the hatch, access to the most abundant bug concentrations, and water temperature. Start deep and work your way from bottom to top until you hit the level where the fish seem to be holding.
There are two things to remember about emerging Callibaetis. First, the thorax turns dark brown or black when the insect is ready to emerge. Second, an air bubble appears where the wings will eventually sprout. Good imitations include Beadhead Flashback Pheasant-tail Nymphs (natural/olive, #12-16), Burk’s Aggravator Nymphs (#14-18), A. K.’s Callibaetis Quills (#12-16), and Poly-wing Spinners (tan/brown,
Damselflies. Damselfly nymphs look like little olive snakes cruising just below the surface—usually in shallow water—until they find land, reeds, or a boat to crawl onto and emerge into brightly colored adults. The most productive stage to imitate is the nymph. I find flies with pulsating tails work best to mimic the telltale wiggling movement. This grabs the trout’s attention and often triggers a strike. Effective patterns include Barr’s Damsel (#10-16), Kaufmann’s Marabou Damsel (#10-16), Barr’s Bouface (olive, #10-14). Use blue foam-body patterns (#10-14) to imitate the large buzzing adults when the opportunity arises.
Fishing begins in early spring when the ice starts melting around the reservoir edges, or on official opening day when the ice has disappeared completely. Spring is one of the best times to pursue large trout as fish work to put on weight after a long winter below a thick layer of ice. Edge-fishing opportunities vary depending on the weather, sometimes lasting only a few weeks during a warm spring, and longer when cooler air temperatures persist.
After ice-off, the water continues to warm, stirring vegetation growth and increasing insect activity. After
the brisk days of spring depart, the trout begin to disperse to various depths and locations in search of food and cover, and pike take over the shallows.
June is the most productive month to pursue trout on all three reservoirs. The hatches are complex and abundant, and the feeding is often frenzied. The best fishing is often during bankers’ hours, with hatches starting around 8 A.M. and lasting into the afternoon, depending on light and weather conditions.
Spring and early summer afternoons often produce the high winds for which South Park is famous, blowing whitecaps into the reservoir bays and at the dams. These afternoon events stir food up from the bottom of the reservoir, and on good days you can hook trout standing on the edge of the wind-lashed shoreline and casting only 10 feet into the choppy water.
Insect activity lasts through late August, when cooler fall temperatures begin to slow the hatches. While the fishing remains good, it becomes less consistent.
By late September, migratory browns become active, and the fish move back into the shallows. This prespawn window produces some exceptional nearshore results late in the evening, and in overcast or low-light conditions.
Rigging and Retrieves
In spring, the reservoirs start out with barren bottoms with minimal vegetation growth.
As the year progresses and water temperatures peak in late August, underwater vegetation grows tall, raising the cruising depths of the trout. This makes understanding depth and bottom structure vitally important.
One of the most common—and effective—ways to present mayfly nymphs, emergers, and subsurface midge offerings is to suspend them below a buoyant strike indicator. For South Park reservoirs, I use a 9- to 12-foot, 2X to 4X tapered fluorocarbon leader with an 18- to 24-inch tippet. I attach a second tippet section (same strength) to the hook bend of my lead fly to add a trailing fly. Longer leaders are more versatile, allowing you to adjust to different depths throughout the day by moving your indicator up or down.
This technique works best while fishing from a boat, tube, or pontoon craft: Cast anywhere from 30 to 60 feet out, let your flies sink to their maximum depth, and begin a slow hand-twist retrieve back toward you. The takes are often hard and fast.
The key is finding the correct depth at which fish are actively feeding. Start near the bottom, 6 to 18 inches above it, and work your way up the water column until you find consistent results.
These large reservoirs can seem daunting compared to typical Colorado river-fishing experiences. Thus, it pays to break them down into sections. Instead of wasting time zipping from one end of the lake to the next, concentrate on specific areas with good shoreline structure and natural habitat.
Look for rising fish and bird activity at or near the surface. Mark areas with heavy concentrations of insect emergences, as well as obvious underwater structure such as downed trees, drop-offs from shoals and shallows to about 8 to 15 feet, and varying underwater anomalies, including deep buckets, springs, and channels (a depth finder is a great tool for pinpointing these areas).
When exploring large stillwaters such as Spinney, Antero, and Elevenmile, these indicators are instrumental to finding trout. Be patient, observant, and do your homework.
Another effective way to present your flies is with full-sinking and sinking-tip lines. In shallow-water situations, a clear intermediate-sinking line is great for fishing scud patterns slowly, but in constant motion, just above the reservoir bottom. Midges can also be fished on a full-sinking line, a technique that works especially well in water 15 to 30 feet deep. Use a short, 3- to 6-foot leader, and cast out as much line as you need to reach the bottom. Once you’re there, start a slow hand-twist retrieve, working your fly up through the water column.
I fish 150- to 300-grain sinking-tip lines for delivering streamers, leeches, crayfish, and other large subsurface baitfish patterns in deeper water. The tips get the flies down where they need to be, fast. For this fishing, use the same kinds of retrieves you would for large streamers in rivers. Also experiment with tandem streamer rigs, and try varying your fly colors and sizes.
Pursuing rising trout in stillwaters is most effective when an obvious hatch is on. Unlike dry-fly fishing in a river, stationary feeding behavior is nonexistent. The key is finding consistent riseforms and being able to plot, stalk, and intercept moving trout.
Once you’ve determined a trout’s feeding direction, lead it by 2 to 3 feet. The goal is to avoid spooking the fish, while presenting the fly accurately enough that the fish sees and eats it. If trout are rising scattershot throughout an area, be patient. Cast near the riseforms and wait for the fish to find your fly. An infrequent, slow twitch is an effective way to grab a trout’s attention.
For fishing drys, typically during the Callibaetis hatch, I use a long, 9- to 12-foot monofilament leader with a fluorocarbon tippet tapered down to 4X or 5X. Because these reservoirs are often windy, and the fish large and strong, it’s important to use 5- to 7-weight rods. Longer rods—9½- and 10-footers—are beneficial for lifting line off the water and setting hooks fast and hard while indicator fishing. Longer rods also give you extra height for longer casts from low positions in a float tube or pontoon boat.
Our sport is defined by the areas we visit, the prized catch, and the challenges that go along with the hunt. This is what makes South Park’s “big three” stillwaters great. Antero, Spinney Mountain, and Elevenmile Canyon produce the strongest trout in this vast valley, and it all begins with the promise of spring and another wonderful year of rod-bending madness.
Reprinted with permission from Fly Fisherman