Cheesman after the Fire
Mid-June through July, Pale Morning Duns (PMDs) begin to hatch. Flows can make or break the dry-fly fishing but nymphing always produces fish. This is the time to switch to a #18 Pheasant-tail Nymph or a #18 PMD Barr Emerger. You don’t always have to fish a #22 or smaller to catch Cheesman trout.
In flows less than 300 cfs, plan on excellent dry-fly fishing with adult PMDs. The hatch starts shortly after 11:30 A.M. and lasts until around 1:30 P.M. During higher flows (300-500 cfs) the hatch starts later in the day. After the PMDs, there is often an excellent midge hatch, and the fish continue to feed on the surface for another hour or two.
Flies of choice are the #18 Cannon’s Bunny Dun (PMD), #18 Stalcup’s Biot CDC PMD, and a #18 Parachute PMD. Look for the subtle rises of fish in the slow tailouts and deep pools.
The Trico spinner fall begins during the first part of August and is the best dry-fly activity of the season. The duns hatch by 8 A.M., and the spinner fall takes place around 10:30. This spinner fall offers the ultimate dry-fly challenge; it’s like hitting from the blue tee markers in the game of golf. Long leaders (12- to 15-foot) and accurate presentations are required to catch these super-
selective surface feeders.
Drowned Tricos are effective after the hatch. Stalcup’s CDC Trico is the best choice when trying to imitate these submerged aquatic insects.
Autumn (September-October)
Autumn brings some of the most consistent dry-fly fishing. By the first week of October, the evenings get cool, so male Tricos don’t hatch the night before and the duns become important. Many anglers confuse Trico duns for Blue-winged Olives, but for practical purposes any #22-24 adult mayfly imitation catches fish.
The best Trico fishing is in the lower canyon between mid-August and the end of September. The best midge hatches of the year start around 8:30 A.M. and last until around 10:30 A.M., then I switch to a Trico dun and fish drys during the Trico hatch. My favorite Trico pattern for the canyon is a #24 Stalcup’s CDC Trico Compara-dun.
Toward the end of September the fall Blue-winged Olive (Pseudocloeon) begins to follow the Trico hatch shortly after 1 P.M. Use small mayfly nymphs (#22-24 RS IIs or Pheasant Tails) or a #24 Parachute Adams if you see trout feeding on duns.
Winter (November-February)
Anglers fish Cheesman Canyon all year but access in the winter is sometimes difficult due to ice and snow covering the treacherous terrain. The canyon receives little sunshine, so dress accordingly.
Until the third week of November you can expect excellent midge hatches in the mornings followed by a tremendous Blue-winged Olive hatch every afternoon between 1 and 3 P.M., and another productive midge hatch around 4 P.M. Fall Blue-winged Olives (#24) are the last mayfly hatch of the year. Depending on the year, it’s not uncommon to see Tricos hatching until the second week of November as well.
The lower canyon has superb dry-fly fishing. The Emerald Pool, the Meat Hole, and the Ice Box always have lots of rising fish this time of year. A #26 Parachute Adams or a #24 Griffith’s Gnat will fool “risers” with regularity at this time of year. Brown trout continue to spawn (which typically starts the third week of October), and egg patterns fished in 18-24 inches of riffled water are deadly.
As Thanksgiving approaches, the trout slip into their slow and deep wintering holes. Dry-fly enthusiasts find a few rising fish in the Ice Box 365 days a year. This is challenging fishing because the fish have a long time to inspect your artificial offering in this deep slow pool. The head of the Ice Box is more forgiving because there are a few distinct seams and more riffled water.
Only an angler who is a master of minutia is effective in the winter months; in fact, December and January offer the toughest fishing of the year. Mercury Blood Midges (#22) are effective, as are #22 Mercury Midges, #22 Mercury Black Beauties, #22 South Platte Brassies, and a #24 Poly Wing RS II Emerger.
Spring (March-May)
By March the big spring midge becomes a major factor. The midge is big by South Platte standards—as a matter of fact, anything over a #18 is gigantic in Cheesman Canyon. It’s common to see two sizes of midges hatching at once. The second midge is the standard small midge, usually about a #24, so I typically fish a #18 Bead-head Black Beauty with a #24 standard gray RS II or a #22 Mercury Black Beauty.
Dry-fly fishing is productive in slow, slack areas such as the Ice Box or the Emerald Pool. A Cannon’s Suspender Midge (#24) or a small Parachute Adams (#26) are great choices.
By the third week of March the rainbows begin to spawn, and this annual ritual can last into June in the lower canyon. One of the biggest areas of spawning activity is in the Steel Riffles, so take extra care not to step on the redds in this section. As you might imagine, egg patterns become effective in the shallow riffles and quick, deep runs.
April is Blue-winged Olive time and the awakening of Cheesman Canyon trout. Flows begin to rise gradually, and fish move into the riffles and start to look for Baetis nymphs. Mercury Baetis, Mercury Pheasant Tails, and Sparkle-Wing RS IIs (#20-22) become the standard fly selection, but midges continue to be an integral part of the trout’s diet when Blue-winged Olives are not hatching. I favor a #22 Mercury Midge with a #22 Sparkle Wing RS II rig for the canyon.
In the spring, you’ll find rising fish in the Meat Hole, Emerald Pool, Ice Box, Jamboree, Blitz, and Rainbow Pools just after 1:30 P.M. Overcast days provide optimum fishing conditions most conducive to rising trout. Prior to the hatch, nymphing is fabulous with small mayfly nymphs. When the hatch begins, the fish move from the deep slots into prime feeding lanes toward the front of the runs where they feed exclusively on mayflies for about two hours. Seasoned anglers make a fly change: two mayfly nymphs, typically consisting of a #20 Mercury Baetis (or Mercury Pheasant Tail), and a #20 Sparkle Wing RS II. I fish with little weight because the fish are suspended and feeding aggressively. Usually one BB is enough lead but in swifter currents, you may need to add some soft weight over the split-shot. This is some of the best nymphing of the year.
These strategies and flies are by no means the only way to approach this fine trout stream, but they have worked well for me over the years.
Pat Dorsey is co-owner of The Blue Quill Angler in Evergreen, Colorado. This article was excerpted from his book A Fly Fisher’s Guide to the South Platte River (Pruett Publishing Company, 2005).
Copyright © 2012 Intermedia Outdoors
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